Search Publications
Terminal Velocities of the Winds from Rapidly Rotating OB Stars
Friend, David B.
This paper presents measurements of terminal velocities of OB stars which are rapid rotators, based on archival high-dispersion IUE spectra of the C IV resonance doublet. The terminal velocities of the most rapidly rotating stars appear to be systematically lower than those of the less rapidly rotating stars (at least for the cooler stars), althou…
The ultraviolet spectrum of solar analogs.
Altamore, A.; Rossi, C.; Rossi, L. +1 more
The ultraviolet high resolution IUE spectrum between 2600 and 3200 A of a sample of stars classified as solar analogs by Hardorp (1982 and references therein), including the southern solar twin HR 2290, is studied. A list of Fe II absorption line identifications and equivalent widths in the considered spectral region is presented. An analysis of t…
The long-period binary UU CANCRI as a system that has reversed its mass ratio.
Eaton, J. A.
UU Cnc is a 96-d binary system (K4 111+?) which has been interpreted as a contact binary, presumably representing the common-envelope stage of evolution. Since this is such a bizarre possibility, we have tested it by using the rotational velocity to determine the mass ratio and by obtaining lUE observations to search for the hot, accreting source …
The photospheric temperature and metal abundance of the compact star H 1504+65.
Barstow, M. A.; Tweedy, R. W.
A new analysis of an Exosat low-energy telescope observation of the hot compact star H1504 + 65 is presented. Earlier results had failed to take into account the large point-spread function produced by the boron filter, and hence the count rate had been underestimated by a large factor. On comparing the data with a new grid of model atmospheres co…
Accretion disk in the high-redshift quasar HS 1700+6416.
Siemiginowska, A.; Dobrzycki, A.
We apply the standard accretion disk model to reproduce the EUV spectrum of the high-redshift (z = 2.72) quasar HS 1700+6416. We find a satisfactory fit to the observed spectrum. The contribution of the accretion disk to the continuum emission in the soft X-ray spectral region may be significant.
COS-B: The highlights
Bennett, Kevin
The COS-B satellite operated from August 1975 until April 1982 during which time an extensive survey of the Galaxy was made in the energy range 50 MeV to 5 Gev. The Caravane Collaboration built the gamma-ray telescope and performed the bulk of the scientific data reduction. Since the data are now available to the Astrophysics community at large, s…
The nature of the hot subdwarf SB 744.
Unglaub, K.; Bues, I.
Various spectra in the visual wavelength range, one low-resolution ultraviolet spectrum, and color measurements in the red region have been taken to clarify the nature of the hot subdwarf SB 744. The colors and weak metallic lines as well as a G-band (CH) in the visual spectra indicate the existence of a cool companion, whereas the hydrogen and he…
Spectro-imagery of small diameter galaxies. I. Markarian 600 = MCG 1-08-008.
Figon, P.; Vanderriest, C.; Augarde, R. +1 more
The blue dwarf irregular galaxy Markarian 600 was observed by classical (slit) spectrography as well as bidimensional (fibre optics) spectrography. This object is found to be metal-deficient (about 1/8 solar) with an underabundant young stellar content. Two knots of gas ionized by hot stars (T_eff_ ~/- 50 000 K) are imbedded in a faint red envelop…
The Hot DOA1 Degenerate HZ 21: A Search for Circumstellar/Photospheric Metals and Peculiar Absorption at He II
Sion, E. M.; Vauclair, G.; Liebert, J. +2 more
A high-resolution IUE spectrum of the hot DO1 degenerate HZ 21 was obtained by combining US1 + European 2 low-background observing shifts. The SWP image reveals a rich spectrum of interstellar absorption lines with an average velocity in the line of sight to HZ 21 of -30 km/s. However, there is no clear evidence of any highly or lowly ionized meta…
The Problem of the HIPPARCOS Reference Frame
Lattanzi, M. G.; Bucciarelli, B.; Bernacca, P. L.
The basic principles of the realization of a fundamental optical reference frame by using space platforms are outlined in the light of the first of such astrometry projects, i.e., the HIPPARCOS mission of the European Space Agency. The available adaptations of these principles, expected to lead to a HIPPARCOS catalog of more than 100,000 star posi…