On the Nature of Rapidly Rotating Single Evolved Stars

TL;DR

This study analyzes the rotational properties of 2010 apparently single evolved stars, identifying 30 with unusual rapid rotation, including among subgiants and supergiants, many showing infrared excess possibly linked to circumstellar dust.

Contribution

First report of rapidly rotating single evolved stars across multiple luminosity classes, expanding understanding of stellar rotation in late evolutionary stages.

Findings

Identified 30 abnormal rotators among 2010 stars.

Detected IRAS infrared excess in most abnormal rotators.

First observation of rapid rotation in subgiant and supergiant stars.

Abstract

We present an analysis of the nature of the rapidly rotating, apparently single giant based on rotational and radial velocity measurements carried out by the CORAVEL spectrometers. From the analyzed sample, composed of 2010 spectroscopic, apparently single, evolved stars of luminosity classes IV, III, II, and Ib with spectral types G and K, we classified 30 stars that presented unusual, moderate to rapid rotation. This work reports, for the first time, the presence of these abnormal rotators among subgiant, bright giant, and Ib supergiant stars. To date, this class of stars was reported only among giant stars of luminosity class III. Most of these abnormal rotators present an IRAS infrared excess, which, in principle, can be related to dust around these stars.