[vsnet-chat 7166] Re: Sequence for new MACHO R CrB star

[Mati Morel]

Hi all,
        A couple of these new RCB stars are about 14.3V at maximum, but as luck 
would have it, one happens to lie within a CCD field imaged by Arne Henden,
USNOFS.  In fact it lies only 20" from a recent nova, V5114 Sgr (2004). I have
extracted some useful comparison stars from Arne's .dat file.

MACHO*18:19:33.9-28:35:58  (name = 135.27132.51)
Position (2000) : 18:19:33.77 -28:35:58.0  from  V5114SGR.dat
V = 14.404 (-0.006)  B-V = 1.761 (-0.015)

Star #    RA2000   DEC2000      V      Verr     B-V    B-Verr
===============================================
1       18:19:35.94 -28:35:37.9  13.385  0.005  0.648  0.001
2       18 19 30.95 -28 36 29.3  13.641  0.048  1.753  0.025
3       18 19 33.68 -28 36 24.6  13.934  0.020  1.336  0.018
4       18 19 37.28 -28 36 28.0  14.242  0.042  1.689  0.019
5       18 19 34.47 -28 35 55.0  14.728  0.013  1.513  0.023
6       18 19 36.23 -28 35 25.1  14.908  0.003  1.829  0.002
7       18 19 34.48 -28 35 09.1  15.467  0.067  1.945  0.029

Notes:  V5114 Sgr position , from  .dat file,
         18 19 32.19 -28 36 35.3
All of these stars lie in the small field chart, downloadable from
the URL below.
Regards,
Mati Morel
morel at ozemail.com.au   
----- Original Message ----- 
Subject: [vsnet-chat 7161] New R CrB stars from MACHO survey
> 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.
> 
> 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............
> \\ ( http://arXiv.org/abs/astro-ph/0507554 ,  197kb)