Young imaged planet/brown dwarf at 2M0122-2439

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Low-mass companion around 2MASS 0122-2439

Post by Edasich on 10th July 2013, 5:53 am

A new super-Jovian planet?

Planets Around Low-Mass Stars (PALMS). III. A Young Dusty L Dwarf Companion at the Deuterium-Burning Limit

We report the discovery of an L-type companion to the young M3.5V star 2MASS J01225093-2439505 at a projected separation of 1.45" (~52 AU) as part of our adaptive optics imaging search for extrasolar giant planets around young low-mass stars. 2MASS 0122-2439 B has very red near-infrared colors similar to the HR 8799 planets and the reddest known young/dusty L dwarfs in the field. Moderate-resolution (R~3800) 1.5-2.4 $\mu$m spectroscopy reveals a near-infrared spectral type of L4-L6 and an angular H-band shape, confirming its cool temperature and young age. The kinematics of 2MASS 0122-2439 AB are marginally consistent with members of the ~120 Myr AB Dor young moving group based on the photometric distance to the primary (36 +/- 4 pc) and our radial velocity measurement of 2MASS 0122-2439 A from Keck/HIRES. We adopt the AB Dor group age for the system, but the high energy emission, lack of Li I $\lambda$6707 absorption, and spectral shape of 2MASS 0122-2439 B suggest a range of ~10-120 Myr is possible. The age and luminosity of 2MASS 0122-2439 B fall in a strip where "hot-start" evolutionary model mass tracks overlap as a result of deuterium burning. The implied mass of 2MASS 0122-2439 B is ~12-13 Mjup or ~22-27 Mjup if it is an AB Dor member, or possibly as low as 11 Mjup if the wider age range is adopted. Evolutionary models predict an effective temperature for 2MASS 0122-2439 B that corresponds to spectral types near the L/T transition (~1300-1500 K) for field objects. However, we find a mid-L near-infrared spectral type, indicating that 2MASS 0122-2439 B represents another case of photospheric dust being retained to cooler temperatures at low surface gravities, as seen in the spectra of young (8-30 Myr) planetary companions.
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Re: Young imaged planet/brown dwarf at 2M0122-2439

Post by Lazarus on 10th July 2013, 6:36 pm

Also has implications for other similar objects which do not have unique mass predictions from evolutionary tracks:

  • 2MASS J01035515 ABb
  • AB Pic b
  • κ And b
  • G196-3 B
  • SDSS 2249+0044 B
  • LP 261-75 B
  • HD 203030 B
  • HN Peg B
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Re: Young imaged planet/brown dwarf at 2M0122-2439

Post by Edasich on 13th July 2013, 2:55 pm

In EPE now:

http://exoplanet.eu/catalog/2m_0122-2439_b/
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Young imaged planet/brown dwarf at 2M0122-2439

Post by Edasich on 29th April 2015, 4:13 am

Early Results from VLT-SPHERE: Long-Slit Spectroscopy of 2MASS 0122-2439B, a Young Companion Near the Deuterium Burning Limit

We present 0.95-1.80 μm spectroscopy of the ∼12-27 MJup companion orbiting the faint (R∼13.6), young (∼120 Myr) M-dwarf 2MASS J01225093--2439505 ("2M0122--2439 B") at 1.5 arcsecond separation (50 AU). Our coronagraphic long-slit spectroscopy was obtained with the new high contrast imaging platform VLT-SPHERE during Science Verification. The unique long-slit capability of SPHERE enables spectral resolution an order of magnitude higher than other extreme AO exoplanet imaging instruments. With a low mass, cool temperature, and very red colors, 2M0122-2439 B occupies a particularly important region of the substellar color-magnitude diagram by bridging the warm directly imaged hot planets with late-M/early-L spectral types (e.g. β Pic b and ROXs 42Bb) and the cooler, dusty objects near the L/T transition (e.g. HR 8799bcde and 2MASS 1207b). We fit BT-Settl atmospheric models to our R≈350 spectrum and find Teff=1600100 K and log(g)=4.50.5 dex. Visual analysis of our 2M0122-2439 B spectrum suggests a spectral type L3-L4, and we resolve shallow J-band alkali lines, confirming its low gravity and youth. Specifically, we use the Allers & Liu (2013) spectral indices to quantitatively measure the strength of the FeH, VO, KI, spectral features, as well as the overall H-band shape. Using these indices, along with the visual spectral type analysis, we classify 2M0122-2439 B as an intermediate gravity (INT-G) object with spectral type L3.71.0.
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Re: Young imaged planet/brown dwarf at 2M0122-2439

Post by Sirius_Alpha on 29th April 2015, 5:37 pm

Merged with the discovery paper's thread.

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Re: Young imaged planet/brown dwarf at 2M0122-2439

Post by Edasich on 30th April 2015, 4:08 am

Sirius_Alpha wrote:Merged with the discovery paper's thread.

Yeah, wise choice.
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Re: Young imaged planet/brown dwarf at 2M0122-2439

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