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arXiv · 2609.28079

First X-ray detection of symbiotic nova CN Cha with eROSITA/SRG

Sara Saeedi·Jaroslav Merc·Manami Sasaki·Lorenzo Ducci·Michael Freyberg
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Abstract

Aims. We report on the first X-ray detection of the symbiotic star CN Cha with eROSITA (extended Roentgen Survey with an Imaging Telescope Array) onboard Spektrum-Roentgen Gamma (Spektr-RG). Methods. We analyse the eROSITA observations from eRASS2 to eRASS5 individually, as well as the combined eRASS:5 data of all five surveys in order to investigate the X-ray spectral and timing properties of CN Cha throughout the eRASS. Results. Although CN Cha was not detected during the first eROSITA All-Sky Survey (eRASS1), it was detected for the first time in the second eRASS2. Our analysis shows that the X-ray emission of CN Cha gradually increased from eRASS2 to eRASS5. The X-ray spectrum of the source, with the main emission at <2.4 keV, allows us to classify it as a \b{eta}-type symbiotic star. However, a more detailed analysis suggests that there is very soft component, which may originate either from thermonuclear burning on the white dwarf, or from the wind collisions. Additional X-ray observations are required to better understand the origin and emission mechanisms of the source.

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Sara Saeedi, Jaroslav Merc, Manami Sasaki, Lorenzo Ducci, Michael Freyberg. 2026-09-23. First X-ray detection of symbiotic nova CN Cha with eROSITA/SRG. https://arxiv.org/abs/2609.28079

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