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CoRoT photometry and high-resolution spectroscopy of the interacting eclipsing binary AU Monocerotis
Analyses of very accurate CoRoT space photometry, past Johnson Vphotoelectric photometry and high-resolution echelle spectra led to thedetermination of improved and consistent fundamental stellar propertiesof both components of AU Monocerotis. We derived new, accurateephemerides for both the orbital motion (with a period of ) and thelong-term, overall brightness variation (with a period of ) of thisstrongly interacting Be + G semi-detached binary. It is shown that thislong-term variation must be due to attenuation of the total light bysome variable circumbinary material. We derived the binary mass ratioMG/MB = 0.17 +/- 0.03 based on the assumption thatthe G-type secondary fills its Roche lobe and rotates synchronously.Using this value of the mass ratio as well as the radial velocities ofthe G-star, we obtained a consistent light curve model and improvedestimates of the stellar masses, radii, luminosities and effectivetemperatures. We demonstrate that the observed lines of the B-typeprimary may not be of photospheric origin. We also discover rapid andperiodic light changes visible in the high-quality residual CoRoT lightcurves. AU Mon is put into perspective by a comparison with knownbinaries exhibiting long-term cyclic light changes.Based on photometry collected by the CoRoT space mission as well asspectroscopy obtained with the FEROS spectrograph attached to the 2.2-mtelescope at European Southern Observatory (ESO), La Silla, Chile, underthe ESO Large Programme LP178.D-0361, and with the SOPHIE spectrographof the Observatoire de Haute-Provence (France). The CoRoT space missionwas developed and is operated by the French space agency CNES, with theparticipation of ESA's RSSD and Science Programmes, Austria, Belgium,Brazil, Germany and Spain. Based on observations collected at the CentroAstronómico Hispano Alemán (CAHA) at Calar Alto, operatedjointly by the Max-Planck-Institut für Astronomie and the Institutode Astrofísica de Andalucía (CSIC).E-mail: maarten.desmet@ster.kuleuven.be
| HD 174884: a strongly eccentric, short-period early-type binary system discovered by CoRoT
Accurate photometric CoRoT space observations of a secondaryseismological target, HD 174884, led to the discovery that this star isan astrophysically important double-lined eclipsing spectroscopic binaryin an eccentric orbit (e˜0.3), unusual for its short 3.65705°orbital period. The high eccentricity, coupled with the orientation ofthe binary orbit in space, explains the very unusual observed lightcurve with strongly unequal primary and secondary eclipses having thedepth ratio of 1-to-100 in the CoRoT “seismo” passband.Without the high accuracy of the CoRoT photometry, the secondaryeclipse, 1.5 mmag deep, would have gone unnoticed. A spectroscopicfollow-up program provided 45 high dispersion spectra. The analysis ofthe CoRoT light curve was performed with an adapted version of PHOEBEthat supports CoRoT passbands. The final solution was obtained by asimultaneous fitting of the light and the radial velocity curves.Individual star spectra were obtained by spectrum disentangling. Theuncertainties of the fit were achieved by bootstrap resampling and thesolution uniqueness was tested by heuristic scanning. The resultsprovide a consistent picture of the system composed of two late B stars.The Fourier analysis of the light curve fit residuals yields twocomponents, with orbital frequency multiples and an amplitude of ~0.1mmag, which are tentatively interpreted as tidally induced pulsations.An extensive comparison with theoretical models is carried out by meansof the Levenberg-Marquardt minimization technique, and the discrepancybetween the models and the derived parameters is discussed. The bestfitting models yield a young system age of 125 million years which isconsistent with the eccentric orbit and synchronous component rotationat periastron.Based on photometry collected by the CoRoT space mission andspectroscopy obtained with the CORALIE spectrograph attached to the 1.2m Euler telescope at ESO, La Silla, Chile. The CoRoT space mission wasdeveloped and is operated by the French space agency CNES, withparticipation of ESA's RSSD and Science Programs, Austria, Belgium,Brazil, Germany and Spain.Postdoctoral fellow of the Fund for Scientific Research of Flanders(FWO).
