Red Giants in Open Clusters with TESS
Abstract
Open clusters are essential testbeds of stellar evolution theories and Galactic archaeology. Asteroseismology complements open cluster studies with the ability to measure accurate masses and ages for a homogeneous sample of stars. However, the detection of oscillations in open cluster red giants using TESS is largely unexplored due to the crowded stellar environments. We demonstrate the exciting feasibility of detecting oscillations in isolated cluster stars, with the asteroseismic analysis of 28 red giant members in the open cluster NGC 188. This represents the largest sample of open cluster red giants analysed using TESS photometry. Additionally, we emphasise the importance of ensemble asteroseismic studies of open clusters, and present a sample of candidate clusters with significant numbers of red giants that can be targeted for asteroseismic analyses at the end of TESS Cycle 8. Finally, we advocate for future observations of stellar clusters with the upcoming Roman Space Telescope, highlighting the scientific value of targeting homogeneous cluster populations.
Full text
Red Giants in Open Clusters with TESS Madeline Howell Jennifer Johnson (OSU), Marc Pinsonneault (OSU), Jamie Tayar (UF), Rafael Garcia (CEA), Dinil B. Palakkatharappil (CEA), Lina Borg (CEA), Dennis Stello (UNSW), Claudia Reyes (ANU) + APO-TESS Collaboration
Simple Stellar Populations 1 Why study Red Giants in Open Clusters? Isochrone fit to open cluster M67 (Reyes et al. 2024, 2025)
Simple Stellar Populations 1 Why study Red Giants in Open Clusters? Laboratories for testing stellar evolution theories Isochrone fit to open cluster M67 (Reyes et al. 2024, 2025)
Laboratories for testing stellar evolution theories Simple Stellar Populations Fundamental age calibrators for Galactic archaeology 1 Why study Red Giants in Open Clusters? Isochrone fit to open cluster M67 (Reyes et al. 2024, 2025)
Simple Stellar Populations 1 Red giant phase represents an interesting stage of a star’s lifetime Why study Red Giants in Open Clusters? Laboratories for testing stellar evolution theories Fundamental age calibrators for Galactic archaeology Isochrone fit to open cluster M67 (Reyes et al. 2024, 2025)
Previous Asteroseismology of Red Giants in Open Clusters 2 (e.g. Miglio et al. 2012; Lagarde et al. 2015; Sandquist et al. 2016; Stello et al. 2016; Handberg et al. 2017; Arentoft et al. 2019; Knudstrup et al. 2020; Sandquist et al. 2020; Brogaard et al. 2023; Pinsonneault et al. 2024; Reyes et al. 2025)
2 Clusters with > 10 red giants Previous Asteroseismology of Red Giants in Open Clusters
Adding TESS Open Clusters with Red Giants 3 Cluster Candidates in TESS with > 10 red giants
Galactic Archaeology with Open Clusters 4
Large Pixel Sizes of TESS Completed our own aperture photometry for TESS light curves 8
Asteroseismology of Red Giants in NGC 188 9 Lower RGB Star Middle RGB Star
Asteroseismology of Red Giants in NGC 188 9 Upper RGB Star RC Star
Asteroseismology of Red Giants in Open Clusters 10 *Preliminary seismic mass results* •Integrated mass loss (see talk by Yaguang Li) •Mixing events (e.g. with [C/N] abundances; Lu et al. 2025, Roberts et al. in prep) •Calibration of stellar model inputs (e.g. Reyes et al. 2025) •Possible merger candidates from seismic mass •Test of seismic scaling relations in the luminous giant regime (Ash et al. 2025) •Comparisons to other asteroseismic cluster studies (e.g. NGC 6791 is old & metal-rich; Miglio et al. 2012) •Measure cluster ages (see talk by Jamie Tayar & Poster #29 by Emily Hatt)
Asteroseismology of Red Giants in Open Clusters 10 *Preliminary seismic mass results* •Integrated mass loss (see talk by Yaguang Li) •Mixing events (e.g. with [C/N] abundances; Lu et al. 2025, Roberts et al. in prep) •Calibration of stellar model inputs (e.g. Reyes et al. 2025) •Possible merger candidates from seismic mass •Test of seismic scaling relations in the luminous giant regime (Ash et al. 2025) •Comparisons to other asteroseismic cluster studies (e.g. NGC 6791 is old & metal-rich; Miglio et al. 2012) •Measure cluster ages (see talk by Jamie Tayar & Poster #29 by Emily Hatt)
See prospects for APOGEE spectroscopy + TESS asteroseismology (APO-TESS) at Poster #77! *Preliminary seismic mass results* Asteroseismology + Spectroscopy of Red Giants in Open Clusters 10 •Integrated mass loss (see talk by Yaguang Li) •Mixing events (e.g. with [C/N] abundances; Lu et al. 2025, Roberts et al. in prep) •Calibration of stellar model inputs (e.g. Reyes et al. 2025) •Possible merger candidates from seismic mass •Test of seismic scaling relations in the luminous giant regime (Ash et al. 2025) •Comparisons to other asteroseismic cluster studies (e.g. NGC 6791 is old & metal-rich; Miglio et al. 2012) •Measure cluster ages (see talk by Jamie Tayar & Poster #29 by Emily Hatt)
Open Science Roman Call: Clusters & Magellanic Clouds Proposal Roman telescope, NASA MW Fig credit: ESA/Gaia/DPAC 11
Open Science Roman Call: Clusters & Magellanic Clouds Proposal Roman telescope, NASA 2 Globular Clusters (47 Tuc & NGC 362) + SMC MW Fig credit: ESA/Gaia/DPAC Galactic Bulge 11
Open Science Roman Call: Clusters & Magellanic Clouds Proposal Globular Cluster Science •Multiple populations •Second parameter problem •Type I vs II clusters Stellar Evolution •Calibrating stellar model parameters (e.g. mass loss, overshoot mixing) •Testing seismic scaling relations in different regimes •Classical pulsators studies •Binary system studies •See white paper by Molnr et al. 2023 Planet Science •Planet detections •Characterising planet hosts •See white paper by Grunblatt et al 2023 Galactic Archaeology •Clusters as age calibrators with asteroseismology 12
Open Science Roman Call: Clusters & Magellanic Clouds Proposal Globular Cluster Science •Multiple populations •Second parameter problem •Type I vs II clusters Stellar Evolution •Calibrating stellar model parameters (e.g. mass loss, overshoot mixing) •Testing seismic scaling relations in different regimes •Classical pulsators studies •Binary system studies •See white paper by Molnr et al. 2023 Planet Science •Planet detections •Characterising planet hosts •See white paper by Grunblatt et al 2023 Galactic Archaeology •Clusters as age calibrators with asteroseismology WE NEED YOU & YOUR SCIENCE IDEAS! 12