A method for batch determination of stellar physical parameters based on photometric data

Abstract

The present invention relates to the technical field of astronomical data processing, and its purpose is to provide a method for batch determining stellar physical parameters based on photometric data, comprising: receiving target position information, and obtaining observation data of target stars corresponding to the target position information in a specified star catalog; obtaining a parameter grid according to the observation data of the target star, and generating a stellar theoretical spectrum of the target star under the physical parameters corresponding to the parameter grid according to the parameter grid; obtaining a synthetic flux of the target star in an observation system corresponding to the specified star catalog according to the stellar theoretical spectrum, and obtaining a relative flux of the target star relative to a standard star according to the synthetic flux of the target star; obtaining the stellar physical parameters of the target star according to the observation data of the target star and the relative flux of the target star. The present invention has high calculation accuracy and can determine the physical parameters of the target star in batches.

Description

Technical Field

[0001] The present invention relates to the technical field of astronomical data processing, and in particular to a method for batch determining stellar physical parameters based on photometric data. Background Art

[0002] The determination of stellar physical parameters is of great significance to stellar physics and even the entire astrophysics. At present, there are two main methods for determining stellar physical parameters: using spectral data and using photometric data. Among them, spectral data has a relatively small scope of application due to its high observation cost. Representative methods for measuring stellar physical parameters using photometric data include: the infrared flux method (IRFM) proposed and developed by Blackwell et al., the photometric grid method, and the machine learning method used in GaiaDR2. Specifically, the IRFM method mainly uses the characteristic that the flux of stars in the infrared band does not change significantly with their effective temperature. It uses the flux of stars in the infrared band and the flux and color index of several other bands to compare and calculate the effective temperature of stars. The photometric grid rule is mainly based on stellar atmospheric models such as ATLAS, giving the flux distribution of stars under the parameter grid, and giving the stellar physical parameters by comparing theoretical values ​​with actual values. GaiaDR2 uses machine learning methods and targets with high-precision parameter values ​​and low interstellar extinction values ​​to train the model of the photometric values ​​and physical parameters of stars in their specific observation bands, and then obtain the effective temperature of stars.

[0003] The above methods of using photometric data to determine stellar physical parameters have been applied to different photometric projects and have made contributions to people's research. However, in the process of using the existing technology, the inventor found that the existing technology has at least the following defects:

[0004] 1) Both the IRFM method and the photometric network method rely on stellar atmosphere models. However, the stellar atmosphere models they use are generally the older ATLAS model, which has lower accuracy and smaller parameter coverage than the latest PHOENIX model. In addition, both methods require careful zero-point correction and scaling correction to obtain reliable solutions.

[0005] 2) The machine learning-based solution method used by GaiaDR2 is mainly limited by the following two aspects: a. Its solution result is directly related to the solution accuracy of the training set, that is, the solution effect of the algorithm is directly related to the solution level of other users it quotes; b. The algorithm is not actually based on any physical model, which makes its solution result not closely related to other research, and cannot play a positive role in the research of the model. At the same time, there is a certain probability that the problem of imperceptible physical pathological solutions will occur. Summary of the invention

[0006] The present invention aims to solve the above technical problems at least to a certain extent. The present invention provides a method for batch determining stellar physical parameters based on photometric data.

[0007] The present invention provides a method for batch determining stellar physical parameters based on photometric data, comprising: receiving target position information, and acquiring observation data of target stars corresponding to the target position information in a specified star catalog;

[0008] Acquire a parameter grid of a specified parameter range according to the observation data of the target star, and generate a stellar theoretical spectrum of the target star under the physical parameters corresponding to the parameter grid based on the PHOENIX atmospheric model according to the parameter grid;

[0009] According to the theoretical spectrum of the star, the synthetic flux of the target star in the observation system corresponding to the specified star catalog is obtained, and according to the synthetic flux of the target star, the relative flux of the target star relative to the standard star is obtained;

[0010] Based on the observation data of the target star, a plurality of random relative flow rates corresponding to the relative flow rate of the target star are obtained, and then a first relative flow rate closest to the relative flow rate of the target star among the plurality of random relative flow rates is obtained, and then the stellar physical parameters of the target star are obtained based on the first relative flow rate.

[0011] In a possible design, obtaining observation data of a target star corresponding to the target position information in a specified star catalog includes:

[0012] It is determined whether there is a star in the specified star catalog whose distance to the target position information is less than a distance threshold. If so, the star closest to the target position information is taken as the target star, and then the observation data of the target star in the specified star catalog is obtained.