| 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.
| Rotational Velocities of the Components of 23 Binaries
By using high dispersion spectra obtained by the 1.8 m telescope ofBohyunsan Optical Astronomy Observatory (South Korea), multilineleast-square deconvolution of line profiles, and Fourier analysistechniques, we obtained the rotational velocities of the components of23 binary systems. The rotational velocities for nine primary, eightsecondary, and one tertiary components of these systems were determinedfor the first time. The rotational velocities for primary components ofseven systems appeared to be significantly different than thecorresponding synchronous values (more than twice as fast for fivesystems, and less than half as fast for two systems). Our velocities forAU Mon, RY Gem, and RZ Eri are significantly lower than the previouslypublished values obtained by using one or very few lines. We show thatthese discrepancies can be explained by strong blending of the lines inthe spectra of the primaries with strong lines of the secondaries, byinfluence of gaseous streams, and maybe by nonsolar chemicalcompositions.
| 35 Visual Minimum Times of 34 Eclipsing Binaries.
Not Available
| A new catalogue of eclipsing binary stars with eccentric orbits
A new catalogue of eclipsing binary stars with eccentric orbits ispresented. The catalogue lists the physical parameters (includingapsidal motion parameters) of 124 eclipsing binaries with eccentricorbits. In addition, the catalogue also contains a list of 150 candidatesystems, about which not much is known at present.Full version of the catalogue is available online (see the SupplementaryMaterial section at the end of this paper) and in electronic form at theCDS via http://cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/MNRAS/(vol)/ (page)E-mail: ibulut@comu.edu.tr
| Revealing the Nature of Algol Disks through Optical and UV Spectroscopy, Synthetic Spectra, and Tomography of TT Hydrae
We have developed a systematic procedure to study the disks inAlgol-type binaries using spectroscopic analysis, synthetic spectra, andtomography. We analyzed 119 Hα spectra of TT Hya, an Algol-typeeclipsing interacting binary, collected from 1985 to 2001. The newradial velocities enabled us to derive reliable orbital elements,including a small nonzero eccentricity, and to improve the accuracy ofthe absolute dimensions of the system. High-resolution IUE spectra werealso analyzed to study the formation of the UV lines and continuum.Synthetic spectra of the iron curtain using our new SHELLSPEC programenabled us to derive a characteristic disk temperature of 7000 K. Wehave demonstrated that the UV emission lines seen during total primaryeclipse cannot originate from the accretion disk but most likely arisefrom a hotter disk-stream interaction region. The synthetic spectra ofthe stars, disk, and stream allowed us to derive a mass transfer rate>=2×10-10 Msolar yr-1. Dopplertomography of the observed Hα profiles revealed a distinctaccretion disk. The difference spectra produced by subtracting thesynthetic spectra of the stars resulted in an image of the disk, whichvirtually disappeared once the composite synthetic spectra of the starsand disk were used to calculate the difference spectra. An intensityenhancement of the resulting tomogram revealed images of the gas streamand an emission arc. We successfully modeled the gas stream usingSHELLSPEC and associated the emission arc with an asymmetry in theaccretion disk.
| CoRoT and asteroseismology. . Preparatory work and simultaneous ground-based monitoring
The successful launch of the CoRoT (COnvection, ROtation and planetaryTransits) satellite opens a new era in asteroseismology. The spacephotometry is complemented by high-resolution spectroscopy andmulticolour photometry from ground, to disclose the pulsational contentof the asteroseismic targets in the most complete way. Some preliminaryresults obtained with both types of data are presented.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Theoretical study of partial frequency redistribution function in irradiated, moving atmospheres of close binary components
We have studied the effects of partial frequency redistribution functionwith angle-averaged RII-A in irradiated and movingatmospheres of close binary components. We have considered theatmospheric extension of the primary component to be twice the radius ofthe primary component in a close binary system. We have considered twocases: (i) when the atmosphere is at rest and (ii) when the atmosphereis moving. In both the cases, we have computed the line profiles alongthe line of sight for a given optical depth. The irradiation from thesecondary component is assumed to be one, five and 10 times theself-radiation. The line fluxes in the line of sight are calculated byusing the total source functions due to self-radiation of the primarycomponent and due to the irradiation from the secondary component. Wehave noted double-peaked emission lines in the case of a static mediumand a reduction of emission peaks in the case of velocity field.
