* Astronomy

Members Login

Post Info

TOPIC: T2.5 Brown Dwarf SIMP J013656.5+093347

Blobrana

L

Posts: 131433

Date: May 5 12:10 2017

SIMP J013656.5+093347	Permalink

Title: SIMP J013656.5+093347 is Likely a Planetary-Mass Object in the Carina-Near Moving Group Author: Jonathan Gagné, Jacqueline K. Faherty, Adam J. Burgasser, Etienne Artigau, Sandie Bouchard, Loïc Albert, David Lafrenière, René Doyon, Daniella C. Bardalez-Gagliuffi We report the discovery that the nearby (~ 6 pc) photometrically variable T2.5 dwarf SIMP~J013656.5+093347 is a likely member of the ~ 200 Myr-old Carina-Near moving group with a probability of > 99.9% based on its full kinematics. Our vsini measurement of 50.9±0.8 km s^-1 combined with the known rotation period inferred from variability measurements provide a lower limit of 1.01±0.02 R_Jup on the radius of SIMP0136+0933, an independent verification that it must be younger than ~ 950 Myr according to evolution models. We estimate a field interloper probability of 0.2% based on the density of field T0-T5 dwarfs. At the age of Carina-Near, SIMP0136+0933 has an estimated mass of 12.7±1.0 M_Jup and is predicted to have burned roughly half of its original deuterium. SIMP0136+0933 is the closest known young moving group member to the Sun, and is one of only a few known young T dwarfs, making it an important benchmark for understanding the atmospheres of young planetary-mass objects. Read more (975kb, PDF) __________________

Blobrana

L

Posts: 131433

Date: Jun 22 12:37 2009

T2.5 Brown Dwarf SIMP J013656.5+093347	Permalink

Title: Photometric Variability of the T2.5 Brown Dwarf SIMP J013656.5+093347; Evidence for Evolving Weather Patterns Authors: Étienne Artigau, Sandie Bouchard, Sandie Bouchard, David Lafrenière We report the discovery of a photometric variability in the bright T2.5 brown dwarf SIMP J013656.5+093347. Continuous J-band photometry has been obtained for several hours on four different nights. The light curves show a periodic modulation with a period of ~2.4 hours, a peak-to-peak amplitude of ~50 mmag and significant night-to-night evolution. We suggest that the light curve modulation is due to the brown dwarf's rotation and that the longer term variations come from surface features evolution and/or differential rotation. We obtained complementary observations over a single night in the J and Ks bands; the object displays correlated photometric variability in both bands, albeit with smaller Ks-band amplitude. The ratio of the Ks and J variability amplitudes puts strong constraints on the physical mechanisms at play. Based on theoretical models of brown dwarf atmospheres, our results suggest that the atmosphere of SIMP0136 is comprised of both grain-free and colder (by ~100 K) grain-bearing cloudy regions. This discovery, and its interpretation, provide a natural explanation of the so-called J-band brightening. Read more (123kb, PDF) __________________

Page 1 of 1 sorted by

Create your own FREE Forum
Report Abuse