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Astron. Astrophys. 351, 519-525 (1999)
Blue horizontal branch stars in metal-rich globular clusters
I. NGC 6388 and NGC 6441 *
S. Moehler 1,
A.V. Sweigart 2 and
M. Catelan *** 2
1 Dr. Remeis-Sternwarte, Astronomisches Institut der Universität Erlangen-Nürnberg, Sternwartstrasse 7, 96049 Bamberg, Germany
(ai13@sternwarte.uni-erlangen.de)
2 NASA Goddard Space Flight Center, Code 681, Greenbelt, MD 20771, USA (sweigart@bach.gsfc.nasa.gov; catelan@virginia.edu)
Received 12 April 1999 / Accepted 14 September 1999
Abstract
We report the first results of an ongoing spectroscopic survey of
blue horizontal branch stars in the metal-rich
(![[FORMULA]](img1.gif)
) globular clusters NGC 6388 and
NGC 6441. Based on data obtained with the ESO-New Technology
Telescope (NTT), we provide gravities and temperatures for four
stars in NGC 6388 and three stars in NGC 6441. These results
are marginally inconsistent with the predictions of canonical
evolutionary theory, but disagree strongly with all non-canonical
scenarios that explain the sloped horizontal branches seen in the
colour-magnitude diagrams of these clusters.
Key words: stars:
early-type 
stars: fundamental
parameters
stars:
horizontal-branch
Galaxy: globular clusters: individual:
NGC 6388
Galaxy: globular clusters: individual: NGC 6441
* Based on observations collected at the European Southern Observatory (ESO No 61.E-0361)
** Hubble Fellow.
*** Visiting Scientist, Universities Space Research Association.
Send offprint requests to: S. Moehler
Contents
- 1. Introduction
- 2. Observations and data reduction
- 3. Atmospheric parameters
- 4. Discussion and future work
- Acknowledgements
- References
© European Southern Observatory (ESO) 1999
Online publication: November 3, 1999
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