IRAS 00450+7401 and the Mid-infrared Fade/Burst Cycle of R Coronae Borealis-type Stars
Abstract
We present optical and infrared imaging and spectroscopy of the R Coronae Borealis-type (R Cor Bor) star IRAS 00450+7401. Optical spectra further confirm its classification as a cool R Cor Bor system, having a hydrogen-deficient carbon star spectral subclass of HdC5 or later. Mid-infrared spectroscopy reveals the typical ~8 μm "hump" seen in other R Cor Bor stars and no other features. A modern-epoch spectral energy distribution shows bright emission from hot dust having T dust > 600 K. Historical infrared data reveal generally cooler dust color temperatures combined with long-term fading trends, but provide no discernible correlation between flux level and temperature. Investigating the most mid-infrared variable R Cor Bor stars found in IRAS, AKARI, and WISE data reveals similar fading trends, bursts that can show a factor of up to 10 change in flux density between epochs, and blackbody-fit dust color temperatures that span 400-1300 K. While some R Cor Bor stars such as IRAS 00450+7401 appear to undergo fade/burst cycles in the mid-infrared, significant gaps in temporal coverage prevent conclusively identifying any preferred timescale for their mid-infrared variability and circumstellar dust temperature changes.
- Publication:
-
The Astronomical Journal
- Pub Date:
- August 2023
- DOI:
- 10.3847/1538-3881/acda93
- arXiv:
- arXiv:2306.11945
- Bibcode:
- 2023AJ....166...40B
- Keywords:
-
- Circumstellar matter;
- R Coronae Borealis variable stars;
- Variable stars;
- 241;
- 1327;
- 1761;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- AJ accepted, 15 pages, 6 figures, 5 tables, and an appendix