The kinematics of very low mass dwarfs: Splinter session summary

Burgasser, Adam J.; Faherty, Jacqueline K.; Schmidt, Sarah J.; West, Andrew A.; Osorio, M. R. Zapatero; Pineda, J. Sebastian; Burningham, B.; Nicholls, C. P.; Sanderson, Robyn E.; Shkolnik, Evgenya L.; Rodríguez, David; Riedel, Adric R.; Joergens, V.

doi:10.1002/asna.201211762

Cited by 3 publications

(3 citation statements)

References 44 publications

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“…In the L/T transition the luminosity is almost constant, and despite the sparse population (only 8 objects between L7 and T1) we note a high scatter, with difference of a factor of 3-4 between objects of the same or very near spectral type. This scatter is not unexpected, as the L/T transition is known to be populated by a high fraction of unresolved binaries (Burgasser 2013), and these objects would clearly result as overluminous compared to single dwarfs of the same spectral type.…”

Section: Physical Parametersmentioning

confidence: 90%

Parallaxes of Southern Extremely Cool Objects (Parsec). Ii. Spectroscopic Follow-Up and Parallaxes of 52 Targets

Marocco

Andrei

Smart

et al. 2013

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We present near-infrared spectroscopy for 52 ultracool dwarfs, including two newly discovered late-M dwarfs, one new late-M subdwarf candidate, three new L and four new T dwarfs. We also present parallaxes and proper motions for 21 of them. Four of the targets presented here have previous parallax measurements, while all the others are new values. This allow us to populate further the spectral sequence at early types (L0-L4). Combining the astrometric parameters with the new near-infrared spectroscopy presented here, we are able to investigate further the nature of some of the objects. In particular, we find that the peculiar blue L1 dwarf SDSS J133148.92−011651.4 is a metal-poor object, likely a member of the galactic thick disk. We discover a new M subdwarf candidate, 2MASS J20115649−6201127. We confirm the low-gravity nature of EROS-MP J0032−4405, DENIS-P J035726.9−441730, and 2MASS J22134491−2136079. We present two new metal-poor dwarfs: the L4pec 2MASS J19285196−4356256 and the M7pec SIPS2346−5928. We also determine the effective temperature and bolometric luminosity of the 21 targets with astrometric measurements, and we obtain a new polynomial relation between effective temperature and nearinfrared spectral type. The new fit suggests a flattening of the sequence at the transition between M and L spectral types. This could be an effect of dust formation, that causes a more rapid evolution of the spectral features as a function of the effective temperature.

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Section: Physical Parametersmentioning

confidence: 90%

Parallaxes of Southern Extremely Cool Objects (Parsec). Ii. Spectroscopic Follow-Up and Parallaxes of 52 Targets

Marocco

Andrei

Smart

et al. 2013

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“…We note that after the Smith & Mauerhan communication there has been a proliferation of electronic telegrams on this transient, with different interpretations on its nature -SN vs. SN impostor -(Margutti et al 2012a;Martin et al 2012a;Brimacombe 2012;Margutti et al 2012b;Smith & Mauerhan 2012b;Leonard et al 2012;Burgasser et al 2012;Prieto et al 2012;Martin et al 2012b;Gall et al 2012;Bohlsen 2012;Jha et al 2012), although it seems that that most authors now favor the SN explosion scenario.…”

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confidence: 91%

INTERACTING SUPERNOVAE AND SUPERNOVA IMPOSTORS: SN 2009ip, IS THIS THE END?

