DISCOVERY OF A 1.6 YEAR MAGNETIC ACTIVITY CYCLE IN THE EXOPLANET HOST STAR {iota} HOROLOGII
- High Altitude Observatory, NCAR, P.O. Box 3000, Boulder, CO 80307 (United States)
- Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30302 (United States)
- Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States)
The Mount Wilson Ca HK survey revealed magnetic activity variations in a large sample of solar-type stars with timescales ranging from 2.5 to 25 years. This broad range of cycle periods is thought to reflect differences in the rotational properties and the depths of the surface convection zones for stars with various masses and ages. In 2007, we initiated a long-term monitoring campaign of Ca II H and K emission for a sample of 57 southern solar-type stars to measure their magnetic activity cycles and their rotational properties when possible. We report the discovery of a 1.6 year magnetic activity cycle in the exoplanet host star {iota} Horologii and obtain an estimate of the rotation period that is consistent with Hyades membership. This is the shortest activity cycle so far measured for a solar-type star and may be related to the short-timescale magnetic variations recently identified in the Sun and HD 49933 from helioseismic and asteroseismic measurements. Future asteroseismic observations of {iota} Hor can be compared to those obtained near the magnetic minimum in 2006 to search for cycle-induced shifts in the oscillation frequencies. If such short activity cycles are common in F stars, then NASA's Kepler mission should observe their effects in many of its long-term asteroseismic targets.
- OSTI ID:
- 21452687
- Journal Information:
- Astrophysical Journal Letters, Vol. 723, Issue 2; Other Information: DOI: 10.1088/2041-8205/723/2/L213; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
The moving group targets of the seeds high-contrast imaging survey of exoplanets and disks: Results and observations from the first three years
KEPLER-21b: A 1.6 R{sub Earth} PLANET TRANSITING THE BRIGHT OSCILLATING F SUBGIANT STAR HD 179070