other query modes : |
Identifier query |
Coordinate query |
Criteria query |
Reference query |
Basic query |
Script submission |
TAP |
Output options |
Object types |
Help |
2009MNRAS.398.1383F - Mon. Not. R. Astron. Soc., 398, 1383-1391 (2009/September-3)
Magnetic cycles of the planet-hosting star τ Bootis - II. A second magnetic polarity reversal.
FARES R., DONATI J.-F., MOUTOU C., BOHLENDER D., CATALA C., DELEUIL M., SHKOLNIK E., CAMERON A.C., JARDINE M.M. and WALKER G.A.H.
Abstract (from CDS):
We detected the magnetic field of the star at three epochs in 2008. It has a weak magnetic field of only a few gauss, oscillating between a predominant toroidal component in January and a dominant poloidal component in June and July. A magnetic polarity reversal was observed relative to the magnetic topology in 2007 June. This is the second such reversal observed in 2 years on this star, suggesting that τ Boo has a magnetic cycle of about 2 years. This is the first detection of a magnetic cycle for a star other than the Sun. The role of the close-in massive planet in the short activity cycle of the star is questioned.
τ Boo has a strong differential rotation, a common trend for stars with shallow convective envelope. At latitude 40°, the surface layer of the star rotates in 3.31 d, equal to the orbital period. Synchronization suggests that the tidal effects induced by the planet may be strong enough to force at least the thin convective envelope into corotation.
τ Boo shows variability in the Caii H & K and Hα throughout the night and on a night-to-night time-scale. We do not detect enhancement in the activity of the star that may be related to the conjunction of the planet. Further data are needed to conclude about the activity enhancement due to the planet.
Abstract Copyright: © 2009 The Authors. Journal compilation © 2009 RAS
Journal keyword(s): stars: activity - stars: individual: τ Boo - stars: magnetic fields - planetary systems
Simbad objects: 2
To bookmark this query, right click on this link: simbad:2009MNRAS.398.1383F and select 'bookmark this link' or equivalent in the popup menu