Ultra-short orbital period contact binaries (Porb

A stellar occultation by Neptune's main satellite, Triton, was observed on 5 October 2017 from Europe, North Africa, and the USA. We derived 90 light curves from this event, 42 of which yielded a central flash detection. We aimed at constraining Triton's atmospheric structure and the seasonal variations of its atmospheric pressure since the Voyager 2 epoch (1989). We also derived the shape of the lower atmosphere from central flash analysis.

We present the results of our ground-based astrometric observation campaign of BepiColombo during its Earth fly-by on 2020 April 10. The observational circumstances induced by the fly-by geometry made this event an excellent proxy for a close fly-by or an imminent impact of a natural body with a diameter of a few meters, with the added benefit of having a ground-truth orbit (from radio tracking) to compare with our purely ...

Binary and multiple stellar systems are numerous in our solar neighbourhood with 80 per cent of the solar-type stars being members of systems with high order multiplicity. The Contact Binaries Towards Merging (CoBiToM) Project is a programme that focuses on contact binaries and multiple stellar systems, as a key for understanding stellar nature. The goal is to investigate stellar coalescence and merging processes, as the final state of stellar evolution of low-mass contact binary systems. Obtaining observational data of approximately 100 eclipsing binaries and multiple systems and more than 400 archival systems, the programme aspires to give insights for their physical and orbital parameters and their temporal variations, e.g. the orbital period ...

The present work contains light curve, spectroscopic, and asteroseismic analyses for KIC 04851217 and KIC 10686876. These systems are detached eclipsing binaries hosting a pulsating component of δ Scuti type and have been observed with the unprecedented accuracy of the Kepler space telescope. Using ground-based spectroscopic observations, the spectral types of the primary components of the systems were estimated as A6V and A5V for KIC 04851217 and KIC 10686876, respectively, with an uncertainty of one subclass. The present spectral classification, together with literature radial velocity curves, were used to model the light curves of the systems and, therefore, to calculate the absolute parameters of their ...

Binary and multiple stellar systems are numerous in our solar neighbourhood with 80 per cent of the solar-type stars being members of systems with high order multiplicity. The Contact Binaries Towards Merging (CoBiToM) Project is a programme that focuses on contact binaries and multiple stellar systems, as a key for understanding stellar nature. The goal is to investigate stellar coalescence and merging processes, as the final state of stellar evolution of low-mass contact binary systems. Obtaining observational data of approximately 100 eclipsing binaries and multiple systems and more than 400 archival systems, the programme aspires to give insights for their physical and orbital parameters and their temporal variations, e.g. the orbital period ...

 There have been 79 lunar impact flashes observed with the 1.2 m Kryoneri telescope in Greece. The masses of the meteoroids range between 0.7 g and 8 kg, and their respective sizes between 1 and 20 cm, depending on their assumed density, impact velocity, and luminous efficiency. We find a strong correlation between the observed magnitudes ...