[0013] In one possible design, the designated star catalog includes the WISE star catalog in the infrared band, the Gaia DR2 star catalog in the visible light band, and / or the GALEX star catalog in the ultraviolet band.

[0014] In a possible design, obtaining the synthetic flux of the target star in the observation system corresponding to the specified star catalog according to the theoretical spectrum of the star, and obtaining the relative flux of the target star relative to the standard star according to the synthetic flux of the target star, including:

[0015] Obtaining a system response function of an observation system corresponding to the specified star catalog;

[0016] According to the CCM89 interstellar extinction model, the extinction coefficient of the theoretical spectrum of the star corresponding to the wavelength is obtained;

[0017] Obtaining a synthetic flux of the target star according to the stellar theoretical spectrum, the system response function and the extinction coefficient;

[0018] The composite flow rate of the standard star is obtained, and the relative flow rate of the target star relative to the standard star is obtained according to the composite flow rate of the target star and the composite flow rate of the standard star.

[0019] In a possible design, the extinction coefficient of the theoretical stellar spectrum corresponding to wavelength λ is:

[0020] A(λ)=A V [a(x)+b(x) / R V ];

[0021] Among them, A V =0.005×t×[1+(4 / 3) t ], Av is the extinction value of the V band, t is the influencing parameter corresponding to the interstellar extinction and reddening effect; R V =A V / E(BV), E(BV) is the reddening value of B band and V band, Rv is the ratio between V band extinction and the reddening value of B band and V band, a(x) and b(x) are calculation coefficients.

[0022] In a possible design, obtaining the synthetic flux of the target star according to the stellar theoretical spectrum, the system response function and the extinction coefficient includes:

[0023] The theoretical spectrum of the star is convolved with the system response function and the extinction coefficient in sequence to obtain the synthetic flux of the target star.

[0024] In a possible design, the star theoretical spectrum is convolved with the system response function and the extinction coefficient in sequence to obtain the synthetic flux of the target star, including:

[0025] Performing a multiplication calculation on the wavelength corresponding to the theoretical spectrum of the star and the system response function to obtain a first multiplication result;

[0026] Multiplying the first multiplication result by the extinction coefficient to obtain a second multiplication result;

[0027] The second multiplication result is calculated by performing full-band integration along the wavelength corresponding to the theoretical spectrum of the star to obtain the synthetic flux of the target star.

[0028] In a possible design, after obtaining the relative flow rate of the target star relative to the standard star, the method further includes calibrating the relative flow rate of the target star, wherein calibrating the relative flow rate of the target star includes:

[0029] Acquire observation data of the standard star in the specified star catalog, wherein the observation data of the standard star includes the measured flow rate of the standard star;

[0030] Adding a plurality of groups of bias values ​​to the observation data of the standard star to obtain corrected observation data of the standard star;

[0031] Calculating the composite flux of the standard star based on the corrected observation data of the standard star to obtain the corrected composite flux of the standard star;

[0032] According to the corrected composite flow of the standard star and the measured flow of the standard star, a set of offset values ​​with the smallest error between the corrected composite flow of the standard star and the measured flow of the standard star is obtained as a calibration result, and the corrected composite flow of the standard star corresponding to the calibration result is the calibrated composite flow of the standard star;

[0033] According to the calibration result, the relative flux of the target star is calibrated to obtain the calibrated relative flux of the target star.

[0034] In a possible design, a plurality of random relative flow rates corresponding to the relative flow rate of the target star are obtained according to the observation data of the target star, and then a first relative flow rate closest to the relative flow rate of the target star is obtained from the plurality of random relative flow rates, and then the stellar physical parameters of the target star are obtained according to the first relative flow rate, including:

[0035] Calculating the mathematical expectation and variance of the observation data of the target star, and obtaining a plurality of random samples that conform to the normal distribution of the observation data of the target star according to the mathematical expectation and variance;

[0036] Calculating random relative fluxes corresponding to a plurality of the random samples, and then obtaining a first relative flux that is closest to the relative flux of the target star among the plurality of the random relative fluxes;

[0037] The mathematical expectation corresponding to the first relative flux is used as the physical parameter of the target star, and the variance corresponding to the first relative flux is used as the parameter error of the target star.

[0038] In a possible design, the first relative flux is a random relative flux corresponding to a plurality of the random samples, and having the smallest vector difference with the relative flux of the target star; wherein the vector difference between the relative flux of the target star and any random relative flux is:

[0039]

[0040] Where n is the relative flux of the target star and the number of relative fluxes in any random relative flux, f obi is the flux value of the relative flux of the target star, f syi are the flow values ​​corresponding to the relative flow of the target star in the random relative flow, σ i is the standard deviation of the relative flux of the target star.

