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Astrophysics in 2005
We bring you, as usual, the Sun and Moon and stars, plus some galaxiesand a new section on astrobiology. Some highlights are short (the newlyidentified class of gamma-ray bursts, and the Deep Impact on Comet9P/Tempel 1), some long (the age of the universe, which will be found tohave the Earth at its center), and a few metonymic, for instance theterm ``down-sizing'' to describe the evolution of star formation rateswith redshift.
| FH Leonis, the first dwarf nova member of a multiple star system?
Aims.Sudden brightenings of HD 96273 or BD+07 2411B were observed withthe HIPPARCOS satellite in 1992, which still require a convincingexplanation. Methods: .A new analysis of all known data of thesetwo stars is given, including additional information on the Balmer lineequivalent widths. Results: .The brightenings can be explained asSU UMa type dwarf nova outbursts, superimposed on the combined light oftwo normal F and G type main sequence stars. Since the hypotheticaldwarf nova turns out to be located at the same distance as HD 96273 andBD+07 2411B, we possibly see here the first case of a cataclysmicvariable as a member of a multiple star system. Questions on history andevolution, as well as possible ways to confirm this interpretation, arebriefly outlined.
| Outbursts on normal stars. FH Leo misclassified as a novalike variable
We present high resolution spectroscopy of the common proper motionsystem FH Leo (components HD 96273 andBD+07 2411B), which has been classified as a novalike variabledue to an outburst observed by Hipparcos, and we present and review theavailable photometry. We show from our spectra that neither star canpossibly be a cataclysmic variable, instead they are perfectly normallate-F and early-G stars. We measured their radial velocities andderived the atmospheric fundamental parameters, abundances of severalelements including Fe, Ni, Cr, Co, V, Sc, Ti, Ca and Mg, and we derivethe age of the system. From our analysis we conclude that the stars doindeed constitute a physical binary. However, the observed outburstcannot be readily explained. We examine several explanations, includingpollution with scattered light from Jupiter, binarity, microlensing,background supernovae, interaction with unseen companions and planetaryengulfment. While no explanation is fully satisfactory, the scatteredlight and star-planet interaction scenarios emerge as the least unlikelyones, and we give suggestions for further study.
| A Catalog and Atlas of Cataclysmic Variables: The Living Edition
The Catalog and Atlas of Cataclysmic Variables (Edition 1: Downes &Shara; Edition 2: Downes, Webbink, & Shara) has been a valuablesource of information for the cataclysmic variable community. However,the goal of having a central location for all objects is slowly beinglost as each new edition is generated. There can also be a long timedelay between new information becoming available on an object and itspublication in the catalog. To eliminate these concerns, as well as tomake the catalog more accessible, we have created a Web site which willcontain a ``living'' edition of the catalog. We have also added orbitalperiod information, as well as finding charts for novae, to thecatalog.
| The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| A preliminary compilation of DS-programme star positions
A catalog is presented of the double-star-program (DS-program) starpositions, listing right ascensions for 930 DSs and declinations for1225 DSs of the program. The positions were compiled from the observedvalues obtained between 1980 and 1987 with the meridian circles of sixUSSR observatories (the Moscow, Kazan', Kiev, Khar'kov, Odessa, andTashkent Observatories) and the Belgrade Observatory. The measurementsand the treatment of the observational material were performed using therelative method, and the FK-4 system stars were used as reference stars.
| Common proper motion stars in the AGK 3
A search was made of common-proper-motion (CPM) systems among AGK 3stars. The selection of physical systems was based upon the ratiobetween the angular separation (rho) and the proper motion (mu); the CPMstars found are presented in two tables. Table I lists systems withrho/mu less than 1000 years. It contains 326 entries, and the proportionof optical pairs is estimated to be 1 percent. Table II lists systemswith rho/mu in the range 1000 to 3500 years; it contains 113 systems,but only 60 percent of them are physical. Nevertheless, these systemsoften have separations larger than 10,000 AU and are the mostinteresting for the study of the tail of the distribution function ofthe semimajor axes.
| Mesures d'etoiles doubles faites a Nice.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1978A&AS...33..275M&db_key=AST
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| Takýmyýldýz: | Aslan |
| Sað Açýklýk: | 11h06m07.42s |
| Yükselim: | +07°02'00.5" |
| Görünürdeki Parlaklýk: | 8.756 |
| Uzaklýk: | 117.371 parsek |
| özdevim Sað Açýklýk: | -14 |
| özdevim Yükselim: | -60.7 |
| B-T magnitude: | 9.237 |
| V-T magnitude: | 8.796 |
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