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Speckle Interferometry of New and Problem Hipparcos Binaries. II. Observations Obtained in 1998-1999 from McDonald Observatory
The Hipparcos satellite made measurements of over 9734 known doublestars, 3406 new double stars, and 11,687 unresolved but possible doublestars. The high angular resolution afforded by speckle interferometrymakes it an efficient means to confirm these systems from the ground,which were first discovered from space. Because of its coverage of adifferent region of angular separation-magnitude difference(ρ-Δm) space, speckle interferometry also holds promise toascertain the duplicity of the unresolved Hipparcos ``problem'' stars.Presented are observations of 116 new Hipparcos double stars and 469Hipparcos ``problem stars,'' as well as 238 measures of other doublestars and 246 other high-quality nondetections. Included in these areobservations of double stars listed in the Tycho-2 Catalogue andpossible grid stars for the Space Interferometry Mission.
| The X-ray view of the central part of IC 1396.
The galactic HII region IC 1396 contains one of the youngest known openstar clusters Trumpler 37, Tr 37. Its very core hosts the multipleO-star system HD 206267, which in many respects is similar to the OrionTrapezium. So far X-ray emission has been observed only from HD 206267with the Einstein observatory. Soft X-ray observations with the ROSATPSPC revealed X-ray emission from an area of 30' radius around thecenter of globule IC 1396A, which was resolved into 85 discrete sources.Some of the emission still remains unresolved. Most of the detectedX-ray sources, except HD 206267, are very weak, which causes themeasured luminosity function to be cut off at log L_x_<30.3(erg/s).X-ray sources are located not only in Tr 37 but are also scatteredaround the molecular globule IC 1396A. From the distribution of sources,their apparently hard spectra, and a steep luminosity function we arguethat this sample contains a large number of previously unknown low-massPMS stars. The X-ray source centered on HD 206267 appeared extendedindicating a multiple source system at the very center of Tr 37. Thetotal X-ray luminosity of the trapezium HD 206267 does compare with theX-ray luminosity of single O-type stars. We set an upper limit oflog(L_x_/L_bol_) to -6.90 and briefly discuss this result in the contextof colliding and eclipsing wind models in early type binaries.
| Kinematical data of two samples of late-type stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1977A&AS...27..267G&db_key=AST
| Determination of size, color indices, and spectral classes of stars in an area centered on R.A.=21h24m, Dec=+58.5deg.
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