[vsnet-rcb 649] New R CrB stars from MACHO survey

[Taichi Kato]

New R CrB stars from MACHO survey

   Most of the objects are rather faint, but at least a few of them are
within reach of moderate-size telescopes (especially with CCDs).  Use the
MACHO names (long!) when reporting observations.

   Other well-known Sagittarius RCB stars were also observed as a by-product.

Paper: astro-ph/0507554
Date: Fri, 22 Jul 2005 21:28:49 GMT   (197kb)

Title: Discovery of Five New R Coronae Borealis Stars in the MACHO Galactic
  Bulge Database
Authors: A. Zaniewski, Geoffrey C. Clayton, D. L. Welch, Karl D. Gordon, D.
  Minniti, and K. H. Cook
Comments: 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
\\
  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.
\\ ( http://arXiv.org/abs/astro-ph/0507554 ,  197kb)