A survey of H-alpha line profiles among metal-deficient field red giants

Details A survey of H-alpha line profiles among metal-deficient field red giants A survey of H-alpha line profiles among metal-deficient field red giants

May 1988

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1988aj.....95.1547s&link_type=abstract

Astronomical Journal (ISSN 0004-6256), vol. 95, May 1988, p. 1547-1557.

Astronomy and Astrophysics

Astronomy

49

Emission Spectra, H Alpha Line, Red Giant Stars, Stellar Atmospheres, Stellar Spectra, Astronomical Catalogs, Color-Magnitude Diagram, Stellar Luminosity

Scientific paper

Echelle spectra have been obtained of the Hα line for a sample of 52 metal-poor field red giants to infer the structure and dynamics of their atmospheres. Emission is found in the wings of the absorption line for ten of these stars. The main properties of this emission are as follows (1) Only giants brighter than MV = -1.7 are found to exhibit Hα emission above the continuum level. (2) Both the absolute strength of the Hα emision wings and the sense of the violet to red (V/R) asymmetry change from star to star. (3) The strength of the emission also varies on a timescale of months for some stars, and may even disappear. Following the precepts of Dupree, Hartmann, and Avrett, the Hα emission is considered to arise from a chromosphere, particularly from relatively high-density regions with temperatures in the range 7000 - 8500K. The V/R emission asymmetries imply the existence of differential mass motions in the line-forming region. It is further proposed that the variability of the emission strength results from fluctuations within the chromosphere, of the column density or the temperature gradient, or both, possibly as the result of pulsation.

Affiliated with

Also associated with

No associations

Rating

A survey of H-alpha line profiles among metal-deficient field red giants does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A survey of H-alpha line profiles among metal-deficient field red giants, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A survey of H-alpha line profiles among metal-deficient field red giants will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-853802