A study of the interacting binary V393Scorpii
ABSTRACT We present high-resolution J-band spectroscopy of V393Scoobtained with the Cryogenic High-Resolution Infrared EchelleSpectrograph (CRIRES) at the ESO Paranal Observatory along with adiscussion of archival International Ultraviolet Explorer (IUE) spectraand published broad-band magnitudes. The best fit to the spectral energydistribution outside eclipse gives K for the gainer, for the donor, magand a distance of pc, although circumstellar material was not consideredin the fit. We argue that V393Sco is not a member of the open clusterM7. The shape of the HeI 1083-nm line shows orbital modulations that canbe interpreted in terms of an optically thick pseudo-photospheremimicking a hot B-type star and relatively large equatorial mass lossthrough the Lagrangian L3 point during long cycle minimum. IUE spectrashow several (usually asymmetric) absorption lines from highly ionizedmetals and a narrow L emission core on a broad absorption profile. Theoverall behaviour of these lines suggests the existence of a wind atintermediate latitudes. From the analysis of the radial velocities (RVs)we find M2/M1 = 0.24 +/- 0.02 and a mass functionof f = 4.76 +/- 0.24M. Our observations favour equatorial mass lossrather than high-latitude outflows as the cause for the longvariability.
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Interacting Binary Stars Environments and the W Ser-DPV-Algol Connection
Recent work on some kinds of interacting binaries is summarized, withemphasis on Cataclysmic Variables, Algol-like variables and the recentlydiscovered Double Periodic Variables (DPVs). The sequence W Serpentids(very massive with irregular variability and large mass loss) ?DPVs (less massive with regular variability and ciclic mass loss) ?Algols (even less massive with small mass loss) could correspond to anevolutionary sequence, and illustrate the importance of the masstransfer rate in shaping observable and mass loss properties for thesesystems.
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A systematic study of variability among OB-stars based on HIPPARCOS photometry
Context: Variability is a key factor for understanding the nature of themost massive stars, the OB stars. Such stars lie closest to the unstableupper limit of star formation. Aims: In terms of statistics, thedata from the HIPPARCOS satellite are unique because of time coverageand uniformity. They are ideal to study variability in this large,uniform sample of OB stars. Methods: We used statisticaltechniques to determine an independant threshold of variabilitycorresponding to our sample of OB stars, and then applied an automaticalgorithm to search for periods in the data of stars that are locatedabove this threshold. We separated the sample stars into 4 maincategories of variability: 3 intrinsic and 1 extrinsic. The intrinsiccategories are: OB main sequence stars (~2/3 of the sample), OBe stars(~10%) and OB Supergiant stars (~1/4).The extrinsic category refers toeclipsing binaries. Results: We classified about 30% of the wholesample as variable, although the fraction depends on magnitude level dueto instrumental limitations. OBe stars tend to be much more variable(≈80%) than the average sample star, while OBMS stars are belowaverage and OBSG stars are average. Types of variables include αCyg, β Cep, slowly pulsating stars and other types from the generalcatalog of variable stars. As for eclipsing binaries, there arerelatively more contact than detached systems among the OBMS and OBestars, and about equal numbers among OBSG stars.
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Unveiling the phenomenon of Double Periodic Variables
In this paper we give a brief report of our recent research on DoublePeriodic Variables (DPVs), including the discovery of DPVs in the Galaxyand some insights on the nature of their long-cycle variability.
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13 New Eclipsing Binaries with Additional Variability in the ASAS Catalogue
We present 13 new ASAS eclipsing binaries that exhibit additionalperiodic variability due to pulsations, eclipses with another period orspots. All contact and semi-detached binaries from the ASAS Cataloguewere investigated.
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A catalogue of eclipsing variables
A new catalogue of 6330 eclipsing variable stars is presented. Thecatalogue was developed from the General Catalogue of Variable Stars(GCVS) and its textual remarks by including recently publishedinformation about classification of 843 systems and making correspondingcorrections of GCVS data. The catalogue1 represents thelargest list of eclipsing binaries classified from observations.
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Up-to-Date Linear Elements of Eclipsing Binaries
About 1800 O-C diagrams of eclipsing binaries were analyzed and up-todate linear elements were computed. The regularly updated ephemerides(as a continuation of SAC) are available only in electronic form at theInternet address: http://www.as.ap.krakow.pl/ephem/.
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Catalogue of Algol type binary stars
A catalogue of (411) Algol-type (semi-detached) binary stars ispresented in the form of five separate tables of information. Thecatalogue has developed from an earlier version by including more recentinformation and an improved layout. A sixth table lists (1872) candidateAlgols, about which fewer details are known at present. Some issuesrelating to the classification and interpretation of Algol-like binariesare also discussed.Catalogue is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/417/263
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Stars with the Largest Hipparcos Photometric Amplitudes
A list of the 2027 stars that have the largest photometric amplitudes inHipparcos Photometry shows that most variable stars are all Miras. Thepercentage of variable types change as a function of amplitude. Thiscompilation should also be of value to photometrists looking forrelatively unstudied, but large amplitude stars.
