Discovery of a Very Young Field L Dwarf, 2MASS J01415823-4633574
While following up L dwarf candidates selected photometrically from theTwo Micron All Sky Survey, we uncovered an unusual object designated2MASS J01415823-4633574. Its optical spectrum exhibits very strong bandsof vanadium oxide but abnormally weak absorptions by titanium oxide,potassium, and sodium. Morphologically, such spectroscopiccharacteristics fall intermediate between old field early-L dwarfs[log(g)~5] and very late M giants [log(g)~0], leading us to favor lowgravity as the explanation for the unique spectral signatures of this Ldwarf. Such a low gravity can be explained only if this L dwarf is muchlower in mass than a typical old field L dwarf of similar temperatureand is still contracting to its final radius. These conditions imply avery young age. Further evidence of youth is found in the near-infraredspectrum, including a triangular-shaped H-band continuum, reminiscent ofyoung brown dwarf candidates discovered in the Orion Nebula Cluster.Using the above information along with comparisons to brown dwarfatmospheric and interior models, our current best estimate is that thisL dwarf has an age of 1-50 Myr and a mass of 6-25MJ. Althoughthe lack of a lithium detection (pseudo-equivalent width <1 Å)might appear to contradict other evidence of youth, we suggest thatlithium becomes weaker at lower gravity like all other alkali lines andthus needs to be carefully considered before being used as a diagnosticof age or mass for objects in this regime. The location of 2MASS0141-4633 on the sky coupled with a distance estimate of ~35 pc and theabove age estimate suggests that this object may be a brown dwarf memberof either the 30 Myr old Tucana/Horologium association or the ~12 Myrold β Pic moving group. Distance as determined throughtrigonometric parallax (underway) and a measure of the total spacemotion are needed to test this hypothesis.Some of the data presented herein were obtained at the W. M. KeckObservatory, which is operated as a scientific partnership among theCalifornia Institute of Technology, the University of California, andthe National Aeronautics and Space Administration. The Observatory wasmade possible by the generous financial support of the W. M. KeckFoundation.
|
Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
|
New aperture photometry for 217 galaxies in the Virgo and Fornax clusters.
We present photo electric multi-aperture photometry in UBVRI of 171 and46 galaxies in the Virgo and Fornax clusters, respectively. Many of thegalaxies have not been observed in at least one of these passbandsbefore. We discuss the reduction and transformation into the Cousinsphotometric system as well as the extinction coefficients obtainedbetween 1990 and 1993.
|
Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
|
Secondary standards for H-beta photometry in the Southern Hemisphere (second series).
Not Available
|
Secondary standards for H-beta photometry in the E regions.
Not Available
|
UBV (RI)c standard stars in the E- and F-regions and in the Magellanic Clouds - a revised catalogue.
Not Available
|
Secondary standards for the Stromgren UVBY system
Observations of 158 E region stars have been made in the Stromgrensystem, using the 46-cm reflector at Cape Town. They are mostly brighterthan eighth magnitude and are intended for use as secondary standardsfor the four-color system. The E region relative zero points are definedwith a precision of + or - 0.001 mag, and the internal standard errorsof the colors life between + or - 0.001 and + or - 0.002 mag.
|
Note on the Photometric Properties of Red Dwarfs in the Cousins VRI System
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1981A&AS...46..105T&db_key=AST
|
Photoelectric standards of intermediate brightness in the E-regions. I. UBV photometry.
Not Available
|
Photometric standard stars for the UBV and (RI)KC systems.
Not Available
|
A photoelectric UBV sequence in the region of the wing of the Small Magellanic Cloud
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978A&AS...33..107J&db_key=AST
|
VRI standards in the E regions
Not Available
|
Standard Stars for VRI Photometry with S25 Response Photocathodes [Errata: 1974MNSSA..33....1C]
Not Available
|
Lichtelektrische UBV-Photometrie von Standardsternen und in vier Sternfeldern am Äquator
Not Available
|
Standard magnitudes in the E regions.
Not Available
|
