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מאמרים קשורים
New beta Cephei and SPB Stars Discovered in Hipparcos Photometry
We discuss 34 stars for which we detected new frequencies in HipparcosHp magnitudes. 13 of these stars are variables discovered in this paper.For 20 stars, we derive log T_eff and log g from Stromgren or Genevaphotometry.We classify one new beta Cep star, HIP 88352, two new beta Cep suspects,HIP 54753 and 88123, four new SPBs, HIP 1030, 39206, 46192 and 111147,and two SPB suspects, HIP 75787 and 98778. We find the last star to betriply-periodic and we show that the frequencies detected in Hpmagnitudes are present in the photoelectric observations of Hill etal(1976).Finally, we discover the hottest variable of the SPB type, namely, HIP1030.
| New Estimates of the Solar-Neighborhood Massive Star Birthrate and the Galactic Supernova Rate
The birthrate of stars of masses >=10 Msolar is estimatedfrom a sample of just over 400 O3-B2 dwarfs within 1.5 kpc of the Sunand the result extrapolated to estimate the Galactic supernova ratecontributed by such stars. The solar-neighborhood Galactic-plane massivestar birthrate is estimated at ~176 stars kpc-3Myr-1. On the basis of a model in which the Galactic stellardensity distribution comprises a ``disk+central hole'' like that of thedust infrared emission (as proposed by Drimmel and Spergel), theGalactic supernova rate is estimated at probably not less than ~1 normore than ~2 per century and the number of O3-B2 dwarfs within the solarcircle at ~200,000.
| Catalog of Galactic β Cephei Stars
We present an extensive and up-to-date catalog of Galactic β Cepheistars. This catalog is intended to give a comprehensive overview ofobservational characteristics of all known β Cephei stars, coveringinformation until 2004 June. Ninety-three stars could be confirmed to beβ Cephei stars. We use data from more than 250 papers publishedover the last nearly 100 years, and we provide over 45 notes onindividual stars. For some stars we reanalyzed published data orconducted our own analyses. Sixty-one stars were rejected from the finalβ Cephei list, and 77 stars are suspected to be β Cepheistars. A list of critically selected pulsation frequencies for confirmedβ Cephei stars is also presented.We analyze the β Cephei stars as a group, such as the distributionsof their spectral types, projected rotational velocities, radialvelocities, pulsation periods, and Galactic coordinates. We confirm thatthe majority of the β Cephei stars are multiperiodic pulsators. Weshow that, besides two exceptions, the β Cephei stars with highpulsation amplitudes are slow rotators. Those higher amplitude starshave angular rotational velocities in the same range as thehigh-amplitude δ Scuti stars (Prot>~3 days).We construct a theoretical HR diagram that suggests that almost all 93β Cephei stars are main-sequence objects. We discuss theobservational boundaries of β Cephei pulsation and the physicalparameters of the stars. We corroborate that the excited pulsation modesare near to the radial fundamental mode in frequency and we show thatthe mass distribution of the stars peaks at 12 Msolar. Wepoint out that the theoretical instability strip of the β Cepheistars is filled neither at the cool nor at the hot end and attempt toexplain this observation.
| The Carina Spiral Feature: Strömgren-Hβ photometry approach. I. The photometric data-base
A data-base collating all uvbybeta photometry available at present forO-B9 stars brighter than 10th visual magnitude in the field of theCarina Spiral Feature is presented. The completeness and homogeneity ofthe data-base are discussed.Based on CDS data.Table 1 is only available in electronic form at the CDS via anonymousftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/410/523
| Catalog of Galactic OB Stars
An all-sky catalog of Galactic OB stars has been created by extendingthe Case-Hamburg Galactic plane luminous-stars surveys to include 5500additional objects drawn from the literature. This work brings the totalnumber of known or reasonably suspected OB stars to over 16,000.Companion databases of UBVβ photometry and MK classifications forthese objects include nearly 30,000 and 20,000 entries, respectively.
| Stromgren and Hβ photometry of OB stars in the region of the Carina Spiral Feature
Stromgren and Hβ photometry of 130 stars in the Carina section ofthe Milky Way is presented. The color excesses and the distances of allstars are obtained. A good agreement is found between the CM and HRdiagrams and the spatial distribution of these stars. Tables 1, 2, 4 and5 are only available in electronic form at the CDS via anonymous ftp to130.79.128.5 or via http://cdsweb.u-strasbg.fr/Abstract.html
| A velocity separation of stars and gas in Carina
In the Carina spiral feature near galactic longitude of 290 deg, asignificant difference of 10-20 km/sec is observed between the motionsof the young stars and neutral hydrogen gas. The region of theseanomalous motions may extend from 3 to 7 kpc from the sun and is only 2deg wide in longitude. This region may best be described as a narrowsheet, particularly since the extent in latitude is uncertain. Twopossible interpretations of the optical and radio evidence for spiralstructure would place this peculiar region either on the inner side ofthe spiral feature or along the central axis of the optical spiral arm.The observed velocity anomaly has the right sign and a reasonableamplitude for a shock-front effect, and the applicability of Roberts'sshock-wave model of spiral structure to this anomalous region isdiscussed.
| The OB stars in Carina-Centaurus
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1969MNRAS.143..273F&db_key=AST
| Spectral classification and photometry of southern B stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1961MNRAS.122..239F&db_key=AST
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | שדרית |
| התרוממות ימנית: | 11h12m36.41s |
| סירוב: | -58°38'38.4" |
| גודל גלוי: | 8.331 |
| מרחק: | 990.099 פארסק |
| תנועה נכונה: | -3.3 |
| תנועה נכונה: | 4.7 |
| B-T magnitude: | 8.338 |
| V-T magnitude: | 8.332 |
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INHABITED SKY
