PI: S Mark Ammons, Lawrence Livermore National Laboratory, firstname.lastname@example.org
Address: Livermore, CA, 94551-9900 USA
CoI: Eugenio Victor Garcia, Lawrence Livermore National Laboratory
CoI: Christian Marois, Herzberg Institute of Astrophysics
CoI: Bruce McIntosh, Stanford U.
CoI: Quinn Konopacky, University of Toronto
CoI: Benoit Neichel, Laboratoire d'Astrophysique de Marseille
CoI: Dmitry Savransky, Cornell U.
Title: The Best Parallaxes and a Limit on the Giant Planet Occurrence Rate for Nearby T Dwarf Hosts
Abstract: For 2017A, we propose to continue our astrometric monitoring program on ten of twenty T dwarfs currently being monitored with Gemini GeMS, Keck NIRC2's medium camera, and ShaneAO at Lick Observatory over 2014-2016. We selected targets from the WISE sample (Kirkpatrick et al. 2012), the UKIDSS Large Area Survey (Lawrence et al. 2012) and the UKIDSS Galactic Plane Survey (Lucas et al. 2008). Our proposed observations will obtain << 1% trigonometric distances for the entire sample, enabling precision luminosity measurements, and obtain an upper limit on the T-dwarf planet occurrence rate for 0.1-0.3 MJUP planets with periods of 0.3 < P < 3 years. These observations may also reveal several new brown dwarf binary pairs, for which direct (model-free) astrometric measurements of the masses of brown dwarfs can constrain evolutionary models (Saumon et al. 2008, Baraffe et al. 2015) by testing whether they are internally consistent (eg. Dupuy et al. 2015). In combination with prior NIRC2 and ShaneAO epochs, the proposed 2017A observations will complete our survey and enable publication of (1) precise trigonometric distances and proper motions for the 20 T dwarfs and (2) an upper limit on the exoplanet occurrence rate for T dwarf hosts. Our team has submitted an ApJ publication on Luhman 16 AB’s relative orbit and masses derived from GeMS astrometry.
Program Type: Standard/Galactic
Run 1 (2017A): GEM-SQ/GSAOI -- 7hrs band 1 (GS-2017A-Q-31)
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