Context. The X-ray source 2S0114+650=LSI+65 010 is a binary system containing a B-type primary and a low mass companion believed to be a neutron star. The system has three reported periodicities: the orbital period, P orb ∼ 11.6 days, X-ray flaring with P flare ∼ 2.7 h and a "superorbital" X-ray periodicity P super = 30.7 days. Aims. The objective of this paper is to show that the puzzling periodicities in the system may be explained in the context of scenarios in which tidal interactions drive oscillations in the B-supergiant star. Methods. We calculate the solution of the equations of motion for one layer of small surface elements distributed along the equator of the star, as they respond to the forces due to gas pressure, centrifugal, Coriolis, viscous forces, and the gravitational forces of both stars, which provides variability timescales that can be compared with those observed for 2S0114+650. In addition, we use observational data obtained at the Observatorio Astronómico Nacional en San Pedro Mártir (OAN/SPM) between 1993-2004 to determine which periodicities may be present in the optical region.Results. The models for circular orbits predict "superorbital" periods while the eccentric orbit models predict strong variations on orbital timescales, associated with periastron passage. Both also predict oscillations on timescales of ∼2 h. We suggest that the tidal oscillations lead to a structured stellar wind which, when fed to the neutron star, produces the X-ray modulations. The connection between the stellar oscillations and the modulation of the mass ejection may lie in the shear energy dissipation generated by the tangential motions that are produced by the tidal effects, particularly in the tidal bulge region. From an observational standpoint, we find indications for variability in the He I 5875 Å line on ∼2 h timescale and, possibly, the "superorbital" timescale. However, the line profile variability exceeds that which is predicted by the tidal interaction model and can be understood in terms of variable emission that is superposed on the photospheric absorption. This emission appears to be associated with the B-supergiant's stellar wind rather than the vicinity of the companion. Conclusions. The model calculations lead us to conclude that the B-supergiant may be the origin of the periodicities observed in the X-ray data, through a combination of a localized structured wind that is fed to the collapsed object and, possibly, by production of X-ray emission on its own surface. This scenario weakens the case for 2S0114+650 containing a magnetar descendent.

Eleven objects that have been reported as proto-planetary nebula or as young planetary nebulae that show very extended Hα wings are presented. The extension of these wings is larger than 800 km s −1 . Data for two symbiotic stars that show this same characteristic is also presented. Raman scattering is the mechanism that best explains the wings in 10 of the PNe and in the 2 symbiotic stars. In the PN IRAS 20462+3416 the wing profile can be explained by very intense stellar wind.

We present spatially-and velocity-resolved echelle spectroscopy for NGC 7009 obtained with the UVES spectrograph at the European Southern Observatory's Very Large Telescope. Our objective is to analyze the kinematics of emission lines excited by recombination and collisions with electrons to determine whether similarities or differences could be useful in elucidating the well-known abundance discrepancy derived from them. We construct position-velocity maps for recombination, fluorescence, charge transfer, and collisionally-excited lines. We find a plasma component emitting in the C II, N II, O II, and Ne II recombination lines whose kinematics are discrepant: They are incompatible with the ionization structure derived from all other evidence and the kinematics derived from all of these lines are unexpectedly very similar. We find direct evidence for a recombination contribution to [N II]λ5755. Once taken into account, the electron temperatures from [N II], [O III], and [Ne III] agree at a given position and velocity. The electron densities derived from [O II] and [Ar IV] are consistent with direct imaging and the distribution of hydrogen emission. The kinematics of the C II, N II, O II, and Ne II lines does not coincide with the kinematics of the [O III] and [Ne III] forbidden emission, indicating that there is an additional plasma component to the recombination emission that arises from a different volume from that giving rise to the forbidden emission from the parent ions within NGC 7009. Thus, the chemical abundances derived from either type of line are correct only for the plasma component from which they arise. Apart from [N II]λ5755, we find no anomaly with the forbidden lines usually used to determine chemical abundances in ionized nebulae, so the abundances derived from them should be reliable for the medium from which they arise.

Important similarities between the objects M1-92, a proto-planetary nebula of bipolar morphology, and MWC 560, a symbiotic star with a jet, have been found. A brief review of the previous studies for both objects is presented for the purpose of proposing mechanisms that best explain these similarities, since up to now both objects have been studied independently. From the comparison of the spectra of both objects, the existence of a jet is confirmed for the proto-planetary nebula M1-92, as well as its binary nature and the existence of a circumnuclear disk. Finally, an evolutionary sequence is proposed for the two objects where M1-92 is $900 yr more evolved than MWC 560. Subject headingg s: binaries: symbiotic -ISM: jets and outflows -planetary nebulae: individual (M1-92) -stars: AGB and post-AGB -stars: individual (MWC 560) Online material: machine-readable table

We analyze the chemical composition of the central star of the planetary nebula NGC 6543 based on a detailed NLTE model of its stellar wind. The logarithmic abundances by number are H ¼ 12:00, He ¼ 11:00, C ¼ 9:03, N ¼ 8:36, O ¼ 9:02, Si ¼ 8:19, P ¼ 5:53, S ¼ 7:57, and Fe ¼ 7:24. Compared with the solar abundances, most of the elements have solar composition with respect to hydrogen, except C, which is overabundant by 0.28 dex, and Fe, which is depleted by $0.2 dex. Contrary to most previous work, we find that the star is not H-poor and has a normal He composition. These abundances are compared with those found in the diffuse X-ray plasma and the nebular gas. Compared to the plasma emitting in diffuse X-rays, the stellar wind is much less depleted in iron. Since the iron depletions in the nebular gas and X-ray plasma are similar, we conclude that the plasma emitting diffuse X-rays is derived from the nebular gas rather than the stellar wind. Excellent agreement is obtained between the abundances in the stellar wind and the nebular recombination line abundances for He, C, and O relative to H. On the other hand, the derived stellar N abundance is smaller than the nebular N abundance derived from recombination lines and agrees with the abundance found from collisionally excited lines. The mean temperature variation determined by five different methods indicates that the difference in the nebular abundances between the recombination lines and collisionally excited lines can be explained as due to the temperature variations in a chemically homogeneous medium. Subject headingg s: planetary nebulae: individual ( NGC 6543)