Astronomy and Astrophysics – Astrophysics
Scientific paper
Aug 1991
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1991apj...376l..45a&link_type=abstract
Astrophysical Journal, Part 2 - Letters (ISSN 0004-637X), vol. 376, Aug. 1, 1991, p. L45-L48. Research supported by NASA.
Astronomy and Astrophysics
Astrophysics
44
Red Giant Stars, Stellar Coronas, X Ray Sources, Hertzsprung-Russell Diagram, Rosat Mission, Stellar Luminosity
Scientific paper
A deep exposure of the bright star Arcturus (Alpha Bootis: K1 III) with the Roentgensatellit (Rosat) failed to detect soft X-ray emission from the archetype 'noncoronal' red giant. The 3-sigma upper limit in the energy band 0.1-2.4 keV corresponds to an X-ray luminosity of less than 3 x 10 to the 25th erg/s, equivalent to a coronal surface flux density of less than 0.0001 solar. The nondetection safely eliminates coronal irradiation as a possible mechanism to produce the highly variable He I 10830 feature and emphasizes the sharp decline in solarlike coronal activity that accompanies the evolution of low-mass single stars away from the main sequence. While the most conspicuous object in the Rosat field of view was not visible in X-rays, at least one fainter star is among the about 60 sources recorded: the Sigma Sct variable CN Boo, an A8 giant in the UMa Stream.
Ayres Thomas R.
Fleming Thomas Anthony
Schmitt Juergen H. M. M.
No associations
LandOfFree
Digging in the coronal graveyard - A ROSAT observation of the red giant Arcturus 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 Digging in the coronal graveyard - A ROSAT observation of the red giant Arcturus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Digging in the coronal graveyard - A ROSAT observation of the red giant Arcturus will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1725166