首页     开始     To Survive in the Universe    
Inhabited Sky
    News@Sky     天文图片     收集     论坛     Blog New!     常见问题     新闻     登录  

HD 188256


目录

图像

上传图像

DSS Images   Other Images


相关文章

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.

Radial-velocity measurements. III - Ground observations accompanying the HIPPARCOS satellite observation program: Measurements of the radial velocities of 391 stars in 12 fields
The radial velocities of 391 stars, obtained with the Fehrenbachobjective prism associated to the Schmidt telescope of the Observatoirede Haute-Provence are presented. These stars belong to fields speciallychosen for containing several Hipparcos input catalog star members. Eachfield is presented independently. The list includes HD and BDidentifiers when available, 1950 coordinates, spectral type, and B and Vmagnitudes as they appear in the CSI catalog, the radial velocity, theprobable error, the number of independent measurements and commentariessuch as known radial velocity and their origin.

提交文章


相关链接

  • - 没有找到链接 -
提交链接


下列团体成员


观测天体数据

星座:天鵝座
右阿森松:19h52m41.55s
赤纬:+38°49'18.1"
视星:8.052
距离:398.406 天文距离
右阿森松适当运动:-7.6
赤纬适当运动:-8.6
B-T magnitude:9.262
V-T magnitude:8.152

目录:
适当名称   (Edit)
HD 1989HD 188256
TYCHO-2 2000TYC 3137-894-1
USNO-A2.0USNO-A2 1275-12589852
HIPHIP 97822

→ 要求更多目录从vizier