<i>ε</i> Indi B: A new benchmark T dwarf

Scholz, R.‐D.; McCaughrean, M. J.; Lodieu, N.; Kuhlbrodt, B.

doi:10.1051/0004-6361:20021847

Cited by 143 publications

(156 citation statements)

References 37 publications

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“…References. Albert et al (2011) [A11]; Artigau et al (2006) [A06]; Artigau et al (2010) [A10]; [B06]; Bouy et al (2003) [B03]; Burgasser et al (1999) [B99]; Burgasser et al (2000) [B00]; Burgasser et al (2003) [B02]; Burgasser et al (2003) [BK03]; Burgasser et al (2004) [B04]; Burgasser et al (2005) [B05]; Burgasser et al (2006) [BK06]; Burgasser et al (2008) [B08]; Burgasser et al (2010) [BC10]; Burningham et al (2010) [B10]; Chiu et al (2006) [C06]; Dahn et al (2002) [D02]; [D12]; Ellis et al (2005) [E05]; Faherty et al (2012) [F12]; Gelino et al (2002) [G02]; Hawley et al (2002) [H02]; Knapp et al (2004) [K04]; Leggett et al (2000) [L00]; Looper et al (2007) [L07]; Looper et al (2008) [L08]; Reid et al (2008) [R08]; Scholz et al (2003) [S03]; Scholz et al (2003) [S10]; Stumpf et al (2011) [S11]; Smart et al (2013) [S13]; Strauss et al (1999) [S99]; Tinney et al (2003) [T03]; Tinney et al (2005) [T05]; Vrba et al (2004) [V04]. …”

Section: Discussionmentioning

confidence: 99%

The brown dwarf atmosphere monitoring (BAM) project

Wilson

Rajan

Patience

2014

A&A

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Using the SofI instrument on the 3.5 m New Technology Telescope, we have conducted an extensive near-infrared monitoring survey of an unbiased sample of 69 brown dwarfs spanning the L0 to T8 spectral range, with at least one example of each spectral type. Each target was observed for a 2−4 h period in the J s -band, and the median photometric precision of the data is ∼0.7%. A total of 14 brown dwarfs were identified as variables with min-to-max amplitudes ranging from 1.7% to 10.8% over the observed duration. All variables satisfy a statistical significance threshold with a p-value ≤5% based on comparison with a median reference star light curve. Approximately half of the variables show pure sinusoidal amplitude variations similar to 2MASSJ2139+0220, and the remainder show multi-component variability in their light curves similar to SIMPJ0136+0933. It has been suggested that the L-T transition should be a region of a higher degree of variability if patchy clouds are present, and this survey was designed to test the patchy cloud model with photometric monitoring of both the L-T transition and non-transition brown dwarfs. The measured frequency of variables is 13 +10 −4 % across the L7−T4 spectral range, indistinguishable from the frequency of variables of the earlier spectral types (30 +11 −8 %), the later spectral types (13 +10 −4 %), or the combination of all non-transition region brown dwarfs (22 +7 −5 %). The variables are not concentrated in the transition, in a specific colour, or in binary systems. Of the brown dwarfs previously monitored for variability, only ∼60% maintained the state of variability (variable or constant), with the remaining switching states. The 14 variables include 9 newly identified variables that will provide important systems for follow-up multi-wavelength monitoring to further investigate brown dwarf atmosphere physics.

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Section: Discussionmentioning

confidence: 99%

The brown dwarf atmosphere monitoring (BAM) project

Wilson

Rajan

Patience

2014

A&A

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“…The discovery of a distant companion (projected separation ∼1500 AU) to the high proper-motion (∼4.7 arcsec/yr) K4.5V star, ε Indi, was reported by Scholz et al (2003). One of our nearest neighbours, ε Indi A has a well-constrained parallax from HIPPARCOS (Perryman & ESA 1997) as refined by van Leeuwen (2007), putting the system at a distance of A&A 510, A99 (2010) 3.6224 ± 0.0037 pc.…”

Section: Introductionmentioning

confidence: 94%

$\mathsf{\varepsilon}$ Indi Ba, Bb: a detailed study of the nearest known brown dwarfs

