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

HD 90731


Contents

Images

Upload your image

DSS Images   Other Images


Related articles

Identification of moving groups and member selection using HIPPARCOS data
A new method to identify coherent structures in velocity space - movinggroups - in astrometric catalogues is presented: the Spaghetti method.It relies on positions, parallaxes and proper motions, and is ideallysuited to searching for moving groups in the Hipparcos Catalogue. Noradial-velocity information is required. The method has been testedextensively on synthetic data, and applied to the Hipparcos measurementsfor the Hyades and IC 2602 open clusters. The resulting lists of membersagree very well with those of Perryman et al. for the Hyades and thoseof Whiteoak & Braes for IC 2602.

Open clusters with Hipparcos. I. Mean astrometric parameters
New memberships, mean parallaxes and proper motions of all 9 openclusters closer than 300 pc (except the Hyades) and 9rich clusters between 300 and 500 pc have been computed using Hipparcosdata. Precisions, ranging from 0.2 to 0.5 mas for parallaxes and 0.1 to0.5 mas/yr for proper motions, are of great interest for calibratingphotometric parallaxes as well as for kinematical studies. Carefulinvestigations of possible biases have been performed and no evidence ofsignificant systematic errors on the mean cluster parallaxes has beenfound. The distances and proper motions of 32 more distant clusters,which may be used statistically, are also indicated. Based onobservations made with the ESA Hipparcos astrometry satellite

Starbursts, binary stars, and blue stragglers in local superclusters and groups. I - The very young disk and young disk populations
The distributions in the HR diagram with theoretical time-constant locifor stars in several young clusters and superclusters are compared todemonstrate that 'blue stragglers' in these aggregates are mostfrequently simply single massive (mode B) stars formed in bursts of starformation that occur at discrete intervals in time following theformation of the bulk of the low-mass (mode A) stars in the aggregate.The characteristics of the close binary systems in these aggregates areexamined to show that, in several cases, mass transfer by Roche lobeoverflow has or will occur and that, in some instances, the system wouldhave appeared as a blue straggler prior to the mass-transfer event, and,in other instances, mass transfer will lead to the identification of thesystem as a blue straggler. Thus, it is concluded that the bluestraggler phenomenon has at least two distinct physical origins: it mayoriginate from delayed formation (starbursts) or from 'delayedevolution' in some close binaries (mass transfer from an evolvedprimary).

Submit a new article


Related links

  • - No Links Found -
Submit a new link


Member of following groups:


Observation and Astrometry data

Constellation:りゅうこつ座
Right ascension:10h26m44.43s
Declination:-64°21'06.1"
Apparent magnitude:7.406
Distance:142.653 parsecs
Proper motion RA:-12.9
Proper motion Dec:12.1
B-T magnitude:7.436
V-T magnitude:7.409

Catalogs and designations:
Proper Names   (Edit)
HD 1989HD 90731
TYCHO-2 2000TYC 8964-310-1
USNO-A2.0USNO-A2 0225-08488356
HIPHIP 51131

→ Request more catalogs and designations from VizieR