NOAO >   Observing Info >   Approved Programs >   2013B-0366

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Proposal Information for 2013B-0366


PI: Stanimir Metchev, Stony Brook University, stanimir.metchev@stonybrook.edu
Address: Physics Department, 100 Nicolls Rd, Stony Brook, NY 11794-3800, USA

CoI: Aren Heinze, Stony Brook University
CoI: Daniel Apai, University of Arizona
CoI: Davin Flateau, University of Arizona
CoI: Mark Marley, NASA Ames

Title: Weather on Other Worlds: Magnetic Fields or Clouds?

Abstract: We propose to obtain optical spectra of L3-T2 dwarfs to search for H(alpha) emission: a tell-tale signature of magnetospheric or coronal activity. All of the sample targets have been observed as part of the Spitzer Cycle 8 Exploration Science program ``Weather on Other Worlds'' in search for cloud-induced photometric variability. With Spitzer's unprecedented photometric precision, we have found that fully half of all L and T dwarfs are variable. However, the existence of inhomogeneous cloud cover is only one of two factors that could produce variability in ultra-cool dwarfs, the other being magnetically-induced hot or cold spots. While the processes that can support stable magnetic fields in the neutral atmospheres of ultra-cool dwarfs are not well established, a very strong positive correlation is known between magnetic activity and H(alpha) emission. Our GMOS spectroscopic observations will be the first to test for a correlation between chromospheric activity and clouds in L and T dwarfs.


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