J/A+A/709/A52 Hot subdwarf stars physical parameter (Feng+, 2026)
From synthetic SEDs to stellar origins: A deep learning model for physical
parameter retrieval in hot subdwarf stars.
Feng M., Lei Z., Kou B., Dong Y., Hu K., Xiao H., Zhao J.
<Astron. Astrophys. 709, A52 (2026)>
=2026A&A...709A..52F 2026A&A...709A..52F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, subdwarf ; Stars, masses ; Stars, diameters
Keywords: binaries: close - stars: evolution - stars: fundamental parameters
Abstract:
The formation mechanisms of spectrally diverse hot subdwarfs remain
unclear. While existing mass distribution analyses suggest additional
channels beyond helium white dwarf (He-WD) mergers contribute to
He-rich subdwarf formation, these conclusions are constrained by
limited sample sizes of mass-measured He-rich objects.
We developed a deep leaning model which combines a convolution neural
network (CNN) together with a squeeze-and-excitation (SE) block to
calculate synthetic spectral energy distributions (SEDs) for 1012
spectroscopically confirmed hot subdwarfs. Through directly comparison
between synthetic SEDs and observed flux density, we derived stellar
parameters (mass, radius, luminosity) for unprecedented number size of
hot subdwarf stars, enabling more conclusive channel discrimination
than prior studies.
The mass distribution of sdB/sdOB stars confirmed the results from
model predictions of binary populations synthesis (BPS). A primary and
secondary peak (i.e., around 0.56 and 0.4 Msun) is obviously presented
in the mass distribution of He-rich hot subdwarf stars. By comparing
with the results from the predictions of recent BPS model, it proposed
that the merger of two He-WDs could produce most of the observed
He-rich hot subdwarf stars, but the mass transfer during the stable
Roche lobe overflow (RLOF) phase in binary evolution should be
partially conserved.
Description:
The table presents the main physical parameters for 1012 selected hot
subdwarf stars. Parameters were derived by comparing synthetic SEDs
calculated with the SENN model with observed flux densities from the
Virtual Observatory. Atmospheric parameters (Teff and logg) were taken
from Culpan et al., (2022A&A...662A..40C 2022A&A...662A..40C, Cat. J/A+A/662/A40), which
were collected from multiple spectroscopic surveys. Distances were
calculated using Gaia DR3 parallaxes with zero-point corrections
(Lindegren et al., 2021A&A...649A...4L 2021A&A...649A...4L). Extinction corrections were
applied using the extinction law of Fitzpatrick (1999PASP..111...63F 1999PASP..111...63F)
with RV=3.1.
This file contains the complete dataset of stellar parameters derived
in this study. For each star, we provide the stellar name, Gaia DR3
source identifier, spectral classification, atmospheric parameters
(effective temperature and surface gravity with their uncertainties),
visual extinction, parallax with zero-point correction (and
uncertainty), angular diameter (in log scale with asymmetric
uncertainties), radius (with asymmetric uncertainties), luminosity
(with asymmetric uncertainties), and mass (with asymmetric
uncertainties). Asymmetric uncertainties are calculated via Monte
Carlo methods (16th, 50th, 84th percentiles). Systematic errors were
determined by comparison with Schaffenroth et al.
(2022A&A...659A.113W 2022A&A...659A.113W) and are incorporated into the final
uncertainties.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 180 1012 Main parameters for 1012 selected hot subdwarf stars
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See also:
J/A+A/662/A40 : Hot subdwarf stars studied with Gaia (Culpan+, 2022)
J/ApJ/953/122 : Masses for hot subdwarf stars in LAMOST & Gaia (Lei+, 2023)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 25 A25 --- Name Star designation
28- 46 A19 --- GaiaDR3 Gaia DR3 source identifier
49- 56 A8 --- SpClass Spectral classification
58- 63 I6 K Teff Effective temperature
65- 69 I5 K e_Teff Uncertainty in Teff
72- 75 F4.2 [cm/s2] logg Log of surface gravity
77- 80 F4.2 [cm/s2] e_logg Uncertainty in Logg
83- 87 F5.3 mag AV Visual extinction
90- 95 F6.4 mas Plx Parallax, Gaia EDR3, after zeropoint
correction
97-102 F6.4 mas e_Plx Uncertainty in Plx
105-111 F7.3 [rad] AngDiam Median Angular diameter, log(radians)
113-117 F5.3 [rad] E_AngDiam Upper uncertainty in AngDiam (1)
119-123 F5.3 [rad] e_AngDiam Lower uncertainty in AngDiam (1)
126-130 F5.3 Rsun Radius Median Stellar radius
132-136 F5.3 Rsun E_Radius Upper uncertainty in Radius (1)
138-142 F5.3 Rsun e_Radius Lower uncertainty in Radius (1)
145-151 F7.1 Lsun Lum Median Stellar luminosity
153-158 F6.1 Lsun E_Lum Upper uncertainty in Lum (1)
160-165 F6.1 Lsun e_Lum Lower uncertainty in Lum (1)
167-170 F4.2 Msun Mass Median Stellar mass
172-175 F4.2 Msun E_Mass Upper uncertainty in Mass (1)
177-180 F4.2 Msun e_Mass Lower uncertainty in Mass (1)
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Note (1): The Upper uncertainty is the difference of the 84th and Median
percentile values; the Lower uncertainty is the difference of the
16th and the Median percentile values.
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Acknowledgements:
From Mengqi Feng, fmqi2000(at)163.com
We greatly thank the referee for his/her valuable comments and useful
suggestions, which help improve the manuscript significantly. We also
thank Nicolas Rodriguez-Segovia for his detailed suggestions on the
discussion of Section 4.3.
This work acknowledges support from the National Natural Science
Foundation of China (Nos. 12073020, 12588202 and 12273055), Scientific
Research Fund of Hunan Provincial Education Department grant No.
20K124 and 23A0132, the Strategic Priority Research Program of Chinese
Academy of Sciences, grant No. XDB1160301. K.H. acknowledges support
from the Scientific Research Funds of Hunan Provincial Education
Department (Nos. 22A0099 and 24A0101).
This research has made use of the Spanish Virtual Observatory
(https://svo.cab.inta-csic.es) project funded by
MCIN/AEI/10.13039/501100011025/ through grant PID2020-112949GB-I00.
Guoshoujing Telescope (the Large Sky Area Multi-Object Fiber
Spectroscopic Telescope LAMOST) is a National Major Scientific Project
built by the Chinese Academy of Sciences. Funding for the project has
been provided by the National Development and Reform Commission.
LAMOST is operated and managed by the National Astronomical
Observatories, Chinese Academy of Sciences.
License: CC-BY-4.0 [see https://spdx.org/licenses/]
(End) Patricia Vannier [CDS] 11-Mar-2026