[0041] The beneficial effects of the present invention are: a parameter grid of a specified parameter range is obtained through the photometric data of the target star, and the parameter grid may include a variety of physical parameters to batch determine the physical parameters corresponding to the target star. At the same time, the present invention generates a stellar theoretical spectrum of the target star based on the PHOENIX atmospheric model, so that the calculation accuracy is higher, and redundant correction processes are avoided. More parameter ranges can also be covered, and the solution results can also be used for further optimization of the PHOENIX atmospheric model. In addition, compared with the prior art, since the designated star catalogs used in the present invention include the WISE star catalog in the infrared band, the Gaia DR2 star catalog in the visible light band, and the GALEX star catalog in the ultraviolet band, the actual measured data quality is relatively high, so that the present invention only needs to perform a pure analytical algorithm with very few corrections, and the solution results are more reliable and close to the actual situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a flow chart of a method for batch determining stellar physical parameters based on photometric data in the present invention;

[0043] Figure 2 It is a schematic diagram of the composite flux of a late-type star and a sun-like star exemplified in the present invention;

[0044] Figure 3 It is a schematic diagram of the result of zero point calibration of relative flow rate according to an example of the present invention;

[0045] Figure 4 It is a schematic diagram of the effective temperature solution result of the target star as an example in the present invention;

[0046] Figure 5 It is a schematic diagram of the surface gravity solution result of the target star as an example in the present invention;

[0047] Figure 6It is a schematic diagram of the solution result of the star radius of the target star as an example in the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0049] It should be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element.

[0050] It should be understood that the term "and / or" that may appear in this document is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B may mean: A exists alone, B exists alone, and A and B exist at the same time.

[0051] It should be understood that it should also be noted that in some alternative embodiments, the functions / actions that appear may be different from the order in which the drawings appear. For example, depending on the functions / actions involved, two figures shown in succession may actually be performed substantially concurrently, or may sometimes be performed in reverse order.

[0052] Embodiment 1:

[0053] A first aspect of this embodiment provides a method for batch determining stellar physical parameters based on photometric data, which can be executed by, but is not limited to, a computer device or a virtual machine with certain computing resources, such as a personal computer, a smart phone, a personal digital assistant, or a wearable device, or by a virtual machine, so as to batch determine stellar physical parameters based on photometric data.

[0054] like Figure 1 As shown, a method for batch determining stellar physical parameters based on photometric data may include but is not limited to the following steps:

[0055] S1. Receive target position information, and obtain observation data of a target star corresponding to the target position information in a specified star catalog; wherein the target position information includes right ascension information and declination information of the intended research object.

[0056] Specifically, obtaining observation data of a target star corresponding to the target position information in a specified star catalog includes:

[0057] Determine whether there is a star in the specified star catalog whose distance to the target position information is less than a distance threshold. The distance threshold is determined according to the query accuracy, such as 5 arc seconds. If yes, the star closest to the target position information is taken as the target star, and then the observation data of the target star in the specified star catalog is obtained, thereby obtaining the observation data of the target star in the specific star catalog; if not, it is determined that the target matching fails.

[0058] It should be noted that the observation data of the target star is obtained according to the target position information, and the cross-matching method is adopted to eliminate the situation where there is no star at the target position information. In this embodiment, in order to accurately query the star at the target position, different observation data with a wide distribution of observation wavelengths should be selected as much as possible, and the infrared band and the visible light band should be included as much as possible. Therefore, the designated star catalog includes the WISE star catalog of the infrared band, the GaiaDR2 star catalog of the visible light band, and the GALEX star catalog of the ultraviolet band, etc. The observation data includes the photometric data of the G, Gbp and Grp bands of the target star in the Gaia DR2 star catalog, and the photometric data of the W1, W2, W3 and W4 bands of the target star in the WISE star catalog. It should be understood that the observation data of each star catalog can be obtained by querying in astronomical databases such as vizier.

[0059] S2. Acquire a parameter grid of a specified parameter range according to the observation data of the target star, and generate a stellar theoretical spectrum of the target star under the physical parameters corresponding to the parameter grid based on the PHOENIX atmospheric model according to the parameter grid.

