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The 74th Special Name-list of Variable Stars
We present the Name-list introducing GCVS names for 3153 variable starsdiscovered by the Hipparcos mission.
| Correlation of the HIPPARCOS and Allegheny Observatory Parallax Catalogs
No significant difference is found between the systems of the Hipparcosand Allegheny Observatory MAP parallax catalogs. The correlation of theparallaxes of 63 stars common to both programs is 0.9995 +/- 0.0001,with an average standard deviation of the difference of 0.0023". Whilethere is no indication of systematic difference in the two programs, ourstudy suggests that the formal errors in one or both catalogs aresomewhat underestimated.
| An Einstein Observatory SAO-based catalog of B-type stars
About 4000 X-ray images obtained with the Einstein Observatory are usedto measure the 0.16-4.0 keV emission from 1545 B-type SAO stars fallingin the about 10 percent of the sky surveyed with the IPC. Seventy-fourdetected X-ray sources with B-type stars are identified, and it isestimated that no more than 15 can be misidentified. Upper limits to theX-ray emission of the remaining stars are presented. In addition tosummarizing the X-ray measurements and giving other relevant opticaldata, the present extensive catalog discusses the reduction process andanalyzes selection effects associated with both SAO catalog completenessand IPC target selection procedures. It is concluded that X-rayemission, at the level of Lx not less than 10 exp 30 ergs/s, is quitecommon in B stars of early spectral types (B0-B3), regardless ofluminosity class, but that emission, at the same level, becomes lesscommon, or nonexistent, in later B-type stars.
| Multichannel astrometric photometer-based parallaxes of evolved stars - Chi Cygni, 51 Andromedae, and OP Andromedae
Using data from Allegheny Observatory's Thaw/MAP astrometric system,absolute parallaxes are presented for Chi Cygni, 51 Andromedae, thenewly discovered RS CVn variable OP Andromedae, and selected stars inthese fields. Using existing angular diameter measures and the newparallaxes, linear diameters for Chi Cygni and 51 And are given. ChiCygni has a perturbation in declination having a period of 0.75 yr andan amplitude of +/- 5 mas. Owing to the extreme variability of ChiCygni, no further characterization of the system is possible at thistime. Other results of spectral interest include the detection of aperturbation in the motion of BD +47 deg 466. This system was found tohave a parallax of 14.4 +/- 1.2 mas.
| Spectral types and luminosity classifications of MAP region stars using UBVRI and DDO photometry
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1989AJ.....98.1768C&db_key=AST
| Spectral types for early-type stars observed by SKYLAB
MK spectral types are presented for 246 early-type stars observed withthe S-019 ultraviolet stellar astronomy experiment on Skylab. K-linetypes are also given where applicable, and various peculiar stars areidentified. The peculiar stars include five silicon stars, a shell star,a helium-rich star, a silicon-strontium star, a chromium-europium star,and two marginal metallic-line stars.
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | ברבור |
| התרוממות ימנית: | 19h50m04.12s |
| סירוב: | +32°38'24.7" |
| גודל גלוי: | 8.212 |
| מרחק: | 400 פארסק |
| תנועה נכונה: | -6.6 |
| תנועה נכונה: | -8.5 |
| B-T magnitude: | 8.192 |
| V-T magnitude: | 8.211 |
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