Characterisation of Galactic carbon stars and related stars from Gaia-EDR3

Abstract

We extend here a previous investigation on the characteristics of Galactic carbon stars using more accurate EDR3 astrometry measurements. Based on a much larger statistics, we confirm that N- and SC-type carbon stars share a very similar luminosity function, while the luminosities of J-type stars (Mbol) are fainter by half a magnitude on average. R-hot type carbon stars have luminosities throughout the RGB, which favours the hypothesis of an external origin for their carbon enhancement. Moreover, the kinematic properties of a significant fraction of the R-hot stars are compatible with the thick-disc population, in contrast with that of N- and SC-type stars, which would belong mostly to the thin disk. We also derive the luminosity function of a large number of Galactic extrinsic and intrinsic (O-rich) S stars and show that the luminosities of the latter are typically higher than the predicted onset of the third dredge-up during the AGB for solar metallicity. This result is consistent with these stars being genuine thermally pulsing AGB stars. On the other hand, using the so-called Gaia-2MASS diagram, we show that the overwhelming majority of the carbon stars identified in the LAMOST survey as AGB stars are probably R-hot and/or CH-type stars. Finally, we report the identification of 2660 new carbon stars candidates that we identified through their 2MASS photometry, their Gaia astrometry, and their location in the Gaia-2MASS diagram.

14 pages, 16 figures, accepted for publication in A&A

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Cited by in corpus (15)

• Reconnaissance with JWST of the J-region Asymptotic Giant Branch in Distance Ladder Galaxies: From Irregular Luminosity Functions to Approximation of the Hubble Constant
• The carbon star mystery: forty years later
• Value-added catalog of M-giant stars in LAMOST DR9
• Identification of late-type stars of class I
• Deep learning interpretability analysis for carbon star identification in Gaia DR3
• S-type stars from LAMOST DR10: classification of intrinsic and extrinsic stars
• Synthetic photometry for carbon-rich giants. V. Effects of grain-size-dependent dust opacities
• An Unsupervised Machine Learning Approach to Identify Spectral Energy Distribution Outliers: Application to the S-PLUS DR4 data
• The evolutionary state of the red giant star L${}_2$ Puppis
• Revisiting symbiotic binaries with interferometry: II. New PIONIER data
• Technetium-rich M Stars: Prime diagnostics of recent third dredge-up events on the Asymptotic Giant Branch
• Carbon- and Oxygen-rich stars in MaStar: identification and classification
• X TrA through the eyes of MATISSE: More evidence of clumpy molecular layers around C-type asymptotic giant branch stars
• Production of n-rich nuclei in red giant stars
• A homogeneous view of asymptotic giant branch carbon stars as seen by Gaia