Observations of H-alpha, iron, and oxygen lines in B, Be, and shell stars

We have carried out a spectroscopic survey of several B, Be, and shell stars in optical and near-infrared regions. Line profiles of the H-alpha line and of selected Fe II and O I lines are presented.Comment: 23 pages, 45 figures; accepted in Astronomy & Astrophysic

Apsidal motion in the eclipsing binary AS Camelopardalis

We report several new reliable times of minimum of the eclipsing binary AS Cam. Using all precise timings found in the literature, the O-C diagram is analyzed and improved values for the elements of the apsidal motion are computed. The discrepancy between observed rotational velocity of the line of apsides and the theoretically expected value still remains unresolved

Period changes in W UMa-type eclipsing binaries: DK Cygni, V401 Cygni, AD Phoenicis and Y Sextantis

We present a period analysis of the four well-known W UMa-type eclipsing binaries DK Cyg (P = 0\hbox{.\!\!^{\rm d}}47 ), V401 Cyg (0\hbox{.\!\!^{\rm d}}58 ), AD Phe (0\hbox{.\!\!^{\rm d}}38 ) and Y Sex (0\hbox{.\!\!^{\rm d}}42 ). Several new times of minimum light, recorded photoelectrically, have been gathered. Analysis of all available eclipse timings of the DK Cygni and V401 Cygni has confirmed a significant increase in period of $1.15 \ 10^{-10}$ and $1.48 \ 10^{-10}$ day cycle-1, respectively. A simultaneous solution of the $B, V$ and R light curves was computed for V401 Cyg using the Binary Maker 2.0 synthetic lightcurve software. This solution indicates that V401 Cyg is in contact with a filing factor of 46%.
The period of AD Phe seems to be constant. Period changes of Y Sex could be explain by a light-time effect caused by a third body in an eccentric orbit with a period of 58 years.

Apsidal motion in eccentric eclipsing binaries: V871 Aql, V345 Lac, V401 Lac and CR Sct

About thirty new times of minimum light recorded with photoelectric or CCD photometers were obtained for several little studied eccentric-orbit eclipsing binaries V871 Aql (P = 3(d).0, e = 0.13), V345 Lac (7(d).5, 0.46), V401 Lac (2(d).0, 0.10) and CR Sct (4(d).2, 0.09). Their O-C diagrams were analyzed using all reliable timings found in the literature and in all cases an apsidal motion was either discovered or confirmed. The new values for the elements of the apsidal motion were derived. We find periods of apsidal motion of about 255, 7000, 79.4 and 4400 years for V871 Aql, V345 Lac, V401 Lac and CR Set, respectively

Tumbling asteroids

We present both a review of earlier data and new results on non-principal axis rotators (tumblers) among asteroids. Among new tumblers found, the best data we have are for 2002 TD60, 2000WL107, and (54789) 2001 MZ7—each of them shows a lightcurve with two frequencies (full terms with linear combinations of the two frequencies are present in the lightcurve). For 2002 TD60, we have constructed a physical model of the NPA rotation. Other recent objects which have been found to be likely tumblers based on their lightcurves that do not fit with a single periodicity are 2002 NY40, (16067) 1999 RH27, and (5645) 1990 SP. We have done a statistical analysis of the present sample of the population of NPA rotators. It appears that most asteroids larger than ~ 0.4 km with estimated damping timescales (Harris, 1994, Icarus 107, 209) of 4.5 byr and longer are NPA rotators. The statistic of two short-period tumblers (D = 0.04 and 0.4 km) with non-zero tensile strength suggests that for them the quantity μQ/T , where μ is the mechanical rigidity, Q is the elastic dissipation factor, and T is a spin excitation age (i.e., a time elapsed since the last significant spin excitation event), is greater by two to four orders of magnitude than the larger, likely rubble-pile tumblers. Among observational conditions and selection effects affecting detections of NPA rotations, there is a bias against detection of low-amplitude (small elongation) tumblers