spossatamente said:We know that solar corona is heated up although we don't know yet the mechanism
spossatamente said:I was wondering which other type of stars, else than G2, in the main sequence suffer of the same effect?
regardsStellar coronae[edit]
Coronal stars are ubiquitous among the stars in the cool half of the Hertzsprung–Russell diagram.[17] These coronae can be detected using X-ray telescopes. Some stellar coronae, particularly in young stars, are much more luminous than the Sun's. For example, FK Comae Berenices is the prototype for the FK Com class of variable star. These are giants of spectral types G and K with an unusually rapid rotation and signs of extreme activity. Their X-ray coronae are among the most luminous (Lx ≥ 1032 erg·s−1 or 1025W) and the hottest known with dominant temperatures up to 40 MK.[17]
The astronomical observations planned with the Einstein Observatory by Giuseppe Vaiana and his group[18] showed that F-, G-, K- and M-stars have chromospheres and often coronae much like our Sun. The O-B stars, which do not have surface convection zones, have a strong X-ray emission. However these stars do not have coronae, but the outer stellar envelopes emit this radiation during shocks due to thermal instabilities in rapidly moving gas blobs. Also A-stars do not have convection zones but they do not emit at the UV and X-ray wavelengths. Thus they appear to have neither chromospheres nor coronae
A hot corona is the outermost layer of a star's atmosphere that is significantly hotter than the surface of the star. It is composed of highly ionized gases and is responsible for the emission of X-rays.
The presence of a hot corona is dependent on a star's magnetic field and its level of activity. Stars with strong magnetic fields and high levels of activity, such as young stars or stars in binary systems, are more likely to have a hot corona.
A hot corona can greatly influence the behavior of a star. It can cause increased levels of magnetic activity, resulting in the emission of X-rays and other high-energy radiation. It can also affect the star's mass loss and energy output.
Studying stars with a hot corona can provide valuable information about the star's magnetic field, internal structure, and evolution. It can also help us understand the mechanisms behind the heating of the corona and the emission of X-rays.
Yes, the X-rays emitted from a hot corona can be hazardous to spacecraft and astronauts, as well as any planets or other objects orbiting the star. It is important for scientists to study and understand these emissions in order to protect our technology and future space exploration.