J/A+A/700/L13 Variable stars in Galactic open clusters (Hunt+, 2025)
A birds's eye view of stellar evolution through populations of variable stars in
Galactic open clusters.
Anderson R.I., Hunt E.L.
<Astron. Astrophys. 700, L13 (2025)>
=2025A&A...700L..13A 2025A&A...700L..13A (SIMBAD/NED BibCode)
ADC_Keywords: Milky Way ; Clusters, open ; Stars, variable ; Optical
Keywords: methods: data analysis - stars: evolution -
stars: variables: general - open clusters and associations: general
Abstract:
Both star clusters and variable stars are sensitive laboratories of
stellar astrophysics and evolution: cluster member stars provide
context for interpreting cluster populations, whereas variability
reveals the nature of individual stellar systems. The European Space
Agency's Gaia mission has revolutionized the census of star clusters
in the Milky Way while simultaneously providing an unprecedented
homogeneous all-sky catalog of variable stars. Here, we leverage the
third Gaia data release (GDR3) to obtain an empirical birds-eye view
of stellar evolution based on 34760 variable stars residing in 1192
Galactic open clusters (OCs) with a total of 173294 members (variable
member fraction 20.0%). Using precise OC distances, de-reddened
magnitudes, and consistently determined ages, we a) pinpoint regions
of pulsational instability across the color-absolute magnitude diagram
(CaMD), b) trace the occurrence rate of variables as a function of
age, and c) consider the temporal evolution of rotation periods and
photometric activity (gyrochronology). The occurrence of pulsating
stars can serve as a model- and reddening-independent age estimator.
Our results underline the power of jointly considering variability and
OC membership and showcase a plethora of further applications, such as
for age dating or dereddening OCs based on expected CaMD locations of
variable stars. Upcoming Gaia data releases and the Vera C. Rubin
Observatory will vastly increase the detail by which variable stars in
OCs can empirically unravel the astrophysics and evolution of stellar
populations.
Description:
We created a high-quality catalog of bona fide variable star members
in high-quality OCs from Hunt & Reffert (2024A&A...686A..42H 2024A&A...686A..42H, Cat
.J/A+A/686/A42 ).
Our high-confidence catalog contains 34762 variable stars across
1192 OCs containing 173294 members.
Variable star classifications (table B1) and absolute dereddened
cluster photometry (table B2).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tableb1.dat 80 34762 Variable star classifications
tableb2.dat 99 173294 Absolute dereddened cluster photometry
--------------------------------------------------------------------------------
See also:
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
I/358 : Gaia DR3 Part 4. Variability (Gaia Collaboration, 2022)
J/A+A/686/A42 : Improving the open cluster census. III. (Hunt+, 2024)
Byte-by-byte Description of file: tableb1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR3 Gaia DR3 source ID
21- 39 A19 --- Cluster Host cluster name
41- 66 A26 --- Class Gaia DR3 best variability classification
(Rimoldini et al., 2023A&A...674A..14R 2023A&A...674A..14R,
See Cat. I/358)
68 I1 --- fCep [0/1] Flag indicating if star is in
Gaia DR3 Cepheid table
70 I1 --- fRB [0/1] Flag indicating if star is in
Gaia DR3 eclipsing binary table
72 I1 --- fLPV [0/1] Flag indicating if star is in
Gaia DR3 long-period variable table
74 I1 --- fMSOsc [0/1] Flag indicating if star is in
Gaia DR3 main sequence oscillators table
76 I1 --- frotmod [0/1] Flag indicating if star is in
Gaia DR3 rotation modulation table
78 I1 --- fRRLyr [0/1] Flag indicating if star is in
Gaia DR3 RR Lyrae table
80 I1 --- fShortTS [0/1] Flag indicating if star is in
Gaia DR3 short-timescale variability table
--------------------------------------------------------------------------------
Byte-by-byte Description of file: tableb2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaDR3 Gaia DR3 source ID
21- 39 A19 --- Cluster Host cluster name
41- 51 F11.8 mag GMAG Absolute dereddened G-band magnitude
53- 63 F11.8 mag BP-RP Absolute dereddened BP-RP color
65- 74 F10.8 [yr] logAge Log of host cluster age (log base 10) (1)
76- 85 F10.8 mag Ext Extinction of host cluster (1)
87- 99 F13.8 pc Dist Distance to host cluster based on parallax (1)
--------------------------------------------------------------------------------
Note (1): Gto, Hunt et al., 2024A&A...686A..42H 2024A&A...686A..42H, Cat. J/A+A/686/A42.
--------------------------------------------------------------------------------
Acknowledgements:
Emily Hunt, emily.hunt.physics(at)gmail.com
(End) Patricia Vannier [CDS] 15-Jul-2025