Near-infrared low-resolution spectroscopy of Pleiades L-type brown dwarfs

Abstract

The fundamental properties of brown dwarfs evolve with age. Models describing the evolution of luminosities and effective temperatures, among other physical parameters, can be empirically constrained using brown dwarfs of various masses in star clusters of well determined age and metallicity. We aim to carry out a spectroscopic and photometric characterization of low-mass brown dwarfs of the ~120 Myr old Pleiades open cluster. We obtained low-resolution near-infrared spectra of the J=17.4-18.8 mag candidate L-type brown dwarfs PLIZ 28 and 35, BRB 17, 21, 23, and 29, which are Pleiades members by photometry and proper motion. We also obtained spectra of the well-known J=15.4-16.1 mag late M-type cluster members PPl 1, Teide 1, and Calar 3. We find that the former six objects have early- to mid-L spectral types and confirm previously reported M-types for the other three objects. The spectra of the L0-type BRB 17 and PLIZ 28 present a triangular H-band continuum shape, indicating that this peculiar spectral feature persists until at least the age of the Pleiades. We add to our sample 36 reported M5-L0-type cluster members, collecting their I_c - and UKIDSS ZYJHK-band photometry. We confirm a possible interleaving of the Pleiades and field L-type sequences in the JHK absolute magnitude versus spectral type diagrams, and quantify marginally redder Pleiades J-K colours, by 0.12+-0.20 mag, possibly related to both reddening and youth. Using field dwarf bolometric correction - and effective temperature - spectral type relations, we obtain the Hertzsprung-Russell diagram of the Pleiades sample. Theoretical models reproduce well the spectral sequence at M5.5-9, but appear to overestimate the luminosity or underestimate the effective temperature at L0-5. For the Pleiades early- to mid L-type brown dwarfs, we estimate theoretical masses to be in the range 0.025-0.035 M_Sol.

11 pages, 7 figures, 4 tables; accepted for publication in A&A; v3: minor corrections

References in corpus (32)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• The WFCAM Science Archive
• The UKIRT Wide Field Camera ZYJHK Photometric System: Calibration from 2MASS
• Young L Dwarfs Identified in the Field: A Preliminary Low-Gravity, Optical Spectral Sequence from L0 to L5
• Direct Imaging and Spectroscopy of a Planetary Mass Candidate Companion to a Young Solar Analog
• A Sample of Very Young Field L Dwarfs and Implications for the Brown Dwarf "Lithium Test" at Early Ages
• Characterizing Young Brown Dwarfs using Low Resolution Near-IR Spectra
• The Disk Population of the Chamaeleon I Star-Forming Region
• The Planetary Mass Companion 2MASS1207-3932 B: Temperature, Mass and Evidence for an Edge-On Disk
• Subtle Signatures of Multiplicity in Late-type Dwarf Spectra: The Unresolved M8.5 + T5 Binary 2MASS J03202839-0446358
• Discovery of Two Nearby, Peculiar L Dwarfs from the 2MASS Proper Motion Survey: Young or Metal-Rich?
• Near and Mid-IR Photometry of the Pleiades, and a New List of Substellar Candidate Members
• Near-infrared cross-dispersed spectroscopy of brown dwarf candidates in the Upper Sco association
• Discovery of a Young Substellar Companion in Chamaeleon
• Finding benchmark brown dwarfs to probe the IMF as a function of time
• Discovery of a wide companion near the deuterium burning mass limit in the Upper Scorpius association
• Direct evidence of a sub-stellar companion around CT Cha
• Discovery of new nearby L and late-M dwarfs at low Galactic latitude from the DENIS database
• New Low-Mass Stars and Brown Dwarfs with Disks in the Chamaeleon I Star-Forming Region
• Discovery of an M9.5 Candidate Brown Dwarf in the TW Hydrae Association - DENIS J124514.1-442907
• The Distances to Open Clusters from Main-Sequence Fitting. IV. Galactic Cepheids, the LMC, and the Local Distance Scale
• Infrared Spectroscopy and Analysis of Brown Dwarf and Planetary Mass Objects in the Orion Nebula Cluster
• An Improbable Solution to the Underluminosity of 2M1207B: A Hot Protoplanet Collision Afterglow
• An accurate distance to 2M1207Ab
• Proper motion L and T dwarf candidate members of the Pleiades
• Pleiades low-mass brown dwarfs: the cluster L dwarf sequence
• Proper motions of field L and T dwarfs
• Spectroscopy of planetary mass brown dwarfs in Orion
• First High-Contrast Science with an Integral Field Spectrograph: the Sub-Stellar Companion to GQ Lup
• L and T dwarfs in the Hyades and Ursa Major moving groups
• HST/NICMOS Observations of NGC 1333: The Ratio of Stars to Sub-Stellar Objects
• Spectroscopy of Young Planetary Mass Candidates with Disks

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