A 2MASS/AllWISE Search for Extremely Red L Dwarfs: The Discovery of Several Likely L Type Members of β Pic, AB Dor, Tuc-Hor, Argus, and the Hyades

Schneider, Adam C.; Windsor, James; Cushing, Michael C.; Kirkpatrick, J. Davy; Shkolnik, Evgenya L.

doi:10.3847/1538-3881/aa6624

Cited by 50 publications

(50 citation statements)

References 78 publications

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“…In addition, very red colours were also believed to be an indication of low surface gravity, because low surface gravity was expected to prevent the settling of the dust in the upper atmosphere. In recent years, several tens of very red L brown dwarfs (Kirkpatrick et al 2006;Stephens et al 2009;Gizis et al 2012;Liu et al 2013;Marocco et al 2014;Filippazzo et al 2015;Faherty et al 2016;Liu et al 2016;Schneider et al 2014Schneider et al , 2017Best et al 2017, among others) have been found in large surveys, such as 2MASS (Two Micron All Sky Survey, Skrutskie et al 2006), SDSS (Sloan Digital Sky Survey, Blanton et al 2017) and PanStarrs (Panoramic Survey Telescope and Rapid Response System, Chambers et al 2016). These very red brown dwarfs were believed to be young; however, some objects did not exhibit clear spectroscopic signposts of low-gravity atmospheres in their spectra, such as, for example, weak alkali lines.…”

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confidence: 99%

Spectral library of age-benchmark low-mass stars and brown dwarfs

Manjavacas

Lodieu

Béjar

et al. 2019

Monthly Notices of the Royal Astronomical Society

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In recent years, some extremely red brown dwarfs have been discovered. They were believed to have a low surface gravity, but many of their spectral characteristics are similar to those of high-surface-gravity brown dwarfs, showing that the spectral characteristics of young brown dwarfs are poorly understood. We aim to test surface-gravity indicators in late-M and early-L brown dwarf spectra using data obtained with the X-shooter spectrograph at the Very Large Telescope. We select a benchmark sample of brown dwarf members of Chamaeleon I (∼2 Myr), Upper Scorpius (5−10 Myr), the Pleiades (132 ± 27 Myr) and Praesepe (590−790 Myr) with well-constrained ages and similar metallicities. We provide a consistent spectral classification of the sample in the optical and in the near-infrared. We measure the equivalent widths of their alkali lines, finding that they have a moderate correlation with age, especially for objects with spectral types M8 and later. We use spectral indices defined in the literature to estimate surface gravity, finding that their gravity assignment is accurate for 75 per cent of our sample. We investigate the correlation between red colour and age, finding that after ∼10 Myr, the colour does not change significantly for our sample with spectral types M6.0–L3.0. In this case, the red colours might be associated with circumstellar discs, ring structures, extinction, or viewing angle. Finally, we calculate the bolometric luminosity, and J and K bolometric corrections for our sample. We find that six objects are overluminous compared with other members of the same association. These objects are flagged as binary candidates by the Gaia survey.

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confidence: 99%

Spectral library of age-benchmark low-mass stars and brown dwarfs

Manjavacas

Lodieu

Béjar

et al. 2019

Monthly Notices of the Royal Astronomical Society

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“…This object was subsequently found to be an approximately equal magnitude binary with a separation of 0 14 (3.6±0.9 au; Best et al 2017). WISEA J114724.10 −204021.3 (hereafter WISEA 1147−2040) was found as part of a larger program focused on finding young, late-type L dwarfs based on their 2MASS and AllWISE colors (Schneider et al , 2017. Both of these objects were found to have spectral types of L7, spectra with clear signs of low surface gravity (i.e., young ages), and kinematic properties consistent with membership in the TW Hya association (Kellogg et al 2015(Kellogg et al , 2016Schneider et al 2016;Gagné et al 2017b).…”

Section: Introductionmentioning

confidence: 99%

Spitzer Light Curves of the Young, Planetary-mass TW Hya Members 2MASS J11193254–1137466AB and WISEA J114724.10–204021.3

Schneider

Hardegree-Ullman

Cushing

et al. 2018

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We present Spitzer Space Telescope time-series photometry at 3.6 and 4.5 μm of 2MASS J11193254−1137466AB and WISEA J114724.10−204021.3, two planetary-mass, late-type (∼L7) brown dwarf members of the ∼10 Myr old TW Hya Association. These observations were taken in order to investigate whether or not a tentative trend of increasing variability amplitude with decreasing surface gravity seen for L3-L5.5 dwarfs extends to later-L spectral types and to explore the angular momentum evolution of low-mass objects. We examine each light curve for variability and find a rotation period of 19.39 −0.035 % at 3.6 μm and 0.453±0.037% at 4.5 μm, which we find is possibly due to the rotation of one component of the binary. Combining our results with 12 other late-type L dwarfs observed with Spitzer from the literature, we find no significant differences between the 3.6 μm amplitudes of low surface gravity and field gravity late-type L brown dwarfs at Spitzer wavelengths, and find tentative evidence (75% confidence) of higher amplitude variability at 4.5 μm for young, late-type Ls. We also find a median rotation period of young brown dwarfs (10-300 Myr) of ∼10 hr, more than twice the value of the median rotation period of field-age brown dwarfs (∼4 hr), a clear signature of brown dwarf rotational evolution.

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“…One of the few methods to precisely constrain the ages of brown dwarfs is to identify those that are members of young stellar associations (e.g., see Zuckerman & Song 2004;Mamajek 2016). Recent efforts have been made to identify such objects at the very low-mass end of the brown dwarf regime, using near-infrared large-area surveys (e.g., Gagné et al 2015b;Aller et al 2016;Schneider et al 2017).…”

Section: Introductionmentioning

confidence: 99%

SIMP J013656.5+093347 Is Likely a Planetary-mass Object in the Carina-Near Moving Group

Gagné

Faherty

Burgasser³

et al. 2017

ApJL

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We report on the discovery that the nearby (∼6 pc) photometrically variable T2.5 dwarf SIMPJ013656.5+093347 is a likely member of the ∼200 Myr old Carina-Near moving group with a probability of >99.9% based on its full kinematics. Our v i sin measurement of 50.9±0.8 km s −1 combined with the known rotation period inferred from variability measurements provide a lower limit of 1.01±0.02 R Jup on the radius of SIMP 0136+0933, an independent verification that it must be younger than ∼950 Myr, according to evolution models. We estimate a field interloper probability of 0.2% based on the density of field T0-T5 dwarfs. At the age of Carina-Near, SIMP 0136+0933 has an estimated mass of 12.7±1.0 M Jup and is predicted to have burned roughly half of its original deuterium. SIMP 0136+0933 is the closest known young moving group member to the Sun and is one of only a few known young T dwarfs, making it an important benchmark for understanding the atmospheres of young planetary-mass objects.

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A 2MASS/AllWISE Search for Extremely Red L Dwarfs: The Discovery of Several Likely L Type Members of β Pic, AB Dor, Tuc-Hor, Argus, and the Hyades

Cited by 50 publications

References 78 publications

Spectral library of age-benchmark low-mass stars and brown dwarfs

Spectral library of age-benchmark low-mass stars and brown dwarfs

Spitzer Light Curves of the Young, Planetary-mass TW Hya Members 2MASS J11193254–1137466AB and WISEA J114724.10–204021.3

SIMP J013656.5+093347 Is Likely a Planetary-mass Object in the Carina-Near Moving Group

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