/ 98 10 50 8 v 1 3 0 O ct 1 99 8 Spectroscopy of Brown Dwarf Candidates in the ρ Ophiuchi Molecular Core
نویسندگان
چکیده
We present an analysis of low resolution infrared spectra for 20 brown dwarf candidates in the core of the ρ Ophiuchi molecular cloud. Fifteen of the sources display absorption-line spectra characteristic of late-type stars. By comparing the depths of water vapor absorption bands in our candidate objects with a grid of M dwarf standards, we derive spectral types which are independent of reddening. Optical spectroscopy of one brown dwarf candidate confirms the spectral type derived from the water bands. Combining their spectral types with published near-infrared photometry, effective temperatures and bolometric stellar luminosities are derived enabling us to place our sample on the Hertzsprung-Russell diagram. We compare the positions of the brown dwarf candidates in this diagram with two sets of theoretical models in order
منابع مشابه
ar X iv : a st ro - p h / 98 10 22 3 v 1 1 4 O ct 1 99 8 Properties of the Neutral ISM in NGC 185 and NGC 205
We describe the properties and kinematics of the neutral gas in the two dwarf elliptical galaxies NGC 185 and NGC 205, companions of M31. The kinematics of the HI suggest that an internal origin of the gas (i.e. stellar mass loss) should be considered, at least in the case of NGC 185. The molecular clouds in these dwarf ellipticals are similar to Galactic giant molecular clouds in many ways. Ho...
متن کاملar X iv : a st ro - p h / 98 10 38 7 v 1 2 3 O ct 1 99 8 Discovery of a Very Low - Mass Binary with HST / NICMOS
Received ; accepted accepted by ApJ Letters – 2 – ABSTRACT Hubble Space Telescope NICMOS observations are presented of six brown dwarf candidates in the Pleiades open cluster. One of them, namely CFHT-Pl-18, is clearly resolved as a binary with an angular separation of 0 " .33. The very low density of contaminating background stars in our images and the photometry of the components support that...
متن کاملar X iv : h ep - p h / 98 03 29 2 v 3 2 8 O ct 1 99 8 NATURE OF THE SCALAR a 0 ( 980 ) AND f 0 ( 980 ) - MESONS
It is presented a critical consideration of all unusual properties of the scalar a 0 (980) and f 0 (980)-mesons in the four-quark, two-quark and molecular models. The arguments are adduced that the four-quark model is more preferable. It is discussed the complex of experiments that could finally resolve this issue.
متن کاملar X iv : a st ro - p h / 97 07 23 9 v 1 2 2 Ju l 1 99 7 A New Benchmark Brown Dwarf
We present optical spectroscopy of three brown dwarf candidates identified in the first 1% of the DENIS sky survey. Low resolution spectra from 6430–9150Å show these objects to have similar spectra to the uncertain brown dwarf candidate GD 165B. High resolution spectroscopy shows that one of the objects – DBD 1228-1547 – has a strong 2.3±0.05Å equivalent width absorption line of Li I 6708Å, and...
متن کاملv 1 8 O ct 1 99 8 JLAB - THY - 98 - 35 WM - 98 - 104 CONFINEMENT THROUGH A RELATIVISTIC GENERALIZATION OF THE LINEAR INTERACTION
Generalizing a covariant framework previously developed, it is shown that confinement insures that meson → q + q̄ decay amplitudes vanish when both quarks are on-shell. Regularization of singularities in a covariant linear potential associated with nonzero energy transfers (i.e. q = 0, q 6= 0) is improved.
متن کامل