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Classification of a selected sample of weak T Tauri stars
We studied a sample of 27 T Tauri stars (TTs) showing a weak Hαline, selected from the Pico dos Dias Survey, a search for young stellarobjects. A model to fit the spectral energy distribution is used inorder to reproduce their observed infrared excess and to evaluate theindividual contribution of the circumstellar components (dust discand/or envelope) to the total emitted flux. The objects were separatedinto different categories of young stars, searching for an agreementwith an evolutionary sequence. The classification is based on thestellar characteristics as spectral type; equivalent width of the Li670.8-nm line; optical and X-ray properties; and infrared excess. Weconclude that only 41 per cent of our sample actually correspond to weakTTs, and the remaining objects are mainly classical TTs or youngmain-sequence stars. Most of the stars have a near-infrared indextypical of Class II objects and show an important fraction of theobserved emission (~30 per cent) being generated by the circumstellarmaterial.
| Search for T Tauri Stars Based on the IRAS Point Source Catalog. II.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995AJ....109.2146T&db_key=AST
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
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| Takýmyýldýz: | Avci |
| Sað Açýklýk: | 05h23m12.40s |
| Yükselim: | +00°54'47.7" |
| Görünürdeki Parlaklýk: | 10.195 |
| özdevim Sað Açýklýk: | 3.1 |
| özdevim Yükselim: | 2 |
| B-T magnitude: | 10.858 |
| V-T magnitude: | 10.25 |
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