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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 693546.0, MPI für Astronomie / Publikationen_mpia
The Gemini NICI Planet-Finding Campaign: the frequency of giant planets around young B and A stars
Authors:Nielsen, E. L.; Liu, M. C.; Wahhaj, Z.; Biller, B. A.; Hayward, T. L.; Close, L. M.; Males, J. R.; Skemer, A. J.; Chun, M.; Ftaclas, C.; Alencar, S. H. P.; Artymowicz, P.; Boss, A.; Clarke, F.; de Gouveia Dal Pino, E.; Gregorio-Hetem, J.; Hartung, M.; Ida, S.; Kuchner, M.; Lin, D. N. C.; Reid, I. N.; Shkolnik, E. L.; Tecza, M.; Thatte, N.; Toomey, D. W.
Date of Publication (YYYY-MM-DD):2013
Title of Journal:The Astrophysical Journal
Issue / Number:1
Start Page:id. 4 (35 pp)
Audience:Not Specified
Abstract / Description:We have carried out high contrast imaging of 70 young, nearby B and A stars to search for brown dwarf and planetary companions as part of the Gemini NICI Planet-Finding Campaign. Our survey represents the largest, deepest survey for planets around high-mass stars (≈1.5-2.5 M ) conducted to date and includes the planet hosts β Pic and Fomalhaut. We obtained follow-up astrometry of all candidate companions within 400 AU projected separation for stars in uncrowded fields and identified new low-mass companions to HD 1160 and HIP 79797. We have found that the previously known young brown dwarf companion to HIP 79797 is itself a tight (3 AU) binary, composed of brown dwarfs with masses 58^{+21}_{-20} M Jup and 55^{+20}_{-19} M Jup, making this system one of the rare substellar binaries in orbit around a star. Considering the contrast limits of our NICI data and the fact that we did not detect any planets, we use high-fidelity Monte Carlo simulations to show that fewer than 20% of 2 M stars can have giant planets greater than 4 M Jup between 59 and 460 AU at 95% confidence, and fewer than 10% of these stars can have a planet more massive than 10 M Jup between 38 and 650 AU. Overall, we find that large-separation giant planets are not common around B and A stars: fewer than 10% of B and A stars can have an analog to the HR 8799 b (7 M Jup, 68 AU) planet at 95% confidence. We also describe a new Bayesian technique for determining the ages of field B and A stars from photometry and theoretical isochrones. Our method produces more plausible ages for high-mass stars than previous age-dating techniques, which tend to underestimate stellar ages and their uncertainties.
Free Keywords:brown dwarfs; instrumentation: adaptive optics; planetary systems; planets and satellites: detection; stars: individual: HIP 79797
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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