| 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.
| SB9: The ninth catalogue of spectroscopic binary orbits
The Ninth Catalogue of Spectroscopic Binary Orbits(http://sb9.astro.ulb.ac.be) continues the series of compilations ofspectroscopic orbits carried out over the past 35 years by Batten andcollaborators. As of 2004 May 1st, the new Catalogue holds orbits for2386 systems. Some essential differences between this catalogue and itspredecessors are outlined and three straightforward applications arepresented: (1) completeness assessment: period distribution of SB1s andSB2s; (2) shortest periods across the H-R diagram; (3)period-eccentricity relation.
| 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
| From the Heart of the Ghoul: C and N Abundances in the Corona of Algol B
Chandra Low Energy Transmission Grating Spectrograph observations ofAlgol have been used to determine the abundances of C and N in thesecondary star for the first time. In order to minimize errors arisingfrom an uncertain coronal differential emission measure as a function oftemperature, the analysis was performed relative to similar observationsof an adopted ``standard'' star, HR 1099. It is demonstrated that HR1099 and Algol are coronal twins in many respects and that their X-rayspectra are very similar in nearly all details, except for the observedstrengths of C and N lines. The H-like2p2P3/2,1/2-->1s2S1/2transitions of C and N in the coronae of Algol and HR 1099 demonstratethat the surface abundances of Algol B have been strongly modified by CNprocessing, as shown earlier by Schmitt & Ness. It is found that Nis enhanced in Algol B by a factor of 3 compared with HR 1099. No Clines are detected in the Algol spectrum, indicating a C depletionrelative to HR 1099 by a factor of 10 or more. These C and N abundancesindicate that Algol B must have lost at least half of its initial massand are consistent with predictions of evolutionary models that includenonconservative mass transfer and angular momentum loss through magneticactivity. Based on H-like and He-like transitions in O and Ne, it isestimated that Algol is slightly metal poor, by 0.2 dex in terms of thecoronal abundances of light elements relative to HR 1099, while the FeXVII2p53d1P1-->2p61S0transition indicates a very similar Fe abundance. In reviewing coronalabundance results for active stars in the literature and drawing on anearlier Chandra study of the coronal abundances of HR 1099, it isconcluded that Fe is very likely depleted in the coronae of both Algoland HR 1099 by 0.5 dex relative to their photospheric compositions, butthat Ne is enhanced by a similar magnitude. Light elements such as C, N,and O are likely depleted in both stars by of order 0.3 dex. Thesimilarities in these large-abundance anomalies in HR 1099 and Algol arenotable. Despite such compositional fractionation in these coronae, therelative C and N abundances in HR 1099, determined by comparing observedline strengths with theoretical C/N line ratios, are consistent withrecent solar values, indicating that differential fractionation betweenthese elements is not significant and that little or no dredge-up ofmaterial subjected to CN processing has occurred on the subgiantcomponent.
| Einige interessante Bedeckungsveraenderliche.
