Local bubble
The local bubble ( English Local Bubble ), occasionally Local volume called, is a largely dust- free region of space in the interstellar environment of the sun . The interstellar matter in this area consists on the one hand of neutral hydrogen with a density of 0.05 to 0.07 atoms per cubic centimeter (50-70 atoms per liter), on the other hand of a very thin and hot plasma with a density of 0.001 to 0.005 atoms per cubic centimeter and a temperature of 1.4 million Kelvin . This plasma is responsible for most of the background x-ray radiation .
Emergence
The local bubble is a super bubble . It is believed that the Local Bubble was formed a few hundred thousand to a few million years ago by one or more supernovae - a candidate for this is Geminga , a neutron star in the constellation of Gemini (in the drawing, Geminga has a right ascension of 4h, in fact it is 6h33). Other theories assume about 20 supernovae 10 to 20 million years ago.
Structure and environment
The local bubble has the shape of an hourglass - it has a diameter of at least 300 light years in the galactic level and expands with increasing distance. Some studies also suggest that the local bubble perpendicular to the galactic plane has no limitation, but is open.
In the direction of the sun apex , the direction of movement of the sun, the local bubble borders the Loop-I super-bubble , which was formed by supernovae in the Scorpius-Centaurus association , about 50 to 130 light years away . Between the sun and this border region lies the local fluff complex , consisting of a series of cloudlets arranged in the shape of a bowl, created by the collision of the two bubbles.
However, the information about the shape of the local bubble is subject to great uncertainty, since the results of the shape derived from investigations of absorption lines do not agree with those obtained from surveys in the UV range . That is why NASA started the CHIPSat mission on January 12, 2003 , the main task of which was to research the local bubble. However, due to the unexpected lack of UV radiation, this goal could not be achieved.
Within the local bubble, the sun is in a region called the local flake . This has a greater density of interstellar matter than the bubble surrounding it.
Web links
Individual evidence
- ↑ TW Berghöfer, D. Breitschwerdt: The origin of the young stellar population in the solar neighborhood - A link to the formation of the Local Bubble? . In: Astronomy and Astrophysics . 390, July 2002, pp. 299-306. doi : 10.1051 / 0004-6361: 20020627 .
- ↑ Jesús Maíz-Apellániz: The Origin of the Local Bubble . In: The Astrophysical Journal Letters . 560, October 10, 2001, p. L83. doi : 10.1086 / 324016 .