Updated astrometry and masses of the LUH 16 brown dwarf binary

Lazorenko, P. F.

doi:10.1051/0004-6361/201833626

Cited by 24 publications

(8 citation statements)

References 22 publications

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“…Our mass of 67 +4 −5 M Jup for the T3.5 2M1059−21B is also significantly higher than its two spectral type equivalents DENIS J2252−1730B (T3.5, 41 ± 4 M Jup ) and 2MASS J1534−2952A (T4.5, 51 ± 5 M Jup ). Sahlmann (2018), andDupuy et al (2019). The curves correspond to isochrones of different ages (0.3, 0.5, 1, 5, and 12 Gyr; Baraffe et al 2015), where we used the spectral type -effective temperature calibrations of Houdebine et al (2019) for M dwarfs and of Stephens et al (2009) for L and T dwarfs to convert theoretically predicted effective temperatures into spectral types.…”

Section: Masses Of T Dwarf Companionsmentioning

confidence: 99%

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

Burgasser

Gagliuffi

Lazorenko

et al. 2020

Monthly Notices of the Royal Astronomical Society

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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.

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Section: Masses Of T Dwarf Companionsmentioning

confidence: 99%

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

Burgasser

Gagliuffi

Lazorenko

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…The mass and radius inferred using two different models for CO (ExoMol using the ".broad" file and HITEMP2019). The astrometric mass is shown in the blue shaded region (Lazorenko & Sahlmann 2018). The dashed lines show the iso-gravity lines.…”

Section: Summary and Limitationmentioning

confidence: 99%

Auto-Differentiable Spectrum Model for High-Dispersion Characterization of Exoplanets and Brown Dwarfs

Kawahara,

Kawashima,

Masuda

et al. 2021

Preprint

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We present an auto-differentiable spectral modeling of exoplanets and brown dwarfs. This model enables a fully Bayesian inference of the high-dispersion data to fit the ab initio line-by-line spectral computation to the observed spectrum by combining it with the Hamiltonian Monte Carlo in recent probabilistic programming languages. An open source code, exojax , developed in this study, was written in Python using the GPU/TPU compatible package for automatic differentiation and accelerated linear algebra, JAX (Bradbury et al. 2018). We validated the model by comparing it with existing opacity calculators and a radiative transfer code and found reasonable agreements of the output. As a demonstration, we analyzed the high-dispersion spectrum of a nearby brown dwarf, Luhman 16 A and found that a model including water, carbon monoxide, and H 2 /He collision induced absorption was well fitted to the observed spectrum (R = 10 5 and 2.28-2.30 µm). As a result, we found that T 0 = 1295 ± 14 K at 1 bar and C/O = 0.62 ± 0.01, which is slightly higher than the solar value. This work demonstrates the potential of full Bayesian analysis of brown dwarfs and exoplanets as observed by high-dispersion spectrographs and also directly-imaged exoplanets as observed by high-dispersion coronagraphy.

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“…Even though it is predicted that the Li I resonance doublet could remain strong down to Teff = 500 K (Burrows et al 2002), this feature has not yet been observed at spectral type later than T3.5±0.5 (this work), and thus we limit our study to objects not later than T3±1.0, corresponding to Teff about 1100 K. The relevant information available in the literature for the sample of seven VLM binaries that meet our criteria, together with that for Sahlmann 2 AB and Reid 1 AB, are summarized in Table 2. Two of the binaries, namely Epsilon Indi Ba,b, and Luhman 16 AB, are the two closest substellar systems to the Sun, they have dynamic mass measurements (Dupuy et al 2019;Lazorenko & Sahlmann 2018), and they have spatially resolved optical spectra of the individual components with sufficient quality to detect the Li I resonance doublet. It is indeed detected in both components of Luhman 16 AB (Faherty et al 2014;Lodieu et al 2015b), but not in the components of Epsilon Indi B (King et al 2010).…”

Section: Lithium In the Individual Components Of Vlm Binaries From Th...mentioning

confidence: 99%

New constraints on the minimum mass for thermonuclear lithium burning in brown dwarfs

Martín,

Lodieu,

del Burgo

2021

Preprint

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The theory of substellar evolution predicts that there is a sharp mass boundary between lithium and non-lithium brown dwarfs, not far below the substellar-mass limit. The imprint of thermonuclear burning is carved on the surface lithium abundance of substellar-mass objects during the first few hundred million years of their evolution, leading to a sharp boundary between lithium and non-lithium brown dwarfs, so-called, the lithium test. The theoretical predictions can be tested by comparing with observations of lithium in the individual components of binaries with dynamical masses measured from orbital motions. New optical spectroscopic observations of the binaries DE-NIS J063001.4−184014AB and DENIS J225210.7−173013AB obtained using the 10.4-m Gran Telescopio de Canarias are reported here. They allow us to re-determine their combined optical spectral types (M9.5 and L6.5, respectively) and to search for the presence of the Li I resonance doublet. The non detection of the Li I feature in the combined spectrum of DENIS J063001.4−184014AB is converted into estimates for the depletion of lithium in the individual components of this binary system. In DENIS J225210.7−173013AB we report the detection of a weak Li I feature which we tentatively ascribe as arising from the contribution of the T3.5-type secondary. Combining our results with data for seven other brown dwarf binaries in the literature treated in a self-consistent way, we confirm that there is indeed a sharp transition in mass for lithium depletion in brown dwarfs, as expected from theoretical calculations. We estimate such mass boundary is observationally located at 51.48 +0.22 −4.00 M Jup , which is lower than the theoretical determinations.

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Updated astrometry and masses of the LUH 16 brown dwarf binary

Cited by 24 publications

References 22 publications

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

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

Auto-Differentiable Spectrum Model for High-Dispersion Characterization of Exoplanets and Brown Dwarfs

New constraints on the minimum mass for thermonuclear lithium burning in brown dwarfs

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