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Affichage des articles dont le libellé est ASTRONOMY - The Medusa Nebula. Afficher tous les articles
Affichage des articles dont le libellé est ASTRONOMY - The Medusa Nebula. Afficher tous les articles

17/03/2023

ASTRONOMY - The Medusa Nebula

 023 March 17

See Explanation.  Clicking on the picture will download
the highest resolution version available.

The Medusa Nebula
Image Credit & Copyright: Martin Bradley Chesterfield Astronomical Society

Explanation: Braided and serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. The Medusa's transforming star is the faint one near the center of the overall bright crescent shape. In this deep telescopic view, fainter filaments clearly extend below and right of the bright crescent region. The Medusa Nebula is estimated to be over 4 light-years across.

26/03/2021

ASTRONOMY - The Medusa Nebula

 2021 March 26

See Explanation.  Clicking on the picture will download
the highest resolution version available.

The Medusa Nebula
Image Credit & Copyright: Josep Drudis

Explanation: Braided and serpentine filaments of glowing gas suggest this nebula's popular name, The Medusa Nebula. Also known as Abell 21, this Medusa is an old planetary nebula some 1,500 light-years away in the constellation Gemini. Like its mythological namesake, the nebula is associated with a dramatic transformation. The planetary nebula phase represents a final stage in the evolution of low mass stars like the sun as they transform themselves from red giants to hot white dwarf stars and in the process shrug off their outer layers. Ultraviolet radiation from the hot star powers the nebular glow. The Medusa's transforming star is the faint one near the center of the overall bright crescent shape. In this deep telescopic view, fainter filaments clearly extend above and right of the bright crescent region. The Medusa Nebula is estimated to be over 4 light-years across.

UNE QUESTION (PRE)HISTORIQUE - Alors qui de l'oeuf ou de la poule ?

Une cellule de C. perkinsii montrant des signes distincts de polarité, avec une localisation corticale claire du noyau avant la première div...