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Multiple Period Search for K, M and C Type Semiregular Variables in TÜBITAK National Observatory
Yeşilyaprak, Cahit; Sahin, Timur; Iskender, Ahmet
In this study, periods obtained from long-term multi-bands (Johnson V and R filters) photometric observations of some K, M and C spectral type semiregular (SR) variables obtained with the T40 telescope (40 cm) and SSP5A photometer at TÜBITAK National Observatory (TNO) between 1998 and 2005 were examined. We have found that some of these SR variabl…
Microquasars: A Brief Overview and a Snapshot of GRS 1915+105 with INTEGRAL
Rodriguez, J.; Hannikainen, D. C.
Microquasars, sources of relativistic motion, have generated a lot of interest since their discovery. In this paper we shall briefly review some general properties of microquasars, and then focus on some recent observations of one of the more notorious microquasars, GRS 1915+105.
Emission Lines in 32 Cygni
Eaton, J. A.
I identify the profusion of emission lines seen in IUE spectra of 32 Cyg (K4-5 Ib+B6-7 IV-V) during total eclipse. With the exception of a very few weak lines, all of these are also seen in zeta Aur during its eclipse, and the stronger features appear in 31 Cyg. Seventy-four percent of these emission lines can be attributed to Fe II. Few are intri…
The upper atmosphere of Venus observed by Venus Express
López-Valverde, M. A.; Gilli, G.; García-Comas, M. +3 more
The upper atmosphere of Venus is still nowadays a highly unknown region in the scientific context of the terrestrial planetary atmospheres. The Earth's stratosphere and mesosphere continue being studied with increasingly sophisticated sounders and in-situ instrumentation. Also on Mars, its intensive on-going exploration is gathering a whole new se…
How unique is the local region of the Galaxy disk?
Heiter, U.; Luck, R. E.
We present the results of a spectroscopic study of over 500 dwarf and giant stars within 100 pc of the Sun. Using stellar metallicity data, the goal of this study is to determine whether there are any significant variations of metallicity related to stellar characteristics or location in the Galaxy. The abundance data are based on high-resolution …
Planetary science: Saturn's southern eye
Langenberg, Heike
Introduction to special section on Double Star-Cluster Coordinated Studies on Magnetospheric Dynamic Processes
Escoubet, C. P.; Zong, Q. -G.; Liu, Z. X. +1 more
The atmosphere of Venus: winds and clouds observed by VIRTIS/VENUS EXPRESS
Hueso, R.; Sánchez-Lavega, A.; Pérez-Hoyos, S. +1 more
After decades without a dedicated space mission, Venus, sometimes referred as Earth's twin planet, is again the subject of intense exploration. Venus Express (VEX), a mission of the European Space Agency, was launched in November 2005 and arrived to the planet in April 2006 where it is now in orbit. Among its scientific payload, the Visible and In…
GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS: Interhemispheric Comparison of Dipole Tilt Angle Effects on Latitude of Mid-Altitude Cusp
Liu, Zhen-Xing; Shi, Jian-Kui; Zhang, Tie-Long +1 more
A statistical study of interhemispheric comparison of dipole tilt angle effect on the latitude of the mid-altitude cusp is preformed by a data set of the Cluster cusp crossings over a 5-year period. The result shows that the dipole tilt angle has a clear control of the cusp latitudinal location. When the dipole tilts sunwards, the cusp is shifted …
Doing physics in star-forming regions with XMM-Newton
Montmerle, T.
Star-forming regions have been observed in X-rays since the first generation of satellites in the late 70s. They are very rich in magnetically-controlled X-ray phenomena: stellar flares and star-disk interactions in hundreds of T Tauri stars, confined winds in massive stars, etc. More recently, in a few low-mass stars, X-ray evidence has been foun…