Search Publications
The effect of rotation on the absolute visual magnitudes of OB stars measured with Hipparcos.
Kudritzki, R. P.; Hoogerwerf, R.; Lamers, H. J. G. L. M. +2 more
We derive the absolute visual magnitudes of 14 OB-stars of luminosity class III to V from the parallaxes measured by Hipparcos. The values of M_V_ can differ by as much as 1.5mag from the M_V_-spectral type calibration. Slowly rotating stars, vsini<100km/s, are significantly fainter in M_V_ than stars with vsini>100km/s of the same spectral …
Candidate polar-ring galaxies in the Hubble Deep Field.
Reshetnikov, V. P.
We discuss the properties of two peculiar galaxies (2-809 and 2-906) selected in the Hubble Deep Field as possible candidates to high-redshift (z=~1) polar-ring galaxies. We found that the presence of polar-ring galaxies in a random deep field gives some support for a galaxy interaction rate steeply increasing with redshift.
EUV Emission from RS Canum Venaticorum binaries.
Doyle, J. G.; Mathioudakis, M.; Mitrou, C. K. +1 more
We performed a study of 104 RS CVn systems in the extreme ultraviolet (EUV) using the all-sky survey data obtained by the Extreme Ultraviolet Explorer (EUVE). The present sample includes several new RS CVn detections; 11 more than in the published EUVE catalogs, and 8 more than in the ROSAT Wide Field Camera catalog. The ratio of detections to non…
Subarcsec structures in the double nucleus of NGC6240 disclosed with HST at 370, 430 and 500 NM
Barbieri, C.; Komossa, S.; Rafanelli, P. +4 more
We present an analysis of three medium band width (FWHM ~ 400 - 450 Angstroms) images of the nuclear region of NGC6240 taken with the pre-COSTAR Faint Object Camera (FOC) on board of the Hubble Space Telescope. The first filter band comprises the [OII]lambda 3727 doublet, the second measures the blue continuum around 4400 { Angstroms} and the thir…
Redshift survey of gravitational arclets in Abell 2390.
Soucail, G.; Bezecourt, J.
In this paper, we present new determinations of redshifts on a sample of gravitational arclets identified in the cluster of galaxies Abell 2390. The arclets candidates were selected from their elongated morphology as seen in recent deep HST images of the cluster. The spectra display various features, and the redshifts of the background objects ran…
HD 111786: a spectroscopic binary λ Boo star.
Gerbaldi, M.; Faraggiana, R.; Burnage, R.
HD 111786 = HR 4881 is one of the most interesting λ Boo stars; in fact it is one of the few stars of this class which shows narrow features that can be interpreted as remnants of the circumstellar matter from which star was formed. On the basis of optical observations and inspection of IUE spectra, we demonstrate that HD 111786 is, as a matter of…
An estimate of the solar background irradiance power spectrum.
Rabello-Soares, M. C.; Roca Cortes, T.; Jimenez, A. +2 more
Knowledge of the solar irradiance background is of great importance to solar and stellar physics. In particular, its contribution to the solar oscillations power spectrum is highly relevant as it represents the ultimate limit to the sensitivity of solar oscillations' observations. An analysis of the power spectra of the solar photometric data comi…
Doppler imaging of stellar surface structure. III. The X-ray source HD 116544 = IN Virginis.
Strassmeier, K. G.
We present the first Doppler image of the EXOSAT X-ray source EXO 1321.8-0203, recently identified to be a chromospherically active star exhibiting periodic light variations and consequently named INVirginis. Our high-resolution spectra show INVirginis to be a single-lined spectroscopic binary with an orbital period of 8.2 days, very strong CaII e…
The iron abundance in helium star HD 144941.
Jeffery, C. S.; Harrison, P. M.
The iron abundance in the helium star HD 144941 has been measured from ultraviolet #1iii lines. It is 1.9+/-0.2dex below solar and confirms the low metallicity (Z=0.0003) previously determined from measurements of CNO and other light elements. The result is important because the low CNO metallicity must be reflected in the iron-group elements in o…
Mid-infrared spectroscopy of the hyperluminous infrared galaxy IRAS P09104+4109.
Kawara, K.; Murayama, T.; Taniguchi, Y. +2 more
We present mid-infrared spectroscopy of the hyperluminous infrared galaxy IRAS 09104+4109 based on observations with ISOCAM CVF. We have detected the emission peak around 8µm as well as the absorption feature around 10µm possibly due to silicate, providing evidence for a dusty torus around the central engine. Comparing the observationa…