Photospheric diagnostics of core helium burning in giant stars

Abstract

Core helium burning primary red clump (RC) stars are evolved red giant stars which are excellent standard candles. As such, these stars are routinely used to map the Milky Way or determine the distance to other galaxies among other things. However distinguishing RC stars from their less evolved precursors, namely red giant branch (RGB) stars, is still a difficult challenge and has been deemed the domain of asteroseismology. In this work, we use a sample of 1,676 RGB and RC stars which have both single epoch infrared spectra from the APOGEE survey and asteroseismic parameters and classification to show that the spectra alone can be used to (1) predict asteroseismic parameters with precision high enough to (2) distinguish core helium burning RC from other giant stars with less than 2% contamination. This will not only allow for a clean selection of a large number of standard candles across our own and other galaxies from spectroscopic surveys, but also will remove one of the primary roadblocks for stellar evolution studies of mixing and mass loss in red giant stars.

8 pages, 7 figures, Accepted to ApJ

References in corpus (8)

• The APOKASC Catalog: An Asteroseismic and Spectroscopic Joint Survey of Targets in the Kepler Fields
• The APOGEE red-clump catalog: Precise distances, velocities, and high-resolution elemental abundances over a large area of the Milky Way's disk
• LAMOST Spectroscopic Survey of the Galactic Anticentre (LSS-GAC): the second release of value-added catalogues
• Red clump stars and Gaia: Calibration of the standard candle using a hierarchical probabilistic model
• Deep Mixing and Metallicity: Carbon Depletion in Globular Cluster Giants
• A New Method for the Asteroseismic Determination of the Evolutionary State of Red-Giant Stars
• Nitrogen depletion in field red giants: mixing during the He flash?
• The spectroscopic indistinguishability of red giant branch and red clump stars

Cited by in corpus (16)

• Ages and Masses of 0.64 million Red Giant Branch stars from the LAMOST Galactic Spectroscopic Survey
• A helium-flash-induced mixing event can explain the lithium abundances of red clump stars
• A variational encoder-decoder approach to precise spectroscopic age estimation for large Galactic surveys
• Universal properties of the high- and low-α disk: small intrinsic abundance scatter and migrating stars
• Identification, mass and age of primary red clump stars from spectral features derived with the LAMOST DR7
• Precise Masses, Ages of ~1.0 million RGB and RC stars observed by the LAMOST
• Masses of RR Lyrae Stars with Different Chemical Abundances in the Galactic Field
• Li-rich Giants in LAMOST Survey. III. The statistical analysis of Li-rich giants
• Difference in chemical composition between the bright and faint red clump stars in the Milky Way bulge
• The chemical enrichment of the Milky Way disk evaluated using conditional abundances
• Red giants evolutionary status determination: the complete Kepler catalog
• 3D Parameter Maps of Red Clump Stars in the Milky Way -- Absolute Magnitudes and Intrinsic Colors
• Mass and Age determination of the LAMOST data with different Machine Learning methods
• Li-rich giant stars under scrutiny: Binarity, magnetic activity and the evolutionary status after Gaia DR2
• CN and CO Features: Key Indicators of Red Giant Evolutionary Phase in Moderate-Resolution X-Shooter Spectra
• Spectroscopic and asteroseismic analysis of the secondary clump red giant HD 226808