scholarly journals Determining the Physical Properties of Very-Low-Mass Stars and Brown Dwarfs in the Near-Infrared

2009 ◽  
Author(s):  
Emily L. Rice ◽  
Travis S. Barman ◽  
Ian S. McLean ◽  
L. Prato ◽  
J. Davy Kirkpatrick ◽  
...  
Keyword(s):  
Physical Properties ◽  
Near Infrared ◽  
Brown Dwarfs ◽  
Low Mass Stars ◽  
Low Mass

scholarly journals A LARGE-SCALE OPTICAL-NEAR-INFRARED SURVEY FOR BROWN DWARFS AND VERY LOW MASS STARS IN THE ORION OB1 ASSOCIATION

2008 ◽  
Vol 136 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Juan José Downes ◽  
César Briceño ◽  
Jesús Hernández ◽  
Nuria Calvet ◽  
Lee Hartmann ◽  
...  
Keyword(s):  
Large Scale ◽  
Near Infrared ◽  
Brown Dwarfs ◽  
Low Mass Stars ◽  
Low Mass ◽  
Infrared Survey

scholarly journals Primeval very low-mass stars and brown dwarfs – VI. Population properties of metal-poor degenerate brown dwarfs

2019 ◽  
Vol 486 (1) ◽  
pp. 1260-1282 ◽  
Author(s):  
Z H Zhang (张曾华) ◽  
A J Burgasser ◽  
M C Gálvez-Ortiz ◽  
N Lodieu ◽  
M R Zapatero Osorio ◽  
...  
Keyword(s):  
Transition Zone ◽  
Spectral Type ◽  
Near Infrared ◽  
Brown Dwarfs ◽  
Absolute Magnitude ◽  
Wide Field ◽  
Low Mass Stars ◽  
Low Mass ◽  
Infrared Survey ◽  
K Band

ABSTRACT We presented 15 new T dwarfs that were selected from UKIRT Infrared Deep Sky Survey, Visible and Infrared Survey Telescope for Astronomy , and Wide-field Infrared Survey Explorer surveys, and confirmed with optical to near-infrared spectra obtained with the Very Large Telescope and the Gran Telescopio Canarias. One of these new T dwarfs is mildly metal-poor with slightly suppressed K-band flux. We presented a new X-shooter spectrum of a known benchmark sdT5.5 subdwarf, HIP 73786B. To better understand observational properties of brown dwarfs, we discussed transition zones (mass ranges) with low-rate hydrogen, lithium, and deuterium burning in brown dwarf population. The hydrogen burning transition zone is also the substellar transition zone that separates very low-mass stars, transitional, and degenerate brown dwarfs. Transitional brown dwarfs have been discussed in previous works of the Primeval series. Degenerate brown dwarfs without hydrogen fusion are the majority of brown dwarfs. Metal-poor degenerate brown dwarfs of the Galactic thick disc and halo have become T5+ subdwarfs. We selected 41 T5+ subdwarfs from the literature by their suppressed K-band flux. We studied the spectral-type–colour correlations, spectral-type–absolute magnitude correlations, colour–colour plots, and HR diagrams of T5+ subdwarfs, in comparison to these of L–T dwarfs and L subdwarfs. We discussed the T5+ subdwarf discovery capability of deep sky surveys in the 2020s.

scholarly journals Astrometric orbits of spectral binary brown dwarfs – I. Massive T dwarf companions to 2M1059−21 and 2M0805+48

2020 ◽  
Vol 495 (1) ◽  
pp. 1136-1147 ◽  
Author(s):  
J Sahlmann ◽  
A J Burgasser ◽  
D C Bardalez Gagliuffi ◽  
P F Lazorenko ◽  
D Ségransan ◽  
...  
Keyword(s):  
Orbit Determination ◽  
Binary Systems ◽  
Near Infrared ◽  
Brown Dwarfs ◽  
Mass Measurements ◽  
Low Mass Stars ◽  
Short Period ◽  
First Results ◽  
Low Mass ◽  
Individual Mass

ABSTRACT Near-infrared spectroscopic surveys have uncovered a population of short-period, blended-light spectral binaries composed of low-mass stars and brown dwarfs. These systems are amenable to orbit determination and individual mass measurements via astrometric monitoring. Here, we present first results of a multiyear campaign to obtain high-precision absolute astrometry for spectral binaries using the Gemini-South and Gemini-North GMOS imagers. We measure the complete astrometric orbits for two systems: 2M0805+48 and 2M1059−21. Our astrometric orbit of 2M0805+48 is consistent with its 2-yr radial velocity orbit determined previously and we find a mass of $66^{+5}_{-14} M_\mathrm{Jup}$ for its T5.5 companion. For 2M1059−21, we find a 1.9-yr orbital period and a mass of $67^{+4}_{-5} M_\mathrm{Jup}$ for its T3.5 companion. We demonstrate that sub-milliarcsecond absolute astrometry can be obtained with both GMOS imagers and that this is an efficient avenue for confirming and characterizing ultracool binary systems.

scholarly journals Empirical near-infrared colors for low-mass stars and brown dwarfs in the Orion Nebula Cluster

2012 ◽  
Vol 545 ◽  
pp. A19 ◽  
Author(s):  
G. Scandariato ◽  
N. Da Rio ◽  
M. Robberto ◽  
I. Pagano ◽  
K. Stassun
Keyword(s):  
Near Infrared ◽  
Brown Dwarfs ◽  
Orion Nebula ◽  
Low Mass Stars ◽  
Low Mass

scholarly journals Primeval very low-mass stars and brown dwarfs – II. The most metal-poor substellar object

2017 ◽  
Vol 468 (1) ◽  
pp. 261-271 ◽  
Author(s):  
Z. H. Zhang 张曾华 ◽  
D. Homeier ◽  
D. J. Pinfield ◽  
N. Lodieu ◽  
H. R. A. Jones ◽  
...  
Keyword(s):  
Brown Dwarfs ◽  
Low Mass Stars ◽  
Low Mass
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