LIKELY MEMBERS OF THE β PICTORIS AND AB DORADUS MOVING GROUPS IN THE NORTH

We present first results from follow-up of targets in the northern hemisphere {beta} Pictoris and AB Doradus moving group candidate list of Schlieder et al. We obtained high-resolution, near-infrared spectra of 27 candidate members to measure their radial velocities and confirm consistent group kinematics. We identify 15 candidates with consistent predicted and measured radial velocities, perform analyses of their six-dimensional (UVWXYZ) Galactic kinematics, and compare to known group member distributions. Based on these analyses, we propose that seven {beta} Pic and eight AB Dor candidates are likely new group members. Four of the likely new {beta} Pic stars are binaries, one a double-lined spectroscopic system. Three of the proposed AB Dor stars are binaries. Counting all binary components, we propose 22 likely members of these young, moving groups. The majority of the proposed members are M2 to M5 dwarfs, the earliest being of type K2. We also present preliminary parameters for the two new spectroscopic binaries identified in the data, the proposed {beta} Pic member and a rejected {beta} Pic candidate. Our candidate selection and follow-up has thus far identified more than 40 low-mass, likely members of these two moving groups. These stars provide a new sample of nearby, youngmore » targets for studies of local star formation, disks and exoplanets via direct imaging, and astrophysics in the low-mass regime.« less

[1]  C. A. O. Torres,et al.  Search for associations containing young stars (SACY). I. Sample and searching method , 2006 .

[2]  Brenda C. Matthews,et al.  Discovery of a Large Dust Disk Around the Nearby Star AU Microscopii , 2004, Science.

[3]  A refurbished convergent-point method for finding moving groups in the Hipparcos Catalogue★ , 1999, astro-ph/9903239.

[4]  A. Boccaletti,et al.  A Giant Planet Imaged in the Disk of the Young Star β Pictoris , 2010, Science.

[5]  B. Goldman,et al.  A CATALOG OF ROTATION AND ACTIVITY IN EARLY-M STARS , 2012, 1201.5774.

[6]  B. Zuckerman,et al.  Discovery of 14 Nearby Double Stars , 2001 .

[7]  T. Fleming A New Sample of Nearby M Dwarfs Discovered by ROSAT , 1998 .

[8]  J. Rowe,et al.  A Spectroscopic Survey of a Sample of Active M Dwarfs , 2002, astro-ph/0207412.

[9]  E. Jensen,et al.  A TEST OF PRE-MAIN-SEQUENCE LITHIUM DEPLETION MODELS , 2010, 1001.3670.

[10]  Inseok Song,et al.  THE TUCANA/HOROLOGIUM, COLUMBA, AB DORADUS, AND ARGUS ASSOCIATIONS: NEW MEMBERS AND DUSTY DEBRIS DISKS , 2011, 1104.0284.

[11]  T. Henry,et al.  THE SOLAR NEIGHBORHOOD. XXVI. AP Col: THE CLOSEST (8.4 pc) PRE-MAIN-SEQUENCE STAR , 2011, 1108.5318.

[12]  Terry Jones,et al.  FIRST LIGHT LBT AO IMAGES OF HR 8799 bcde AT 1.6 AND 3.3 μm: NEW DISCREPANCIES BETWEEN YOUNG PLANETS AND OLD BROWN DWARFS , 2012, 1203.2615.

[13]  R. McMahon,et al.  The FIRST Unbiased Survey for Radio Stars , 1999 .

[14]  J. Gizis,et al.  Identification of new M dwarfs in the solar neighborhood , 2006 .

[15]  A. Reiners,et al.  RADIUS-DEPENDENT ANGULAR MOMENTUM EVOLUTION IN LOW-MASS STARS. I , 2011, 1111.7071.

[16]  Bradford A. Smith,et al.  A Circumstellar Disk Around β Pictoris , 1984, Science.