Pastorello

Cappellaro

Inserra

et al. 2013

ApJ

227

318

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We report the results of a 3 year-long dedicated monitoring campaign of a restless Luminous Blue Variable (LBV) in NGC 7259. The object, named SN 2009ip, was observed photometrically and spectroscopically in the optical and near-infrared domains. We monitored a number of erupting episodes in the past few years, and increased the density of our observations during eruptive episodes. In this paper we present the full historical data set from 2009-2012 with multi-wavelength dense coverage of the two high luminosity events between August -September 2012. We construct bolometric light curves and measure the total luminosities of these eruptive or explosive events. We label them the 2012a event (lasting ∼ 50 days) with a peak of 3 × 10 41 ergs −1 , and the 2012b event (14 day rise time, still ongoing) with a peak of 8 × 10 42 ergs −1 . The latter event reached an absolute Rband magnitude of about -18, comparable to that of a core-collapse supernova (SN). Our historical monitoring has detected high-velocity spectral features (∼13000 km s −1 ) in September 2011, one year before the current SN-like event. This implies that the detection of such high velocity outflows cannot, conclusively, point to a core-collapse SN origin. We suggest that the initial peak in the 2012a event was unlikely to be due to a faint core-collapse SN. We propose that the high intrinsic luminosity of the latest peak, the variability history of SN 2009ip, and the detection of broad spectral lines indicative of high-velocity ejecta are consistent with a pulsational pair-instability event, and that the star may have survived the last outburst. The question of the survival of the LBV progenitor star and its future fate remain open issues, only to be answered with future monitoring of this historically unique explosion.

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“…For example, consider the the strong J-band brightening that brown dwarfs undergo as they cross the L-to T-dwarf transition. This is widely interpreted as clouds clearing from the atmospheres of the L-dwarfs (Marley et al 2010), though the precise mechanism for this process is not well understood (Burgasser 2013). Direct imaging observations of the HR 8799 planets, which are giant planets at or past the L/T transition, do not show a similar J-band brightening (Faherty et al 2013).…”

Section: Introductionmentioning

confidence: 99%

SPITZERANDz′ SECONDARY ECLIPSE OBSERVATIONS OF THE HIGHLY IRRADIATED TRANSITING BROWN DWARF KELT-1b

Beatty

Collins

Fortney

et al. 2014

ApJ

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We present secondary eclipse observations of the highly irradiated transiting brown dwarf KELT-1b. These observations represent the first constraints on the atmospheric dynamics of a highly irradiated brown dwarf, the atmospheres of irradiated giant planets at high surface gravity, and the atmospheres of brown dwarfs that are dominated by external, rather than internal, energy. Using the Spitzer Space Telescope, we measure secondary eclipse depths of 0.195 ± 0.010% at 3.6µm and 0.200 ± 0.012% at 4.5 µm. We also find tentative evidence for the secondary eclipse in the z ′ band with a depth of 0.049 ± 0.023%. These measured eclipse depths are most consistent with an atmosphere model in which there is a strong substellar hotspot, implying that heat redistribution in the atmosphere of KELT-1b is low. While models with a more mild hotspot or even with dayside heat redistribution are only marginally disfavored, models with complete heat redistribution are strongly ruled out. The eclipse depths also prefer an atmosphere with no TiO inversion layer, although a model with TiO inversion is permitted in the dayside heat redistribution case, and we consider the possibility of a daynight TiO cold trap in this object. For the first time, we compare the IRAC colors of brown dwarfs and hot Jupiters as a function of effective temperature. Importantly, our measurements reveal that KELT-1b has a [3.6] − [4.5] color of 0.07 ± 0.11, identical to that of isolated brown dwarfs of similarly high temperature. In contrast, hot Jupiters generally show redder [3.6] − [4.5] colors of ∼0.4, with a very large range from ∼0 to ∼1. Evidently, despite being more similar to hot Jupiters than to isolated brown dwarfs in terms of external forcing of the atmosphere by stellar insolation, KELT-1b appears to have an atmosphere most like that of other brown dwarfs. This suggests that surface gravity is very important in controlling the atmospheric systems of substellar mass bodies.

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The kinematics of very low mass dwarfs: Splinter session summary

Cited by 3 publications

References 44 publications

Parallaxes of Southern Extremely Cool Objects (Parsec). Ii. Spectroscopic Follow-Up and Parallaxes of 52 Targets

Parallaxes of Southern Extremely Cool Objects (Parsec). Ii. Spectroscopic Follow-Up and Parallaxes of 52 Targets

INTERACTING SUPERNOVAE AND SUPERNOVA IMPOSTORS: SN 2009ip, IS THIS THE END?

SPITZERANDz′ SECONDARY ECLIPSE OBSERVATIONS OF THE HIGHLY IRRADIATED TRANSITING BROWN DWARF KELT-1b

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