King¹,

McCaughrean

Homeier

et al. 2010

A&A

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The discovery of ε Indi Ba, Bb, a binary brown dwarf system very close to the Sun, makes possible a concerted campaign to characterise the physical parameters of two T dwarfs. Recent observations suggest substellar atmospheric and evolutionary models may be inconsistent with observations, but there have been few conclusive tests to date. We therefore aim to characterise these benchmark brown dwarfs to place constraints on such models. We have obtained high angular resolution optical, near-infrared, and thermal-infrared imaging and medium-resolution (up to R ∼ 5000) spectroscopy of ε Indi Ba, Bb with the ESO VLT and present VRIzJHKL M broad-band photometry and 0.63−5.1 μm spectroscopy of the individual components. The photometry and spectroscopy of the two partially blended sources were extracted with a custom algorithm. Furthermore, we use deep AO-imaging to place upper limits on the (model-dependent) mass of any further system members. We derive luminosities of log L/L = −4.699 ± 0.017 and −5.232 ± 0.020 for ε Indi Ba, Bb, respectively, and using the dynamical system mass and COND03 evolutionary models predict a system age of 3.7−4.3 Gyr, in excess of previous estimates and recent predictions from observations of these brown dwarfs. Moreover, the effective temperatures of 1352−1385 K and 976−1011 K predicted from the COND03 evolutionary models, for ε Indi Ba and Bb respectively, are in disagreement with those derived from the comparison of our data with the BT-Settl atmospheric models where we find effective temperatures of 1300−1340 K and 880−940 K, for ε Indi Ba and Bb respectively, with surface gravities of log g = 5.25 and 5.50. Finally, we show that spectroscopically determined effective temperatures and surface gravities for ultra-cool dwarfs can lead to underestimated masses even where precise luminosity constraints are available.

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“…Lane et al 2001;Bouy et al 2003;Siegler et al 2005;Forveille et al 2005;Burgasser & McElwain 2006;Caballero 2007a -see also Bouy et al 2005 andBurgasser et al 2007 for compilations); -"classic" systems in the Solar neighbourhood with late-Mtype companions and q < 0.5, such us V1054 Oph + GJ 643 + vB 8, GX And + GQ And, EQ Peg AB, V1428 Aql + vB 10, and o 2 Eri AC; -field stellar systems with late-M-, L-, and T-type companions and q < 0.5 (e.g. Rebolo et al 1998;Goldman et al 1999;Burgasser et al 2000;Kirkpatrick et al 2001;Gizis et al 2001;Scholz et al 2003;Seifahrt et al 2005). …”

Section: A Comparison Of Binding Energiesmentioning

confidence: 99%

Reaching the boundary between stellar kinematic groups and very wide binaries

Caballero¹

2009

A&A

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Aims. I look for and characterise very wide binaries and multiple systems with projected physical separations larger than s = 0.1 pc, which is generally believed to be a sharp upper limit to the distribution of wide binary semimajor axes. Methods. I investigated in detail 30 Washington double stars with angular separations of ρ > 1000 arcsec. I discarded 23 of them as probably unbound systems based on discordant astrometry, photometry, spectral types, and radial velocities. The remaining seven systems were subject to a comprehensive data compilation and derivation (multi-wavelength photometry, heliocentric distance, multiplicity, age, mass, metallicity, membership in a young kinematic group). Results. Of the seven very wide systems, six have projected physical separations greater than the hypothetical cutoff at s = 0.1 pc and four have separations s > 0.2 pc. Although there are two systems in young kinematic groups (namely HD 136654 and BD+32 2572 in the Hyades Supercluster, and AU Mic and AT Mic AB in the β Pictoris moving group), there is no clear prevalence of young systems (τ < 1 Ga) among these very wide binaries. Finally, I compare the binding energies of the seven systems with those of other weakly bound systems in the field.

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ε Indi B: A new benchmark T dwarf

Cited by 143 publications

References 37 publications

The brown dwarf atmosphere monitoring (BAM) project

The brown dwarf atmosphere monitoring (BAM) project

$\mathsf{\varepsilon}$ Indi Ba, Bb: a detailed study of the nearest known brown dwarfs

Reaching the boundary between stellar kinematic groups and very wide binaries

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