Not Available
| Ultraviolet Spectrophotometry of Variable Early-Type Be and B Stars Derived from High-Resolution IUE Data
High-dispersion IUE data encode significant information about aggregateline absorptions that cannot be conveniently extracted from individualstellar spectra. Here we apply a new technique in which fluxes from eachechelle order of a short-wavelength IUE spectrum are binned together toconstruct low-resolution spectra of a rapidly varying B or Be star. Thedivision of binned spectra obtained during a ``bright-star'' phase byspectra from a ``faint-star'' phase leads to a ratioed spectrum thatcontains information about the mechanism responsible for a star'svariability. The most likely candidate mechanisms are either theperiodic or episodic occultations of the star by ejected matter or achange in photospheric structure, e.g., from pulsation. We model thevariations caused by these mechanism by means of model atmosphere andabsorbing-slab codes. Line absorptions strength changes are rathersensitive to physical conditions in circumstellar shells and ``clouds''at temperatures of 8000-13,000 K, which is the regime expected forcircumstellar structures of early B stars. To demonstrate proofs of thisconcept, we construct spectral ratios for circumstellar structuresassociated with flux variability in various Be stars: (1) Vela X-1 has abow-shock wind trailing its neutron star companion; at successive phasesand hence in different sectors, the wind exhibits spectrophotometricsignatures of a 13,000 or 26,000 K medium; (2) 88 Her undergoes episodic``outbursts'' during which its UV flux fades, followed a year later by adimming at visible wavelengths as well; the ratioed spectrum indicatesthe ``phase lag'' is a result of a nearly gray opacity that dominatesall wavelengths as the shell expands from the star and cools, permittingthe absorptions in the visible to ``catch up'' to those in the UV; and(3) ζ Tau and 60 Cyg exhibit periodic spectrum and flux changes,which match model absorptions for occulting clouds but are actually mosteasily seen from selective variations of various resonance lines. Inaddition, ratioed UV spectra of radial and large-amplitude nonradialpulsating stars show unique spectrophotometric signatures, which can besimulated with model atmospheres. An analysis of ratioed spectraobtained for a representative sample of 18 classical Be stars known tohave rapid periodic flux variations indicates that 13 of them haveratioed spectra that are relatively featureless or have signatures ofpulsation. Ratioed spectra of three others in the sample exhibitsignatures that are consistent with the presence of corotating clouds.
| Survey of Hα Mass Transfer Structures in Classical Algol-Type Binaries
Five years of Hα survey data for 37 ``classical'' Algol-typebinaries are presented. All these systems have primaries with a spectraltype of A or B, have a period of less than 5 days, and are visible inthe Northern Hemisphere. Data were collected with the 1.02 m reflectorat the US Naval Observatory, Flagstaff Station. The survey consists ofover 460 system spectra. Each system was observed at least once duringthe 5 years, with many systems observed several times over severalepochs. Difference profiles are calculated for most spectra by modelingand subtracting the spectrum of the photospheres of the stellarcomponents. We examined each spectrum for the presence of mass transfer,stream-star and stream-disk interaction, a disk or circumstellar bulge,and chromospheric emission. We present information on the prevalence ofmass transfer activity, disk presence, and system states associated withparticular mass transfer structures. We show that no currently publishedstudy, including this one, has enough data for a rigorous statisticalidentification of system states.
| 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.
| Morphologies of Hα Accretion Regions in Algol Binaries
We have investigated a group of 18 Algol-type binaries to determine thegeneral morphologies and physical properties of the accretion regions inthese systems. The systems studied were V505 Sgr, RZ Cas, AI Dra, TVCas, TW Cas, delta Lib, RW Tau, TW Dra, beta Per, TX UMa, U Sge, S Equ,U CrB, RS Vul, SW Cyg, CX Dra, TT Hya, and AU Mon, in order ofincreasing orbital period P=1.18-11.11 days. In addition, the RSCVn-type binary HR 1099 (V711 Tau) was observed to illustrate theappearance of chromospheric Hα emission. Nearly 2200 time-resolvedHα spectra were collected from 1992 March to 1994 December withthe McMath-Pierce Solar Telescope at NSO and mostly with theCoudé Feed Telescope at KPNO. The spectra were obtained at phasesaround the entire orbit of each binary and were closely spaced