[0060] Specifically, in this embodiment, the physical parameters corresponding to the parameter grid include effective temperature, surface gravity, metallicity and helium abundance, and the theoretical spectra corresponding to different physical parameters constitute a grid in the parameter space, namely the parameter grid. The parameter distribution of the parameter grid is as follows: effective temperature ranges from 2300K to 12000K, the effective temperature is 100K interval when it is below 6000K, and the effective temperature is 200K interval when it is above 6000K; surface gravity ranges from 0.0 to 6.0, with an interval of 0.5 dex; iron metallicity Z: -4.0≤[Fe / H]≤1.0, with an interval of 0.1 dex; helium abundance α: -0.2≤[α / Fe]≤1.2, with an interval of 0.1 dex.

[0061] It should also be noted that the PHOENIX atmospheric model is obtained based on a large number of stars with high-resolution spectral observations, so it is very accurate. By combining the solution of stellar physical parameters with the latest PHOENIX model, the accuracy of determining the stellar physical parameters in this embodiment can be improved; at the same time, the solution results of this embodiment can be used as initial values ​​of stellar physical parameters on the one hand, and on the other hand, improvement suggestions can be given to the PHOENIX atmospheric model, the latest stellar atmospheric model.

[0062] S3. According to the theoretical spectrum of the star, the synthetic flow rate of the target star in the observation system corresponding to the specified star catalog is obtained, and according to the synthetic flow rate of the target star, the relative flow rate of the target star relative to the standard star is obtained.

[0063] Specifically, step S3 includes:

[0064] S301. Obtain a system response function of the observation system corresponding to the specified star catalog; specifically, the system response function is a function obtained by convolving a filter transmittance function and a CCD (charge coupled device) radiation response function corresponding to the observation system, wherein the filter transmittance function and the CCD radiation response function are both one-dimensional functions of response values ​​with respect to wavelength, and the system response function can be obtained by convolving these two functions, and the atmospheric mass in the filter transmittance function and the CCD radiation response function can be calculated based on the Pickering (2002) model, and the atmospheric mass is:

[0065] Among them, h is the apparent altitude, which is the complementary angle of the zenith distance.

[0066] S302. Obtaining the extinction coefficient of the theoretical spectrum of the star corresponding to the wavelength according to the CCM89 interstellar extinction model;

[0067] Specifically, the extinction coefficient of the theoretical stellar spectrum corresponding to wavelength λ is:

[0068] A(λ)=A V [a(x)+b(x) / R V ];

[0069] Among them, A V =0.005×t×[1+(4 / 3) t ], Av is the extinction value of the V band, t is the influencing parameter corresponding to the interstellar extinction and reddening effect; R V =A V / E(BV), E(BV) is the reddening value of the B band and the V band, Rv is the ratio of the V band extinction and the reddening value of the B band and the V band, specifically, the parameter Rv is set to 3.1 in this embodiment, a(x) and b(x) are both calculation coefficients, and a(x) and b(x) are directly given by the CCM89 interstellar extinction model.

[0070] S303. Obtaining the synthetic flux of the target star according to the theoretical spectrum of the star, the system response function and the extinction coefficient;

[0071] Specifically, step S303 includes:

[0072] The theoretical spectrum of the star is convolved with the system response function and the extinction coefficient in sequence to obtain the synthetic flux of the target star.

[0073] In this embodiment, the process of performing convolution calculation on the stellar theoretical spectrum, the system response function and the extinction coefficient in sequence includes:

[0074] Performing a multiplication calculation on the wavelength corresponding to the theoretical spectrum of the star and the system response function to obtain a first multiplication result;

[0075] Multiplying the first multiplication result by the extinction coefficient to obtain a second multiplication result;

[0076] The second multiplication result is calculated by performing full-band integration along the wavelength corresponding to the theoretical spectrum of the star to obtain the synthetic flux of the target star.

[0077] It should be understood that, based on the synthetic flux of the target star, the radiation flux of each observation band of the target star under each set of physical parameters can be obtained.

[0078] In this embodiment, after obtaining the relative flow rate of the target star relative to the standard star, the method further includes: using an interpolation algorithm to perform linear interpolation calculation on the relative flow rate, reducing the effective temperature grid interval to 10K, and obtaining a very dense flow grid corresponding to the theoretical spectrum of the star.

[0079] S304. Obtain the composite flow rate of the standard star, and obtain the relative flow rate of the target star relative to the standard star according to the composite flow rate of the target star and the composite flow rate of the standard star.

