A Young Brown Dwarf Companion to DH Tauri

We present the detection of a young brown dwarf companion, DH Tau B, associated with the classical T Tauri star DH Tau. Near-infrared coronagraphic observations with CIAO on the Subaru Telescope have revealed DH Tau B with H = 15 mag located 23 (330 AU) away from the primary, DH Tau A. Comparing its position with a Hubble Space Telescope archive image, we confirmed that DH Tau A and B share a common proper motion, suggesting that they are physically associated with each other. The near-infrared color of DH Tau B is consistent with those of young stellar objects. The near-infrared spectra of DH Tau B show deep water absorption bands, a strong K I absorption line, and a moderate Na I absorption line. We derived its effective temperature and surface gravity of Teff = 2700-2800 K and log g = 4.0-4.5, respectively, by comparing the observed spectra with synthesized spectra of low-mass objects. The location of DH Tau B on the H-R diagram gives its mass of 30MJ-50MJ.

[1]  B. Jones,et al.  Proper motions of T Tauri variables and other stars associated with the Taurus-Auriga dark clouds. , 1979 .

[2]  Tom Herbst,et al.  The Transitional Pre-Main-Sequence Object DI Tauri: Evidence for a Substellar Companion and Rapid Disk Evolution , 1997 .

[3]  George H. Rieke,et al.  Gravity Indicators in the Near-Infrared Spectra of Brown Dwarfs , 2003, astro-ph/0305147.

[4]  Michael F. Skrutskie,et al.  Circumstellar Material Associated with Solar-Type Pre-Main-Sequence Stars: A Possible Constraint on the Timescale for Planet Building , 1989 .

[5]  Substellar companions and isolated planetary-mass objects from protostellar disc fragmentation , 2003, astro-ph/0310679.

[6]  Matthew Holman,et al.  Long-Term Stability of Planets in Binary Systems , 1996 .

[7]  Austin,et al.  Observational Constraints on the Formation and Evolution of Binary Stars , 2001, astro-ph/0103098.

[8]  Hideki Takami,et al.  Computer Simulations of Stellar-Coronagraph Observations , 1998 .

[9]  Laird M. Close,et al.  Adaptive Optics Imaging of the Orion Trapezium Cluster , 1999 .

[10]  S. Strom,et al.  Are wide pre-main-sequence binaries coeval? , 1994 .

[11]  I. Bonnell,et al.  Fragmentation of Elongated Cylindrical Clouds. V. Dependence of Mass Ratios on Initial Conditions , 1992 .

[12]  Saeko S. Hayashi,et al.  Coronagraph imager with adaptive optics (CIAO): description and first results , 2000, Astronomical Telescopes and Instrumentation.

[13]  M. Tamura,et al.  A two micron polarization survey of T Tauri stars , 1989 .

[14]  Ian S. McLean,et al.  Using Narrowband Photometry to Detect Young Brown Dwarfs in IC 348 , 2003 .

[15]  M. Meyer,et al.  Intrinsic near-infrared excesses of T tauri stars: Understanding the classical T tauri star locus , 1997 .

[16]  M. Tamura,et al.  A Near-Infrared Survey of the Taurus Molecular Cloud: Near-Infrared Luminosity Function , 1996 .

[17]  D. Mouillet,et al.  A giant planet candidate near a young brown dwarf - Direct VLT/NACO observations using IR wavefront sensing , 2004 .

[18]  I. McLean,et al.  Identifying Young Brown Dwarfs Using Gravity-Sensitive Spectral Features , 2003, astro-ph/0309634.

[19]  J. Munn,et al.  The USNO-B Catalog , 2002, astro-ph/0210694.

[20]  S. Kulkarni,et al.  Discovery of a cool brown dwarf , 1995, Nature.

[21]  B. Reipurth,et al.  The Formation of Brown Dwarfs as Ejected Stellar Embryos , 2001, astro-ph/0103019.

[22]  M. Tamura,et al.  A Deep Near-Infrared Survey of the Chamaeleon I Dark Cloud Core , 1999 .

[23]  T. Guillot,et al.  A Nongray Theory of Extrasolar Giant Planets and Brown Dwarfs , 1997, astro-ph/9705201.

[24]  P. H. Hauschildt,et al.  Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458 , 2003 .

[25]  T. Nakajima,et al.  Dust in the Photospheric Environment. II. Effect on the Near-Infrared Spectra of L and T Dwarfs , 2004, astro-ph/0402192.

[26]  Stefano Casertano,et al.  THE PERFORMANCE AND CALIBRATION OF WFPC2 ON THE HUBBLE SPACE TELESCOPE , 1995 .

[27]  Andrea M. Ghez,et al.  A Test of Pre-Main-Sequence Evolutionary Models across the Stellar/Substellar Boundary Based on Spectra of the Young Quadruple GG Tauri , 1999, astro-ph/9902318.

[28]  IPAC,et al.  A Candidate Substellar Companion to CD –33°7795 (TWA 5) , 1999 .

[29]  A Census of the Young Cluster IC 348 , 2003, astro-ph/0304409.

[30]  M. Tamura,et al.  Near-Infrared Coronagraphy of the GG Tauri A Binary System ∗ , 2002 .

[31]  R. J. Terrile,et al.  A Candidate Substellar Companion to HR 7329 , 2000 .

[32]  P. H. Hauschildt,et al.  Infrared Spectra and Spectral Energy Distributions of Late M and L Dwarfs , 2000, astro-ph/0010174.

[33]  B. Oppenheimer,et al.  Infrared Spectrum of the Cool Brown Dwarf Gl 229B , 1995, Science.

[34]  M. Bate.  Predicting the properties of binary stellar systems: the evolution of accreting protobinary systems , 2000, astro-ph/0002143.

[35]  E. Young,et al.  Hubble Space Telescope/NICMOS Imaging Survey of the Ophiuchus (Lynds 1688) Cluster , 2001, astro-ph/0110096.

[36]  F. Allard,et al.  Infrared Spectroscopy of Substellar Objects in Orion , 2001, astro-ph/0105154.

[37]  et al,et al.  Infrared Photometry of Late-M, L, and T Dwarfs , 2001, astro-ph/0108435.

[38]  M. Bessell,et al.  JHKLM PHOTOMETRY: STANDARD SYSTEMS, PASSBANDS, AND INTRINSIC COLORS , 1988 .

[39]  R. Rebolo,et al.  A Methane, Isolated, Planetary-Mass Object in Orion , 2002, astro-ph/0206353.

[40]  M. Tamura,et al.  Investigation of the Physical Properties of Protoplanetary Disks around T Tauri Stars by a 1 Arcsecond Imaging Survey: Evolution and Diversity of the Disks in Their Accretion Stage , 2002 .

[41]  C. Hayashi,et al.  Evolution of Stars of Small Masses in the Pre-Main-Sequence Stages , 1963 .