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An international team, led by Czech astronomers, is at the origin of the revelation of the characteristics of the star, which are found in the constellation Lion, in which apparently contradictory phenomena are observed and behave differently. what contemporary science imagines. And the Moravian – although this division between the cosmic dimensions and the international character of the research is not particularly emphasized.
The hot star HD 99458 is unique in that it is bound in the system with an orbital duration of only 2.7 days and has an excess of silicon and titanium that are badociated with the spots. According to current theories, such chemical stains can only be found in single stars or in binary stars with very distant components. Which is not the case
Surprising spots
"In addition, the stars must spin slowly, have a strong magnetic field – and not show high-amplitude pulsations," said Marek Skarka (the lead author of the newly discovered novel published in the prestigious monthly astronomical magazine). Opinion of the Royal Astronomical Society). But this is not the case here: the star shakes – that is to say, it grows and contracts regularly – with a main period of 1.2 hours.
"The discovery of chemical stains on a fast-paced, pulsating star in a narrow two-star system was a big surprise for us," admits Skarka. The star with chemical spots in the eclipse system with the cold component was observed for the first time. And the nature of the orbital period and the pulsation do not correspond either to previous observations of stars with chemical stains.
The present discovery should therefore help scientists better understand how magnetic fields, chemical spots – and their links to stellar pulsations – form and grow in warm stars.
Red dwarf
Originally, the HD 99458 was considered a star hosting a giant gas planet. The combination of data from NASA's Kepler space probe telescope with the spectra obtained by a two-meter Perk telescope at Ondrejov showed that the exoplanet was not the companion but another star.
Petr Kabáth, head of the exoplanetary group of the stellar department of the Institute of Astronomy of the Academy of Sciences of the Czech Republic, said: "A small star of the red dwarf type."
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