J/A+A/695/A226 HST Yellow supergiants in nearby galaxies (Tranin+, 2025)
Hertzsprung gap stars in nearby galaxies and the quest for luminous red novae
progenitors.
Tranin H., Blagorodnova N., Karambelkar V., Groot P.J., Bloemen S.,
Vreeswijk P.M., Pieterse D.L.A., van Roestel J.
<Astron. Astrophys. 695, A226 (2025)>
=2025A&A...695A.226T 2025A&A...695A.226T (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, nearby ; Stars, supergiant ; Photometry, HST
Keywords: binaries: general - stars: evolution -
Hertzsprung-Russell and C-M diagrams - novae, cataclysmic variables -
supergiants - galaxies: stellar content
Abstract:
After the main sequence phase, stars more massive than 2.5M☉
rapidly evolve through the Hertzsprung gap as yellow giants and
supergiants (YSG), before settling into the red giant branch.
Identifying YSG in nearby galaxies is crucial for pinpointing
progenitors of luminous red novae (LRNe) - astrophysical transients
attributed to stellar mergers. In the era of extensive transient
surveys like the Vera Rubin Observatory's LSST, this approach offers a
new way to predict and select common envelope transients. This study
investigates potential progenitors and precursors of LRNe by analysing
Hubble Space Telescope (HST) photometry of stellar populations in
galaxies within 20Mpc to identify YSG candidates. Additionally, we
use ZTF and MeerLICHT/BlackGEM to identify possible precursors,
preparing for future observations by the LSST. We compiled a sample of
369 galaxies with HST exposures in the F475W, F555W, F606W, and F814W
filters. We identified YSG candidates using MESA stellar evolution
tracks and statistical analysis of color-magnitude diagrams (CMDs).
Our sample includes 154,494 YSG candidates with masses between 3 and
20M☉ and is affected by various contaminants, such as
foreground stars and extinguished main-sequence stars. After excluding
foreground stars using Gaia proper motions, contamination is estimated
at 1% from foreground stars and 20% from extinction affecting
main-sequence stars. Combining our YSG candidates with time-domain
catalogs yielded several interesting candidates. Notably, we
identified 12 LRN precursor candidates for which followup is
encouraged. We highlight the importance of monitoring future
transients that match YSG candidates to avoid missing potential LRNe
and other rare transients. LSST will be a game changer in the search
for LRN progenitors and precursors, discovering over 300000 new YSG
and 100 precursors within 20Mpc.
Description:
The Hubble Source Catalog version 3 and some MAST automatically
extracted catalogues are cross-correlated with the galaxy catalogue
HECATE to obtain observed stellar populations. They are studied in a
colour-magnitude diagram using physical and statistical modelling to
extract yellow supergiants. Foreground stars are removed using Gaia
proper motions. The TRILEGAL simulation of the Milky Way content is
used to quantify remaining foreground contamination. The catalogue is
cross-correlated with Simbad and Chandra to identify other
contaminants. The scatter of the red giant branch is used to quantify
the fraction of extinguished main sequence stars in the selection.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 298 154494 List of YSG candidates obtained in this study
table4.dat 270 353 List of YSG hosts obtained in this study
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See also:
J/ApJ/703/441 : Yellow supergiants in M31 (Drout+, 2009)
J/ApJ/750/97 : The yellow and red supergiants of M33 (Drout+, 2012)
J/ApJ/825/50 : Variable stars in M31 & M33. III. YSGs & RSGs (Gordon+, 2016)
J/AJ/152/62 : Revised LGGS UBVRI photometry of M31 and M33 stars
(Massey+, 2016)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID Internal identifier of YSG candidate
8- 30 A23 --- Galaxy Simbad name of the host
32- 52 F21.17 deg RAdeg Right Ascension (J2000)
54- 73 F20.16 deg DEdeg Declination (J2000)
75- 93 F19.15 mag F475W ? F475W observed magnitude
95-113 F19.15 mag F555W ? F555W observed magnitude
115-133 F19.15 mag F606W ? F606W observed magnitude
135-152 F18.15 mag F814W ? F814W observed magnitude
154-173 F20.16 Msun Mstar ? MIST-interpolated stellar mass
175-193 F19.16 [K] logTeff ? MIST-interpolated log temperature
195-213 F19.16 [Lsun] logL ? MIST-interpolated log luminosity
215-236 E22.17 --- Pextin Probability to be extinguished MS star
238-255 F18.16 --- CIavg Average concentration index between bands
257-277 F21.18 --- Xsep ? Separation to nearest Chandra source
279-283 A5 --- Gaiastar Is a high proper-motion Gaia star
285-292 A8 --- SType Simbad main type
294-298 A5 --- Scontam Is a contaminant according to Simbad type
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 23 A23 --- Galaxy Simbad name of the host
25- 38 F14.10 deg RAdeg Right Ascension (J2000)
40- 53 F14.10 deg DEdeg Declination (J2000)
55- 67 F13.8 arcsec R1 Semi-major axis of D25 ellipse of the host
69- 88 F20.15 arcsec R2 Semi-minor axis of D25 ellipse of the host
90-102 F13.9 deg PA Position angle of D25 ellipse of the host
104-115 F12.9 Mpc Dist Luminosity distance of the host
117-134 F18.16 --- covHST Fraction imaged by HST
136-145 A10 --- database Data provenance of HST sources
147-157 A11 --- CamFilter Camera and filter of HST observations used
159-166 I8 --- Nsources Number of HST sources in host area
168-169 A2 Msun Mstarref Reference stellar mass for CMD analysis
171-192 F22.19 mag AV Host extinction used for CMD analysis
194-213 F20.17 --- [Fe/H] Metallicity used for CMD analysis
215-218 F4.1 --- pctGM Density cut percentile level of Gaussian
Mixture along Hertzsprung gap MIST track
220-224 I5 --- Ncand Number of YSG candidates
226-247 E22.17 --- fextin Fraction of selected extinguished MS stars
249-270 F22.19 --- ftrilegal ? Milky Way stars fraction before cleaning
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Acknowledgements:
Hugo Tranin, htranin(at)icc.ub.edu
(End) Hugo Tranin [ICCUB, Univ. Barcelona], Patricia Vannier [CDS] 15-Jan-2025