Parallaxes of southern extremely cool objects (PARSEC). II: Spectroscopic follow-up and parallaxes of 52 targets

F. Marocco, A.H. Andrei, R.L. Smart, H.R.A. Jones, D.J. Pinfield, A. C. Day-Jones, J. R. A. Clarke, A. Sozzetti, P.W. Lucas, B. Bucciarelli, J.L. Penna

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)
62 Downloads (Pure)

Abstract

We present near-infrared spectroscopy for 52 ultracool dwarfs, including two newly discovered late-M dwarfs, one new late-M subdwarf candidate, three new L, and four new T dwarfs. We also present parallaxes and proper motions for 21 of them. Four of the targets presented here have previous parallax measurements, while all the others are new values. This allow us to populate further the spectral sequence at early types (L0-L4). Combining the astrometric parameters with the new near-infrared spectroscopy presented here, we are able to investigate further the nature of some of the objects. In particular, we find that the peculiar blue L1 dwarf SDSS J133148.92-011651.4 is a metal-poor object, likely a member of the galactic thick disk. We discover a new M subdwarf candidate, 2MASS J20115649-6201127. We confirm the low-gravity nature of EROS-MP J0032-4405, DENIS-P J035726.9-441730, and 2MASS J22134491-2136079. We present two new metal-poor dwarfs: the L4pec 2MASS J19285196-4356256 and the M7pec SIPS2346-5928. We also determine the effective temperature and bolometric luminosity of the 21 targets with astrometric measurements, and we obtain a new polynomial relation between effective temperature and near-infrared spectral type. The new fit suggests a flattening of the sequence at the transition between M and L spectral types. This could be an effect of dust formation, which causes a more rapid evolution of the spectral features as a function of the effective temperature.

Original languageEnglish
Article number161
Number of pages19
JournalThe Astronomical Journal
Volume146
Issue number6
DOIs
Publication statusPublished - Dec 2013

Keywords

  • brown dwarfs
  • parallaxes
  • proper motions
  • stars: fundamental parameters
  • ALL-SKY SURVEY
  • LOW-MASS STARS
  • PROPER MOTION SURVEY
  • INFRARED SPECTRAL CLASSIFICATION
  • COLOR-MAGNITUDE DIAGRAMS
  • DWARF/T DWARF TRANSITION
  • TW-HYDRAE ASSOCIATION
  • SURVEY-EXPLORER WISE
  • YOUNG BROWN DWARF
  • K-BAND SPECTRA

Fingerprint

Dive into the research topics of 'Parallaxes of southern extremely cool objects (PARSEC). II: Spectroscopic follow-up and parallaxes of 52 targets'. Together they form a unique fingerprint.

Cite this