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Unveiling SU Aurigae in the Near-Infrared: New High Spatial Resolution Results Using Adaptive Optics
We present new results on the circumstellar nebulosity around SUAurigae, a T Tauri star of about 2 Msolar and 5 Myr old at152 pc in the J, H, and K bands using high-resolution adaptive opticsimaging (0.30") with the Penn State Near-IR Imager and Spectrograph atthe 100 inch (2.5 m) Mount Wilson telescope. A comparison with HubbleSpace Telescope STIS optical (0.2-1.1 μm) images shows that theorientation of the circumstellar nebulosity in the near-IR extends fromposition angle 210° to 270° in the H and K bands and up to300° in the J band. We call the circumstellar nebulosity seenbetween 210° and 270° an ``IR nebulosity.'' We find that the IRnebulosity (which extends up to 3.5" in the J band and 2.5" in the Kband) is due to scattered light from the central star. The IR nebulosityis either a cavity formed by the stellar outflows or part of thecircumstellar disk. We present a schematic three-dimensional geometricmodel of the disk and jet of SU Aur based on STIS and our near-IRobservations. According to this model, the IR nebulosity is part of thecircumstellar disk seen at high inclination angles. The extension of theIR nebulosity is consistent with estimates of the disk diameter of50-400 AU in radius, from earlier millimeter K-band interferometricobservations and SED fittings.
| Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics
The Catalogue, available at the Centre de Données Stellaires deStrasbourg, consists of 13 573 records concerning the results obtainedfrom different methods for 7778 stars, reported in the literature. Thefollowing data are listed for each star: identifications, apparentmagnitude, spectral type, apparent diameter in arcsec, absolute radiusin solar units, method of determination, reference, remarks. Commentsand statistics obtained from CADARS are given. The Catalogue isavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcar?J/A+A/367/521
| Photometric Measurements of the Fields of More than 700 Nearby Stars
In preparation for optical/IR interferometric searches for substellarcompanions of nearby stars, we undertook to characterize the fields ofall nearby stars visible from the Northern Hemisphere to determinesuitable companions for interferometric phase referencing. Because theKeck Interferometer in particular will be able to phase-reference oncompanions within the isoplanatic patch (30") to about 17th magnitude atK, we took images at V, r, and i that were deep enough to determine iffield stars were present to this magnitude around nearby stars using aspot-coated CCD. We report on 733 fields containing 10,629 measurementsin up to three filters (Gunn i, r and Johnson V) of nearby stars down toabout 13th magnitude at V.
| The catalogue of nearby stars metallicities.
Not Available
| Multiplicity among solar-type stars in the solar neighbourhood. II - Distribution of the orbital elements in an unbiased sample
An unbiased sample of 164 primary G-dwarf stars in the solarneighborhood are studied with the aid of 4200 radial velocities obtainedduring almost 13 yrs. Several present-day distributions of the orbitalelements are derived. For systems with M(2)/M(1) above 0.1 in the nearbyG-dwarf sample, the following results are obtained: (1) The orbitalperiod distribution is unimodal and can be approximated by aGaussian-type relation with a median period of 180 yrs. (2) The shortbinaries are circularized up to orbital periods of about 11 d due to thetidal evolution effects - a result compatible with the mean age of theGalactic disk. (3) The tight binaries not affected by tidal effects (inthe range between 11 and 1000 d) may reflect the initial binaryformation process, and they have a mean eccentricity of 0.31 +/-0.04.For systems with M(2)/M(1) not greater than 0.1, the proportion of browndwarf companions among the IAU velocity standards is estimated at 10percent of the primaries, a value in good agreement with that found inthe G-dwarf sample.
| CA II H and K measurements made at Mount Wilson Observatory, 1966-1983
Summaries are presented of the photoelectric measurements of stellar CaII H and K line intensity made at Mount Wilson Observatory during theyears 1966-1983. These results are derived from 65,263 individualobservations of 1296 stars. For each star, for each observing season,the maximum, minimum, mean, and variation of the instrumental H and Kindex 'S' are given, as well as a measurement of the accuracy ofobservation. A total of 3110 seasonal summaries are reported. Factorswhich affect the ability to detect stellar activity variations andaccurately measure their amplitudes, such as the accuracy of the H and Kmeasurements and scattered light contamination, are discussed. Relationsare given which facilitate intercomparison of 'S' values with residualintensities derived from ordinary spectrophotometry, and for convertingmeasurements to absolute fluxes.
