We present first results of a long term study: Searching for OB-type runaway stars inside supernova remnants (SNRs). We identified spectral types and measured radial velocities (RV) by optical spectroscopic observations and we found an early type runaway star inside SNR S147. HD 37424 is a B0.5V type star with a peculiar velocity of 74±8 km s −1 . Tracing back the past trajectories via Monte Carlo simulations, we found that HD 37424 was located at the same position as the central compact object, PSR J0538+2817, 30±4 kyr ago. This position is only ∼4 arcmin away from the geometrical center of the SNR. So, we suggest that HD 37424 was the pre-supernova binary companion to the progenitor of the pulsar and the SNR. We found a distance of 1333 +103 −112 pc to the SNR. The zero age main sequence progenitor mass should be greater than 13 M . The age is 30 ± 4 kyr and the total visual absorption towards the center is 1.28±0.06 mag. For different progenitor masses, we calculated the presupernova binary parameters. The Roche Lobe radii suggest that it was an interacting binary in the late stages of the progenitor.

We examine the possibility of probing dynamo action in mass‐losing stars, components of Algol‐type binaries. Our analysis is based on the calculation of non‐conservative evolution of these systems. We model the systems U Sge and β Per where the more massive companion fills its Roche lobe at the main sequence (case AB) and where it has a small helium core (early case B) respectively. We show that to maintain evolution of these systems at the late stages which are presumably driven by stellar ‘magnetic braking’, an efficient mechanism for producing large‐scale surface magnetic fields in the donor star is needed. We discuss the relevance of dynamo operation in the donor star to the accelerated mass transfer during the late stages of evolution of Algol‐type binaries. We suggest that the observed X‐ray activity in Algol‐type systems may be a good indicator of their evolutionary status and internal structure of the mass‐losing stellar components.

A global site selection for astronomy was performed with 1 km spatial resolution (∼ 1 Giga pixel in size) using long term and up-to-date datasets to classify the entire terrestrial surface on the Earth. Satellite instruments are used to get the following datasets of Geographical Information System (GIS) layers: Cloud Coverage, Digital Elevation Model, Artificial Light, Precipitable Water Vapor, Aerosol Optical Depth, Wind Speed and Land Use -Land Cover. A Multi Criteria Decision Analysis (MCDA) technique is applied to these datasets creating four different series where each layer will have a specific weight. We introduce for the first time a "Suitability Index for Astronomical Sites" namely, SIAS. This index can be used to find suitable locations and to compare different sites or observatories. Mid-western Andes in South America and Tibetan Plateau in west China were found to be the best in all SIAS Series. Considering all the series, less than 3 % of all terrestrial surfaces are found to be the best regions to establish an astronomical observatory. In addition to this, only approximately 10 % of all current observatories are located in good locations in all SIAS series. Amateurs, institutions or countries aiming to construct an observatory could create a short-list of potential site locations using layout of SIAS values for each country without spending time and budget. The outcomes and datasets of this study has been made available through a web site, namely "Astro GIS Database" on www.astrogis.org.

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