Exoplanets and Stellar Physics

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Constraining the atmosphere of GJ 1214b using an optimal estimation technique

(2013)

Authors:

Joanna K Barstow, Suzanne Aigrain, Patrick GJ Irwin, Leigh N Fletcher, Jae-Min Lee
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Robust elements of Snowball Earth atmospheric circulation and oases for life

Journal of Geophysical Research: Atmospheres American Geophysical Union (AGU) 118:12 (2013) 6017-6027

Authors:

Dorian S Abbot, Aiko Voigt, Dawei Li, Guillaume Le Hir, Raymond T Pierrehumbert, Mark Branson, David Pollard, Daniel DB Koll
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The Monitor Project: Stellar rotation at 13~Myr: I. A photometric monitoring survey of the young open cluster h~Per

(2013)

Authors:

E Moraux, S Artemenko, J Bouvier, J Irwin, M Ibrahimov, T Magakian, K Grankin, E Nikogossian, C Cardoso, S Hodgkin, S Aigrain, TA Movsessian
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Atmospheric composition, irreversible climate change, and mitigation policy.

Chapter in Climate Science for Serving Society Research, Modeling and Prediction Priorities, Springer Science & Business Media (2013) 15

Authors:

S Solomon, RT Pierrehumbert, HD matthews, JS Daniel, P Friedlingstein

Abstract:

This volume offers a comprehensive survey and a close analysis of efforts to develop actionable climate information in support of vital decisions for climate adaptation, risk management and policy.
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The Gemini NICI Planet-Finding Campaign: The Frequency of Giant Planets around Young B and A Stars

ArXiv 1306.1233 (2013)

Authors:

Eric L Nielsen, Michael C Liu, Zahed Wahhaj, Beth A Biller, Thomas L Hayward, Laird M Close, Jared R Males, Andrew J Skemer, Mark Chun, Christ Ftaclas, Silvia HP Alencar, Pawel Artymowicz, Alan Boss, Fraser Clarke, Elisabete de Gouveia Dal Pino, Jane Gregorio-Hetem, Markus Hartung, Shigeru Ida, Marc Kuchner, Douglas NC Lin, I Neill Reid, Evgenya L Shkolnik, Matthias Tecza, Niranjan Thatte, Douglas W Toomey

Abstract:

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_sun) conducted to date and includes the planet hosts beta 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_sun 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.
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