Failed Stars and Super Planets A Report Based on the January 1998 Workshop on Substellar-Mass Objects (1998) / Chapter Skim
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2 Observational Characterization of Nearby SMOs
2 Observational Characterization of Nearby SMOs
Pages 19-26
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From page 19... ...
are important environments in which to search for brown dwarfs. In young stellar clusters, where even low-mass objects are bright and hence relatively easy to detects eight candidate SMOs leave been discovered.
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From page 20... ...
Sensitive upper limits on molecular species that are present in cool stars but should be condensed out of the observable atmospheres of lower-mass and hence cooler objects is another spectroscopic test of SMOs membership that further emphasizes else need for high sensitivity. The direct detection and analysis of spectra of the most massive SMOs have proceeded sufficiently that many observers are endorsing the creation of an additional letter in the traditional stellar classification sequence of main sequence objects: Or B
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From page 21... ...
This approach yielded what stood for almost a decade as the most intriguing brown dwarf candidate, GD 1 65B, as well as what now stands as the most incontrovertible brown dwarf: Gliese 229B. The former object is unfortunately near tire minimum possible main sequence temperature (1700 K, though this remains uncertain)
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From page 22... ...
In this review I focus on what we can learn from the spectroscopic detection of molecules in these atmospheres and illustrate with examples from Gliese 229 B and the solar system s Jovian planets. The composition of a static planetary atmosphere, with no external perturbation, tencis toward local thermodynamic chemical equilibrium.
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From page 23... ...
COMPARATIVE SPECTROSCOPY OF BROWN DWARFS AND VERY LATE MAIN SEQUENCE STARS Rafael Rebolo Ir~sti~uto de Astrof sica de Can arias To tell a brown dwarf from a very-late-type dwarf star was, until very recently an extremely complex task. To the renowned difficulty of measuring masses witty sufficient precision, one had to add the lack of reliable spectroscopic substelIarity criteria.
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Since there is no reason to believe otherwise, we can assume that the mass function (MF) of a globular cluster extends beyond the hydrogen burning limit, into the brown dwarf domain.
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Hillenbrand University of California, Berkeley Understanding the origin of stellar masses and of the initial mass function remains one of the primary goals in star formation studies. Is the production of a stellar- or substellar-mass object mostly a self-regulating process (i.e., controlled by the interplay of mass accretion and outflow)
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From page 26... ...
witty infrared spectroscopy, this traditionally optical technique has been successfully employed in regions where most of the stellar population is fully embedded in molecular cloud material. We are thus able to determine stellar masses and ages for stars that are obscured by 10 to 50 magnitudes of interstellar and local circumstelIar extinction.
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