to permitthe detection of transitions in the profiles. Moreover, the spectra wereobtained typically within three orbital cycles to reduce the influenceof secular variations. Difference profiles were calculated bysubtracting a composite theoretical photospheric spectrum from theobserved spectrum. The analysis of the Hα difference profilesdemonstrates that the accretion structures in Algol binaries have fourbasic morphological types: (1) double-peaked emission systems in whichthe accretion structure is a transient or classical accretion disk; (2)single-peaked emission systems in which the accreted gas was found alongthe trajectory of the gas stream and also between the two stars in anaccretion annulus; (3) alternating single- and double-peaked emissionsystems, which can change between a single-peaked and a double-peakedtype within an orbital cycle; and (4) weak spectrum systems in whichthere was little evidence of any accretion structure since thedifference spectra are weak at all phases. The first two types are thedominant morphologies. The first type can be interpreted physically as adisklike distribution, while the second is a gas stream-likedistribution. The most common type in short-period Algols with 2.7days6 days)were found to have slightly variable but permanent accretion disks atall epochs (i.e., CX Dra, TT Hya, and AU Mon), similar to those found incataclysmic variables. SW Cyg (P=4.57 days) was found to be anintermediate case between the shorter period systems with P<4.5 daysand the longer period group with P>6 days. Two systems, U Sge and UCrB, displayed alternating single- and double-peaked emission atdifferent epochs (Type 3), and changes from one type to another weredetected within a 12 hour time interval. Observations at multiple epochssuggest that four members of the single-peaked emission group, namely RWTau, TX UMa, S Equ, and RS Vul, may actually belong to the alternatinggroup. So, the complete group of alternating systems covers periods of2.7 days
| Identifications for Wachmann's Variables in SA 98
Not Available
| Analysis of the Si IV Ultraviolet Spectra of U Sagittae
Archival IUE spectra of U Sge have been used to study hot (~10^5 K)circumstellar gas in this system. The observed spectra contain severalUV resonance lines, of which the Si IV lines (lambdalambda1394 and 1405)are the strongest. These lines are observed in absorption, so we mustremove the photospheric absorption line contribution to the spectra inorder to see the emission produced by the circumstellar gas. We havedeveloped a robust method for creating such difference spectra from IUEdata. In the observed spectra we see a variation in the line profilesand line centers with an orbital phase suggesting the presence ofcircumstellar gas. The residual emission seen in the difference spectrais strongest between phases phi=0.3 and phi=0.7, with a strength of upto 0.2 of the continuum flux. This is confirmed by the presence of anemission region visible in the Doppler tomogram of the lambda1394 line.This is consistent with the location of an Hα ``absorption zone''seen in tomograms of U Sge and U CrB, and with theoretical predictionsof a high temperature accretion region.
| Apsidal Motion in Double Stars. I. Catalog
A catalog of 128 double stars with measured periods of apsidal motion iscompiled. Besides the apsidal periods, the orbital elements of binariesand physical parameters of components (masses, radii, effectivetemperatures, surface gravities) are given. The agreement of the apsidalperiods found by various authors is discussed.
| ORFEUS-SPAS II Observations of Algol-type Interacting Binaries
The first results from ORFEUS-SPAS II observations of five Algol-typebinary systems obtained during the shuttle mission STS-80 in 1996November/December are reported. Single spectra covering 900-1220 A of AUMon, Z Vul, U CrB, and TX UMa were acquired with the Berkeleyspectrograph. TT Hya was observed at three phases (0.19, 0.63, and 0.95)to study mass flow and to investigate asymmetry in the circumstellarmaterial in the system. O VI was not detected in any of the binaries,which allows us to place an upper limit on Tion in the high-temperatureplasma seen in Algol-type binaries. Circumstellar material, presumablyassociated with the accretion disk, was detected in Fe III (UV1) in AUMon. We estimate a particle density in the range 108-109 cm-3 for theregion of the disk sampled during the observations. Evidence for massinfall was found in the phase 0.95 spectrum of TT Hya. From theadditional (redshifted) absorption in N II (1085 A) and N I (1135 A), wefind evidence for superionization in this plasma and estimate a lowerlimit of 10-12 Msolar yr-1 for the current infall rate.
