Search Publications
Proper motions of Hipparcos stars in two plate areas.
Wang, Shuhe; Tang, Zhenghong; Jin, Wenjing
By using the ACT Reference Catalogue as a preliminary reference catalogue, the authors have reduced 31 exposures on 15 plates in areas of two plates taken with the 40 cm refractor at She-Shan Station of Shanghai Astronomical Observatory. By means of the central overlapping technique and the iterative process, the highly precise positions and prope…
Ultraluminous Infrared Galaxies: Far-Infrared Highlights
Clements, D. L.
We discuss two significant recent developments in the far-IRwith relevance to the study of Ultraluminous Infrared Galaxies(ULIRGs). The first of these is the discovery of an isotropiccosmological infrared background radiation (CIB). This has beendetected in observations by two different instruments (FIRAS (Puget etal. 1996, Hauser et al. 1998) and…
Metallicities of Nearby K-Dwarfs
Flynn, Chris; Kotoneva, Eira
The so-called ``G-dwarf problem'' emerged in the 1960's when it was noticed that the observed metal distribution of nearby stars differs from what is expected in simple models of the evolution of the Galaxy. We have determined metallicities for a sample of over 100 K dwarfs drawn from the Hipparcos catalog, using R-I colours to estimate effective …
A new view of our star: observations from SOHO.
Harrison, R. A.
The ESA/NASA Solar and Heliospheric Observatory (SOHO) spacecraft is revolutionizing our view of our star, the Sun. Its 12 instrument payload allows one to delve into the body of the Sun itself, to observe the mysterious solar atmosphere and to investigate the influence of the Sun on interplanetary space. The mission has come up with a string of n…
Kinematics of RS CVn and W UMa binaries in the Hipparcos catalogue.
Yesilyaprak, C.; Özdemir, T.; Aslan, Z. +1 more
Space motions of RS CVn and W UMa binaries have been calculated using parallaxes and proper motions from Hipparcos catalogue and radial velocities from the literature. The authors have calculated the mean motions and velocity dispersions. They have excluded those binaries with relative parallax errors ≥0.5. The comparison of the asymmetric drift, …
The evolutionary status of HD 104237, ɛ Cha and HD 100546
Hu, Jing-yao; Shen, Chuan-jian
Using the new data from Hipparcos and the TD-1 UV data, we fix the positions of three objects, HD 104237, HD 100546 and ɛ Cha in the HR diagram and discuss their theoretical evolutionary status.
Galactic kinematics derived from classical Cepheids.
Zhu, Zi
On the basis of radial velocity and Hipparcos proper motion data, the author has analyzed the galactic kinematics of classical Cepheids. Using the 3-D Ogorodnikov-Milne model he has determined the rotational velocity of the Galaxy to be V0 = 240.5±10.2 km/s, on assuming a galactocentric distance of the Sun of R0 = 8.5 kpc. Th…
A Survey for Hα emitting galaxies AT z ≃ 2.2
Oliva, E.; Moorwood, A. F. M.; Cuby, J. G. +1 more
The deepest survey for Hα emitting galaxies at z ≃ 2.2has recently been made in narrow-band (≃ 1%) filters around2.1µm using SOFI at the ESO NTT telescope. An effective area of≃ 100 sq. arcmin and a comoving volume of 9000 Mpc3 (forH0 = 50, q0 = 0.5) has been covered to a volume weighted 3σ line flux limit of…
Massive accretion disks
Scoville, N. Z.
Recent high resolution near infrared (HST-NICMOS) and mm-interferometric imaging have revealed dense gas and dust accretion disks in nearby ultra-luminous galactic nuclei. In the best studied ultraluminousIR galaxy, Arp 220, the 2µm imaging shows dust disks in both of the merging galactic nuclei and mm-CO line imaging indicates molecular gas…
Voyager Far-Ultraviolet Observations of Globular Clusters
Chavez, M.; Landsman, Wayne B.; Holberg, Jay B.
We report on the observations of nine globular clusters carried out by the Voyager ultraviolet spectrometers (UVSs). Three of the observed clusters, M13, NGC 6752, and M70, exhibit an intense far-ultraviolet (FUV) spectrum down to the Lyman limit. However, the spectrum obtained for NGC 6752 is heavily contaminated by the nearby star HD 177999 for …