Fra kosmisk reservehjul til æterisk blomst
IC 5148 er en smuk planetarisk tåge, der ligger omkring 3000 lysår væk i stjernebilledet Grus (Tranen). Tågen har en diameter på et par lysår, og den vokser stadig med over 50 kilometer i sekundet – en af de hurtigst voksende planetariske tåger, vi kender. Navnet ”planetarisk tåge” opstod i det 19. århundrede, hvor disse objekter for første gang blev observeret. Set gennem de små teleskoper, der var til rådighed på det tidspunkt, lignede de lidt kæmpeplaneter. Men planetariske tågers sande natur er helt anderledes.
Det handler om stjerner, der er lige så tunge eller nogle få gange tungere end vores stjerne, Solen. Når en sådan stjerne nærmer sig afslutningen af sit liv, slynger den sine yderste lag af gas ud i rummet. De ekspanderende lag af gas oplyses af den varme tilbageværende kerne af stjernen i midten og danner den planetariske tåge, som oftest har en smuk glødende form.
Når den observeres med et mindre amatørteleskop, ses netop denne planetariske tåge som en ring af materiale med stjernen – som vil køle ned og blive til en hvid dværg – skinnende i midten af et centralt hulrum. Dette udseende har fået astronomer til at give IC 5148 navnet Reservehjulstågen.
ESO Faint Object Spectrograph and Camera (EFOSC2) på New Technology Telescope på La Silla-observatoriet giver en noget mere elegant gengivelse af dette objekt. Her ligner tågen mere end æterisk blomst med lagdelte kronblade end et reservehjul.
Kilde:ESO
Om billedet
| Id: | potw1242a |
| Sprog: | da |
| Type: | Observation |
| Udgivelsesdato: | 15. oktober 2012 10:00 |
| Størrelse: | 1042 x 1041 px |
Om objektet
Baggrundsbilleder
Koordinater
| Position (RA): | 21 59 35.21 |
| Position (Dec): | -39° 23' 8.15" |
| Field of view: | 4.18 x 4.18 arcminutes |
| Orientering: | Nord er 0.9° venstre fra lodret |
Farver & filtre
| Bånd | Teleskop |
|---|---|
| Optisk B | New Technology Telescope EFOSC2 |
| Optisk H-beta | New Technology Telescope EFOSC2 |
| Optisk V | New Technology Telescope EFOSC2 |
| Optisk R | New Technology Telescope EFOSC2 |
| Optisk H-alpha | New Technology Telescope EFOSC2 |
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