Astronomy and Astrophysics – Astronomy
Scientific paper
Jul 1987
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1987aj.....94..150h&link_type=abstract
Astronomical Journal (ISSN 0004-6256), vol. 94, July 1987, p. 150-157. Research supported by the Research Corp.
Astronomy and Astrophysics
Astronomy
32
Dwarf Stars, H Alpha Line, K Stars, M Stars, Stellar Spectrophotometry, Variable Stars, Emission Spectra, Hertzsprung-Russell Diagram, Main Sequence Stars, Stellar Magnitude
Scientific paper
Hα photometry of 188 dM and dK stars has been obtained with the Perkin telescope at Van Vleck Observatory. The photometric index, N-W, has been calibrated using 56 stars with equivalent widths determined spectroscopically by Stauffer and Hartmann (1986). An external standard error of 0.08 Å is found for the equivalent width (EW) measurements of non-emission stars; it may be higher for those with emission lines. The distribution of stars in the N-W, R-I plane is discussed. Most lie along a single "main sequence" of absorption which slopes up towards 0 EW with increasing R-I. Eighteen dKe or dMe stars are found, all clearly separated from the absorption sequence. The absorption EWs are large compared with expectation based on photospheric models, indicating either that the models are in error or that chromospheres are present in essentially all late-type dwarfs. Three stars (Gl 182, Gl 873AB, and Gl 890) were found to vary significantly in N-W. All are emission stars, and the variability can probably be attributed to flares.
Herbst William
Layden Andrew Choisy
No associations
LandOfFree
H-alpha photometry of dwarf K and M stars 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 H-alpha photometry of dwarf K and M stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and H-alpha photometry of dwarf K and M stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-789401