Pressemeddelelse
Et anarkistisk område af stjernedannelse
2. maj 2013
Det danske 1,54-meter teleskop beliggende på ESOs La Silla-observatorium i Chile har taget et iøjefaldende billede af NGC 6559, et objekt der fremviser det anarki, der hersker når stjerner dannes indeni en interstellar sky.
NGC 6559 er en sky af gas og støv, der ligger i en afstand på omkring 5000 lysår fra Jorden i stjernebilledet Sagittarius (Skytten). Det glødende område er et forholdsvis lille objekt, kun få lysår bredt i modsætning til dens berømte et hundrede lysår mere langstrakte nabo Lagunetågen (Messier 8, eso0936). Selvom den normalt overses til fordel for dens fornemme ledsager, har NGC 6559 hovedrollen i dette nye billede.
Gassen i NGC 6559's skyer, der hovedsageligt er brint, er råmaterialet til stjernedannelse. Når et område indeni denne stjernetåge samler nok stof, begynder det at kollapse under sin egen tyngdekraft. Skyens centrum bliver endnu varmere og tættere, indtil termonuklear fusion begynder, og en stjerne er født. Brintatomerne kombineres og danner helium atomer, der frigør den energi, der får stjernen til at skinne.
Disse lysende, varme unge stjerner født ud af skyen, giver energi til brintgassen, der stadigvæk findes omkring dem i stjernetågen [1]. Gassen videresender denne energi, hvilket skaber den glødende trådlignende røde sky, der ses nær midten af dette billede. Sådan et objekt kaldes for en emissionståge.
Men NGC 6559 er ikke kun udgjort af brintgas. Den indeholder også faste partikler af støv, lavet af tungere stoffer som kulstof, jern og silicium. Det blålige område ved siden af den røde emissionståge viser lyset fra nydannede stjerner, der bliver spredt - reflekteret i mange forskellige retninger - af mikroskopiske partikler i stjernetågen. Astronomerne kalder disse for refleksionståger, og denne type objekter virker sædvanligvis blå, fordi de spredes mere effektivt i lysets kortere bølgelængder.
I områder med stor tæthed, blokeres lyset bagfra fuldstændigt. Det er også tilfældet for de mørke isolerede pletter i bugtende baner i de nederste venstre og højre sider af billedet. For at se igennem skyerne, på hvad der ligger bagved, må astronomerne observere stjernetågen i længere bølgelængder, der ikke absorberes.
Mælkevejen fylder baggrunden af billedet med utallige gule ældre stjerner. Nogle af den virker svagere og rødere på grund af støvet i NGC 6559.
Dette iøjefaldende billede af stjernedannelse blev taget med det Danish Faint Object Spectograph and Camera (DFOSC) på det danske 1,54-meter teleskop på La Silla i Chile. Det nationale teleskop har været i brug på La Silla siden 1979, og blev fornyligt renoveret for at lave det om til et fjernstyrret topmoderne teleskop.
Noter
[1] Disse unge stjerner er normalt af spektraltype O og B, med temperaturer mellem 10000 og 60000 K, som udsender enorme mængder højenergi ultraviolet lys der ioniserer brintatomer.
Mere information
ESO er den mest fremtrædende internationale astronomi-organisation i Europa og verdens mest produktive astronomiske observatorium. ESO har i dag følgende 15 medlemslande: Belgien, Brasilien, Danmark, Finland, Frankrig, Holland, Italien, Portugal, Schweiz og Storbritannien, Spanien, Sverige, Tjekkiet, Tyskland og Østrig. ESOs aktiviteter er fokuseret på design, konstruktion og drift af jordbaserede observationsfaciliteter for at muliggøre vigtige videnskabelige opdagelser inden for astronomi. ESO spiller også en ledende rolle for at fremme og organisere samarbejdet inden for astronomisk forskning. I Chile driver ESO tre unikke observatorier i verdensklasse: La Silla, Paranal og Chajnantor. På Paranal driver ESO Very Large Telescope (VLT), der er verdens mest avancerede astronomiske observatorium til observationer i synligt lys samt to kortlægningsteleskoper. VISTA arbejder i infrarødt lys og er verdens største kortlægningsteleskop, mens VLT Survey Telescope (VST) er det største teleskop, der udelukkende er bygget til at kortlægge himlen i synligt lys. ESO er den europæiske partner i et revolutionerede astronomisk teleskop kaldet ALMA, det største igangværende astronomiske projekt. ESO planlægger i øjeblikket et 39 meter optisk/nær-infrarødt teleskop kaldet European Extremely Large Telescope (E-ELT), der vil blive ”verdens største øje mod himlen”.
Links
- Billeder af det danske teleskop
- Billeder taget med det danske teleskop
- ESO pressemeddelelse med resultater fra det danske teleskop
Kontakter
Richard Hook
ESO Public Information Officer
Garching bei München, Germany
Tel: +49 89 3200 6655
Mobil: +49 151 1537 3591
E-mail: rhook@eso.org
Ole J. Knudsen (Pressekontakt Danmark)
ESOs formidlingsnetværk
og Aarhus Space Centre, Aarhus Universitet
Aarhus, Danmark
Tel: +45 8715 5597
E-mail: eson-denmark@eso.org
Om pressemeddelelsen
| Pressemeddelelse nr.: | eso1320da |
| Navn: | NGC 6559 |
| Type: | Milky Way : Nebula : Type : Star Formation |
| Facility: | Danish 1.54-metre telescope |
| Instruments: | DFOSC |
Billeder
Videoer
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