Meisner, Aaron M. and Leggett, S. K. and Logsdon, Sarah E. and Schneider, Adam C. and Tremblin, Pascal and Phillips, Mark (2023) Exploring the Extremes: Characterizing a New Population of Old and Cold Brown Dwarfs. The Astronomical Journal, 166 (2). p. 57. ISSN 0004-6256
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Abstract
Mapping out the populations of thick disk and halo brown dwarfs is important for understanding the metallicity dependence of low-temperature atmospheres and the substellar mass function. Recently, a new population of cold and metal-poor brown dwarfs has been discovered, with Teff ≲ 1400 K and metallicity ≲−1 dex. This population includes what may be the first known "extreme T-type subdwarfs" and possibly the first Y-type subdwarf, WISEA J153429.75−104303.3. We have conducted a Gemini YJHK/Ks photometric follow-up campaign targeting potentially metal-poor T and Y dwarfs, utilizing the GNIRS and Flamingos-2 instruments. We present 14 near-infrared photometric detections of eight unique targets: six T subdwarf candidates, one moderately metal-poor Y dwarf candidate, and one Y subdwarf candidate. We have obtained the first-ever ground-based detection of the highly anomalous object WISEA J153429.75−104303.3. The F110W − J color of WISEA J153429.75−104303.3 is significantly bluer than that of other late T and Y dwarfs, indicating that WISEA J153429.75−104303.3 has an unusual spectrum in the 0.9–1.4 μm wavelength range which encompasses the J-band peak. Our J-band detection of WISEA J153429.75−104303.3 and corresponding model comparisons suggest a subsolar metallicity and temperature of 400–550 K for this object. JWST spectroscopic follow-up at near-infrared and mid-infrared wavelengths would allow us to better understand the spectral peculiarities of WISEA J153429.75−104303.3, assess its physical properties, and conclusively determine whether or not it is the first Y-type subdwarf.
Item Type: | Article |
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Subjects: | Science Global Plos > Physics and Astronomy |
Depositing User: | Unnamed user with email support@science.globalplos.com |
Date Deposited: | 15 Nov 2023 07:31 |
Last Modified: | 15 Nov 2023 07:31 |
URI: | http://ebooks.manu2sent.com/id/eprint/2116 |