Home     Baþlangýç     Evrende yaþayabilmek için    
Inhabited Sky
    News@Sky     Gökyüzü görüntüsü     Koleksiyon     Forum     Blog New!     SSS     Basýn     Giriþ  

HD 89971


Ýçindekiler

Görüntüler

Resim Yükleyin

DSS Images   Other Images


Ýlgili Makaleler

Statistical Constraints for Astrometric Binaries with Nonlinear Motion
Useful constraints on the orbits and mass ratios of astrometric binariesin the Hipparcos catalog are derived from the measured proper motiondifferences of Hipparcos and Tycho-2 (Δμ), accelerations ofproper motions (μ˙), and second derivatives of proper motions(μ̈). It is shown how, in some cases, statistical bounds can beestimated for the masses of the secondary components. Two catalogs ofastrometric binaries are generated, one of binaries with significantproper motion differences and the other of binaries with significantaccelerations of their proper motions. Mathematical relations betweenthe astrometric observables Δμ, μ˙, and μ̈ andthe orbital elements are derived in the appendices. We find a remarkabledifference between the distribution of spectral types of stars withlarge accelerations but small proper motion differences and that ofstars with large proper motion differences but insignificantaccelerations. The spectral type distribution for the former sample ofbinaries is the same as the general distribution of all stars in theHipparcos catalog, whereas the latter sample is clearly dominated bysolar-type stars, with an obvious dearth of blue stars. We point outthat the latter set includes mostly binaries with long periods (longerthan about 6 yr).

Yeni bir Makale Öner


Ýlgili Baðlantýlar

  • - Baðlantý Bulunamadý -
Yeni Bir Baðlantý Öner


sonraki gruplarýn üyesi:


Gözlemler ve gökölçümü verileri

Takýmyýldýz:Altilik
Sað Açýklýk:10h23m10.95s
Yükselim:+03°39'06.4"
Görünürdeki Parlaklýk:8.25
Uzaklýk:210.084 parsek
özdevim Sað Açýklýk:2.4
özdevim Yükselim:-1.3
B-T magnitude:8.745
V-T magnitude:8.291

Kataloglar ve belirtme:
Özgün isimleri   (Edit)
HD 1989HD 89971
TYCHO-2 2000TYC 249-857-1
USNO-A2.0USNO-A2 0900-06676333
HIPHIP 50865

→ VizieR 'den daha fazla katalog ve tanýmlama isteyin