J/ApJ/927/222 Active giant binaries from VSX and Gaia EDR3 (Leiner+, 2022)
Revealing the field sub-subgiant population using a catalog of active giant
stars and Gaia EDR3.
Leiner E.M., Geller A.M., Gully-Santiago M.A., Gosnell N.M.,
Tofflemire B.M.
<Astrophys. J., 927, 222 (2022)>
=2022ApJ...927..222L 2022ApJ...927..222L
ADC_Keywords: Stars, giant; Stars, variable; Stars, distances; Colors; Optical
Keywords: Starspots ; Stellar physics ; Stellar magnetic fields ;
Stellar activity ; Red giant stars ; Red straggler stars
Abstract:
Sub-subgiant stars (SSGs) fall below the subgiant branch and/or red of
the giant branch in open and globular clusters, an area of the
color-magnitude diagram (CMD) not populated by standard stellar
evolution tracks. One hypothesis is that SSGs result from rapid
rotation in subgiants or giants due to tidal synchronization in a
close binary. The strong magnetic fields generated inhibit convection,
which in turn produces large starspots, radius inflation, and
lower-than-expected average surface temperatures and luminosities.
Here we cross-reference a catalog of active giant binaries (RS CVns)
in the field with Gaia EDR3. Using the Gaia photometry and parallaxes,
we precisely position the RS CVns in a CMD. We identify stars that
fall below a 14Gyr, metal-rich isochrone as candidate field SSGs. Out
of a sample of 1723 RS CVn, we find 448 SSG candidates, a dramatic
expansion from the 65 SSGs previously known. Most SSGs have rotation
periods of 2-20 days, with the highest SSG fraction found among RS CVn
with the shortest periods. The ubiquity of SSGs among this population
indicates that SSGs are a normal phase in evolution for RS CVn-type
systems, not rare by-products of dynamical encounters found only in
dense star clusters as some have suggested. We present our catalog of
1723 active giants, including Gaia photometry and astrometry, and
rotation periods from the Transiting Exoplanet Survey Satellite and
International Variable Star Index (VSX). This catalog can serve as an
important sample to study the impacts of magnetic fields in evolved
stars.
Description:
To begin, we take the entire sample of RS CVn variable stars
identified in the American Association of Variable Star Observers'
(AAVSO) International Variable Star Index (VSX) catalog
(Watson+ 2006SASS...25...47W 2006SASS...25...47W ; see B/vsx). We use the 2021 April
version of this catalog. See Section 2.1.
We match this sample of 73203 VSX RS CVns to the Gaia EDR3 catalog
starting with a 1.4" searching radius. We find unique Gaia matches for
71463 sources in the VSX catalog and the cuts yield a sample of 22372
stars. See Section 2.2.
Out of our original list we select a total of 1723 stars that have
well-determined Gaia matches, astrometric solutions, and
low-extinction values, which appear to be true RS CVns rather than
misclassified MS stars. See Section 2.3.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 149 1895 RS CVn sample
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See also:
B/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-)
II/287 : Northern Sky Variability Survey (NSVS) (Wozniak+, 2004)
II/264 : ASAS Variable Stars in Southern hemisphere (Pojmanski+, 2002-2005)
IV/38 : TESS Input Catalog - v8.0 (TIC-8) (Stassun+, 2019)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)
J/ApJ/640/1018 : Differential photometry of V1061 Cyg (Torres+, 2006)
J/ApJ/696/870 : Catalina Real-time Transient Survey (CRTS) (Drake+, 2009)
J/ApJS/211/2 : Revised properties of Q1-16 Kepler targets (Huber+, 2014)
J/AJ/154/250 : Kepler EB classif. and rotation periods (Lurie+, 2017)
J/MNRAS/483/1125 : Inflation in Praesepe active M-dwarfs (Jackson+, 2019)
J/AJ/160/12 : J, Ks, NUV emission of 133 red giant stars (Dixon+, 2020)
J/A+A/634/A1 : NGC 1068 GRAVITY reconstructed image (GRAVITY+, 2020)
J/AJ/161/190 : Radial Velocities of binary pop. in M67 (Geller+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- Gaia Gaia EDR3 source identifier
21- 48 A28 --- VSX Identifier in the VSX catalog
50- 58 I9 --- TIC [854203/953395322]?=-999 TESS Input Catalog
identifier
60- 68 F9.5 deg RAdeg Gaia EDR3 Right Ascension (J2000)
70- 78 F9.5 deg DEdeg Gaia EDR3 Declination (J2000)
80- 83 I4 pc Dist [29/2000] Gaia EDR3 distance
85- 89 F5.2 mag Gmag [3.16/16.37] Gaia EDR3 G band magnitude
91- 94 F4.2 mag BP-RP [0.6/2.51] Gaia EDR3 Blue-Red passband color
96- 100 F5.2 --- RUWE [0.79/37.3] Gaia EDR3 Renormalized Unit Weight
Error
102- 110 F9.2 --- chi2 [116.9/598982] Gaia EDR3 astrometric goodness
of fit
112- 115 I4 --- NAL [131/1231] Number of good Gaia EDR3 observations
117- 121 F5.2 d PVSX [0.13/96] VSX catalog period
123- 129 F7.2 d PTess [0.13/279]?=-999 TESS period
131- 137 F7.2 --- Amp [0/5]?=-999 TESS amplitude
139- 140 I2 --- Nsec [0/23] Number of TESS sectors
142- 145 F4.2 mag Av [0.02/0.5] Line-of-sight V band extinction
147- 149 A3 --- Class Classification (1)
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Note (1): Classification as follows:
RS = an RS CVn star (1275 occurrences)
SSG = a sub-subgiant (see Section 4; 448 occurrences)
cut = removed from sample due to astrometric quality cuts
(see Section 2.3; 172 occurrences)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 19-Jan-2024