Trigonometric parallaxes in the TW Hydrae Association
نویسندگان
چکیده
منابع مشابه
Silicate Emission in the TW Hydrae Association
The TW Hydrae Association is the nearest young stellar association. Among its members are HD 98800, HR 4796A, and TW Hydrae itself, the nearest known classical T Tauri star. We have observed these three stars spectroscopically between 3 and 13 μm. In TW Hya the spectrum shows a silicate emission feature that is similar to many other young stars with protostellar disks. The 11.2 μm feature indic...
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Spitzer Space Telescope infrared measurements are presented for 24 members of the TW Hydrae association (TWA). High signal-to-noise 24 μm photometry is presented for all of these stars, including 20 stars that were not detected by IRAS. Among these 20 stars, only a single object, TWA 7, shows excess emission at 24 μm and at the level of only 40% above the star’s photosphere. TWA 7 also exhibits...
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We present optical and infrared photometry of stars near the MBM 12 dark cloud. The optical data indicate that there are about 40 candidate pre–main sequence stars in the same area currently occupied by eight bona–fide PMS stars. Analysis of 2MASS data suggests that 60% of PMS candidates had been detected. Some of these show evidence of optically thick disks. Our study of the 2MASS data also re...
متن کاملA Chandra Observation of a TW Hydrae Association Brown Dwarf
We present Chandra observations of the young brown dwarf 2MASSW J1207334-393254, which is a probable member of the TW Hya association. Although this substellar object has strong Hα emission, it has no detected X Ray flux in a fifty kilosecond ACIS-S observation. We place a conservative upper limit of 1.2× 10 erg/sec on its X-ray luminosity. We compare our M8 target to the similar mass object TW...
متن کاملThe Lutz-Kelker bias in trigonometric parallaxes
The theoretical prediction that trigonometric parallaxes suffer from a statistical effect, has become topical again now that the results of the Hipparcos satellite have become available. This statistical effect, the so-called Lutz-Kelker bias, causes measured parallaxes to be too large. This has the implication that inferred distances, and hence inferred luminosities are too small. Published an...
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ژورنال
عنوان ژورنال: Proceedings of the International Astronomical Union
سال: 2012
ISSN: 1743-9213,1743-9221
DOI: 10.1017/s1743921312021771