[0080] In this embodiment, Vega is selected as the standard star. Accordingly, the composite flux of Vega can be obtained by convolving the theoretical spectrum of Vega and the specified system response function and extinction coefficient. Specifically, the composite flux of the target star is divided by the composite flux of the standard star to obtain the relative flux of the target star.

[0081] S4. Calibrate the relative flux of the target star. It should be understood that the relative flux of the target star can be calibrated by using, but not limited to, the zero-point correction method and the scaling correction. In this embodiment, since the latest PHOENIX stellar atmosphere model is used, the theoretical synthetic flux obtained in step S3 is relatively accurate, and thus only the zero-point correction method is used, that is, the observation data obtained in step S1 is corrected, so as to realize the calibration of the relative flux of the target star.

[0082] Specifically, step S4 includes:

[0083] Acquire observation data of the standard star in the specified star catalog, wherein the observation data of the standard star includes the measured flow rate of the standard star;

[0084] Adding multiple groups of bias values ​​to the observation data of the standard star respectively, under initial conditions, each bias value in the group of bias values ​​is the same, that is, a same bias value is added to each observation band in the observation data of the standard star, and each group of bias values ​​is randomly generated according to the error magnitude, so as to obtain the corrected observation data of the standard star;

[0085] Calculating the composite flux of the standard star based on the corrected observation data of the standard star to obtain the corrected composite flux of the standard star;

[0086] According to the corrected synthetic flow of the standard star and the measured flow of the standard star, a set of bias values ​​with the smallest error between the corrected synthetic flow of the standard star and the measured flow of the standard star is obtained as a calibration result, and the corrected synthetic flow of the standard star corresponding to the calibration result is the calibrated synthetic flow of the standard star; in this embodiment, the error between the corrected synthetic flow of the standard star and the measured flow of the standard star is the difference between the root mean square mean of the corrected synthetic flow of the standard star and the root mean square mean of the measured flow of the standard star, and the difference is the smallest, that is, the error between the corrected synthetic flow of the standard star and the measured flow of the standard star is the smallest.

[0087] According to the calibration result, the relative flux of the target star is calibrated to obtain the calibrated relative flux of the target star.

[0088] S5. Based on the observation data of the target star, a plurality of random relative flow rates corresponding to the relative flow rate of the target star are obtained, and then a first relative flow rate closest to the relative flow rate of the target star among the plurality of random relative flow rates is obtained, and then the stellar physical parameters of the target star are obtained based on the first relative flow rate.

[0089] Specifically, step S5 includes:

[0090] S501. Calculate the mathematical expectation and variance of the observation data of the target star, and obtain a plurality of random samples that conform to the normal distribution of the observation data of the target star according to the mathematical expectation and variance;

[0091] S502. Calculate the random relative fluxes corresponding to the plurality of random samples, and then obtain a first relative flux that is closest to the relative flux of the target star among the plurality of random relative fluxes;

[0092] In this embodiment, the first relative flow rate is the random relative flow rate with the smallest vector difference with the relative flow rate of the target star among the random relative flows corresponding to the multiple random samples; wherein the vector difference between the relative flow rate of the target star and any random relative flow rate is:

[0093]

[0094] Where n is the relative flux of the target star and the number of relative fluxes in any random relative flux, f obi is the flux value of the relative flux of the target star, f syi are the flow values ​​corresponding to the relative flow of the target star in the random relative flow, σ i is the standard deviation of the relative flux of the target star.

[0095] It should be understood that, in this embodiment, the first relative flow rate may also be obtained by the root mean square difference between the relative flow rate of the target star and any random relative flow rate, which will not be elaborated here.

[0096] S503. Taking the mathematical expectation corresponding to the first relative flux as the physical parameter of the target star, and taking the variance corresponding to the first relative flux as the parameter error of the target star.

[0097] Specifically, in this embodiment, after the relative flow rate of the target star is calibrated, the multiple random relative flow rates corresponding to the relative flow rate of the target star are multiple random relative flow rates corresponding to the calibrated relative flow rate of the target star.

[0098] This embodiment obtains a parameter grid of a specified parameter range through the photometric data of the target star. The parameter grid may include multiple physical parameters to batch determine the physical parameters corresponding to the target star. At the same time, this embodiment generates a stellar theoretical spectrum of the target star based on the PHOENIX atmospheric model, so that the calculation accuracy is higher, avoiding the execution of redundant correction processes, and covering more parameter ranges. It can not only accurately solve the effective temperature of the target star, but also have better solution results for the surface gravity and radius of the target star. The solution results can also be used for further optimization of the PHOENIX atmospheric model. In addition, compared with the prior art, since the designated star catalogs used in this embodiment include the WISE star catalog in the infrared band, the Gaia DR2 star catalog in the visible light band, and the GALEX star catalog in the ultraviolet band, the actual measured data quality is relatively high, so that this embodiment only needs to perform a pure analytical algorithm with very few corrections, and the solution results are more reliable and close to the actual situation.

