News
Congratulations to Kyle Davis
8. January, 2024
Kyle Davis successfully defended his master thesis (Spectral classification and analysis of hot white dwarfs in the LAMOST Data Release 8). We send our greetings to Texas and wish him all the best for the future.
Blue horizontal branch stars revisited
May, 2024
Spectral energy distribution of a candidate BHB star from the catalogue. Image credit: A&A.
In this paper we continued our work generating catalogues of stars that are found on the horizontal branch of the Hertzsprung-Russell (HR) diagram. Understanding such very old stars gives us an insights into the mechanisms and processes that influence the properties of stars as they evolve over time. The starting point for this catalogue is the rich dataset from the European Space Agency's Gaia space observatory’s astrometric and photometric measurements in their latest data release. Blue horizontal-branch (BHB) stars aren’t, however, the only stars that occupy this region of the HR diagram and using temperature and luminosity alone to identify such stars leaves many contaminants in such a catalogue. We have refined and extended our 2021 catalogue of blue horizontal-branch stars using spectra acquired during the “Workshops on observing techniques” in 2021 – 2023. These workshops we held in the Ondrejov Observatory in the Czech Republic and jointly organised between Potsdam University and the Astronomical Institute of the Czech Academy of Sciences. These spectra together with the use of spectral energy distributions have allowed us to increase the number of BHB candidates identified as well as reduce the contamination levels and independently verify these levels of contamination in the new catalogue. This catalogue and the new methods developed have been presented in a paper led by Rick Culpan has now been published in Astronomy & Astrophysics.
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