Astronomy and Astrophysics – Astrophysics
Scientific paper
Jan 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004a%26a...413..657f&link_type=abstract
Astronomy and Astrophysics, v.413, p.657-667 (2004)
Astronomy and Astrophysics
Astrophysics
5
Stars: Activity, Stars: Individual: Hd 111456
Scientific paper
We present spectroscopic and photometric observations of the young F5-6 V field star HD 111456 which exhibits emission cores in the Ca Ii H and K lines and a filling in the H\alpha line. Absorption lines of He I D_3 and Li I are clearly detected and we give a new value of v\sin i=41.5 km s-1. Although the limit of magnetic activity detectability at optical wavelengths occurs around F5-6 spectral types, HD 111456 shows unusual chromospheric activity. High UV fluxes in the C Ii, C Iv, Si Ii and Si Iv lines and a strong X-ray emission confirm that HD 111456 is one of the most active F5-6 V star. The Ca Ii and H\alpha chromospheric emission fluxes do not show any detectable variation on time scales of few days, as well as uvby photometry. A possible explanation in terms of a very high level of magnetic activity and a homogeneous distribution of active regions, both at chromospheric and photospheric level, or a very low inclination of the rotation axis with respect to the line of sight is proposed. From 1998 to 2001 the radial velocity varies indicating a possible binary system, but the spectral distribution of HD 111456 is better reproduced by a single normal F5 V star, and composite spectra simulations (Ca Ii, H\alpha) with a normal inactive F star and a very active low-mass K-M star are not able to reproduce the observed emissions.
Based on observations collected at the Observatoire de Haute Provence (CNRS), France, and at the Osservatorio Astrofisico di Catania, Italy.
Catalano Santo
Frasca Antonio
Freire Ferrero R.
Marilli Ettore
No associations
LandOfFree
Magnetic activity in HD 111456, a young F5-6 main-sequence star 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 Magnetic activity in HD 111456, a young F5-6 main-sequence star, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Magnetic activity in HD 111456, a young F5-6 main-sequence star will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1837470