[0099] As an example, a star in the PASTEL star catalog is used as a target star to test the method for batch determining stellar physical parameters in this embodiment. The measured data selected during the test are observation data in the Gaia DR2 star catalog and observation data in the WISE star catalog. A total of 5 observation bands are selected, namely the G, GBP and GRP bands of the Gaia DR2 star catalog and the W1 and W2 bands of the WISE star catalog.

[0100] 1) Using the star catalog cross-matching method, the PASTEL star catalog, Gaia DR2 star catalog and WISE star catalog were matched, and the observation data of 1860 target stars were obtained.

[0101] 2) Generate a theoretical stellar spectrum of the target star under the physical parameters corresponding to the specified parameter grid, and then obtain the composite flux of the target star in the Gaia DR2 observation system and the WISE observation system based on the theoretical stellar spectrum, and use the system response functions of the Gaia DR2 observation system and the WISE observation system to determine the composite flux through the theoretical spectrum.

[0102] Specifically, Figure 2 (a) and (b) in the figure show the synthetic flux determination process of a late-type star and a Sun-like star, respectively. Figure 2 The horizontal axis is the wavelength (nm), and the vertical axis is the normalized flow rate. Figure 2 The theoretical spectrum in is marked, and the remaining solid lines are response functions of each observation band. The remaining spectra except the theoretical spectrum are the actual spectra that should be observed according to this embodiment, and the flow value of each band can be obtained by integrating the spectrum.

[0103] In this process, the CCM89 interstellar extinction model is used to obtain the synthetic flux after considering effects such as interstellar reddening (since Gaia and WISE are space observation projects, the influence of atmospheric extinction does not need to be considered here).

[0104] 3) Taking Vega as the standard, the relative flux corresponding to each group of composite flux of the target star is obtained.

[0105] 4) Zero-point calibration of relative flux. Since Gaia and WISE are representative projects of the European Space Agency and NASA respectively, the measured data quality is relatively high, with only obvious zero-point errors but no obvious scaling errors. Therefore, the zero-point calibration was completed here using the PASTEL star catalog. The calibration results are shown in Figure 2. Figure 3 shown. Figure 3 The horizontal axis is the effective temperature of stars in the PASTEL star catalog (K), the vertical axis is the effective temperature of stars (K) calculated based on the method of this embodiment, the dotted points are the points after calibration, the plus sign points are the points before calibration, and the inclined solid line in the coordinate system is the baseline, that is, the points distributed on this line are zero error points. Obviously, after the zero point calibration, the calibrated point cloud is closer to the baseline, and the solution quality is significantly improved.

[0106] 5) Using the calibrated relative flux obtained after calibration, combined with the stellar physical parameter solution method introduced in step S5 above, the stellar physical parameter solution of all target stars is completed. Among them, the stellar effective temperature solution result is as follows Figure 4 As shown, Figure 4 , the horizontal coordinates of the upper two figures (a) and (b) are the effective temperature of PASTEL, and the vertical coordinates are the effective temperature obtained based on the method of this embodiment, wherein the dotted points are the results obtained based on the method of this embodiment, and the plus-shaped points are the results obtained by Gaia (a space exploration project initiated by the European Space Agency). The upper left figure (a) represents a giant star, and the upper right figure (b) represents a main sequence star. The lower two figures (c) and (d) are histograms of the effective temperature error distribution (where PASTEL is the true value, and only the error distribution based on the method of this embodiment is shown), the lower left figure (c) represents a giant star, and the lower right figure (d) represents a main sequence star; the stellar surface gravity solution results are shown in FIG. Figure 5 As shown, Figure 5 In the figure, the horizontal axis of the left figure (a) is the surface gravity of PASTEL, and the vertical axis is the surface gravity result obtained based on the method of this embodiment. The right figure (b) is the error distribution histogram of the main sequence star. The solution of the stellar radius is shown in FIG. Figure 6 As shown, Figure 6In the figure, the upper left figure (a) is a comparison result of the star radius given by this embodiment and Gaia, the horizontal axis is the star radius obtained by Gaia, and the vertical axis is the star radius obtained based on the method of this embodiment. The upper right figure (b) is a comparison result of the surface gravity given by PASTEL and the star radius obtained by this embodiment, wherein the horizontal axis is the surface gravity of PASTEL, and the vertical axis is the star radius obtained based on the method of this embodiment. The lower two figures (c) and (d) are respectively a histogram of the results obtained based on the method of this embodiment with Gaia radius as the true value and an enlarged histogram containing 90% of the target results. From Figures 4 to 6 It is not difficult to find that the solution accuracy of this embodiment is very high, basically meeting the unbiased distribution near the literature value, and the discreteness is also small, and the result distribution is highly consistent with the solution result of Gaia.

