Planetary mass companion to VHS J125601.92-125723.9

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Planetary mass companion to VHS J125601.92-125723.9

Post by Edasich on 6th May 2015, 3:36 am

Discovery of a young planetary mass companion to the nearby M dwarf VHS J125601.92-125723.9

In a search for common proper motion companions using the VISTA Hemisphere Survey and 2MASS catalogs we have identified a very red (J-Ks=2.47 mag) late-L dwarf companion of a previously unrecognized M dwarf VHS J125601.92-125723.9, located at a projected angular separation of 8.06"+/-0.03". From low-resolution optical and near-IR spectroscopy we classified the primary and the companion as an M7.5+/-0.5 and L7+/-1.5, respectively. The primary shows weaker alkali lines than field dwarfs of similar spectral type, but still consistent with either a high-gravity dwarf or a younger object of hundreds of millions of years. The secondary shows spectral features characteristic for low surface gravity objects at ages below several hundred Myr, like the triangular shape of the H-band continuum and alkali lines weaker than in field dwarfs of the same spectral type. The absence of lithium in the atmosphere of the primary and the likely membership to the Local Association allowed us to constrain the age of the system to the range of 150-300 Myr. We report a measurement of the trigonometric parallax pi=78.8+/-6.4 mas, which translates into a distance of 12.7+/-1.0 pc; the pair thus has a projected physical separation of 102+/-9 AU. We derived the Lbol of the components and compared them with theoretical evolutionary models to estimate the masses and effective temperatures. For the primary, we determined log(Lbol/LSun)=-3.14+/-0.10, and a mass of 73 (+20,-15} MJup at the boundary between stars and brown dwarfs and Teff of 2620+/-140 K. For the companion we obtained log(Lbol/LSun)=-5.05+/-0.22 and a mass of 11.2 (+9.7,-1.8 ) MJup placing it near the deuterium-burning mass limit. The effective temperature derived from evolutionary models is 880 (+140,-110) K, about 400-700 K cooler than expected for field late-L dwarfs.
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Re: Planetary mass companion to VHS J125601.92-125723.9

Post by Stalker on 6th May 2015, 6:57 am

VHS is so 1990, why not a netflix planet? Laughing

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Re: Planetary mass companion to VHS J125601.92-125723.9

Post by Edasich on 6th May 2015, 3:00 pm

Stalker wrote:VHS is so 1990, why not a netflix planet? Laughing

Or a Blue-Ray one? Cool Wink
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Re: Planetary mass companion to VHS J125601.92-125723.9

Post by Lazarus on 14th January 2016, 2:39 pm

Update to this one: the spectrophotometric distance is larger than the parallax distance. If the spectrophotometric distance is correct then the companion's mass increases to 35 Jupiter masses.

Stone et al. "Adaptive Optics imaging of VHS 1256-1257: A Low Mass Companion to a Brown Dwarf Binary System"
http://arxiv.org/abs/1601.03377
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Re: Planetary mass companion to VHS J125601.92-125723.9

Post by PlutonianEmpire on 15th January 2016, 8:25 pm

Edasich wrote:
Stalker wrote:VHS is so 1990, why not a netflix planet? Laughing

Or a Blue-Ray one? Cool Wink
Blu-Ray is soooo 2010! I can see it now, the 2020's shall bring... Gamma-Rays! All the power of a hypernova packed into a tiny cube. Perfect for 64k entertainment! Very Happy

And scorched planets too, of course! Laughing

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Re: Planetary mass companion to VHS J125601.92-125723.9

Post by Sirius_Alpha on 20th July 2016, 8:23 pm

Thermal Infrared Imaging and Atmospheric Modeling of VHS J125601.92-125723.9 b: Evidence for Moderately Thick Clouds and Equilibrium Carbon Chemistry in a Hierarchical Triple System
http://arxiv.org/abs/1607.06007

We present and analyze Subaru/IRCS L' and M' images of the nearby M dwarf VHS J125601.92-125723.9 (VHS 1256), which was recently claimed to have a ~11 M_Jup companion (VHS 1256 b) at ~102 au separation. Our AO images partially resolve the central star into a binary, whose components are nearly equal in brightness and separated by 0.106" +/- 0.001". VHS 1256 b occupies nearly the same near-IR color-magnitude diagram position as HR 8799 bcde and has a comparable L' brightness. However, it has a substantially redder H - M' color, implying a relatively brighter M' flux density than for the HR 8799 planets and suggesting that non-equilibrium carbon chemistry may be less significant in VHS 1256 b. We successfully match the entire SED (optical through thermal infrared) for VHS 1256 b to atmospheric models assuming chemical equilibrium, models which failed to reproduce HR 8799 b at 5 microns. Our modeling favors slightly thick clouds in the companion's atmosphere, although perhaps not quite as thick as those favored recently for HR 8799 bcde. We estimate that the system is at least older than 200 Myr and the masses of the stars comprising the central binary are at least 58 M_Jup each. Moreover, we find some of the properties of VHS 1256 are inconsistent with the recent suggestion that it is a member of the AB Dor moving group. Given the possible ranges in distance (12.7 pc vs. 17.1 pc), the lower mass limit for VHS 1256 b ranges from 10.5 - 26.2 M_Jup. Our detection limits rule out companions more massive than VHS 1256 b exterior to 6-8 au, placing significant limits on and providing some evidence against a second, more massive companion that may have scattered the wide-separation companion to its current location. VHS 1256 is most likely a very low mass hierarchical triple system, and could be the third such system in which all components reside in the brown dwarf mass regime.
(emphasis mine)

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Re: Planetary mass companion to VHS J125601.92-125723.9

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