NOAO >   Observing Info >   Approved Programs >   2012B-0314

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Proposal Information for 2012B-0314


PI: Beth Biller, Max-Planck-Institute for Astronomy, biller@mpia.de
Address: Germany

CoI: Jacqueline Radigan, University of Toronto
CoI: Michael Liu, University of Hawaii
CoI: Zahed Wahhaj, University of Hawaii
CoI: Eric Nielsen, University of Hawaii
CoI: Thomas Hayward, Gemini Observatory
CoI: Laird Close, University of Arizona
CoI: Andrew Skemer, University of Arizona

Title: Weather on Planets: A Search for Photometric Variability in the Young Exoplanets HR 8799bc

Abstract: A number of L/T transition brown dwarfs have displayed photometric variations consistent with patchy surface clouds. The HR 8799 planets have temperatures and spectral characteristics similar to late-L and T type brown dwarfs, with HR 8799c falling particularly close to the L/T transition regime where variability is observed. Thus, we propose for variability monitoring observations for two of the brightest directly imaged exoplanets, HR 8799b and HR 8799c, to determine if they share similar cloud features as the variable LT transition brown dwarfs. Time-resolved photometry of the HR 8799 system will (i)allow us to determine whether clouds are patchy, providing the first visualization tool of an exoplanet atmosphere, (ii)guide future atmospheric modeling efforts for this system, and (iii)test whether a link exists between the common spectral features observed for HR 8799b and the variable brown dwarfs 2M2139 and 2M0758. If variability is detected, we can further (iv)place constraints on the composition and temperature differences between heterogeneous features using NICI's unique 2-channel capability and (v) perhaps determine rotation periods for the planets. NICI is uniquely suited for exploring the time domain for young giant planets as NICI's 2-channel capability provides simultaneous color information, allowing us to characterize the source of any variability. The 0.32'' semi-transparent focal plane mask offers a boost in the detector dynamic range by a factor of 400, necessary to get unsaturated images of the primary and planets simultaneously. Comprised of the core NICI Campaign team and experts on brown dwarf variability, our team is uniquely well placed to conduct these observations.


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NOAO >   Observing Info >   Approved Programs >   2012B-0314

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