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Study investigates X-ray variability of binary system HD 189733

Newton image of XMM-HD 189733. Credit: Pillitteri et al. , 2022.

Italian and Spanish astronomers have used ESA’s XMM-Newton satellite to observe a binary system known as HD 189733. The results of the observation campaign, published on arXiv.org on January 28, provide important information about the inherent X-ray variability of this binary.


Located at about 63 Light year Located far from Earth, HD 189733 is a wide binary consisting of K1 stars (HD 189733 A) and M-type stars (HD 189733 B).Primary and secondary Performer The mass is about 0.8 and 0.2 Solar mass, The orbital period of the system is estimated to be 3,200 years, respectively. HD 189733 A is known to host a hot Jupiter exoplanet that expands and evaporates vigorously in orbit for 2.2 days.

A detailed study of the X-ray spectrum of a star, for example in the form of flares, and its temporal variation may be essential for a better understanding of the formation and evolution of star systems. A team of astronomers, led by Ignazio Pillitteri of the Palermo Observatory in Italy, analyzed XMM-Newton observations over nearly eight years with the aim of investigating the X-ray radiation of HD 189733 A.

“This paper presents a comprehensive analysis of HD 189733 observations made using XMM-Newton at a total of approximately 958ks, especially coronary artery variability and flare development, their duration, shape, and energy. “Researchers wrote in a dissertation.

The HD 189733 A had a total exposure time of about 958,000 seconds, which was 423,600 seconds in flare. It was found that the number of flares observed around the planetary eclipse stage was not statistically different from the number of flares during the transit stage. Astronomers have noticed hints that flare on the second pass was more active. In addition, four bright flares on HD 189733B are identified by XMM-Newton data.

In this study, the average temperature of the corona of HD 189733A was found to be about 0.4 keV. During the flare, the temperature of this star rises to about 0.9 keV. But the corona remained relatively cold, even during the most energetic flare events.

Moreover, Astronomer In general, it has been found that the variation of HD 189733 A on X-rays is completely different from the variation observed in the optical band.When trying to explain this difference, they say it Angular momentum transmission From an exoplanet Host star..

“The complete difference between activity observed in X-rays and optical bands and relatively cold flares is related to the transfer of angular momentum from planet to star and its effect on the mechanism of the magnetic dynamo that produces it. In addition, magnetic interactions between stars can generate a significant portion of the observed X-ray radiation. VolatilityThe researchers concluded.


Various fluctuation phenomena observed in the binary DQ Tau


For more information:
I. Pillitteri et al, X-ray variation of HD 189733 in XMM-Newton observations for 8 years. arXiv: 2201.12149v2 [astro-ph.SR], arxiv.org/abs/2201.12149

© 2022 Science X Network

Quote: In the survey, the binary system HD 189733 (2022, February 8) obtained from https: //phys.org/news/2022-02-x-ray-variability-binary-hd.html on February 8, 2022. We are investigating the X-ray fluctuations of (Sun).

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Study investigates X-ray variability of binary system HD 189733

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