| AU Monocerotis-improved elements
From an analysis, using Wilson-Devinney method, of the corrected yellowlight curve of the semi detached eclipsing binary system AU Monocerotis(AU Mon), obtained by \cite[Lorenzi (1980b),]{80b} an improved value forthe mass ratio, q, equal to 0.1985 and reliable geometrical elementswere derived.They give the absolute elements as:{m_h/m_sun}=5.93+/-0.31; {m_c/m_sun}=1.18+/-0.16; R_h/R_sun=5.28+/-0.16;R_c/R_sun=10.04+/-0.74; Log\ L_h/L_sun=3.16+/-0.14; Log\L_c/L_sun=2.07+/-0.21; Log\ g_h=3.76+/-0.06; and Log\ g_c=2.51+/-0.02.When compared to main sequence stars of similar mass, the primary isfound to have normal luminosity, bigger size and lower temperature whilethe secondary is found to have higher luminosity, bigger size and normaltemperature for their masses. On the HR diagram of the normal mainsequence stars, the primary is found to lie near but above the mainsequence (brighter by 1fm 4). The secondary component is far above themain sequence and is overluminous by about 4fm 5.
| The Interacting Eclipsing Binary AU Monocerotis Revisited
New spectrographic observations of the Algol binary AU Monocerotis havepermitted the determination of the orbital elements of the twocomponents of the system. They have further suggested that the imagetube spectrograph that was attached to the CTIO 1m-reflecting telescopein 1978 and 1979 was not quite suitable for radial velocity work.(SECTION: Stars)
| My experiences as an astronomer and a survey of binary star research carried out at CASA
Not Available
| GSC1657.1754: a New Deeply Eclipsing Binary System in Delphinus
Not Available
| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| On Accretion Component of the Flare Activity in Algol
A critical assessment of the observational data on flare activity inAlgol-type binaries is given. Two sites of the flare activity have beenidentified in Algol through observations in the X-ray and microwaveregions. One of them is apparently the accretion shock region on theB8-type primary component. Another, the predominant one, is associatedwith coronal mass ejection from the Roche lobe filling late-typesecondary. We still do not know the morphology of the circumbinary gaswith sufficient precision to determine the relative contribution fromboth these sources of activity. Future observations should concentrateboth on systems like U Cep with mass-loss dot M =~ 10(-6}M_{sun) /y andon Z Vul-type objects where secondaries are earlier than F2-type stars,i.e. presumably without an extensive convection zone. A simple model ofradially expanding stellar wind in a binary system is presented. Theeffect of anisotropy which appears due to displacement of a sonic point,caused by the gravitational field of the companion star, isinvestigated. We estimate the X-ray flux for Algol, caused by theaccretion to the primary component and find satisfactory agreement withthe X-ray Ginga data for a mass transfer rate dot M =(0.4-2.0) *10(-11}M_{sun) /y.
| Circumstellar material in Algol - A study of the Balmer line profiles
The kinematics and the spatial distribution of the circumstellarmaterial the short-period Algol-type system Beta Persei are studied byanalyzing its H-alpha line profile. Photographic spectra are used whichover the entire orbit of the Algol binary, with a resolution of about0.02 in phase. This single data set is more comprehensive than any otherspectroscopic observations of Beta Persei in the literature. Theobservations can be used to provide 2D information about thecircumstellar material. From the observations, it is found that theH-alpha difference profiles of Algol arise from three main circumstellarregions: (1) a transient high-density low-mass localized region close tothe photosphere of the primary but high above the orbital plane; (2) atransient rotating accretion disk which surrounds the primary; and (3) ahigh-velocity disk component surrounding the primary.
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Pozíciós és asztrometriai adatok
| Csillagkép: | Egyszarvú |
| Rektaszcenzió: | 06h54m54.71s |
| Deklináció: | -01°22'32.9" |
| Vizuális fényesség: | 8.43 |
| Távolság: | 1149.425 parszek |
| RA sajátmozgás: | -1.5 |
| Dec sajátmozgás: | -1.2 |
| B-T magnitude: | 8.453 |
| V-T magnitude: | 8.432 |
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