The Gemini NICI planet-finding campaign: the frequency of giant planets around young B and A stars
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
12/12/2013
12/12/2013
2013
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Resumo |
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. |
Identificador |
The Astrophysical Journal, Chicago, v.776, n.1, p.4/1-4/35, 2013 http://www.producao.usp.br/handle/BDPI/43664 10.1088/0004-637X/776/1/4 http://iopscience.iop.org/0004-637X/776/1/4/pdf/0004-637X_776_1_4.pdf |
Idioma(s) |
eng |
Publicador |
Chicago |
Relação |
The Astrophysical Journal |
Direitos |
restrictedAccess Copyright 2013 The American Astronomical Society |
Palavras-Chave | #brown dwarfs #instrumentation: adaptive optics #planetary systems #planets and satellites: detection #stars: individual (HIP 79797) #ESTRELAS #INSTRUMENTAÇÃO (ASTRONOMIA) #PLANETAS #SATÉLITES |
Tipo |
article original article publishedVersion |