2MASS J05185995-2828372: Discovery of an Unresolved L/T Binary

Abstract

We present the peculiar near-infrared spectrum of the newly discovered brown dwarf 2MASS J05185995-2828372, identified in the Two Micron All-Sky Survey. Features characteristic of both L and T dwarfs are present, namely strong carbon monoxide absorption in K-band, strong methane absorption in J- and H-bands, and red near-infrared colors. We consider several scenarios that could produce these features and conclude that the object is most likely to be an unresolved L/T binary system. We discuss how the estimated photometric properties of this object are consistent with the observed J-band brightening of brown dwarfs between late-L and early-T dwarfs, making detailed study of this system an important probe of the L/T transition.

arXiv comment4 pages, 4 figures (2 color), accepted to ApJ Letters

References in corpus (18)

• The Sloan Digital Sky Survey: Technical Summary
• Evolutionary models for very-low-mass stars and brown dwarfs with dusty atmospheres
• A Method of Correcting Near-Infrared Spectra for Telluric Absorption
• Astrometry and Photometry for Cool Dwarfs and Brown Dwarfs
• Sixty-seven Additional L Dwarfs Discovered by the Two Micron All Sky Survey (2MASS)
• Towards Spectral Classification of L and T Dwarfs: Infrared and Optical Spectroscopy and Analysis
• The Spectra of T Dwarfs I: Near-Infrared Data and Spectral Classification
• Meeting the Cool New Neighbors V: A 2MASS-Selected Sample of Ultracool Dwarfs
• The 2MASS Wide-Field T Dwarf Search. III. Seven New T Dwarfs and Other Cool Dwarf Discoveries
• Evidence for Cloud Disruption in the L/T Dwarf Transition
• Infrared Parallaxes for Methane T dwarfs
• A search for L dwarf binary systems
• Hubble Space Telescope Observations of Binary Very-Low-Mass Stars and Brown Dwarfs
• The First Substellar Subdwarf? Discovery of a Metal-poor L Dwarf with Halo Kinematics
• Theoretical Spectral Models of T Dwarfs at Short Wavelengths and Their Comparison with Data
• Modeling Intra-Cluster Gas in Triaxial Dark Halos : An Analytical Approach
• Transition from L to T Dwarfs on the Color-Magnitude Diagram
• L Dwarfs Found in Sloan Digital Sky Survey Commissioning Data II. Hobby-Eberly Telescope Observations

Cited by in corpus (75)

