Pas ontdek: ster wat 1500 jaar gelede gesterf het


‘n Span sterrekundiges het ‘n seldsame ster ontdek wat sowat 1500 jaar gelede gesterf het. Die ster sou destyds helderder as al die sterre in die Orion-konstellasie geskyn het. Dr. Brent Miszalski van die Suider-Afrikaanse Groot Teleskoop sê in ‘n verklaring dat astronome van Suid-Afrika, Engeland, Chili, Spanje en Mexiko sedert 2010 soos speurders verskillende stukke van die legkaart bymekaargebring het.

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Die ster HD 44179 word omring deur ‘n buitengewone struktuur bekend as die Rooi Reghoek. Foto: ESA/Hubble en NASA

Foto’s van ander sterwende sterre:

A dying star’s final moments are captured in this image from the NASA/ESA Hubble Space Telescope. The death throes of this star may only last mere moments on a cosmological timescale, but this star’s demise is still quite lengthy by our standards, lasting tens of thousands of years! The star’s agony has culminated in a wonderful planetary nebula known as NGC 6565, a cloud of gas that was ejected from the star after strong stellar winds pushed the star’s outer layers away into space. Once enough material was ejected, the star’s luminous core was exposed and it began to produce ultraviolet radiation, exciting the surrounding gas to varying degrees and causing it to radiate in an attractive array of colours. These same colours can be seen in the famous and impressive Ring Nebula (heic1310), a prominent example of a nebula like this one. Planetary nebulae are illuminated for around 10 000 years before the central star begins to cool and shrink to become a white dwarf. When this happens, the star’s light drastically diminishes and ceases to excite the surrounding gas, so the nebula fades from view. A version of this image was entered into the Hubble’s Hidden Treasures basic image competition by contestant Matej Novak.

‘n Sterwende ster se sterwensoomblikke mag letterlik oomblikke duur op die kosmologiese tydskaal, maar in ons begrip van tyd kan dit tienduisende jare duur. In die geval van ster NGC 6565, is ‘n gaswolk vrygestel nadat sterk sterwinde die ster se buitelae die ruimte in gestoot het. Sodra genoeg materiaal weggewaai is, word die ster se helderskynende kern sigbaar en begin dit om ultravioletstrale vry te stel, wat die gas verwarm en laat straal in mooi skakering van kleur. Ster nebulae is helder vir sowat 10 000 jaar voor die sentrale ster begin afkoel en krimp om ‘n wit dwergster te word. Sodra dit gebeur, kwyn die ster se lig dramaties en dit stimuleer nie meer die omringende gaswolk nie, en die nebula kan word dan te vaag om gesien te word.

Só het NASA die geboorte en sterfte van sterre in die Orion nebula waargeneem.

Só het NASA die geboorte en sterfte van sterre in die Orion nebula waargeneem.

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