Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (69) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (1)
· Reads History
· Translate This Page
The enigmatic H alpha line of FK Comae - Last stages of a coalescing binary
Walter, F. M.; Basri, G. S.
AA(California, University, Berkeley, CA), AB(California, University, Berkeley, CA)
Astrophysical Journal, Part 1, vol. 260, Sept. 15, 1982, p. 735-743. (ApJ Homepage)
Publication Date:
NASA/STI Keywords:
Binary Stars, Emission Spectra, G Stars, H Alpha Line, Stellar Evolution, Stellar Spectra, Stellar Spectrophotometry, High Resolution, Photosphere, Radial Velocity, Radiant Flux Density, Spectral Line Width, Spectral Resolution, Stellar Mass Accretion, Stellar Models, Stellar Rotation, Visual Photometry
Bibliographic Code:


The apparently single, rapidly rotating G giant FK Comae displays an unusual hydrogen alpha emission line which is very broad, strong, and variable. Extensive high-resolution studies of this line with complete phase coverage are presented. The alpha hydrogen emission centroid shows a radial velocity modulation on the 2.4 days stellar rotation period with a semiamplitude identical to the photospheric rotational velocity. These data, when phased with optical photometry, indicate that the star has a bright, rather than dark, region on its surface and that the phase may have been stable for seven years. A qualitative model wherein the bright spot is caused by accretion from a low mass unseen companion onto the surface of the G giant is considered. Such a model explains many of the observed characteristics of the stellar spectrum and hydrogen alpha feature, and it is concluded that FK Comae is not yet a single star, but is still evolving toward coalescence of the system.

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences

More Article Retrieval Options

HELP for Article Retrieval

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Find Similar Abstracts:

Use: Authors
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
arXiv e-prints