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Doppler imaging of stellar surface structure. IX. A high-resolution image of the weak-lined T Tauri star HDE 283572 = V987 Tauri
We present a Doppler image of the T Tauri star HDE 283572 from a set ofhigh-quality spectroscopic line profiles and simultaneous multicolorphotometry from October 1997. Additional photometry throughout theentire observing season was obtained with a robotic telescope and isused to determine the precise photometric period of 1.5495+/-0.0002 daysthat we interpret to be the stellar rotation period. Further relevantastrophysical parameters like mass, luminosity, radius, effectivetemperature, gravity, and elemental abundances are obtained anddiscussed. HDE 283572 shows one of the largest and coolest polar spotsever observed and confirms an earlier map by Joncour et al. fromPic-du-Midi data. We also compare our map with predicted magneticflux-tube distributions from MHD simulations and suggest that the polarspot on HDE 283572 was possibly created by a strong poleward meridionalflow.
| 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.
| A new optical extinction law and distance estimate for the Taurus-Auriga molecular cloud
This paper presents optical spectrophotometry of field stars projectedon the Taurus-Auriga molecular cloud. We derive extinction laws forheavily reddened stars in this sample and show that the reddening lawthrough the dark cloud is nearly identical to the standard law forlambda-lambda(3600-6100) and AV approximately less than 3mag. Our spectroscopic parallaxes suggest a distance of 140 +/- 10 pcfor the northern portion of the cloud and show no compelling evidencefor a substantial variation in distance across the leading edge of thecloud.
| Longterm Photometry of Variables at ESO - Part Two - the Second Data Catalogue 1986-1990
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&AS..102...79S&db_key=AST
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