High-Precision Radio and Infrared Astrometry of LSPM J1314+1320ab. Ii. Testing Pre-Main-Sequence Models at the Lithium Depletion Boundary With Dynamical Masses

Dupuy, Trent J.; Forbrich, Jan; Rizzuto, Aaron C.; Mann, Andrew W.; Aller, Kimberly M.; Liu, Mengmeng; Kraus, Adam L.; Berger, E.

doi:10.3847/0004-637x/827/1/23

Cited by 42 publications

(32 citation statements)

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“…It was later reported as a young (80.8 ± 2.5 Myr (Dupuy et al 2016)) tight binary, with a distance between the companions of only 2.1 AU (Schlieder et al 2014). The total mass of the system is 184.5 ± 1.6 M J (or 0.176 ± 0.002 M ⊙ ), and the two components have masses of 92.8 ± 0.6 and 91.7 ± 1.0 M J (Dupuy et al 2016). The distance to NLTT 33370 is 17.249 ± 0.013 pc ).…”

Section: Nltt 33370mentioning

confidence: 98%

Modelling the environment around five ultracool dwarfs via the radio domain

Metodieva

Kuznetsov

Antonova

et al. 2016

Mon. Not. R. Astron. Soc.

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We present the results of a series of short radio observations of six ultracool dwarfs made using the upgraded VLA in S (2-4GHz) and C (4-7GHz) bands. LSR J1835+3259 exhibits a 100 percent right-hand circularly polarised burst which shows intense narrowband features with a fast negative frequency drift of about −30 MHz s −1 . They are superimposed on a fainter broadband emission feature with a total duration of about 20 minutes, bandwidth of about 1 GHz, centred at about 3.5 GHz, and a slow positive frequency drift of about 1 MHz s −1 . This makes it the first such event detected below 4 GHz and the first one exhibiting both positive and negative frequency drifts. Polarised radio emission is also seen in 2MASS J00361617+1821104 and NLTT 33370, while LP 349-25 and TVLM 513-46546 have unpolarised emission and BRI B0021-0214 was not detected. We can reproduce the main characteristics of the burst from LSR J1835+3259 using a model describing the magnetic field of the dwarf as a tilted dipole. We also analyse the origins of the quiescent radio emission and estimate the required parameters of the magnetic field and energetic electrons. Although our results are non-unique, we find a set of models which agree well with the observations.

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Section: Nltt 33370mentioning

confidence: 98%

Modelling the environment around five ultracool dwarfs via the radio domain

Metodieva

Kuznetsov

Antonova

et al. 2016

Mon. Not. R. Astron. Soc.

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“…These VLBA observations, combined with Keck adaptive optics near-infrared camera (NIRC2) astrometry and near-infrared optical spectroscopy, permitted Dupuy et al (2016) to measure the component masses as 92.8 ± 0.6 M J and 91.7 ± 1.0 M J , with T ef f of 2950 ± 5 K and 2770 ± 100 K, respectively.…”

Section: Target Selection and Observationsmentioning

confidence: 99%

THE SECOND ARECIBO SEARCH FOR 5 GHz RADIO FLARES FROM ULTRACOOL DWARFS

Route

Wolszczan

2016

ApJ

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We describe our second installment of the 4.75 GHz survey of ultracool dwarfs (UCDs) conducted with the Arecibo radio telescope, which has observed 27 such objects and resulted in the detection of sporadic flaring from the T6 dwarf, WISEPC J112254.73+255021.5. We also present follow up observations of the first radio-emitting T dwarf, 2MASS J10475385+2124234, a tentatively identified radio emitting L1 dwarf, 2MASS J1439284+192915, and the known radio-flaring source, 2MASS J13142039+132011 AB. Our new data indicate that 2MASS J1439284+192915 is not a radio flaring source. The overall detection rate of our unbiased survey for radio-flaring UCDs is ∼5% for new sources, with a detection rate for each spectral class of ∼5-10%. Evidently, radio luminosity of the UCDs does not appear to monotonically decline with spectral type from M7 dwarfs to giant planets, in contradiction to theories of the magnetic field generation and internal structure of these objects. Along with other, recently published results, our data exemplify the unique value of using radio surveys to reveal and study properties of substellar magnetic activity.

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“…Gravity classifications are lacking for the individual components, so this object is not included in our work here. A detailed analysis of this system, including its component dynamical masses, is in Dupuy et al (2016a). SIPS J2045−6332 (M9/L1; Schmidt et al 2007;Marocco et al 2013) has a parallax from Dieterich et al (2014), but the only published youth signatures are a triangular H-band spectrum from Marocco et al (2013) and lithium from Gálvez-Ortiz et al (2014).…”

Section: Objects Not Included In Our Analysismentioning

confidence: 99%

The Hawaii Infrared Parallax Program. Ii. Young Ultracool Field Dwarfs* †

Liu

Dupuy

Allers

2016

ApJ

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320

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We present a large, uniform analysis of young (≈10-150 Myr) ultracool dwarfs, based on new high-precision infrared (IR) parallaxes for 68 objects. We find that low-gravity (vl-g) late-M and L dwarfs form a continuous sequence in IR color-magnitude diagrams, separate from the field population and from current theoretical models. These vl-g objects also appear distinct from young substellar (brown dwarf and exoplanet) companions, suggesting the two populations may have a different range of physical properties. In contrast, at the L/T transition, young, old, and spectrally peculiar objects all span a relatively narrow range in near-IR absolute magnitudes. At a given spectral type, the IR absolute magnitudes of young objects can be offset from ordinary field dwarfs, with the largest offsets occurring in the Y and J bands for late-M dwarfs (brighter than the field) and mid/late-L dwarfs (fainter than the field). Overall, low-gravity (vl-g) objects have the most uniform photometric behavior while intermediate-gravity (int-g) objects are more diverse, suggesting a third governing parameter beyond spectral type 1 This work is largely based on observations obtained with WIRCam, a joint project of CFHT, Taiwan, Korea, Canada, France, and the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii.2 Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. -2 -and gravity class. We examine the moving group membership for all young ultracool dwarfs with parallaxes, changing the status of 23 objects (including 8 previously identified planetary-mass candidates) and fortifying the status of another 28 objects. We use our resulting age-calibrated sample to establish empirical young isochrones and show a declining frequency of vl-g objects relative to int-g objects with increasing age. Notable individual objects in our sample include high-velocity ( 100 km s −1 ) int-g objects; very red late-L dwarfs with high surface gravities; candidate disk-bearing members of the MBM20 cloud and β Pic moving group; and very young distant interlopers. Finally, we provide a comprehensive summary of the absolute magnitudes and spectral classifications of young ultracool dwarfs, using a combined sample of 102 objects found in the field and as substellar companions to young stars.Subject headings: brown dwarfs -proper motions -parallaxes -solar neighborhood IntroductionObservational studies of brown dwarfs have been inspired by two complementary perspectives. One has been the desire to expand the parameter space of classical stellar astrophysics. Brown dwarfs are t...

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High-Precision Radio and Infrared Astrometry of LSPM J1314+1320ab. Ii. Testing Pre-Main-Sequence Models at the Lithium Depletion Boundary With Dynamical Masses

Cited by 42 publications

References 87 publications

Modelling the environment around five ultracool dwarfs via the radio domain

Modelling the environment around five ultracool dwarfs via the radio domain

THE SECOND ARECIBO SEARCH FOR 5 GHz RADIO FLARES FROM ULTRACOOL DWARFS

The Hawaii Infrared Parallax Program. Ii. Young Ultracool Field Dwarfs* †

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