We report the detection of an orbital, ellipsoidal modulation at a period of 16.8h for V2107 Oph (Nova Ophiuchi 1977, H1705-25), from R-band photometry. From this period and the observed magnitude, constraints on the distance are calculated (2.0-8.4 kpc), which are consistent with that obtained previously from X-ray observations (3kpc). By

We first discovered the presence of a particularly massive cloud in the neighborhood of the Sun, close to the Galactic plane in the direction of Perseus, toward l = 150 deg, b = -10 deg, using interstellar absorption by the 7699 A resonance line of K I (Trapero et al. 1992). In the present investigation we show the results of mapping the cloud in

Planetary Nebulae (PNe) are highly representative of the lastest stages of intermediate mass stellar evolution. However, there are still many unresolved questions in their evolutionary scheme. Mass loss processes during the Asymptotic Giant Branch (AGB) are not fully understood. Binarity, rotation and magnetic fields may play an important role in

New optical and near-infrared (NIR) K-band images of the inner 3 kpc region of the nearby Virgo spiral M100 (NGC 4321) display remarkable morphological changes with wavelength. While in the optical the light is dominated by circumnuclear zone of enhanced star formation, the morphological features in the 2.2 micrometer image correspond to a newly

We present the data and initial results from a combined Hubble Space Telescope (HST)/IUE/ground-based spectroscopic monitoring campaign on the Seyfert 1 galaxy NGC 5548 that was undertaken in order to address questions that require both higher temporal resolution and higher signal-to-noise ratios than were obtained in our previous multiwavelength

In this paper, we intend to explain the behaviour of the evolved double-lined eclipsing binary TZ Fornacis on the basis of tidal evolution derived from standard theories and the use of modern internal structure stellar models. TZ For is a binary system with a period of 75.7days and a circular orbit, in which the less massive component (1.95Msun_)