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Title: BROWN DWARFS IN YOUNG MOVING GROUPS FROM PAN-STARRS1. I. AB DORADUS

Abstract

Substellar members of young (≲150 Myr) moving groups are valuable benchmarks to empirically define brown dwarf evolution with age and to study the low-mass end of the initial mass function. We have combined Pan-STARRS1 (PS1) proper motions with optical–IR photometry from PS1, Two Micron All Sky Survey (2MASS), and WISE to search for substellar members of the AB Dor Moving Group within ≈50 pc and with spectral types of late M to early L, corresponding to masses down to ≈30 M {sub Jup} at the age of the group (≈125 Myr). Including both photometry and proper motions allows us to better select candidates by excluding field dwarfs whose colors are similar to young AB Dor Moving Group members. Our near-IR spectroscopy has identified six ultracool dwarfs (M6–L4; ≈30–100 M {sub Jup}) with intermediate surface gravities (int-g) as candidate members of the AB Dor Moving Group. We find another two candidate members with spectra showing hints of youth but consistent with field gravities. We also find four field brown dwarfs unassociated with the AB Dor Moving Group, three of which have int-g gravity classification. While signatures of youth are present in the spectra of our ≈125 Myr objects, neither their Jmore » – K nor W 1 – W 2 colors are significantly redder than field dwarfs with the same spectral types, unlike younger ultracool dwarfs. We also determined PS1 parallaxes for eight of our candidates and one previously identified AB Dor Moving Group candidate. Although radial velocities (and parallaxes, for some) are still needed to fully assess membership, these new objects provide valuable insight into the spectral characteristics and evolution of young brown dwarfs.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ;  [1];  [2]
  1. University of Hawaii, Institute of Astronomy, 2860 Woodlawn Drive, Honolulu, HI 96822 (United States)
  2. Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom)
Publication Date:
OSTI Identifier:
22663103
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 821; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BENCHMARKS; CLASSIFICATION; DWARF STARS; EVOLUTION; GRAVITATION; INFRARED SPECTRA; MASS; PHOTOMETRY; PROPER MOTION; RADIAL VELOCITY; STARS; SURFACES

Citation Formats

Aller, Kimberly M., Liu, Michael C., Magnier, Eugene A., Best, William M. J., Kotson, Michael C., Burgett, William S., Chambers, Kenneth C., Hodapp, Klaus W., Flewelling, Heather, Kaiser, Nick, Tonry, John L., Wainscoat, Richard J., Waters, Christopher, and Metcalf, Nigel. BROWN DWARFS IN YOUNG MOVING GROUPS FROM PAN-STARRS1. I. AB DORADUS. United States: N. p., 2016. Web. doi:10.3847/0004-637X/821/2/120.
Aller, Kimberly M., Liu, Michael C., Magnier, Eugene A., Best, William M. J., Kotson, Michael C., Burgett, William S., Chambers, Kenneth C., Hodapp, Klaus W., Flewelling, Heather, Kaiser, Nick, Tonry, John L., Wainscoat, Richard J., Waters, Christopher, & Metcalf, Nigel. BROWN DWARFS IN YOUNG MOVING GROUPS FROM PAN-STARRS1. I. AB DORADUS. United States. doi:10.3847/0004-637X/821/2/120.
Aller, Kimberly M., Liu, Michael C., Magnier, Eugene A., Best, William M. J., Kotson, Michael C., Burgett, William S., Chambers, Kenneth C., Hodapp, Klaus W., Flewelling, Heather, Kaiser, Nick, Tonry, John L., Wainscoat, Richard J., Waters, Christopher, and Metcalf, Nigel. Wed . "BROWN DWARFS IN YOUNG MOVING GROUPS FROM PAN-STARRS1. I. AB DORADUS". United States. doi:10.3847/0004-637X/821/2/120.
@article{osti_22663103,
title = {BROWN DWARFS IN YOUNG MOVING GROUPS FROM PAN-STARRS1. I. AB DORADUS},
author = {Aller, Kimberly M. and Liu, Michael C. and Magnier, Eugene A. and Best, William M. J. and Kotson, Michael C. and Burgett, William S. and Chambers, Kenneth C. and Hodapp, Klaus W. and Flewelling, Heather and Kaiser, Nick and Tonry, John L. and Wainscoat, Richard J. and Waters, Christopher and Metcalf, Nigel},
abstractNote = {Substellar members of young (≲150 Myr) moving groups are valuable benchmarks to empirically define brown dwarf evolution with age and to study the low-mass end of the initial mass function. We have combined Pan-STARRS1 (PS1) proper motions with optical–IR photometry from PS1, Two Micron All Sky Survey (2MASS), and WISE to search for substellar members of the AB Dor Moving Group within ≈50 pc and with spectral types of late M to early L, corresponding to masses down to ≈30 M {sub Jup} at the age of the group (≈125 Myr). Including both photometry and proper motions allows us to better select candidates by excluding field dwarfs whose colors are similar to young AB Dor Moving Group members. Our near-IR spectroscopy has identified six ultracool dwarfs (M6–L4; ≈30–100 M {sub Jup}) with intermediate surface gravities (int-g) as candidate members of the AB Dor Moving Group. We find another two candidate members with spectra showing hints of youth but consistent with field gravities. We also find four field brown dwarfs unassociated with the AB Dor Moving Group, three of which have int-g gravity classification. While signatures of youth are present in the spectra of our ≈125 Myr objects, neither their J – K nor W 1 – W 2 colors are significantly redder than field dwarfs with the same spectral types, unlike younger ultracool dwarfs. We also determined PS1 parallaxes for eight of our candidates and one previously identified AB Dor Moving Group candidate. Although radial velocities (and parallaxes, for some) are still needed to fully assess membership, these new objects provide valuable insight into the spectral characteristics and evolution of young brown dwarfs.},
doi = {10.3847/0004-637X/821/2/120},
journal = {Astrophysical Journal},
number = 2,
volume = 821,
place = {United States},
year = {Wed Apr 20 00:00:00 EDT 2016},
month = {Wed Apr 20 00:00:00 EDT 2016}
}