New observations of cool carbon stars in the halo

TL;DR

This paper reports the discovery of 18 new cool carbon stars in the galactic halo, including some at unprecedented distances, and estimates their mass-loss rates, contributing to understanding of stellar evolution in the galaxy's outskirts.

Contribution

The study provides new observations of rare halo carbon stars, including their distances, infrared properties, and mass-loss estimates, expanding knowledge of stellar populations far from the galactic plane.

Findings

18 new halo carbon stars discovered

Six stars show strong infrared excess and high galactic latitude

Some stars are at distances exceeding 30 kpc, with two at 150 kpc

Abstract

We report new results of our search for rare, cool carbon stars located at large distances from the galactic plane. Eighteen new C stars were discovered. Six are remarkable by showing the two peculiarities of a strong infrared excess at 12 microns and a large height above the Galactic plane, from 1.7 to 6 kpc. The number of C stars with these properties has been increased to 16. Mass-loss rates were tentatively estimated by assuming that all these 16 stars are Miras and by using the correlation between Mdot and the K-12 colour index. It is found that several stars have large mass loss, with median Mdot around 4E-06 solar mass per year. It would be desirable to detect their CO emission ... Eight stars might be at more than 30 kpc from the Sun, and two at the unprecedented distance of 150 kpc (this abstract has been abridged).