Protoplanetêre skyf

'n ALMA-foto van die T Tauri-ster HL Tauri.[1][2]
Kunstenaarsvoorstelling van ’n protoplanetêre skyf.

’n Protoplanetêre skyf is ’n skyf van digte gas wat om ’n pas gevormde ster of protoster, ’n T Tauri- of Herbig Ae/Be-ster, draai. Dit is teoreties ’n voorloper van ’n planetêre stelsel. Deurdat ons eie Sonnestelsel ook eindelik uit ’n protoplanetêre skyf gevorm het, lê al die planete in ’n elliptiese vlak om die Son.

Die radius van protoplanetêre skywe kan tot 1 000 AE wees. Hul temperatuur is laag in vergelyking met dié van sterre; slegs in hul middel kan die temperatuur tot sowat 1 000 kelvin wees. Met die Hubble-ruimteteleskoop is protoplanetêre skywe om verskeie sterre in die Melkweg waargeneem, onder meer in die Orion-newel.

Protosterre word gewoonlik uit ’n gaswolk gevorm wat hoofsaaklik uit waterstof bestaan. Wanneer die wolk ’n kritieke stadium bereik, begin dit onder sy eie swaartekrag instort. Terwyl die wolk digter word, kan ’n deel van die gas om die wolk begin draai. Namate die rotatiesnelheid vergroot, plat die gas af tot dit ’n skyf vorm.

Die aanvanklike instorting van die gaswolk duur sowat 100 000 jaar. Eindelik word dit ’n T Tauri- of Herbig Ae/Be-ster. Ná sowat 10 miljoen jaar verdwyn die skyf.

Verwysings

  1. ↑ Johnathan Webb (6 November 2014). "Planet formation captured in photo" (in Engels). BBC. Geargiveer vanaf die oorspronklike op 25 Februarie 2020.
  2. ↑ "Birth of Planets Revealed in Astonishing Detail in ALMA's 'Best Image Ever'" (in Engels). NRAO. 6 November 2014. Geargiveer vanaf die oorspronklike op 12 Oktober 2016.

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