HI line observations of 290 evolved stars made with the Nancay Radio Telescope -- I. Data

TL;DR

This paper provides a comprehensive survey of HI 21-cm line emissions from 290 evolved stars, mainly AGB stars, using the Nancay Radio Telescope, offering valuable data for understanding circumstellar envelopes and guiding future observations.

Contribution

It presents the first extensive dataset of HI observations for a large sample of evolved stars, including new detections and upper limits, with optimized procedures for distinguishing stellar emission from Galactic background.

Findings

34 clear detections of HI emission from circumstellar envelopes

33 objects with measurable HI flux and envelope size

95 targets with upper limits established

Abstract

We present a compendium of HI 21-cm line observations of circumstellar envelopes (CSEs) of 290 evolved stars, mostly (~84%) on the asymptotic giant branch (AGB), made with the 100m-class, single-dish Nancay Radio Telescope. The observational and data reduction procedures were optimised for separating genuine CSE HI emission from surrounding Galactic line features. For most targets (254) the results have not been previously published. Clear detections were made of 34 objects, for 33 of which the total HI flux and the size of the CSE could be determined. Possible detections were made of 21 objects, and upper limits could be determined for 95 undetected targets, while for 140 objects confusion from Galactic HI emission along the line-of-sight precluded meaningful upper limits. The collective results of this survey can provide guidance on detectability of circumstellar HI gas for future mapping and imaging studies.