Issue |
A&A
Volume 438, Number 3, August II 2005
|
|
---|---|---|
Page(s) | 867 - 874 | |
Section | Galactic structure, stellar clusters, and populations | |
DOI | https://doi.org/10.1051/0004-6361:20052820 | |
Published online | 18 July 2005 |
Cool carbon stars in the halo
II. A study of 25 new objects
1
Groupe d'Astrophysique, UMR 5024 CNRS, Case CC72, Place Bataillon, 34095 Montpellier Cedex 5, France e-mail: mauron@graal.univ-montp2.fr
2
Laboratoire d'Astrophysique, Observatoire de Grenoble, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 9, France
3
378433 Byurakan Astrophysical Observatory & Isaac Newton Institute of Chile, Armenian Branch, Ashtarak d-ct, Armenia
Received:
4
February
2005
Accepted:
29
March
2005
We present new results from an ongoing survey of carbon-rich
asymptotic giant (AGB) stars in the halo of our Galaxy. After selecting candidates
primarily through their 2MASS colours, slit spectroscopy was achieved at
the ESO NTT telescope. Twenty-one new AGB carbon stars
were discovered, increasing the total of presently known similar
AGB C stars to ~120.
A further four were observed again in order to confirm their carbon-rich nature
and measure radial velocities.
Two main findings emerge from this work. First, we found
a C star located at ≈130 kpc
from the Sun and at . This
distant star is remarkably close (5 kpc) to the principal plane of the Stream of the
Sagittarius dwarf galaxy, and is likely to be a tracer of a distant poorly populated
southern warp of the Stream. Such a warp is predicted by model simulations,
but it passes ~45 kpc from that star.
The second result is that, mainly in the North,
several already known or newly discovered AGB
carbon stars lie far, up to 60 kpc, from the mean plane of the Sagittarius Stream.
Key words: stars: carbon / Galaxy: halo / galaxies: stellar content
© ESO, 2005
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.