A TARGETED SEARCH FOR PECULIARLY RED L AND T DWARFS IN SDSS, 2MASS, AND<i>WISE</i>: DISCOVERY OF A POSSIBLE L7 MEMBER OF THE TW HYDRAE ASSOCIATION

Kellogg, Kendra; Metchev, Stanimir; Geißler, K.; Hicks, Shannon; Kirkpatrick, J. Davy; Kurtev, R.

doi:10.1088/0004-6256/150/6/182

Cited by 54 publications

(56 citation statements)

References 75 publications

(104 reference statements)

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“…Considering the low-to-intermediate gravitybased spectral classification, nearly all σ Orionis objects present infrared colors in excess of those of the majority of the known dwarfs of related types, in line with observations of other young L dwarfs in the field (e.g., Chauvin et al 2004;Cruz et al 2009;Kirkpatrick et al 2010;Faherty et al 2012;Liu et al 2013;Schneider et al 2014;Marocco et al 2014b;Gizis et al 2015;Gauza et al 2015;Kellogg et al 2015). This implies that the very red nature of L dwarfs develops early in the evolution of cool, low-mass objects and lasts up to 120-150 Myr for the early-L types.…”

Section: Conclusion and Final Remarkssupporting

confidence: 80%

“…For each spectral subtype, the field sequence has a color dispersion of typically ±0.15-0.25 mag. The 2016), and members of the TW Hydrae (TWA) moving group compiled by Chauvin et al (2004Chauvin et al ( , 2005a, Gagné et al (2015a), Kellogg et al (2015Kellogg et al ( , 2016, and Schneider et al (2016a) also have colors resembling the indices of the σ Orionis L0-L4.5 objects of this paper. Figure 11 shows the location of the σ Orionis, Upper Scorpius and TWA sequences using different symbols.…”

Section: Photometric Colorssupporting

confidence: 51%

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Optical and Near-infrared Spectra of σ Orionis Isolated Planetary-mass Objects

Osorio

Béjar

Ramírez

2017

ApJ

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We have obtained low-resolution optical (0.7-0.98 µm) and near-infrared (1.11-1.34 µm and 0.8-2.5 µm) spectra of twelve isolated planetary-mass candidates (J = 18.2-19.9 mag) of the 3-Myr σ Orionis star cluster with a view to determining the spectroscopic properties of very young, substellar dwarfs and assembling a complete cluster mass function. We have classified our targets by visual comparison with high-and low-gravity standards and by measuring newly defined spectroscopic indices. We derived L0-L4.5 and M9-L2.5 using high-and low-gravity standards, respectively. Our targets reveal clear signposts of youth, thus corroborating their cluster membership and planetary masses (6-13 M Jup ). These observations complete the σ Orionis mass function by spectroscopically confirming the planetary-mass domain to a confidence level of ∼75 percent. The comparison of our spectra with BT-Settl solar metallicity model atmospheres yields a temperature scale of 2350-1800 K and a low surface gravity of log g ≈ 4.0 [cm s−2 ], as would be expected for young planetary-mass objects. We discuss the properties of the cluster least-massive population as a function of spectral type. We have also obtained the first optical spectrum of S Ori 70, a T dwarf in the direction of σ Orionis. Our data provide reference optical and near-infrared spectra of very young L dwarfs and a mass function that may be used as templates for future studies of low-mass substellar objects and exoplanets. The extrapolation of the σ Orionis mass function to the solar neighborhood may indicate that isolated planetarymass objects with temperatures of ∼200-300 K and masses in the interval 6-13-M Jup may be as numerous as very low-mass stars.

