Discovery of Five New R Coronae Borealis Stars in the MACHO Galactic Bulge Database

Abstract

We have identified five new R Coronae Borealis (RCB) stars in the Galactic bulge using the MACHO Project photometry database, raising the total number of known Galactic RCB stars to about 40. We have obtained spectra to confirm the identifications. The fact that four out of the five newly identified RCB stars are ``cool'' (T(eff) < 6000 K) rather than ``warm'' (T(eff) > 6000 K) suggests that the preponderance of warm RCB stars among the existing sample is a selection bias. These cool RCB stars are redder and fainter than their warm counterparts and may have been missed in surveys done with blue plates. Based on the number of new RCB stars discovered in the MACHO bulge fields, there may be ~250 RCB stars in the reddened "exclusion" zone toward the bulge.

16 pages, 5 figures, AJ in press High resolution versions of Figures 1 and 2 can be downloaded from http://morpheus.phys.lsu.edu/~gclayton/figs.pdf (more typos corrected)

References in corpus (5)

• The MACHO Project LMC Variable Star Inventory: X. The R Coronae Borealis Stars
• The Large-Scale Extinction Map of the Galactic Bulge from the MACHO Project Photometry
• EROS 2 photometry of probable R Coronae Borealis stars in the Small Magellanic Cloud
• A High-resolution Spectrum of the R CrB Star V2552 Ophiuchi
• The Newly Active R Coronae Borealis Star, V2552 Oph

Cited by in corpus (23)

• Very Large Excesses of 18O in Hydrogen-Deficient Carbon and R Coronae Borealis Stars: Evidence for White Dwarf Mergers
• Post-merger evolution of carbon-oxygen + helium white dwarf binaries and the origin of R Coronae Borealis and extreme helium stars
• V605 Aql: The Older Twin of Sakurai's Object
• New Magellanic Cloud R Coronae Borealis and DY Per type stars from the EROS-2 database: the connection between RCBs, DYPers and ordinary carbon stars
• Fluorine in R Coronae Borealis Stars
• The ongoing pursuit of R Coronae Borealis stars: ASAS-3 survey strikes again
• Tracking down R Coronae Borealis stars from their mid-infrared WISE colours
• R Coronae Borealis stars in the Galactic Bulge discovered by EROS-2
• The Dust Properties of Two Hot R Coronae Borealis Stars and a Wolf-Rayet Central Star of a Planetary Nebula: in Search of a Possible Link
• A plethora of new R Coronae Borealis stars discovered from a dedicated spectroscopic follow-up survey
• Dust around R Coronae Borealis stars: I. Spitzer/IRS observations
• R Coronae Borealis Stars are Viable Factories of Pre-solar Grains
• The dawn of a new era for dustless HdC stars with GAIA eDR3
• Discovery of Bright Galactic R Coronae Borealis and DY Persei Variables: Rare Gems Mined from ACVS
• Census of R Coronae Borealis stars I: Infrared light curves from Palomar Gattini IR
• New R Coronae Borealis stars discovered in OGLE-III Galactic Bulge fields from their mid- and near- infrared properties
• A Spectral Classification System for Hydrogen-deficient Carbon Stars
• Astrophysics in 2006
• Abundance analyses of the new R Coronae Borealis stars: ASAS-RCB-8 and ASAS-RCB-10
• Do Hydrogen-deficient Carbon Stars have Winds?
• HE 1015-2050: Discovery of a Hydrogen-deficient carbon star at high galactic latitude
• NSV 11154 Is a New R Coronae Borealis Star
• MACHO 311.37557.169: A VY Scl star