J/ApJ/664/1154 Light curve of 2MASS J05352184-0546085 (Stassun+, 2007)
A surprising reversal of temperatures in the brown dwarf eclipsing binary
2MASS J05352184-0546085.
Stassun K.G., Mathieu R.D., Valenti J.A.
<Astrophys. J., 664, 1154-1166 (2007)>
=2007ApJ...664.1154S 2007ApJ...664.1154S
ADC_Keywords: Binaries, eclipsing ; Photometry, infrared
Keywords: binaries: eclipsing - stars: formation -
stars: fundamental parameters - stars: low-mass, brown dwarfs -
stars: individual (2MASS J05352184-0546085)
Abstract:
The newly discovered brown dwarf eclipsing binary 2MASS
J05352184-0546085 provides a unique laboratory for testing the
predictions of theoretical models of brown dwarf formation and
evolution. The finding that the lower mass brown dwarf in this system
is hotter than its higher mass companion represents a challenge to
brown dwarf evolutionary models, none of which predict this behavior.
Here we present updated determinations of the basic physical
properties of 2M0535-05, bolstering the surprising reversal of
temperatures with mass in this system. We compare these measurements
with widely used brown dwarf evolutionary tracks, and find that the
temperature reversal can be explained by some models if the components
of 2M0535-05 are mildly non-coeval, possibly consistent with dynamical
simulations of brown dwarf formation. Alternatively, a strong magnetic
field on the higher mass brown dwarf might explain its anomalously low
surface temperature, consistent with emerging evidence that convection
is suppressed in magnetically active, low-mass stars. Finally, we
discuss future observational and theoretical work needed to further
characterize and understand this benchmark system.
Description:
We observed 2M0535-05 with the Phoenix spectrograph on Gemini South
on eight separate nights from 2002 December to 2003 January (first
reported in Paper I, Stassun et al., 2006Natur.440..311S 2006Natur.440..311S) and again
on 2005 March 3 (newly reported here).
Objects:
-----------------------------------------------------------
RA (2000) DE Designation(s)
-----------------------------------------------------------
05 35 21.8 -05 46 09 2M0535-05 = 2MASS J05352184-0546085
-----------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table4.dat 29 2404 Differential IC-band light curve of 2M0535-05
--------------------------------------------------------------------------------
See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 F13.5 d HJD Heliocentric Julian Date
15- 20 F6.3 mag DIcmag Differential Cousins I magnitude (1)
22- 26 F5.3 mag e_DIcmag The 1σ error in DIcmag
28- 29 I2 --- Obs Observation code (2)
--------------------------------------------------------------------------------
Note (1): Arbitrary zero-point.
Note (2): Observation code as follows:
------------------------------------------------
Telescope HJD range Nobs
------------------------------------------------
1 = KPNO 0.9-m 2449699.70 - 2449703.93 40
2 = WISE 1.0-m 2449698.35 - 2449714.42 47
3 = WIYN 0.9-m 2452227.78 - 2452238.01 102
4 = WIYN 0.9-m 2452595.75 - 2452624.95 144
5 = SMARTS 0.9-m 2452622.57 - 2452631.51 122
6 = SMARTS 1.3-m 2452922.73 - 2453081.57 347
7 = SMARTS 0.9-m 2453011.57 - 2453024.77 205
8 = SMARTS 1.3-m 2453280.74 - 2453340.73 230
9 = SMARTS 1.0-m 2453373.56 - 2453386.79 184
10 = SMARTS 1.3-m 2453403.53 - 2453445.60 338
11 = SMARTS 1.3-m 2453646.82 - 2453727.69 204
12 = SMARTS 1.0-m 2453719.59 - 2453727.83 190
13 = SMARTS 1.3-m 2453745.64 - 2453846.48 251
------------------------------------------------
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Stassun et al., Paper I 2006Natur.440..311S 2006Natur.440..311S
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 05-Sep-2009