WISE J163940.83–684738.6: A Y Dwarf Identified by Methane Imaging
Abstract
We have used methane imaging techniques to identify the near-infrared counterpart of the bright Wide-field Infrared Survey Explorer (WISE) source WISE J163940.83–684738.6. The large proper motion of this source (≈3."0 yr^(–1)) has moved it, since its original WISE identification, very close to a much brighter background star—it currently lies within 1farcs5 of the J = 14.90 ± 0.04 star 2MASS 16394085–6847446. Observations in good seeing conditions using methane-sensitive filters in the near-infrared J band with the FourStar instrument on the Magellan 6.5 m Baade telescope, however, have enabled us to detect a near-infrared counterpart. We have defined a photometric system for use with the FourStar J2 and J3 filters, and this photometry indicates strong methane absorption, which unequivocally identifies it as the source of the WISE flux. Using these imaging observations we were then able to steer this object down the slit of the Folded-port Infrared Echellette spectrograph on a night of 0."6 seeing, and so obtain near-infrared spectroscopy confirming a Y0-Y0.5 spectral type. This is in line with the object's near-infrared-to-WISE J3 – W2 color. Preliminary astrometry using both WISE and FourStar data indicates a distance of 5.0 ± 0.5 pc and a substantial tangential velocity of 73 ± 8 km s^(–1). WISE J163940.83–684738.6 is the brightest confirmed Y dwarf in the WISE W2 passband and its distance measurement places it among the lowest luminosity sources detected to date.
Additional Information
© 2012 American Astronomical Society. Received 2012 August 28; accepted 2012 September 19; published 2012 October 17. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. C.G.T. gratefully acknowledges the support of ARC Australian Professorial Fellowship grant DP0774000. Australian access to the Magellan Telescopeswas supported through the National Collaborative Research Infrastructure Strategy of the Australian Federal Government. Travel support for Magellan observing was provided by the Australian Astronomical Observatory. This publication makes use of data products from the Widefield Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This publication also makes use of data products from 2MASS, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This research has made extensive use of the NASA/IPAC Infrared Science Archive (IRSA), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. And finally, this research has benefited from the M, L, and T dwarf compendium housed at DwarfArchives.org, whose server was funded by a NASA Small Research Grant, administered by the American Astronomical Society. We gratefully acknowledge the assistance of Phil Lucas and Ben Burningham who provided a digital copy of their UGPS 0722 spectrum. Facilities: Magellan:Baade (FourStar, FIRE), WISEAttached Files
Published - 0004-637X_759_1_60.pdf
Files
| Name | Size | Download all |
|---|---|---|
|
md5:34996f2e86bb3c874d41b6e6e9f20c15
|
895.9 kB | Preview Download |
Additional details
- Eprint ID
- 36014
- Resolver ID
- CaltechAUTHORS:20121217-122044695
- DP0774000
- Australian Research Council
- NSF
- NASA/JPL/Caltech
- NASA Small Research Grant
- Created
-
2012-12-17Created from EPrint's datestamp field
- Updated
-
2021-11-09Created from EPrint's last_modified field