A spectral classification system for hydrogen-deficient carbon stars
Date
2023
Authors
L Crawford, Courtney
Tisserand, Patrick
Clayton, Geoffrey C
Soon, Jamie
Bessell, Mike
Wood, Peter R
Garcıa–Hernandez, D.A.
Ruiter, Ashley J
Seitenzahl, Ivo R
Journal Title
Journal ISSN
Volume Title
Publisher
Oxford University Press
Abstract
Stellar spectral classification has been highly useful in the study of stars. While there is a currently accepted spectral classification system for carbon stars, the subset of hydrogen-deficient carbon (HdC) stars has not been well described by such a system, due predominantly to their rarity and their variability. Here we present the first system for the classification of HdCs based on their spectra, which is made wholly on their observable appearance. We use a combination of dimensionality reduction and clustering algorithms with human classification to create such a system with eight total classes corresponding to temperature, and an additional second axis corresponding to the carbon molecular band strength. We classify over half of the known sample of HdC stars using this, and roughly calibrate the temperatures of each class using their colours. Additionally, we express trends in the occurrence of certain spectral peculiarities such as the presence of hydrogen and lithium lines. We also present three previously unpublished spectra, report the discovery of two new Galactic dustless HdC stars, and additionally discuss one especially unique star that appears to border between the hottest HdCs and the coolest extreme helium stars.
Description
Keywords
atlases, stars: carbon, stars: chemically peculiar, stars: variables, general
Citation
Collections
Source
Monthly Notices of the Royal Astronomical Society
Type
Journal article
Book Title
Entity type
Access Statement
Open Access
License Rights
Creative Commons Attribution licence
Restricted until
Downloads
File
Description