Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published November 10, 2018 | Published + Accepted Version
Journal Article Open

Y Dwarf Trigonometric Parallaxes from the Spitzer Space Telescope

Abstract

Y dwarfs provide a unique opportunity to study free-floating objects with masses <30 M_(Jup) and atmospheric temperatures approaching those of known Jupiter-like exoplanets. Obtaining distances to these objects is an essential step toward characterizing their absolute physical properties. Using Spitzer's Infrared Array Camera (IRAC) [4.5] images taken over baselines of ~2–7 years, we measure astrometric distances for 22 late-T and early Y dwarfs, including updated parallaxes for 18 objects and new parallax measurements for 4 objects. These parallaxes will make it possible to explore the physical parameter space occupied by the coldest brown dwarfs. We also present the discovery of six new late-T dwarfs, updated spectra of two T dwarfs, and the reclassification of a new Y dwarf, WISE J033605.04−014351.0, based on Keck/NIRSPEC J-band spectroscopy. Assuming that effective temperatures are inversely proportional to absolute magnitude, we examine trends in the evolution of the spectral energy distributions of brown dwarfs with decreasing effective temperature. Surprisingly, the Y dwarf class encompasses a large range in absolute magnitude in the near- to mid-infrared photometric bandpasses, demonstrating a larger range of effective temperatures than previously assumed. This sample will be ideal for obtaining mid-infrared spectra with the James Webb Space Telescope because their known distances will make it easier to measure absolute physical properties.

Additional Information

© 2018 The American Astronomical Society. Received 2018 April 17; revised 2018 September 5; accepted 2018 September 6; published 2018 November 5. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This publication makes use of data products from WISE, 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 work has made use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, http://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This research has made use of the NASA/ IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This work is based in part on observations made with the Hale Telescope at Palomar Observatory, which is operated by the California Institute of Technology. R.L.S' research was supported by the 2015 Henri Chrétien International Research Grant administered by the American Astronomical Society. E.C.M. thanks Dr. Gregory Mace for useful discussions, feedback, and mentoring. Facilities: Spitzer(IRAC) - Spitzer Space Telescope satellite, Keck:II(NIRSPEC) - , Palomar(WIRC) - , IRSA. - Software: REDSPEC (http://www2.keck.hawaii.edu/inst/nirspec/redspec.html); Astropy (Astropy Collaboration et al. 2013; The Astropy Collaboration et al. 2018); MOPEX (http://irsa.ipac.caltech.edu/data/SPITZER/docs/dataanalysistools/tools/mopex/); Scipy (http://www.scipy.org/); Numpy (Oliphant 2006); Matplotlib (Hunter 2007). Note added in proof: We also note that in Bedin & Fontanive (2018), they measured a parallax for WISE J154151.65–225024.9 to be 169 ±2 mas, which is consistent with our own value of 167.1 ± 4.2 mas.

Attached Files

Published - Martin_2018_ApJ_867_109.pdf

Accepted Version - 1809.06479.pdf

Files

Martin_2018_ApJ_867_109.pdf
Files (3.9 MB)
Name Size Download all
md5:412c8a34a0e37a139e21ce7018f67d64
2.3 MB Preview Download
md5:b06326b572aeae4b042d1cc2e91d18ef
1.6 MB Preview Download

Additional details

Created:
August 19, 2023
Modified:
October 19, 2023