[0107] Embodiment 2:

[0108] This embodiment provides a system for batch determining stellar physical parameters based on photometric data, which is used to implement the method for batch determining stellar physical parameters based on photometric data in embodiment 1; the system for batch determining stellar physical parameters based on photometric data includes:

[0109] A star observation data acquisition module, used to receive target position information and acquire observation data of a target star corresponding to the target position information in a specified star catalog;

[0110] The stellar theoretical spectrum generation module is used to obtain a parameter grid of a specified parameter range according to the observation data of the target star, and generate a stellar theoretical spectrum of the target star under the physical parameters corresponding to the parameter grid based on the PHOENIX atmospheric model according to the parameter grid.

[0111] A stellar relative flux calculation module is used to obtain the synthetic flux of the target star in the observation system corresponding to the specified star catalog according to the stellar theoretical spectrum, and to obtain the relative flux of the target star relative to the standard star according to the synthetic flux of the target star;

[0112] The stellar physical parameter calculation module is used to obtain a plurality of random relative flow rates corresponding to the relative flow rate of the target star based on the observation data of the target star, then obtain a first relative flow rate that is closest to the relative flow rate of the target star among the plurality of random relative flow rates, and then obtain the stellar physical parameters of the target star based on the first relative flow rate.

[0113] Embodiment 3:

[0114] Based on Embodiment 1 or 2, this embodiment discloses an electronic device, which may be a smart phone, a tablet computer, a laptop computer, or a desktop computer, etc. The electronic device may be referred to as a terminal, a portable terminal, a desktop terminal, etc., and the electronic device includes:

[0115] a memory for storing computer program instructions; and,

[0116] A processor is used to execute the computer program instructions to complete the operation of the method for batch determining stellar physical parameters based on photometric data as described in any one of Example 1.

[0117] Embodiment 4:

[0118] Based on any one of embodiments 1 to 3, this embodiment discloses a computer-readable storage medium for storing computer program instructions readable by a computer, wherein the computer program instructions are configured to execute the operations of the method for batch determining stellar physical parameters based on photometric data as described in embodiment 1 when running.

[0119] It should be noted that if the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

[0120] Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, and optionally, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Thus, the present invention is not limited to any specific combination of hardware and software.

[0121] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention is described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0122] Finally, it should be noted that the present invention is not limited to the above optional implementations, and anyone can derive other various forms of products under the enlightenment of the present invention. The above specific implementations should not be understood as limiting the scope of protection of the present invention. The scope of protection of the present invention should be based on the definition in the claims, and the description can be used to interpret the claims.