| Multiplicity among solar type stars in the solar neighbourhood. I - CORAVEL radial velocity observations of 291 stars
Results obtained on stellar radial velocity of 291 stars of spectraltypes FO to G9, measured with CORAVEL spectrometers at theHaute-Provence and la Silla Observatories, are discussed. The paperdescribes the observational procedure, reduction technique, andvelocity-data calibration and presents a list of individualradial-velocity measurements. Few histograms describing the survey arealso presented.
| IRAS Point Source Catalogue cross-identifications
Not Available
| Photometry of dwarf K and M stars
Broadband photometry in BVRI colors for 120 nearby dwarf K and M starsis presented. The apparent magnitude distributions of Vyssotsky and VanVleck stars with photometry and without photometry are studied. Therelationship between apparent and photoelectric magnitudes is analyzed.The proper motion and transverse velocity of the two star types areexamined and compared.
| UBVRI photoelectric photometry of nearby stars
In order to complete the photometric data of the Gliese (1969) 'Catalogof Nearby Stars', and in addition use these data for the Hipparcos spaceastrometry mission, program stars have been selected from the catalogand its supplements on the basis of their having an incomplete set ofUBVRI photometric data of magnitude lower than 13. The program developedrejects determinations of any magnitude or color index having a residualgreater than 2(sigma-prime), where sigma-prime is the standard deviationfor the determinations of unit weight.
| Predicted infrared brightness of stars within 25 parsecs of the sun
Procedures are given for transforming selected optical data intoinfrared flux densities or irradiances. The results provide R, T(eff)blackbody approximations for about 2000 of the stars in Woolley et al.'sCatalog of Stars (1970) within 25 pc of the sun, and additional whitedwarfs, with infrared flux densities predicted for them at ninewavelengths from 2.2 to 101 microns including the Infrared AstronomySatellite bands.
| The degree of completeness of nearby stars and the stellar luminosity function
The aim of this study is the determination of the degree of completenessof nearby star catalogs for stars of as many spectral classes aspossible, by means of a novel method which eliminates giants, subgiantsand white dwarfs from the data sample. It is shown that main-sequencestars earlier than M0 are essentially complete and identified withinabout 20 pc of the sun, by determining V/V(max) as a function of B-V forthe main sequence stars. The luminosity function produced by the M0stars has been known to differ from the commonly accepted and smoothedluminosity function, which increases monotonically with absolutemagnitude, between the absolute visual magnitudes +6 and +9. It isconcluded that the deficiency between these magnitude limits is real,suggesting either (1) that stars of masses equivalent to this absolutemagnitude range are rarer than those of greater mass, or (2) that themass-luminosity relation is not as linear as is believed at present.
| A survey of chromospheric CA II H and K emission in field stars of the solar neighborhood
Fluxes in 1 A bands at the centers of the H and K lines are beingmeasured in main-sequence F-G-K-M stars in the northern half of theWoolley et al. (1970) 'Catalog of stars within twenty-five parsecs ofthe sun', in a survey not yet completed. Results for 486 stars arepresented in the form of flux-color diagrams and discussed in light ofevidence that chromospheric activity declines with age in main-sequencestars. Support is noted for the reality of the Sirius moving group. Therelative numbers of more-active (Hyades-like) and less-active(solar-like) F-G stars are tolerably in agreement with a nearly constantrate of formation, but there exists an apparent deficiency in the numberof F-G stars exhibiting intermediate activity. The possibility that thegap is an accidental characteristic of the sample will be investigatedby extending the survey to southern declinations and greater distances.
| Positions et Mouvements propres de 357 Etoiles de Repère de la Zone + 16° à + 18° pour l'époque et l'équinoxe 1950,0
Not Available
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Pozíciós és asztrometriai adatok
| Csillagkép: | Halak |
| Rektaszcenzió: | 01h00m15.73s |
| Deklináció: | +18°11'56.5" |
| Vizuális fényesség: | 7.348 |
| Távolság: | 152.905 parszek |
| RA sajátmozgás: | 18.5 |
| Dec sajátmozgás: | -77.1 |
| B-T magnitude: | 8.72 |
| V-T magnitude: | 7.462 |
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