[17]  I. Neill Reid,et al.  IDENTIFYING THE YOUNG LOW-MASS STARS WITHIN 25 PC. I. SPECTROSCOPIC OBSERVATIONS , 2009, 0904.3323.

[18]  Laird M. Close,et al.  THE GEMINI NICI PLANET-FINDING CAMPAIGN: DISCOVERY OF A SUBSTELLAR L DWARF COMPANION TO THE NEARBY YOUNG M DWARF CD−35 2722 , 2011, 1101.2893.

[19]  Markus Janson,et al.  THE ASTRALUX LARGE M-DWARF MULTIPLICITY SURVEY , 2012, 1205.4718.

[20]  E. Weis Photometric Parallaxes for Selected Stars of Color Class M from the NLTT Catalog. III. The Declination Zone + 20 Degrees to +45 Degrees , 1986 .

[21]  Alan T. Tokunaga,et al.  CSHELL: a high spectral resolution 1-5-μm cryogenic echelle spectrograph for the IRTF , 1993, Defense, Security, and Sensing.

[22]  W. Voges,et al.  The Hamburg/RASS Catalogue of optical identifications. Northern high-galactic latitude ROSAT Bright , 2003, astro-ph/0305535.

[23]  J. Schlieder,et al.  COOL YOUNG STARS IN THE NORTHERN HEMISPHERE: β PICTORIS AND AB DORADUS MOVING GROUP CANDIDATES , 2012, 1201.4047.

[24]  C. Johns–Krull,et al.  MAGNETIC FIELD TOPOLOGY IN LOW-MASS STARS: SPECTROPOLARIMETRIC OBSERVATIONS OF M DWARFS , 2009, 0909.2355.

[25]  O. C. Wilson On the Determination of Mass Ratios of Spectroscopic Binaries. , 1941 .

[26]  Michael C. Liu,et al.  SEARCHING FOR YOUNG M DWARFS WITH GALEX , 2010, 1011.2708.

[27]  B. Macintosh,et al.  CLOUDS AND CHEMISTRY IN THE ATMOSPHERE OF EXTRASOLAR PLANET HR8799b , 2011, 1103.3895.

[28]  J. Schlieder,et al.  β PICTORIS AND AB DORADUS MOVING GROUPS: LIKELY NEW LOW-MASS MEMBERS , 2010, 1005.0025.

[29]  Saurav Dhital,et al.  THE SLOAN DIGITAL SKY SURVEY DATA RELEASE 7 SPECTROSCOPIC M DWARF CATALOG. I. DATA , 2011, 1101.1082.

[30]  Ben Zuckerman,et al.  Young Stars Near the Sun , 2004 .

[31]  Michael C. Liu,et al.  Substructure in the Circumstellar Disk Around the Young Star AU Microscopii , 2004, Science.

[32]  Stephen T. Ridgway,et al.  The Phoenix spectrograph at Gemini South , 2003, SPIE Astronomical Telescopes + Instrumentation.

[33]  F. V. Leeuwen Validation of the new Hipparcos reduction , 2007, 0708.1752.

[34]  D. Ehrenreich,et al.  High-resolution imaging of young M-type stars of the solar neighbourhood: probing for companions down to the mass of Jupiter , 2011, 1112.3008.

[35]  Pavel Kroupa The Initial Mass Function of Stars: Evidence for Uniformity in Variable Systems , 2002, Science.

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

[37]  B. Zuckerman,et al.  A NEW METHOD TO IDENTIFY NEARBY, YOUNG, LOW-MASS STARS , 2010, 1010.2493.

[38]  B. Macintosh,et al.  Direct Imaging of Multiple Planets Orbiting the Star HR 8799 , 2008, Science.

[39]  David A. Golimowski,et al.  ERRATUM: “THE LUMINOSITY AND MASS FUNCTIONS OF LOW-MASS STARS IN THE GALACTIC DISK. II. THE FIELD” (2010, AJ, 139, 2679) , 2010, 1004.4002.