Claims

1. A method for batch determining stellar physical parameters based on photometric data, characterized in that: include: Receive target position information, and obtain observation data of a target star corresponding to the target position information in a specified star catalog; Acquire a parameter grid of a specified parameter range according to the observation data of the target star, and generate a stellar theoretical spectrum of the target star under the physical parameters corresponding to the parameter grid based on the PHOENIX atmospheric model according to the parameter grid; According to the theoretical spectrum of the star, the synthetic flux of the target star in the observation system corresponding to the specified star catalog is obtained, and according to the synthetic flux of the target star, the relative flux of the target star relative to the standard star is obtained; According to the observation data of the target star, a plurality of random relative flow rates corresponding to the relative flow rate of the target star are obtained, and then a first relative flow rate closest to the relative flow rate of the target star is obtained from the plurality of random relative flow rates, and then the stellar physical parameters of the target star are obtained according to the first relative flow rate; According to the theoretical spectrum of the star, the synthetic flux of the target star in the observation system corresponding to the specified star catalog is obtained, and according to the synthetic flux of the target star, the relative flux of the target star relative to the standard star is obtained, including: Obtaining a system response function of an observation system corresponding to the specified star catalog; According to the CCM89 interstellar extinction model, the extinction coefficient of the theoretical spectrum of the star corresponding to the wavelength is obtained; Obtaining the synthetic flux of the target star according to the stellar theoretical spectrum, the system response function and the extinction coefficient; Acquire the composite flux of the standard star, and obtain the relative flux of the target star relative to the standard star according to the composite flux of the target star and the composite flux of the standard star; The extinction coefficient of the theoretical spectrum of the star corresponding to wavelength λ is: ； in, , A v is the extinction value of the V band, t are the influencing parameters corresponding to interstellar extinction and reddening effects; , is the reddening value of the B band and the V band, R v is the ratio between the extinction of the V band and the reddening value of the B band and the V band, a(x) and b(x) All are calculation coefficients; According to the observation data of the target star, a plurality of random relative flow rates corresponding to the relative flow rate of the target star are obtained, and then a first relative flow rate closest to the relative flow rate of the target star is obtained from the plurality of random relative flow rates, and then a stellar physical parameter of the target star is obtained according to the first relative flow rate, including: Calculating the mathematical expectation and variance of the observation data of the target star, and obtaining a plurality of random samples that conform to the normal distribution of the observation data of the target star according to the mathematical expectation and variance; Calculating random relative fluxes corresponding to a plurality of the random samples, and then obtaining a first relative flux that is closest to the relative flux of the target star among the plurality of the random relative fluxes; Taking the mathematical expectation corresponding to the first relative flux as the physical parameter of the target star, and taking the variance corresponding to the first relative flux as the parameter error of the target star; The first relative flow is a random relative flow with the smallest vector difference with the relative flow of the target star among the random relative flows corresponding to the plurality of random samples; wherein the vector difference between the relative flow of the target star and any random relative flow is: ； in, n is the relative flux of the target star and the number of relative fluxes in any random relative flux, f obi are the flux values ​​in the relative flux of the target star, f syi are the flow values ​​corresponding to the relative flow of the target star in the random relative flow, σ i is the standard deviation of the relative flux of the target star.

2. The method for batch determining stellar physical parameters based on photometric data according to claim 1, characterized in that: Obtaining observation data of a target star corresponding to the target position information in a specified star catalog, including: It is determined whether there is a star in the specified star catalog whose distance to the target position information is less than a distance threshold. If so, the star closest to the target position information is taken as the target star, and then the observation data of the target star in the specified star catalog is obtained.

3. The method for batch determining stellar physical parameters based on photometric data according to claim 1, characterized in that: The designated star catalogs include the WISE star catalog in the infrared band, the Gaia DR2 star catalog in the visible light band, and / or the GALEX star catalog in the ultraviolet band.

4. The method for batch determining stellar physical parameters based on photometric data according to claim 1, characterized in that: Obtaining the synthetic flux of the target star according to the theoretical spectrum of the star, the system response function and the extinction coefficient, including: The theoretical spectrum of the star is convolved with the system response function and the extinction coefficient in sequence to obtain the synthetic flux of the target star.

5. The method for batch determining stellar physical parameters based on photometric data according to claim 4, characterized in that: The theoretical spectrum of the star is sequentially convolved with the system response function and the extinction coefficient to obtain the synthetic flux of the target star, including: Performing a multiplication calculation on the wavelength corresponding to the theoretical spectrum of the star and the system response function to obtain a first multiplication result; Multiplying the first multiplication result by the extinction coefficient to obtain a second multiplication result; The second multiplication result is calculated by performing full-band integration along the wavelength corresponding to the theoretical spectrum of the star to obtain the synthetic flux of the target star.

6. The method for batch determining stellar physical parameters based on photometric data according to claim 1, characterized in that: After obtaining the relative flow rate of the target star relative to the standard star, the method further includes calibrating the relative flow rate of the target star, wherein calibrating the relative flow rate of the target star includes: Acquire observation data of the standard star in the specified star catalog, wherein the observation data of the standard star includes the measured flow rate of the standard star; Adding a plurality of groups of bias values ​​to the observation data of the standard star to obtain corrected observation data of the standard star; Calculating the composite flux of the standard star based on the corrected observation data of the standard star to obtain the corrected composite flux of the standard star; According to the corrected composite flow of the standard star and the measured flow of the standard star, a set of offset values ​​with the smallest error between the corrected composite flow of the standard star and the measured flow of the standard star is obtained as a calibration result, and the corrected composite flow of the standard star corresponding to the calibration result is the calibrated composite flow of the standard star; According to the calibration result, the relative flow rate of the target star is calibrated to obtain the calibrated relative flow rate of the target star.

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