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Section: Conclusion and Final Remarkssupporting

confidence: 80%

Section: Photometric Colorssupporting

confidence: 51%

Optical and Near-infrared Spectra of σ Orionis Isolated Planetary-mass Objects

Osorio

Béjar

Ramírez

2017

ApJ

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“…g Possible unresolved T0+T2 binary from Kellogg et al (2015). No peculiarities detected in our spectrum.…”

Section: Discussionmentioning

confidence: 92%

A Brown Dwarf Census From the Simp Survey

Jasmin

Gagné

Artigau

et al. 2016

ApJ

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We have conducted a near-infrared (NIR) proper motion survey, the Sondage Infrarouge de Mouvement Propre, in order to discover field ultracool dwarfs (UCD) in the solar neighborhood. The survey was conducted by imaging ∼ 28% of the sky with the Caméra PAnoramique Proche-InfraRouge both in the southern hemisphere at the Cerro Tololo Inter-American Observatory 1.5 m telescope, and in the northern hemisphere at the Observatoire du Mont-Mégantic 1.6 m telescope and comparing the source positions from these observations with the Two Micron All-Sky Survey Point Source Catalog (2MASS PSC). Additional color criteria were used to further discriminate unwanted astrophysical sources. We present the results of an NIR spectroscopic follow-up of 169 M, L, and T dwarfs. Among the sources discovered are 2 young field brown dwarfs, 6 unusually red M and L dwarfs, 25 unusually blue M and L dwarfs, 2 candidate unresolved L+T binaries, and 24 peculiar UCDs. Additionally, we add 9 L/T transition dwarfs (L6-T4.5) to the already known objects.

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“…We cross-correlated the Sloan Digital Sky Survey (SDSS), 2-Micron All-Sky Survey (2MASS), and Wide-Field Infrared Survey Explorer (WISE) catalogs to seek candidate peculiarly red brown dwarfs based solely on photometric criteria. From the first batch of candidates, presented in Kellogg et al (2015, hereafter Paper 1 or P1), we discovered one of the brightest and least massive free-floating planetary-mass objects known to date, 2MASS J11193254-1137466 (Kellogg et al 2016;TWA 42), which was recently resolved into a planetary-mass binary system where each object is ∼3M Jup (Best et al 2017a). With this new survey, we determine the occurrence rate of various kinds of ultra-cool dwarfs by comparing our sample of peculiar L and T dwarfs to our full sample of ultra-cool dwarfs.…”

Section: Introductionmentioning

confidence: 99%

“…a We indicate in which portion of the survey these objects were identified: P1- Kellogg et al (2015), P2-this work.…”

mentioning

confidence: 99%

A Statistical Survey of Peculiar L and T Dwarfs in SDSS, 2MASS, and WISE

Kellogg

Metchev

Miles-Páez

et al. 2017

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We present the final results from a targeted search for brown dwarfs with unusual near-infrared colors. From a positional cross-match of the Sloan Digital Sky Survey (SDSS), 2-Micron All-Sky Survey (2MASS), and WideField Infrared Survey Explorer (WISE) catalogs, we have identified 144 candidate peculiar L and T dwarfs. Spectroscopy confirms that 20 of the objects are peculiar or are candidate binaries. Of the 420 objects in our full sample 9 are young (200 Myr; 2.1%) and another 8 (1.9%) are unusually red, with no signatures of youth. With a spectroscopic -J K s color of 2.58±0.11mag, one of the new objects, the L6 dwarf 2MASS J03530419 +0418193, is among the reddest field dwarfs currently known and is one of the reddest objects with no signatures of youth known to date. We have also discovered another potentially very-low-gravity object, the L1 dwarf 2MASS J00133470+1109403, and independently identified the young L7 dwarf 2MASS J00440332+0228112, which was first reported by Schneider and collaborators. Our results confirm that signatures of low gravity are no longer discernible in low to moderate resolution spectra of objects older than ∼200 Myr. The 1.9% of unusually red L dwarfs that do not show other signatures of youth could be slightly older, up to ∼400 Myr. In this case a red -J K s color may be more diagnostic of moderate youth than individual spectral features. However, its is also possible that these objects are relatively metal-rich, and thus have enhanced atmospheric dust content.

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A TARGETED SEARCH FOR PECULIARLY RED L AND T DWARFS IN SDSS, 2MASS, ANDWISE: DISCOVERY OF A POSSIBLE L7 MEMBER OF THE TW HYDRAE ASSOCIATION

Cited by 54 publications

References 75 publications

Optical and Near-infrared Spectra of σ Orionis Isolated Planetary-mass Objects

Optical and Near-infrared Spectra of σ Orionis Isolated Planetary-mass Objects

A Brown Dwarf Census From the Simp Survey

A Statistical Survey of Peculiar L and T Dwarfs in SDSS, 2MASS, and WISE

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