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The Age of AB Doradus We have derived a new age estimate for the nearby young star AB Dor andhave investigated the resulting implications for testing theoreticalevolutionary models with the data reported by Close and coworkers forthe low-mass companion AB Dor C. Using color-magnitude diagrams, we findthat the AB Dor moving group is roughly coeval with the Pleiades(τ=100-125 Myr) and is clearly older than IC 2391 (τ=35-50 Myr).In fact, based on a comparison of the kinematics of AB Dor and thePleiades, we suggest that the stars identified by Zuckerman andcoworkers as members of a moving group with AB Dor are remnants of thelarge-scale star-formation event that formed the Pleiades. Using the ageof τ=50+50-20 Myr adopted by Close, theluminosity predicted by the models of Chabrier and Baraffe for AB Dor Cis larger than the value reported by Close but is still within thequoted uncertainties. Meanwhile, the agreement is good when our ageestimate for AB Dor C is adopted. Thus, we find no evidence in the datapresented by Close for AB Dor C to suggest that previous studies usingthe models of Chabrier and Baraffe and bolometric luminosity as the massindicator have significantly underestimated the masses of young low-massstars and brown dwarfs.This publication makes use of data products from the Two Micron All SkySurvey, which is a joint project of the University of Massachusetts andthe Infrared Processing and Analysis Center/California Institute ofTechnology, funded by the National Aeronautics and Space Administrationand the National Science Foundation.
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Takýmyýldýz: | Saat |
Sað Açýklýk: | 03h03m22.78s |
Yükselim: | -48°41'57.6" |
Görünürdeki Parlaklýk: | 9.198 |
özdevim Sað Açýklýk: | 20.4 |
özdevim Yükselim: | 21.2 |
B-T magnitude: | 10.213 |
V-T magnitude: | 9.282 |
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