[40]  David R. Soderblom,et al.  Calculating Galactic Space Velocities and Their Uncertainties, with an Application to the Ursa Major Group , 1987 .

[41]  D. Fernández,et al.  On the kinematic evolution of young local associations and the Scorpius-Centaurus complex , 2008, 0801.0605.

[42]  M. Simon,et al.  NEARBY YOUNG STARS SELECTED BY PROPER MOTION. I. FOUR NEW MEMBERS OF THE β PICTORIS MOVING GROUP FROM THE TYCHO-2 CATALOG , 2008, 0812.1159.

[43]  A. Szalay,et al.  The On-Orbit Performance of the Galaxy Evolution Explorer , 2004, astro-ph/0411310.

[44]  H. Zinnecker,et al.  The initial mass function 50 years later , 2005 .

[45]  Search for nearby stars among proper motion stars selected by optical-to-infrared photometry - III. Spectroscopic distances of 322 NLTT stars , 2005, astro-ph/0507284.

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

[47]  M. Skrutskie,et al.  The Two Micron All Sky Survey (2MASS) , 2006 .

[48]  A. Boccaletti,et al.  The position of β Pictoris b position relative to the debris disk , 2012, 1202.2578.

[49]  J. Bochanski,et al.  A WIDELY SEPARATED, HIGHLY OCCLUDED COMPANION TO THE NEARBY LOW-MASS T TAURI STAR TWA 30 , 2010, 1008.4340.

[50]  K. Geissler,et al.  Lucky Imaging survey for southern M dwarf binaries , 2010, 1006.2377.

[51]  G. Chabrier,et al.  Effect of episodic accretion on the structure and the lithium depletion of low-mass stars and planet-hosting stars , 2010, 1008.4288.

[52]  S. Hawley,et al.  The Palomar/MSU Nearby Star Spectroscopic Survey. III. Chromospheric Activity, M Dwarf Ages, and the Local Star Formation History , 2002, astro-ph/0203499.

[53]  U. Toronto,et al.  Lithium Depletion of Nearby Young Stellar Associations , 2008, 0808.3584.

[55]  L. Hartmann,et al.  Pre-Main-Sequence Evolution in the Taurus-Auriga Molecular Cloud , 1995 .

[56]  A MOVING CLUSTER DISTANCE TO THE EXOPLANET 2M1207b IN THE TW HYDRAE ASSOCIATION , 2005, astro-ph/0507416.

[57]  Eric Gaidos,et al.  AN ALL-SKY CATALOG OF BRIGHT M DWARFS , 2011, 1108.2719.

[58]  B. Macintosh,et al.  Images of a fourth planet orbiting HR 8799 , 2010, Nature.

[59]  E. Feigelson,et al.  The η Chamaeleontis Cluster: Origin in the Sco-Cen OB Association , 2000 .

[60]  J. Bochanski,et al.  THE ENIGMATIC YOUNG, LOW-MASS VARIABLE TWA 30 , 2010, 1003.3447.

[61]  Caltech,et al.  THE LOWEST-MASS MEMBER OF THE β PICTORIS MOVING GROUP , 2010, 1005.2190.

[62]  D. Jones The kinematics of the Scorpio-Centaurus association and Gould's belt. , 1971 .

[63]  Adam L. Kraus,et al.  PLANETS AROUND LOW-MASS STARS (PALMS). I. A SUBSTELLAR COMPANION TO THE YOUNG M DWARF 1RXS J235133.3+312720 , 2012, 1205.2084.

[64]  R. Rutledge,et al.  XID II: STATISTICAL CROSS-ASSOCIATION OF ROSAT BRIGHT SOURCE CATALOG X-RAY SOURCES WITH 2MASS POINT SOURCE CATALOG NEAR-INFRARED SOURCES , 2009, 0910.3229.