Astronomy and Astrophysics – Astrophysics
Scientific paper
1998-12-14
Astronomy and Astrophysics
Astrophysics
32 pages incl. 14 figures and 3 tables. To appear in the 1999 April 10 issue of The Astrophysical Journal
Scientific paper
10.1086/307009
We present Extreme Ultraviolet Explorer spectroscopy and photometry of the nearby F8 V star HD 35850 (HR 1817). The EUVE spectra reveal 28 emission lines from Fe IX and Fe XV to Fe XXIV. The Fe XXI 102, 129 A ratio yields an upper limit for the coronal electron density, log n < 11.6 per cc. The EUVE SW spectrum shows a small but clearly detectable continuum. The line-to-continuum ratio indicates approximately solar Fe abundances, 0.8 < Z < 1.6. The resulting emission-measure distribution is characterized by two temperature components at log T of 6.8 and 7.4. The EUVE spectra have been compared with non-simultaneous ASCA SIS spectra of HD 35850. The SIS spectrum shows the same temperature distribution as the EUVE DEM analysis. However, the SIS spectral firs suggest sub-solar abundances, 0.34 < Z < 0.81. Although some of the discrepancy may be the result of incomplete X-ray line lists, we cannot explain the disagreement between the EUVE line-to-continuum ratio and the ASCA-derived Fe abundance. Given its youth (t ~ 100 Myr), its rapid rotation (v sin i ~ 50 km/s), and its high X-ray activity (Lx ~ 1.5E+30 ergs/s), HD 35850 may represent an activity extremum for single, main-sequence F-type stars. The variability and EM distribution can be reconstructed using the continuous flaring model of Guedel provided that the flare distribution has a power-law index of 1.8. Similar results obtained for other young solar analogs suggest that continuous flaring is a viable coronal heating mechanism on rapidly rotating, late-type, main-sequence stars.
Covino Stefano
Gagne Marc
Guedel Manuel
Linsky Jeffrey L.
Tagliaferri Gianpiero
No associations
LandOfFree
The Active Corona of HD 35850 (F8 V) 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 The Active Corona of HD 35850 (F8 V), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Active Corona of HD 35850 (F8 V) will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-388368