Radio star catalogue observed in San Juan (RSSJ95)
Using the data observed in San Juan with the photoelectric AstrolabeMark II of the Beijing Astronomical Observatory from February, 1992 toMarch, 1997, the radio star catalogue in San Juan(RSSJ95) has beencompiled. There are 69 radio stars in this catalogue. The positions ofthe radio stars are for the epoch of observation and the equinox J2000.0and a system close to that of the system FK5. The mean precisions are+/-2.2 ms and +/-0.035'' in right ascensions and declinations,respectively. The magnitudes of stars are from 0.9 to 10.7. Thedeclinations are from -2fdg 5 to -60(deg) . The mean epoch is 1995.1.Finally, the comparison results between the Hipparcos catalogue andRSSJ95 are given.
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San Juan radio star catalogue and comparison with HIPPARCOS catalogue.
Not Available
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Radio continuum emission from stars: a catalogue update.
An updated version of my catalogue of radio stars is presented. Somestatistics and availability are discussed.
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Lithium in Rs-Canum Binaries and Related Chromospherically Active Stars - Part Two - Spectrum Synthesis Analysis
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&A...273..194R&db_key=AST
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Lithium in RS CVn binaries and related chromospherically active stars. I - Observational results
The present survey of the Li I 6708 A line in a sample of spectral typeG and K stars with luminosity classes III, IV, and V shows that manyK-type stars in the sample, including a large number of RS CVn binaries,show an anomalously high Li abundance relative to typical inactive starsof the same spectral type. Only a few stars in the sample are likely tobe premain sequence objects of stars which have recently arrived on themain sequence. Mechanisms that could lead to the enhanced Li absorptionin chromospherically active stars are discussed; these encompass largecool spots on the stellar surface, the production of Li in stellarflares by spallation reactions, and the evolution from main-sequenceprogenitors without, or with very shallow, outer convective zones.
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An astrometric catalogue of radio stars
The first part is presented of a radio star catalog encompassing 186objects whose selection was guided by the priority criteria of theHipparchos Input Catalogue Consortium. Since these criteria are wellsuited to the need for linkage of ground-based optical systems to radioreference frames, this first selection is also considered a suitablebase for the catalog. Seventeen categories of stellar parameters arefurnished for each of the stars, including optical and radio positions,optical and radio parallax, radial velocity, type of variability, andoptical structure.
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Optical positions of radiostars. II
Precise optical positions, relative to either the Perth 70 or the AGK3Rcatalogs, have been obtained for 40 radiostars proposed to the Hipparcosobserving list. Precision levels between 0.18 and 0.29 arcsecs wereobtained.
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A microwave survey of southern active stars
The results of a survey of 153 active-chromosphere stars made with theParkes 64-m telescope at 5.0/8.4 GHz from 1981 to 1987 are reported.Microwave emission was detected from 70 stars on at least one occasion,with the highest detection rate of 68 percent from the RS CVn group. TheCa II stars and Algol-type binaries yielded detection rates of 44 and 30percent, respectively. The maximum powers emitted by the stars at5.0/8.4 GHz ranged over five orders of magnitude, with a median of 2.5 x10 to the 10th W/Hz. The maximum brightness temperatures had a smallerrange of three orders of magnitude, with a median of 3.6 x 10 to the 9thK.
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Observations of active stars at 843 MHz
The Molonglo Observatory Synthesis Telescope is being used in ancontinuing program of observation of known Southern active stars. By May1987, a total of 41 stars had been observed, and 843-MHz quiescentemission, presumably associated with the star, had been detected in nineinstances. The emission from five of these stars has shown markedvariation on a time scale over 1 day.
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Results of a Southern Radio Survey of Active Chromosphere Stars
Not Available
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A search for 843 MHz radio emission from active stars
Emissions from flare stars and RSCVn type stars obtained using theMolonglo synthesis telescope at 843 MHz are studied. Seven flare starfields and eight RSCVn fields were observed, and 843 MHz emission wasfound from the flare star AT Mic and the RSCVn type star AB Dor. It isdetected that all sources have mean flux densities below 10 mJy.
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Radio emission from RS CVn binaries. I - VLA survey and period-radio luminosity relationship
A VLA survey of radio emission from 36 close binary stellar systems withRS CVn properties is reported. Eight new sources were detected. Asummary of all published reports of radio emission from RS CVn systemsis presented. There appears to be a correlation between maximum radioluminosity and rotational period, with a tentative functional form L(R)varies as P to the (-0.7) power. Rapid rotators (periods approximately 2days) may be underluminous compared with the extrapolated trend fromlonger-period systems. The luminosity-period correlation probablyresults from a dynamo mechanism which produces strong magnetic fieldsand, in turn, enhances the nonthermal radio emission. The decrease inradio luminosity at short periods may be caused by a saturation ofenergy deposition in the chromosphere, possibly because the surface ofthe active star has become covered with spotted regions.
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New southern radio binaries
Observations with the Parkes 64-m telescope in 1982 and 1983 haveresulted in the detection of eight new southern readio binaries, six ofwhich are believed to be RS CVn binaries. The peak 5-GHz luminosities ofthree of these stars exceed 10 to the 10th W/Hz sr and equal the extremevalues measured for one or two northern binaries. For a source diameterequal to that of the cooler active giant or sub-giant component, thederived peak brightness temperatures of around 10 to the 10th K for twostars are probably inconsistent with the incoherent synchrotron emissionmechanism, especially if the emission is strongly circularly polarized.An electron-cyclotron maser appears to be a possible alternativeemission mechanism, but there may be difficulties with such a model ifthe source is as large as the diameter of the active component.
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Near infrared photometry of some RS CVn systems and candidates
Infrared observations in the J, H, and K bands were made on eleven RSCVn systems. IR excess greater than about 0.3 mag in the J, H, and Kbands was observed from the three systems UX Ari, HR 1099 and sigma CrB.Similar observations were also made on the RS CVn candidates HD 26354,39937, 42449, 51268, and 86005. The IR excess in the RS CVn systems forwhich near-infrared photometric data are available is found to becorrelated with the maximum optical wave amplitude of these systems. Theobserved excess cannot be explained on the basis of a single processsuch as emission from cool spots on the photosphere; free-free emissionfrom an optically thin circumstellar plasma; or dust-grain emission fromcircumstellar material.
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INHABITED SKY
