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Short-period line profile and light variations in the Herbig Ae star V351 Orionis
We present 318 high-dispersion echelle spectra and 450UBVRCIC observations of the pre-main-sequence starV351 Orionis. These data were obtained simultaneously over a two-weekperiod. The star is unusual in that it no longer shows the frequentsharp fadings that occurred prior to 1986. We find featurescharacteristic of Herbig Ae stars: Hα emission, sharp and broadNaII absorption components and weak HeI absorption. The Hα profileis strongly variable with a time-scale of 1d and normally is an inverseP Cygni profile, but on occasions overt emission disappears altogether.The equivalent widths of the sharp NaII absorption lines have decreasedquite markedly since 1995, indicating a decrease in the column densityof gas in the line of sight. We also detect very weak forbidden [OI]emission. There is no evidence for veiling of the star, but a possible1.0-d or 0.5-d period in the equivalent widths of the lines couldindicate the presence of an accretion hotspot. The star is of particularinterest because it is pulsating. We detect at least two periods in thelight variation and a further period from the radial velocityvariations. Attempts at photometric mode identification were notsuccessful, but from the morphology of the line profiles we can identifyone mode as non-radial. In addition, we see on some nights severalresidual absorption subfeatures moving across the line profile from blueto red. These are almost certainly caused by one or more modes of highdegree (l~8).
| ICCD Speckle Observations of Binary Stars. XXIII. Measurements during 1982-1997 from Six Telescopes, with 14 New Orbits
We present 2017 observations of 1286 binary stars, observed by means ofspeckle interferometry using six telescopes over a 15 year period from1982 April to 1997 June. These measurements constitute the 23dinstallment in CHARA's speckle program at 2 to 4 m class telescopes andinclude the second major collection of measurements from the MountWilson 100 inch (2.5 m) Hooker Telescope. Orbital elements are alsopresented for 14 systems, seven of which have had no previouslypublished orbital analyses.
| Pulsation in two Herbig Ae stars: HD 35929 and V351 Ori
New photometric observations of seven intermediate mass pre-mainsequence delta Scuti candidates are presented. The periods and pulsationmodes are derived for two of these stars, namely HD 35929 and V351 Ori.The comparison between observations and nonlinear pulsational modelsallows us to provide some initial constraints on their mass andevolutionary state. As an illustration we discuss the use of periods toidentify the mode of pulsation in these two stars and to have anindependent estimate of their distances. Based on observations carriedout at the European Southern Observatory, La Silla, Chile underproposals number 62-I-0533, 63-I-0053
| The remarkable Herbig AE star V 351 Orionis=HD 38238.
The photometric behaviour of the irregular variable Herbig Ae star V 351Ori was investigated combining data from the literature with newphotometric data in the Stroemgren system. It is shown that thisenigmatic object changed its photometric behaviour from that of a HerbigAe star with strong photometric variations, due to extinction bycircumstellar dust clouds, to that of an almost non-variable star. Sucha behaviour is not unique; it has been found also in the star BN Ori(Shevchenko et al. 1996). This suggests that such transitions must occurquite often during the evolution of intermediate mass HAeBe starstowards the main-sequence (MS). However, it is equally probable thatbefore such a star arrives at the MS, it will become strongly variableagain after collecting enough dust from its environment. During theprocess of V 351 Ori's transition from a Herbig Ae star with strongphotometric variations to a non-variable one, the maximum brightness inthe Stroemgren v, b and y magnitudes decreased, whereas that in uincreased, causing a strong blueing effect in the colour-magnitudediagrams. It should be noted that this effect happened at a decrease invisual brightness by about 0.2mag magnitude only. It is therefore causedby a different mechanism than that in V 351 Ori before the transitionand in UX Ori type stars, where the blueing effect occurs at a decreasein V of about 2.5mag. The transition, from a strongly variable star tothe state in which V 351 Ori is nearly constant at a level equal to thatof its maximum brightness before the transition, happened very fast(within 50 days), and went along the interstellar reddening line in thecolour-magnitude diagrams. A provisional model to explain V 351 Ori'sbehaviour, in which it is assumed that a temporarily strong accretion ofmatter onto the star took place, is proposed.
| Longterm Photometry of Variables at ESO - Part Two - the Second Data Catalogue 1986-1990
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&AS..102...79S&db_key=AST
| Observations of double stars and new pairs. XIV
Results of a continuing survey of visual double stars are presented,including 4880 measurements made from February 1987 to November 1989.The positions in WDS format and Durchmusterung numbers are given for 194pairs first reported here. Micrometer measurements of 1142 doubles madewith the Swarthmore 61 cm refractor are presented. Magnitudes areestimated for some of the objects. Plate measurements, plateorientations, position angles, number of nights, and measured exposuresare given. Visual observations of 342 pairs obtained in May 1989 atCerro Tololo, mostly with the 1.0 m reflector, are reported.
| Walraven photometry of nearby southern OB associations
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.
| Micrometer Observations of Double Stars and New Pairs - Part Ten
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1980ApJS...44..111H&db_key=AST
| Mesures d'etoiles doubles faites AU refracteur de 38cm de l'Observatoire de Nice.
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | אוריון |
| התרוממות ימנית: | 05h43m48.07s |
| סירוב: | +01°03'13.8" |
| גודל גלוי: | 8.884 |
| מרחק: | 211.416 פארסק |
| תנועה נכונה: | 4.5 |
| תנועה נכונה: | -2.5 |
| B-T magnitude: | 9.23 |
| V-T magnitude: | 8.913 |
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