Home     Getting Started     To Survive in the Universe    
Inhabited Sky
    News@Sky     Astro Photo     The Collection     Forum     Blog New!     FAQ     Press     Login  

HD 7931


Contents

Images

Upload your image

DSS Images   Other Images


Related articles

Pulkovo compilation of radial velocities for 35495 stars in a common system.
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.

Are there optical counterparts to gamma-ray bursts?
Detailed studies are presented of three new starlike images identifiedon archival optical plates as located within the boundaries of the errorboxes associated with three gamma ray bursts (GRBs). One of the imagesis found to be a plate defect, and troubling aspects are found in theother two images. The results indicate that suggestions that GRBs arenecessarily associated with optical flashes should be treated with greatcaution.

A kinematic and abundance survey at the galactic poles
The DDO intermediate band system is used to obtain detailed informationabout abundance gradients and velocity dispersions in the galaxy, withan emphasis on the properties of halo stars in the range of from 1 to 5kpc. The DDO abundance index is calibrated agianst (Fe/H) for metal-poorstars, with a resulting gradient of about -0.2 per kpc. However, whenthe sample is divided into two subsamples with (Fe/H) less than -0.5 andequal to or greater than -0.5, the gradients are -0.14 and 0.00,respectively. DDO observations of about 1000 stars, mostly G5-K5 giants,show that the velocity dispersion increases both with decrease inmetallicity and increase in z distance. The abundances found for high-zstars are similar to the A-star results of Rodgers (1971) in that abouthalf the K giants above 1 kpc appear to have solar abundances.

The K-giant population at the South Galactic Pole
CN anomalies and distances from the galactic plane have been derivedthrough DDO photometry for 171 late-type giant and subgiant stars nearthe South Galactic Pole. The previously found trend of the difference inCN concentration with distance (approximately equal to 0.09/kpc) holdsto approximately 2 kpc, but at greater distances from the plane theslope becomes approximately zero. The giants beyond 2 kpc are ofessentially normal composition or only slightly underabundant in heavierelements.

Submit a new article


Related links

  • - No Links Found -
Submit a new link


Member of following groups:


Observation and Astrometry data

Constellation:Sculpteur
Right ascension:01h18m32.25s
Declination:-28°43'58.6"
Apparent magnitude:7.926
Distance:110.988 parsecs
Proper motion RA:75.6
Proper motion Dec:5.1
B-T magnitude:9.209
V-T magnitude:8.032

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 7931
TYCHO-2 2000TYC 6427-1018-1
USNO-A2.0USNO-A2 0600-00503826
HIPHIP 6116

→ Request more catalogs and designations from VizieR