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Ýlgili Makaleler
On the PMS Star HBC 498 and Its Associated Nebulous Stars (Research Note)
We present recent spectroscopic (resolution ≥ 1750 at λ =6708 Å) and photometric (ubvy- β ) observations of thesingular weak-line Tstar HBC 498 (= DL Ori/G1) still associated with itsparental dust cloud and of at least four other bright neighboring starsassociated with reflection nebulosities that together form a tighttrapezium in L1641 in Orion. Most of them have the youth signature of Li0 in their spectra. We find that two of the objects are "classic" Tandanother two are "weak-line" Tstars. From the data and their comparisonwith models of pre-main sequence stellar evolution we find that they arecoeval, and that they have masses of the order of 1 Mȯ and ages ofthe order of their gravitational contraction times or less (≈ 1 -5×105 yr). Finally, we briefly discuss theirevolutionary state and its repercussions.
| Detection of Circumstellar Dust Shells of Some Distant B Type Stars
The analisys of the IRAS data proved the existence of circumstellar dustshells in 8 B type stars, that were suggested to be embedded in smalldust clouds or circumstellar dust shells on the basis of the Glazar UVSpace Telescope observations. The presence of circumstellar dust shellsin two other stars is suspected.
| A study of some stars with circumstellar dust envelopes. I
We present the results of a study of circumstellar dust envelopes of 36stars of early(O-B-A) types in the directions of the associations CasOB1, Cas OB2, Per OB1, and Ori OB1. We determine the absorption at 1640Å, the linear radius of the dust envelopes, the mean value of thecoefficient k, and the masses of the envelopes. They differsignificantly from one another.
| Far-ultraviolet stellar photometry: A field in Orion
Far-ultraviolet photometry for 625 objects in Orion is presented. Thesedata were extracted from electrographic camera images obtained duringsounding rocket flights in 1975 and 1982. The 1975 images were centeredclose to the belt of Orion while the 1982 images were centeredapproximately 9 deg further north. One hundred and fifty stars fell inthe overlapping region and were observed with both cameras. Sixty-eightpercent of the objects were tentatively identified with known starsusing the SIMBAD database while another 24% are blends of objects tooclose together to separate with our resolution. As in previous studies,the majority of the identified ultraviolet sources are early-type stars.However, there are a significant number for which no such identificationwas possible, and we suggest that these are interesting objects whichshould be further investigated. Seven stars were found which were brightin the ultraviolet but faint in the visible. We suggest that some ofthese are nearby white dwarfs.
| The Orion complex according to observations of the space telescope Glazar.
Not Available
| 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.
| Stars of Early Types in the Region of Stellar Association OB1 Observed with the Glazar Telescope
Not Available
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Avci |
| Sað Açýklýk: | 05h41m00.40s |
| Yükselim: | -08°03'16.1" |
| Görünürdeki Parlaklýk: | 8.037 |
| Uzaklýk: | 320.513 parsek |
| özdevim Sað Açýklýk: | 1.3 |
| özdevim Yükselim: | -7.8 |
| B-T magnitude: | 8.154 |
| V-T magnitude: | 8.047 |
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