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A Tale of Two Herbig Ae Stars, MWC 275 and AB Aurigae: Comprehensive Models for Spectral Energy Distribution and Interferometry
We present comprehensive models for the Herbig Ae stars MWC 275 and ABAur that aim to explain their spectral energy distribution (from UV tomillimeter) and long-baseline interferometry (from near-infrared tomillimeter) simultaneously. Data from the literature, combined with newmid-infrared (MIR) interferometry from the Keck Segment TiltingExperiment, are modeled using an axisymmetric Monte Carlo radiativetransfer code. Models in which most of the near-infrared (NIR) emissionarises from a dust rim fail to fit the NIR spectral energy distribution(SED) and sub-milliarcsecond NIR CHARA interferometry. Following recentwork, we include an additional gas emission component with similar sizescale to the dust rim, inside the sublimation radius, to fit the NIR SEDand long-baseline NIR interferometry on MWC 275 and AB Aur. In theabsence of shielding of starlight by gas, we show that the gas-dusttransition region in these YSOs will have to contain highly refractorydust, sublimating at ~1850 K. Despite having nearly identical structurein the thermal NIR, the outer disks of MWC 275 and AB Aur differsubstantially. In contrast to the AB Aur disk, MWC 275 lacks smallgrains in the disk atmosphere capable of producing significant 10-20μm emission beyond ~7 AU, forcing the outer regions into the``shadow'' of the inner disk.
| Catalogue of H-alpha emission stars in the Northern Milky Way
The ``Catalogue of Stars in the Northern Milky Way Having H-alpha inEmission" appears in Abhandlungen aus der Hamburger Sternwarte, Band XIin the year 1997. It contains 4174 stars, range {32degr <= l() II< 214degr , -10degr < b() II < +10degr } having the Hαline in emission. HBH stars and stars of further 99 lists taken from theliterature till the end of 1994 were included in the catalogue. We givethe cross-identification of stars from all lists used. The catalogue isalso available in the Centre de Données, Strasbourg ftp130.79.128.5 or http://cdsweb.u-strasbg.fr and at the HamburgObservatory via internet.
| On the confinement of one-armed oscillations in discs of Be stars.
We discuss the effects due to the rotational deformation and theoptically-thin line force on the confinement of one-armed oscillationsin the inner part of Be-star discs. The period of these oscillations isidentified with the observed V/R variations in Balmer emission lines. Wetake into account the effect of rotation by including the quadrupolecontribution to the potential around the rotationally-distorted centralstar. For the radiative force due to an ensemble of optically thinlines, we adopt the parametric form proposed by Chen & Marlborough(1994ApJ...427.1005C). The disc is assumed to be isothermal. Based onthese assumptions, we examine the linear, one-armed eigenmodes confinedto the inner part of the disc. Our study strongly suggests that themechanism that causes the confinement of one-armed oscillations inearly-type Be stars is different from that in late-type Be stars. Inlate-type Be stars, the confinement occurs because of the deviation fromthe point-mass potential around the rotationally deformed star. On thispoint, we confirm the conclusions obtained by Papaloizou et al.(1992A&A...265L..45P). In early-type Be stars, however, it is theweak-line force that mainly contributes to the confinement. Therotational effect plays a much smaller role for these stars. The periodof the eigenmode confined to the disc depends sensitively on the effectby rotation or radiation. This sensitiveness, together with the range ofthe period of observed V/R variations, places rather narrow constraintson the parameters characterizing these effects. We compare our resultswith observed V/R properties, for which a list of 53 stars has beencompiled.
| Catalogue of stars in the northern Milky Way having H-alpha in emission
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.
| Distances, reddenings and distribution of emission B-stars in the galactic centre region /l/ not greater than 45 deg
The distribution of Be stars in the region surrounding the Galacticcenter and their correlation to the spiral structure of the Galaxy hasbeen studied. The results are discussed in terms of reddenings anddistances of these stars. Data are presented on the Galacticcoordinates, colors, interstellar color excesses, reddening-freemagnitudes and colors, adopted absolute magnitudes, distances in kpc,distances from the Galactic plane, and MK spectral type.
| Photometric observations of emission B-stars in the southern Milky Way
In order to study the distribution of Be stars and their correlation tothe local spiral structure of the Galaxy photoelectric UBV photometrywas carried out for a total of 488 Be stars located in the southernMilky Way between galactic longitudes 315 and 45 deg. UBV magnitudes arepresented for these stars.
| Spectral Classifications of some Emission B Stars
Not Available
| Spectroscopic studies of 60 Be stars over a period of 24 years
Not Available
| Kinematic studies of early-type stars. I. Photometric survey, space motions, and comparison with radio observations.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1962AJ.....67..491R&db_key=AST
| A Spectroscopic and Photometric Study of the be Stars.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1958ApJ...128..207M&db_key=AST
| General Catalogue of Stellar Radial Velocities
Not Available
| The radial velocities and spectral features of twenty-one Be stars with special features
Not Available
| Catalogue and Bibliography of Stars of Classes B and a whose Spectra have Bright Hydrogen Lines
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1933ApJ....78...87M&db_key=AST
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | נשר |
| התרוממות ימנית: | 19h46m13.56s |
| סירוב: | +05°59'17.3" |
| גודל גלוי: | 8.46 |
| מרחק: | 473.934 פארסק |
| תנועה נכונה: | 0.1 |
| תנועה נכונה: | 0.6 |
| B-T magnitude: | 8.422 |
| V-T magnitude: | 8.457 |
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