• The Hawaii Infrared Parallax Program. I. Ultracool Binaries and the L/T Transition
• A Unified Near Infrared Spectral Classification Scheme for T Dwarfs
• The 0.8-14.5 micron Spectra of Mid-L to Mid-T Dwarfs: Diagnostics of Effective Temperature, Grain Sedimentation, Gas Transport, and Surface Gravity
• Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime
• A Near-Infrared Spectroscopic Study of Young Field Ultracool Dwarfs
• Young L Dwarfs Identified in the Field: A Preliminary Low-Gravity, Optical Spectral Sequence from L0 to L5
• Meeting the Cool Neighbors. IX. The Luminosity Function of M7-L8 Ultracool Dwarfs in the Field
• A Sample of Very Young Field L Dwarfs and Implications for the Brown Dwarf "Lithium Test" at Early Ages
• Discovery of a Very Young Field L Dwarf, 2MASS J01415823-4633574
• Hubble Space Telescope NICMOS Observations of T Dwarfs: Brown Dwarf Multiplicity and New Probes of the L/T Transition
• Strong Brightness Variations Signal Cloudy-to-Clear Transition of Brown Dwarfs
• Binaries and the L Dwarf/T Dwarf Transition
• Subtle Signatures of Multiplicity in Late-type Dwarf Spectra: The Unresolved M8.5 + T5 Binary 2MASS J03202839-0446358
• Discovery of 11 New T Dwarfs in the Two Micron All-Sky Survey, Including a Possible L/T Transition Binary
• SDSS J1534+1615AB: A Novel T Dwarf Binary Found with Keck Laser Guide Star Adaptive Optics and the Potential Role of Binarity in the L/T Transition
• High Precision Dynamical Masses of Very Low Mass Binaries
• VIRAC: The VVV Infrared Astrometric Catalogue
• Clouds, Gravity and Metallicity in Blue L dwarfs: The Case of 2MASS J11263991-5003550
• SpeX Spectroscopy of Unresolved Very Low Mass Binaries. II. Identification of Fourteen Candidate Binaries with Late-M/Early-L and T Dwarf Components
• Photometry and Proper Motions of M, L, and T Dwarfs from the Pan-STARRS1 3$\pi$ Survey
• A Uniform Analysis of 118 Stars with High-Contrast Imaging: Long Period Extrasolar Giant Planets are Rare around Sun-like Stars
• Auroral radio emission from late L and T dwarfs: A new constraint on dynamo theory in the substellar regime
• A Volume-Limited Sample of Ultracool Dwarfs. I. Construction, Space Density, and a Gap in the L/T Transition
• Discovery of the Young L Dwarf WISE J1741102.78-464225.5
• Discovery of a T Dwarf Binary with the Largest Known J-Band Flux Reversal
• Star Formation via the Little Guy: A Bayesian Study of Ultracool Dwarf Imaging Surveys for Companions
• Discovery of an Unusually Red L-type Brown Dwarf
• Two Directly Imaged, Wide-orbit Giant Planets around the Young, Solar Analog TYC 8998-760-1
• Flares in Open Clusters with K2. II. Pleiades, Hyades, Praesepe, Ruprecht 147, and M67
• Multiepoch Radial Velocity Observations of L Dwarfs
• Discovery of a High Proper Motion L Dwarf Binary: 2MASS J15200224-4422419AB
• WISEA J114724.10-204021.3: A Free-Floating Planetary Mass Member of the TW Hya Association
• SDSS J141624.08+134826.7: A Nearby Blue L Dwarf From the Sloan Digital Sky Survey
• A Proper Motion Survey Using the First Sky Pass of NEOWISE-Reactivation Data
• NPARSEC: NTT Parallaxes of Southern Extremely Cool objects. Goals, targets, procedures and first results
• SDSS J042348.57-041403.5AB: A Brown Dwarf Binary Straddling the L/T Transition
• The Ultracool SpeXtroscopic Survey. I. Volume-Limited Spectroscopic Sample and Luminosity Function of M7$-$L5 Ultracool Dwarfs
• SDSS J080531.84+481233.0: An Unresolved L Dwarf/T Dwarf Binary
• Young Galaxy Candidates in the Hubble Frontier Fields - III. MACSJ0717.5+3745
• The sub-stellar birth rate from UKIDSS
• Photometric brown-dwarf classification. II. A homogeneous sample of 1361 L and T dwarfs brighter than J = 17.5 with accurate spectral types
• Exploring the Role of Sub-micron Sized Dust Grains in the Atmospheres of Red L0 - L6 Dwarfs
• Characterization of High Proper Motion Objects from the Wide-field Infrared Survey Explorer
• Discovery of a nearby L-T transition object in the Southern Galactic plane
• WISE J072003.20-084651.2: An Old and Active M9.5 + T5 Spectral Binary 6 pc from the Sun
• A 2MASS/AllWISE Search for Extremely Red L Dwarfs -- The Discovery of Several Likely L Type Members of $\beta$ Pic, AB Dor, Tuc-Hor, Argus, and the Hyades
• Photometric brown-dwarf classification. I. A method to identify and accurately classify large samples of brown dwarfs without spectroscopy
• Discovery of a 66 mas Ultracool Binary with Laser Guide Star Adaptive Optics
• Discovery of a Very Low Mass Triple with Late-M and T Dwarf Components: LP 704-48/SDSS J0006-0852AB
• Hubble Space Telescope Observations of Field Ultracool Dwarfs at High Galactic Latitude
• Discovery of a directly imaged planet to the young solar analog YSES 2
• A Brown Dwarf Census from the SIMP Survey
• Retrieval Study of Brown Dwarfs Across the L-T Sequence
• High-redshift galaxies and low-mass stars
• Discovery of Four High Proper Motion L Dwarfs, Including a 10 pc L Dwarf at the L/T Transition
• High Resolution Imaging of Very Low Mass Spectral Binaries: Three Resolved Systems and Detection of Orbital Motion in an L/T Transition Binary
• Hubble Space Telescope Imaging and Spectral Analysis of Two Brown Dwarf Binaries at the L Dwarf/T Dwarf Transition
• WISEP J180026.60+013453.1: A Nearby Late L Dwarf Near the Galactic Plane
• A Statistical Survey of Peculiar L and T Dwarfs in SDSS, 2MASS, and WISE
• GPI Spectroscopy of the Mass, Age, and Metallicity Benchmark Brown Dwarf HD 4747 B
• The Orbit of the L dwarf + T dwarf Spectral Binary SDSS J080531.84+481233.0
• Parallaxes of southern extremely cool objects III: 118 L \& T dwarfs
• 2MASS J20261584-2943124: An Unresolved L0.5 + T6 Spectral Binary
• Astrometric orbits of spectral binary brown dwarfs I: Massive T dwarf companions to 2M1059$-$21 and 2M0805$+$48
• Disk or Companion: Characterizing Excess Infrared Flux in Seven White Dwarf Systems with Near-Infrared Spectroscopy
• NICMOS Kernel-Phase Interferometry I: Catalogue of Brown Dwarfs Observed in F110W and F170M
• COol Companions ON Ultrawide orbiTS (COCONUTS). III. A Very Red L6 Benchmark Brown Dwarf around a Young M5 Dwarf
• Environment of the submillimeter-bright massive starburst HFLS3 at $z\sim$6.34
• An L+T Spectral Binary with Possible AB Doradus Kinematics
• $L$-band Spectra of Young Brown Dwarfs
• Large Scale Searches for Brown Dwarfs and Free-Floating Planets
• The L dwarf/T dwarf transition: multiplicity, magnetic activity and mineral meteorology across the hydrogen burning limit
• SpeX Spectroscopy of Unresolved Very Low-Mass Binaries. I. Identification of Seventeen Candidate Binaries Straddling the L Dwarf/T Dwarf Transition
• Disentangling the Signatures of Blended-Light Atmospheres in L/T Transition Brown Dwarfs
• Substellar Hyades Candidates from the UKIRT Hemisphere Survey