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The Planetary Mass Companion 2MASS 1207-3932B: Temperature, Mass, and Evidence for an Edge-on Disk
We present J-band imaging and H+K-band low-resolution spectroscopy of2MASS 1207-3932AB, obtained with VLT NACO. For the putative planetarymass secondary, we find J=20.0+/-0.2 mag. The HK spectra of bothcomponents imply low gravity and a dusty atmosphere for the secondary.Comparisons to synthetic spectra yield Teff,A~2550+/-150 Kand Teff,B~1600+/-100 K, consistent with their late-M andmid- to late-L types. For these Teff and an age of 5-10 Myr,evolutionary models imply MA~24+/-6 MJup andMB~8+/-2 MJup. Independent comparisons of thesemodels to the observed colors, spanning ~I to L', also yield the samemasses and temperatures. Our primary mass agrees with other recentanalyses; however, our secondary mass, while still in the planetaryregime, is 2-3 times larger than claimed previously. This discrepancycan be traced to the luminosities: while the absolute photometry andMbol of the primary agree with theoretical predictions, thesecondary is ~2.5+/-0.5 mag fainter than expected in all bands from I toL' and in Mbol. This accounts for the much lower secondarymass (and temperature) derived earlier. We argue that this effect ishighly unlikely to result from a variety of model-related problems andis instead real. This conclusion is bolstered by the absence of anyluminosity problems in either the primary or AB Pic B, which we alsoanalyze. We therefore suggest gray extinction in 2M1207B, due toocclusion by an edge-on circumsecondary disk. This is consistent withthe observed properties of edge-on disks around T Tauri stars and withthe known presence of a high-inclination evolved disk around theprimary. Finally, the system's implied mass ratio of ~0.3 suggests abinary-like formation scenario.
| Pulkovo compilation of radial velocities for 35495 stars in a common system.
Not Available
| Five-colour photometry of OB-stars in the Southern Hemisphere
Observations of OB-stars, made in 1959 and 1960 at the Leiden SouthernStation near Hartebeespoortdam, South Africa, with the VBLUW photometerattached to the 90 cm light-collector, are given in this paper. They arecompared with photometry obtained by \cite[Graham (1968),]{gra68}\cite[Walraven & Walraven (1977),]{wal77} \cite[Lub & Pel(1977)]{lub77} and \cite[Van Genderen et al. (1984).]{gen84} Formulaefor the transformation of the present observations to those of\cite[Walraven & Walraven (1977)]{wal77} and \cite[Lub & Pel(1977)]{lub77} are given. Table 4 is only available in electronic format the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/Abstract.html
| 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
| 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.
| Far-ultraviolet stellar photometry: Fields in Sagittarius and Scorpius
Far-ultraviolet photometry for 741 objects in a field in Sagittariuscentered near M8 and 541 objects in a field centered near sigma Scorpiiis presented. These data were extracted from electographic imagesobtained with two cameras during a shuttle flight in 1991 April/May. Thecameras provided band passes with lambdaeff = 1375 A andlambdaeff = 1781 A. Synthetic colors show that these bandsare sensitive to effective temperature for hot stars. Our measurementswere placed on a quantitative far-ultraviolet magnitude scale byconvolving the spectra of stars observed by IUE with our cameras'spectral response functions. Fifty-eight percent of the ultravioletobjects were identified with visible stars using the SIMBAD databasewhile another 40% of the objects are blends of early type stars tooclose together to separate with our resolution. Our photometry iscompared with that from the TD-1, OAO 2, and ANS satellites and the S201(Apollo 16) far-ultraviolet camera and found to agree at the level of afew tenths of a magnitude. Unlike previous studies, almost half of theidentified visual counterparts to the ultraviolet objects are early Bstars. A plot of distance modulus against ultraviolet color excessreveals a significant population of stars with strong ultravioletexcess.
| Uvby-beta observations of 528 type B stars with V between the 8th and 9th magnitude
The paper presents uvby-beta measurements of 528 type B stars selectedfrom the SAO Catalog on the basis of two criteria: the spectral types inthe range B3-B5 and mV between the 8th and the 9th magnitude. Reddeningindependent (c1) values are estimated from the spectral classificationand compared to the observed values. No systematic trend with observed(b-y), H-beta, or spectral type appears to be present, but the range of(c1) residuals is surprisingly large. A rather large part of the starshas small beta values, smaller than for the BIa supergiants. Only twoare classified as O stars and most of them have the suffix e, ne, ornne. Most beta values for the O type stars are slightly above the upperlimit of 2.585 m.
| Catalog of O-B stars observed with Tokyo Meridian Circle
A catalog of the O-B stars, selected from 'Blaauw-Parenago' list andRubin's catalog, has been compiled on the FK4 system by the observationsmade with Gautier 8-inch Meridian Circle at the Tokyo AstronomicalObservatory during the period, 1971 to 1979. It contains 1059 stars andwas compiled for the future establishment of high precision propermotions of O-B stars.
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Besorolás csoportokba:
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Pozíciós és asztrometriai adatok
| Csillagkép: | Nyilas |
| Rektaszcenzió: | 18h03m06.06s |
| Deklináció: | -17°24'49.9" |
| Vizuális fényesség: | 7.58 |
| Távolság: | 456.621 parszek |
| RA sajátmozgás: | -2.1 |
| Dec sajátmozgás: | -4.5 |
| B-T magnitude: | 7.704 |
| V-T magnitude: | 7.591 |
Katalógusok és elnevezések:
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