Local Bubble

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Local Bubble
Superbubble
Map of open star clusters and bright stars in the Local Bubble, viewed from top down
Observation data
Distance0 ly   (0 pc)
Physical characteristics
Radius500 ly
DesignationsLocal Hot Bubble, LHB,[1] Local Bubble, Local Interstellar Bubble[2]
See also: Lists of nebulae

The Local Bubble, or Local Cavity,

light years in size,[clarification needed] and is defined by its neutral-hydrogen density of about 0.05 atoms/cm3, or approximately one tenth of the average for the ISM in the Milky Way (0.5 atoms/cm3), and one sixth that of the Local Interstellar Cloud (0.3 atoms/cm3).[dubious – discuss][4]

The exceptionally sparse gas of the Local Bubble is the result of

supershell.[6] Other research suggests that the subgroups Lower Centaurus–Crux (LCC) and Upper Centaurus–Lupus (UCL), of the Scorpius–Centaurus association created both the local bubble and the Loop I Bubble. With LCC being responsible for the Local Bubble and UCL being responsible for the Loop I Bubble.[7] It was found that 14 to 20 supernovae originated from LCC and UCL, which could have formed these bubbles.[8]

Description

The Solar System has been traveling through the region currently occupied by the Local Bubble for the last five to ten million years.[9] Its current location lies in the Local Interstellar Cloud (LIC), a minor region of denser material within the Bubble. The LIC formed where the Local Bubble and the Loop I Bubble met. The gas within the LIC has a density of approximately 0.3 atoms per cubic centimeter.

The Local Bubble is not spherical, but seems to be narrower in the

Loop III Bubble. In 2019, researchers found interstellar iron in Antarctica which they relate to the Local Interstellar Cloud, which might be related to the formation of the Local Bubble.[11]

Local stars in the galactic plane (click for rotation)

Observation

Launched in February 2003 and active until April 2008, a small space observatory called

Cosmic Hot Interstellar Plasma Spectrometer (CHIPS or CHIPSat) examined the hot gas within the Local Bubble.[12] The Local Bubble was also the region of interest for the Extreme Ultraviolet Explorer mission (1992–2001), which examined hot EUV sources within the bubble. Sources beyond the edge of the bubble were identified but attenuated by the denser interstellar medium. In 2019, the first 3D map of the Local Bubble has been reported using the observations of diffuse interstellar bands.[13]
In 2020, the shape of the dusty envelop surrounding the Local Bubble was retrieved and modeled from 3D maps of the dust density obtained from stellar extinction data.[14]

Impact on star formation

As the bubble expands it sweeps interstellar gas and dust which collapse to form new stars on its surface but not inside. The Sun entered the bubble around five million years ago.[15][16]
Local Bubble and its molecular clouds

In January 2022, a paper in the journal Nature found that observations and modelling had determined that the action of the expanding surface of the bubble had collected gas and debris and was responsible for the formation of all young, nearby stars.[17]

These new stars are typically in molecular clouds like the Taurus molecular cloud and the open star cluster Pleiades.

Connection to radioactive isotopes on earth

On earth several radioactive isotopes were connected to supernovae occurring relative nearby to the solar system. The most common source is found in deep sea ferromanganese crusts. Such nodules are constantly growing and deposits iron, manganese and other elements. Samples are divided into layers which are dated for example with Beryllium-10. Some of these layers have higher concentrations of radioactive isotopes.[18] The isotope most commonly associated with supernovae on earth is Iron-60 from deep sea sediments,[19] Antarctic snow,[20] and lunar soil.[21] Other isotopes are Manganese-53[22] and Plutonium-244[18] from deep sea materials. Supernova originated Aluminium-26, which was expected from cosmic ray studies, was not confirmed.[23] Iron-60 and Manganese-53 have a peak 1.7–3.2 Million years ago and Iron-60 has a second peak 6.5–8.7 Million years ago. The older peak likely originated when the solar system moved through the Orion-Eridanus superbubble and the younger peak was generated when the solar system entered the local bubble 4.5 Million years ago.[24] One of the supernovae creating the younger peak might have created the pulsar PSR B1706-16 and turned Zeta Ophiuchi into a runaway star. Both originated from UCL and were released by a supernova 1.78 ± 0.21 Million years ago.[25] Another explanation for the older peak is that it was produced by one supernova in the Tucana-Horologium association 7-9 Million years ago.[26]

See also

References

  1. Bibcode:1995A&A...294L..25E
    .
  2. ^ "NAME Local Bubble". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 15 March 2014.
  3. S2CID 124774683
    .
  4. ^ "Our local galactic neighborhood". Interstellar.jpl.nasa.gov. National Aeronautics and Space Administration (NASA). 8 February 2000. Archived from the original on 21 November 2013. Retrieved 23 July 2013.
  5. S2CID 6002327
    .
  6. ^ Gabel, J.R.; Bruhweiler, F.C. (8 January 1998). "[51.09] Model of an expanding supershell structure in the LISM". American Astronomical Society. Archived from the original on 15 March 2014. Retrieved 14 March 2014.
  7. ISSN 0004-637X
    .
  8. ISSN 0035-8711
    .
  9. ^ "Local Chimney and Superbubbles". Solstation.com.
  10. doi:10.1051/0004-6361:20031214
    .
  11. S2CID 201868513
    .
  12. ^ "Cosmic Hot Interstellar Plasma Spectrometer (CHIPS)". Chips.ssl.berkeley.edu. University of California – Berkeley. 12 January 2003. Archived from the original on 21 November 2013. Retrieved 23 July 2013.
  13. S2CID 197402894
    .
  14. doi:10.1051/0004-6361/201937157
    .
  15. S2CID 245906333
    .
  16. ^ "1,000-Light-Year Wide Bubble Surrounding Earth is Source of All Nearby, Young Stars | Center for Astrophysics". www.cfa.harvard.edu. Retrieved 17 January 2022.
  17. ^ "Star Formation near the Sun is driven by expansion of the Local Bubble". The Local Bubble. Retrieved 7 February 2022.
  18. ^
    ISSN 0036-8075
    .
  19. ISSN 0031-9007
    .
  20. ISSN 0031-9007
    .
  21. ISSN 0031-9007
    .
  22. ISSN 0031-9007
    .
  23. ISSN 0031-9007
    .
  24. ISSN 0004-6361
    .
  25. ISSN 0035-8711
    .
  26. ISSN 0004-6337
    .

Further reading

External links

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