ИСТИНА |
Войти в систему Регистрация |
|
ИПМех РАН |
||
This workshop on astrospheres, here it includes the heliosphere, is very timely and comes at a tipping point in research on astrospheres in general and their associated bow waves and bow shocks in particular. Only recently, large space facilities, such as the Spitzer Space Telescope, the WISE infrared all-sky survey and the Herschel Space Observatory, have shed new lights on the presence and properties of astrospheres, the stellar-wind interaction with the local medium. In particular Spitzer and WISE revealed in the last few years many bow shocks and shells around young massive stars, previously only vaguely detected with IRAS and MSX in the 1980-1990s. Next, Herschel has, somewhat surprisingly, revealed and resolved bow shocks structures and detached shells around a large fraction of nearby evolved stars. Notable results include the large far-infrared (dusty) bow shock around Betelgeuse as illustrated in the figure above. Other cases reveal detailed structures reminiscent to turbulent instabilities. Furthermore, new observations from the IBEX spacecraft suggest there is no bow shock associated to the heliosphere (the astrosphere of the Sun), only a hydrogen wall. Astrospheres have also been detected around nearby solar-type stars via Lyб absorption lines obtained with the Hubble Space Telescope. More ``exotic'' cases are related to, for example, pulsar winds or strong interstellar matter flows. These new observational results have also rejuvenated numerical and theoretical work on astrospheres, bow shocks and bow waves. Traditional hydrodynamical codes are evolving through inclusion of dust grains and radiative transfer, while also new techniques, such as “particle in cell”, are being applied to dusty plasmas.