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

HD 156296


Ýçindekiler

Görüntüler

Resim Yükleyin

DSS Images   Other Images


Ýlgili Makaleler

Photometric Variability in a Sample of 187 G and K Giants
We have used three automatic photoelectric telescopes to obtainphotometric observations of 187 G, K, and (a few) M0 field giants. Wefind low-amplitude photometric variability on timescales of days toweeks on both sides of the coronal dividing line (CDL) in a total of 81or 43% of the 187 giants. About one-third of the variables haveamplitudes greater than 0.01 mag in V. In our sample the percentage ofvariable giants is a minimum for late-G spectral classes and increasesfor earlier and later classes; all K5 and M0 giants are variable. Wealso obtained high-resolution, red wavelength spectroscopic observationsof 147 of the giants, which we used to determine spectralclassifications, vsini values, and radial velocities. We acquiredadditional high-resolution, blue wavelength spectra of 48 of the giants,which we used to determine chromospheric emission fluxes. We analyzedthe photometric and spectroscopic observations to identify the cause(s)of photometric variability in our sample of giants. We show that thelight variations in the vast majority of G and K giant variables cannotbe due to rotation. For giants on the cool side of the CDL, we find thatthe variability mechanism is radial pulsation. Thus, the variabilitymechanism operating in M giants extends into the K giants up to aboutspectral class K2. On the hot side of the CDL, the variability mechanismis most likely nonradial, g-mode pulsation.

Yeni bir Makale Öner


Ýlgili Baðlantýlar

  • - Baðlantý Bulunamadý -
Yeni Bir Baðlantý Öner


sonraki gruplarýn üyesi:


Gözlemler ve gökölçümü verileri

Takýmyýldýz:Herkul
Sað Açýklýk:17h15m22.29s
Yükselim:+32°34'00.2"
Görünürdeki Parlaklýk:8.284
Uzaklýk:277.008 parsek
özdevim Sað Açýklýk:-17.1
özdevim Yükselim:-20.4
B-T magnitude:9.761
V-T magnitude:8.406

Kataloglar ve belirtme:
Özgün isimleri   (Edit)
HD 1989HD 156296
TYCHO-2 2000TYC 2596-474-1
USNO-A2.0USNO-A2 1200-08284688
HIPHIP 84408

→ VizieR 'den daha fazla katalog ve tanýmlama isteyin