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Stellar wind

A stellar wind is a flow of gas ejected from the upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spherically symmetric.

This image shows the wind from the star LL Orionis generating a bow shock (the bright arc) as it collides with material in the surrounding Orion Nebula.

Different types of stars have different types of stellar winds.

Post-main-sequence stars nearing the ends of their lives often eject large quantities of mass in massive ( solar masses per year), slow (v = 10 km/s) winds. These include red giants and supergiants, and asymptotic giant branch stars. These winds are understood to be driven by radiation pressure on dust condensing in the upper atmosphere of the stars.[1][2][3][4][5][6]

Young T Tauri stars often have very powerful stellar winds.[citation needed]

Massive stars of types O and B have stellar winds with lower mass loss rates ( solar masses per year) but very high velocities (v > 1–2000 km/s). Such winds are driven by radiation pressure on the resonance absorption lines of heavy elements such as carbon and nitrogen.[7] These high-energy stellar winds blow stellar wind bubbles.

In planetary nebula NGC 6565, a cloud of gas was ejected from the star after strong stellar winds.[8]

G-type stars like the Sun have a wind driven by their hot, magnetized corona. The Sun's wind is called the solar wind. These winds consist mostly of high-energy electrons and protons (about 1 keV) that are able to escape the star's gravity because of the high temperature of the corona.

Stellar winds from main-sequence stars do not strongly influence the evolution of lower-mass stars such as the Sun. However, for more massive stars such as O stars, the mass loss can result in a star shedding as much as 50% of its mass whilst on the main sequence: this clearly has a significant impact on the later stages of evolution. The influence can even be seen for intermediate mass stars, which will become white dwarfs at the ends of their lives rather than exploding as supernovae only because they lost enough mass in their winds.[citation needed]

See also edit

References edit

  1. ^ Lamers, Henny J. G. L. M. (1999). Introduction to stellar winds. Cassinelli, Joseph P. Cambridge, U.K.: Cambridge University Press. ISBN 0521593980. OCLC 38738913.
  2. ^ . Stellar Physics. Astrophysical Institute Potsdam. Archived from the original on 1 October 2016. Retrieved 7 April 2014.
  3. ^ Mattsson, L.; Wahlin, R.; Höfner, S. (January 2010). "Dust driven mass loss from carbon stars as a function of stellar parameters". Astronomy and Astrophysics. 509: A14. arXiv:1107.1771. doi:10.1051/0004-6361/200912084. ISSN 0004-6361. S2CID 17360256.
  4. ^ Höfner, S.; Gautschy–Loidl, R.; Aringer, B.; Jørgensen, U. G. (February 2003). "Dynamic model atmospheres of AGB stars". Astronomy & Astrophysics. 399 (2): 589–601. doi:10.1051/0004-6361:20021757. ISSN 0004-6361.
  5. ^ Sandin, C.; Höfner, S. (June 2003). "Three-component modeling of C-rich AGB star winds". Astronomy & Astrophysics. 404 (3): 789–807. arXiv:astro-ph/0304278. doi:10.1051/0004-6361:20030515. ISSN 0004-6361.
  6. ^ Sandin, C.; Höfner, S. (January 2004). "Three-component modeling of C-rich AGB star winds". Astronomy & Astrophysics. 413 (3): 789–798. arXiv:astro-ph/0309822. doi:10.1051/0004-6361:20031530. ISSN 0004-6361. S2CID 15641925.
  7. ^ Castor, J.; Abbott, D. C.; Klein, R. I. (1975). "Radiation-driven winds in Of stars". Astrophys. J. 195: 157–174. Bibcode:1975ApJ...195..157C. doi:10.1086/153315.
  8. ^ "The long goodbye". Retrieved 27 July 2015.

