Spinning-Up the Envelope Before Entering a Common Envelope Phase

We calculate the orbital evolution of binary systems where the primary star is an evolved red giant branch (RGB) star, while the secondary star is a low-mass main sequence (MS) star or a brown dwarf. The evolution starts with a tidal interaction causes the secondary to spiral-in. Than either a common envelope (CE) is formed in a very short time, or alternatively the system reaches synchronization and the spiraling-in process substantially slows down. Some of the latter systems later enter a CE phase. We find that for a large range of system parameters, binary systems reach stable synchronized orbits before the onset of a CE phase. Such stable synchronized orbits allow the RGB star to lose mass prior to the onset of the CE phase. Even after the secondary enters the giant envelope, the rotational velocity is high enough to cause an enhanced mass-loss rate. Our results imply that it is crucial to include the pre-CE evolution when studying the outcome of the CE phase. We find that many more systems survive the CE phase than would be the case if these preceding spin-up and mass-loss phases had not been taken into account. Although we have made the calculations for RGB stars, the results have implications for other evolved stars that interact with close companions.Comment: New Astronomy, in pres

Adding virtual objects to Apollo lunar photos

This dataset provides a computer code that enables the addition of virtual objects, such as stars, to Apollo lunar photos taken during missions from Apollo 11 to 14. It includes all required data files, along with a comprehensive guide and sample images. The calculations are based on 3D photogrammetric models of the landing sites that I have created. A peer-reviewed article describing the mathematical foundations of the algorithm is currently in progress. For further information, please refer to the readme.docx file

ON THE EVOLUTIONARY HISTORY OF PROGENITORS OF EHBS AND RELATED BINARY SYSTEMS BASED ON ANALYSIS OF THEIR OBSERVED PROPERTIES

It has been shown quite recently (Morales-Rueda et al., 2003) that dB stars, extreme horisontal branch (EHB) objects in high probability all belong to binary systems. Assuming that the progenitors of EHB objects belong to the binaries with initial separations of a roughly a hundred solar radii and fill in their critical Roche lobes when being close to the tip of red giant branch, we have found in our earlier study that considerable shrinkage of the orbit can be achieved due to a combined effect of angular momentum loss from the red giant and appreciable accretion on its low mass companion on the hydrodynamical timescale of the donor, resulting in formation of helium WD with masses roughly equal to a half solar mass and thus evading the common envelope stage. Far UV upturn phenomenon discovered in elliptical galaxies and spiral galaxy bulges was interpreted in terms of predominant contribution from EHB objects (Dorman, O'Connell, Rood, 1995). This circumstance can provide a reasonable constraint on the initial masses of EHB progenitors and thus the ages of EHB objects

Photogrammetric analysis of the Apollo 14 surface imagery

This set of data contains 3D model of Apollo 14 landing site based on photogrammetric analysis of approximately 65 images made by the crew during their EVAs and from the windows of the Lunar Module. For more details, see readme.docx file

Apollo 12 landing site photogrammetry data

Photogrammetric data for Apollo 12 landing site: coordinates of camera stations, selected objects on the surface, map, raw data data for ImageModeler 2009. It is based on Hasselblad photographs made by the crew during their EVAs and from the LM windows. Positions of camera stations, artifacts (Lunar Module, Surveyor 3 space probe, ALSEP instruments ets) and landscape features were determined, topocentric coordinates were introduced

Apollo 12 landing site photogrammetry data

Photogrammetric data for Apollo 12 landing site: coordinates of camera stations, selected objects on the surface, map, *.rzi files with raw data for ImageModeler. It is based on Hasselblad photographs made by the crew during their EVAs. Positions of camera stations, artifacts (Lunar Module, Surveyor 3 space probe, ALSEP instruments ets) and landscape features were determined

Adding virtual objects to Apollo lunar photos

This dataset contains a computer code that adds virtual objects like stars to Apollo lunar photos (missions from the Apollo 11 to 14). All necessary data files are provided together with a detailed guide and example images. Calculations are based on my 3D photogrammetric models of the landing sites. I'm working on a peer-reviewed article with a detailed description of the underlying math. Pleas see the readme.docx file for more details.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV