The "coronal hole" star GJ 745b

3D ModelNoAI

The model is an artist’s illustration of GJ 745b an M dwarf star belonging to a binary system consisting of two nearly twin stars (GJ 745 a and b) with equal radii (R∗ = 0.34 R⊙ ) and masses (M∗ = 0.34M⊙).

The two stars were the targets of an observation campaign with the XMM-Newton X-ray observatory of the European Space Agency. Both showed exceptionally low X-ray emission values consistent with the emission of solar coronal holes (regions of relatively cold, low-density plasma in the solar corona that appear as dark areas in X-ray images of the Sun), suggesting that the level of activity of the coronae of these stars is very low and compatible with that of our Sun at the minimum of its activity.

The model shows the coronal structure of GJ 745b in the X-band, consisting of an isolated active region hosting a flare, as inferred from the analysis of the X-ray observations.

Reference: Caramazza et al. 2023, A&A 676, id.A14