External links edit

stellar, wind, this, article, about, ejected, from, atmosphere, stars, other, uses, disambiguation, stellar, wind, flow, ejected, from, upper, atmosphere, star, distinguished, from, bipolar, outflows, characteristic, young, stars, being, less, collimated, alth. This article is about gas ejected from the atmosphere of stars For other uses see Stellar wind disambiguation A stellar wind is a flow of gas ejected from the upper atmosphere of a star It is distinguished from the bipolar outflows characteristic of young stars by being less collimated although stellar winds are not generally spherically symmetric This image shows the wind from the star LL Orionis generating a bow shock the bright arc as it collides with material in the surrounding Orion Nebula Different types of stars have different types of stellar winds Post main sequence stars nearing the ends of their lives often eject large quantities of mass in massive M gt 10 3 displaystyle scriptstyle dot M gt 10 3 solar masses per year slow v 10 km s winds These include red giants and supergiants and asymptotic giant branch stars These winds are understood to be driven by radiation pressure on dust condensing in the upper atmosphere of the stars 1 2 3 4 5 6 Young T Tauri stars often have very powerful stellar winds citation needed Massive stars of types O and B have stellar winds with lower mass loss rates M lt 10 6 displaystyle scriptstyle dot M lt 10 6 solar masses per year but very high velocities v gt 1 2000 km s Such winds are driven by radiation pressure on the resonance absorption lines of heavy elements such as carbon and nitrogen 7 These high energy stellar winds blow stellar wind bubbles In planetary nebula NGC 6565 a cloud of gas was ejected from the star after strong stellar winds 8 G type stars like the Sun have a wind driven by their hot magnetized corona The Sun s wind is called the solar wind These winds consist mostly of high energy electrons and protons about 1 keV that are able to escape the star s gravity because of the high temperature of the corona Stellar winds from main sequence stars do not strongly influence the evolution of lower mass stars such as the Sun However for more massive stars such as O stars the mass loss can result in a star shedding as much as 50 of its mass whilst on the main sequence this clearly has a significant impact on the later stages of evolution The influence can even be seen for intermediate mass stars which will become white dwarfs at the ends of their lives rather than exploding as supernovae only because they lost enough mass in their winds citation needed See also edit nbsp Space portal Cosmic ray Cosmic wind Planetary wind Colliding wind binary Pulsar wind nebula Galactic superwind SuperwindReferences edit Lamers Henny J G L M 1999 Introduction to stellar winds Cassinelli Joseph P Cambridge U K Cambridge University Press ISBN 0521593980 OCLC 38738913 Dust Envelopes Stellar Physics Astrophysical Institute Potsdam Archived from the original on 1 October 2016 Retrieved 7 April 2014 Mattsson L Wahlin R Hofner S January 2010 Dust driven mass loss from carbon stars as a function of stellar parameters Astronomy and Astrophysics 509 A14 arXiv 1107 1771 doi 10 1051 0004 6361 200912084 ISSN 0004 6361 S2CID 17360256 Hofner S Gautschy Loidl R Aringer B Jorgensen U G February 2003 Dynamic model atmospheres of AGB stars Astronomy amp Astrophysics 399 2 589 601 doi 10 1051 0004 6361 20021757 ISSN 0004 6361 Sandin C Hofner S June 2003 Three component modeling of C rich AGB star winds Astronomy amp Astrophysics 404 3 789 807 arXiv astro ph 0304278 doi 10 1051 0004 6361 20030515 ISSN 0004 6361 Sandin C Hofner S January 2004 Three component modeling of C rich AGB star winds Astronomy amp Astrophysics 413 3 789 798 arXiv astro ph 0309822 doi 10 1051 0004 6361 20031530 ISSN 0004 6361 S2CID 15641925 Castor J Abbott D C Klein R I 1975 Radiation driven winds in Of stars Astrophys J 195 157 174 Bibcode 1975ApJ 195 157C doi 10 1086 153315 The long goodbye Retrieved 27 July 2015 External links edit nbsp Wikimedia Commons has media related to Stellar wind Retrieved from https en wikipedia org w index php title Stellar wind amp oldid 1168500671, wikipedia, wiki, book, books, library,

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