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ASYMMETRIES IN THE SPECTRAL LINES OF EVOLVED HALO STARS
- Source :
- The Astronomical Journal. 135:2033-2037
- Publication Year :
- 2008
- Publisher :
- American Astronomical Society, 2008.
-
Abstract
- We do an initial reconnaissance of asymmetries of spectral lines in metal-poor field stars using high-resolution observations of four red horizontal-branch and 11 red giant branch stars taken with the coude spectrograph at the Canada-France-Hawaii Telescope. We find that (1) the shapes of the line bisectors for metal-poor stars hotter than 4100 K mimic the well-known C shape of bisectors for solar-metallicity stars on the cool side of the granulation boundary while (2) metal-poor stars cooler than 4100 K, or higher up the red giant branch than M V = ?1.5, show bisectors with a reversed-C shape, similar to those for solar-metallicity stars on the hot side of the granulation boundary and similar to the reversed-C shape found in a previous study for the M-type supergiant Betelgeuse. The well-documented radial-velocity jitter of high-luminosity stars and the line bisector characteristics vary in concert up the red giant branch; both phenomena are probably signatures of large convection cells.
- Subjects :
- Betelgeuse
Physics
K-type main-sequence star
Astronomy
Astronomy and Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Spectral line
Red-giant branch
Stars
Space and Planetary Science
Astrophysics::Solar and Stellar Astrophysics
Astrophysics::Earth and Planetary Astrophysics
Halo
Supergiant
Astrophysics::Galaxy Astrophysics
Line (formation)
Subjects
Details
- ISSN :
- 15383881 and 00046256
- Volume :
- 135
- Database :
- OpenAIRE
- Journal :
- The Astronomical Journal
- Accession number :
- edsair.doi...........ec07c0bc1f2e2449454859e45da05e87