NOAO >   Observing Info >   Approved Programs >   2014A-0527

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Proposal Information for 2014A-0527


PI: Stanimir Metchev, University of Western Ontario, smetchev@uwo.ca
Address: Department of Astronomy, London, Ontario, N6A 3K7, Canada

CoI: Aren Heinze, State University of New York at Stony Brook
CoI: Daniel Apai, University of Arizona (Astronomy)
CoI: Davin Flateau, University of Arizona (Astronomy)
CoI: Mark Marley, NASA Ames Research Center

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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NOAO >   Observing Info >   Approved Programs >   2014A-0527

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