Census of R Coronae Borealis Stars. I. Infrared Light Curves from Palomar Gattini IR - Archive ouverte HAL Access content directly
Journal Articles The Astrophysical Journal Year : 2021

Census of R Coronae Borealis Stars. I. Infrared Light Curves from Palomar Gattini IR

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Viraj R. Karambelkar
  • Function : Author
Mansi M. Kasliwal
  • Function : Author
Kishalay De
  • Function : Author
Shreya Anand
  • Function : Author
Michael C. B. Ashley
  • Function : Author
Alex Delacroix
  • Function : Author
Matthew Hankins
  • Function : Author
Jacob E. Jencson
  • Function : Author
Ryan M. Lau
  • Function : Author
Dan Mckenna
  • Function : Author
Anna Moore
  • Function : Author
Eran O. Ofek
  • Function : Author
Roger M. Smith
  • Function : Author
Roberto Soria
  • Function : Author
Jamie Soon
  • Function : Author
Samaporn Tinyanont
  • Function : Author
Tony Travouillon
  • Function : Author
Yuhan Yao
  • Function : Author

Abstract

We are undertaking the first systematic infrared (IR) census of R Coronae Borealis (RCB) stars in the Milky Way, beginning with IR light curves from the Palomar Gattini IR (PGIR) survey. The PGIR is a 30 cm J-band telescope with a 25 deg2 camera that is surveying 18,000 deg2 of the northern sky (δ > -28°) at a cadence of 2 days. We present PGIR light curves for 922 RCB candidates selected from a mid-IR color-based catalog. Of these 922, 149 are promising RCB candidates, as they show pulsations or declines similar to RCB stars. The majority of the candidates that are not RCB stars are either long-period variables (LPVs) or RV Tauri stars. We identify IR color-based criteria to better distinguish between RCB stars and LPVs. As part of a pilot spectroscopic run, we obtain NIR spectra for 26 of the 149 promising candidates and spectroscopically confirm 11 new RCB stars. We detect strong He I λ10830 features in the spectra of all RCB stars, likely originating within high-velocity (200-400 km s-1) winds in their atmospheres. Nine of these RCB stars show 12C16O and 12C18O molecular absorption features, suggesting that they are formed through a white dwarf merger. We detect quasiperiodic pulsations in the light curves of five RCB stars. The periods range between 30 and 125 days and likely originate from the strange-mode instability in these stars. Our pilot run results motivate a dedicated IR spectroscopic campaign to classify all RCB candidates.

Dates and versions

insu-03748211 , version 1 (09-08-2022)

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Cite

Viraj R. Karambelkar, Mansi M. Kasliwal, Patrick Tisserand, Kishalay De, Shreya Anand, et al.. Census of R Coronae Borealis Stars. I. Infrared Light Curves from Palomar Gattini IR. The Astrophysical Journal, 2021, 910, ⟨10.3847/1538-4357/abe5aa⟩. ⟨insu-03748211⟩
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