Local Bubble: Wikis

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Updated live from Wikipedia, last check: June 02, 2012 15:14 UTC (43 seconds ago)

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Artist's conception of the Local Bubble (containing the Sun and Beta Canis Majoris) and the Loop I Bubble (containing Antares).

The Local Bubble is a cavity in the interstellar medium (ISM) of the Orion Arm of the Milky Way. It is at least 300 light years across and has a neutral hydrogen density of about 0.05 atoms per cubic centimetre, or approximately one tenth of the average for the ISM in the Milky Way (0.5 atoms/cc), and half that for the "Local Fluff," or Local Interstellar Cloud (0.1 atoms/cc). The hot diffuse gas in the Local Bubble emits X-rays. The very sparse, hot gas of the Local Bubble is the result of supernovae that exploded within the past two to four million years.^[1] The most likely candidate for the remains of this supernova is "Geminga" ("Gemini gamma-ray source"), a pulsar in the constellation Gemini.

1 Description
2 See also
3 References
4 External links

Description

3D representation of the Local Bubble (White) with neighbouring Molecular Clouds (Magenta) and a section of the Loop I Bubble (Teal).

The Solar System has been traveling through the region currently occupied by the Local Bubble for the last five to ten million years.^[1] Its current location lies in the Local Interstellar Cloud, a minor region of denser material within the Bubble. The cloud formed where the Local Bubble and the Loop I Bubble met. The gas within the LIC has a density of approximately 0.1 atoms per cubic centimeter.

The Local Bubble is not spherical, but seems to be narrower in the galactic plane, becoming somewhat egg-shaped or elliptical, and may widen above and below the galactic plane, becoming shaped like an hourglass. It abuts other bubbles of less dense intersteallar medium (ISM), including, in particular, the Loop I Bubble. The Loop I Bubble was created by supernovae and stellar winds in the Scorpius-Centaurus Association, some 500 light years from the Sun. The Loop I Bubble contains the star Antares, (also known as Alpha Scorpii) as shown on the diagram above right. Other bubbles which abut the Local Bubble are the Loop II Bubble and the Loop III Bubble.

References

^ ^a ^b Local Chimney and Superbubbles, Solstation.com

Further reading

3D mapping of the dense interstellar gas around the Local Bubble R. Lallement, B. Y. Welsh, J. L. Vergely, F. Crifo and D. Sfeir (2003)
Near-Earth Supernovas, NASA
A Breeze from the Stars, NASA
Anderson, Mark. "Don't stop till you get to the Fluff", New Scientist Issue 2585, 6 Jan, 2007, pp. 26-30. doi:10.1016/S0262-4079(07)60043-8

External links

A 3D map of the Milky Way Galaxy and the Orion Arm

Earth's location in the universe

Earth → Solar System → Local Interstellar Cloud → Local Bubble → Gould Belt → Orion Arm → Milky Way → Milky Way subgroup → Local Group → Local Supercluster → Pisces-Cetus Supercluster Complex → Large-scale structure of the cosmos → Observable universe → Universe

Each arrow should be read as "within" or "part of".