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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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Further discussion of binary star radio survey data
Statistical information on 8280 individual radio observations of binarystars, predominantly at 8.4 GHz using the Parkes 64 m antenna, ispresented. Three main groups are distinguished: (i) RS CVn stars, (ii)classical Algol binaries (EA2s) and (iii) detached pairs of generallyearly type (ETBs). The RS CVn stars more frequently gave rise todetectable fluxes, while the ETBs, in this data, are a small and ratherheterogeneous class. The Algols' emission appears to increase nearconjunction phases, though we cannot clearly distinguish any specialproperty of the Algols' phase-dependent behaviour which is not alsoshared by the RS CVn binaries. Both these categories' data show abimodal, phase-dependent pattern to the distribution of detections,suggesting both binary types share similar underlying physicalproperties, though there could also be other factors at play. The samplesizes of the Algols and particularly the ETB detections are too smallfor effective, discriminatory statistics, however.
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San Juan radio star catalogue and comparison with HIPPARCOS catalogue.
Not Available
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Far-Ultraviolet Stellar Photometry: Fields Centered on rho Ophiuchi and the Galactic Center
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1996ApJS..104..101S&db_key=AST
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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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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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Radio emission from EA eclipsing binaries - Evidence for kilogauss surface fields on both early-type and late-type stars
Radio observations of a sample of EA eclipsing binaries, includingearly-type main-sequence pairs as well as classical Algol-type eclipsingbinaries, indicate the presence of a moderately strong coronal magneticfield, B of about 100 G, between the component stars. This translates toa surface magnetic field of about 1000-10,000 G on one or both stars.This is the first compelling evidence for magnetic fields on early-typestars, apart from the Ap and Bp magnetic stars first detected in 1947.
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Optical positions of radiostars.
Precise optical positions, relative to either the Perth 70 or the AGK3Rcatalogs, are presented for 38 radiostars which have been proposed ascandidates for the Hipparcos observing list. The observations wereobtained with the 70/100/210 cm Maksutov Astrograph at the EstacionAstronomica de Cerro El Roble. The precision levels are shown to beabout 0.2 arcsec in both coordinates.
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Do all stars have magnetic fields?
The sun and other late-type stars have the ability to generate andmaintain strong localized magnetic field regions on and above thestellar surface. Recent observational results strongly suggest that amuch higher range of upper-main-sequence spectral types have appreciablesurface magnetic fields. The data refer to stars of spectral types B, A,and F in eclipsing binary systems.
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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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The List of the Nearest and Bright Eclipsing Binaries from the HIPPARCOS Program
Not Available
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Results of a Southern Radio Survey of Active Chromosphere Stars
Not Available
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Eclipsing binaries in open clusters. I - Preliminary study
A preliminary list of suspected eclipsing binaries in open clusters ispresented. The period, the mass ratio, the correlation between the massratio and cluster age, and the periodicity diagram are investigated.
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A Catalogue of Classical Evolved Algol-Type Binary Candidate Stars
Not Available
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Catalogue of Eclipsing and Spectroscopic Binary Stars in the Regions of Open Clusters
Not Available
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Statistics of categorized eclipsing binary systems Lightcurve shapes, periods, and spectral types
The statistics of the light curve morphologies, eclipse depths, orbitalperiods, and spectral types of about 1000 eclipsing binary systems areexamined, after attempting to subdivide these binaries into variousbasic evolutionary categories. The applicability of statisticalcriteria, based on light curve morphologies and eclipse depths, for thecategorization of eclipsing binaries has been found more limited thanpreviously believed. In particular, EW-type light curves turn out to begood indicators of contact systems (though not conversely), while EA-and EB-type light curves have little physical significance. Moreover,the study reveals a strong deficit of short-period noncontact systems inthe whole spectral range, together with an underabundance of early-typecontact binaries (compared with the number of late-type contact pairs).Interestingly, the distribution of evolved Algol-type systems isshifted, on average, to periods longer than those of unevolved detachedsystems in the OB and early A spectral range (and to shorter periods inthe F spectral range).
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A uvby, beta photometric survey of southern hemisphere
A uvby, beta photometric study of southern hemisphere eclipsing binarystars has been undertaken at Cerro Tololo Inter-American Observatory.The standardized colors and V magnitudes for 288 binaries at quadratureand/or at minimum are presented, along with an indication of theaccuracy of the standardization and photometry. Discussions of theresolving time of the pulse-counting photometers and of the atmosphericextinction at CTIO are included.
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A catalogue of parameters for eclipsing binaries
Not Available
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Survey of Spectra of Southern Eclipsing Binaries.
Not Available
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