NGC 2261

Variabler Nebel (Reflexionsnebel)
NGC 2261
Aufnahme des Hubble-Weltraumteleskops
Aufnahme des Hubble-Weltraumteleskops
SternbildEinhorn
Position
Äquinoktium: J2000.0
Rektaszension06h 39m 09,5s [1]
Deklination+08° 44′ 40″ [1]
Weitere Daten
Helligkeit (visuell)

9,0 mag

Winkelausdehnung

3′,0 × 2′,0 [2]

Entfernung

2600 Lj

Geschichte
Entdeckung

William Herschel

Datum der Entdeckung

26. Dezember 1783

Katalogbezeichnungen
NGC 2261 • Caldwell 46, H IV 2, h 399, GC 1437
AladinLite

NGC 2261 (auch Hubble's Variable Nebula und Caldwell 46) ist ein variabler Reflexionsnebel im Sternbild Einhorn, der etwa 2600 Lichtjahre von der Sonne entfernt ist. Er wird durch einen jungen Riesenstern vom Spektraltyp B0 namens R Monocerotis (R Mon) beleuchtet, der aber selbst nicht sichtbar ist.[3]

NGC 2261 wurde als „first light“ des Hale-Teleskops von Edwin Hubble am 26. Januar 1949 fotografiert. Hubble studierte den Nebel bereits am Yerkes- und Mount-Wilson-Observatorium.[4]

Eine These für die Variabilität sind dichte Staubwolken in der Umgebung von R Mon, die dessen Beleuchtung periodisch blockieren.[5]

Das Objekt wurde am 26. Dezember 1783 von Wilhelm Herschel entdeckt.[6]

Weblinks

Einzelnachweise

  1. ↑ NASA/IPAC EXTRAGALACTIC DATABASE
  2. ↑ SEDS: NGC 2261
  3. ↑ Objekte des Monats: Zwei Reflexionsnebel am Winterhimmel – NGC 2261 und Messier 78. In: Sterne und Weltraum. Nr. 1, 2017, S. 58 ff.
  4. ↑ January 26: 60th Anniversary of Hale Telescope „First Light“. In: 365 Days of Astronomy. Abgerufen am 6. November 2021 (englisch).
  5. ↑ SAO/NASA ADS Astronomy Abstract Service (Hrsg.): A model for the cometary nebula NGC 2261. bibcode:1978ApJ...226..455A.
  6. ↑ Seligman

Auf dieser Seite verwendete Medien

Caldwell Catalogue.jpg
Autor/Urheber: Roberto Mura, Lizenz: CC BY-SA 3.0
Caldwell Catalogue objects.
Hubble's Variable Nebula - NGC 2261.png
Autor/Urheber: Judy Schmidt from Fresh Meadows, NY, USA, Lizenz: CC BY 2.0

This is a reprocessing of one of the older Hubble Heritage releases. I believe that when it was originally processed that the individuals responsible did the best they could with the tools they had. Better software and faster computing allow me to improve significantly upon the original, which was created in 1999.

This object lies along the Milky Way's dusty plane in the constellation Monoceros. One of my favorite things about this kind of nebula is that it reminds us that there can be a lot unseen in space. An optical illusion is produced by human intuition: it may look to you as though this is a bright cloud against a dark surface. In reality, this is a small hole in a largely unseen cloud which allows for light from a newly forming star to shine through.

The variation in the nebula is most likely caused by shadows being cast by blobs of dust accreting near the young star. Note that the accretion process and the star itself are impossible to see in this image, and they occur at a scale too small and too distant for Hubble to see in any detail. The presence of the dusty knots and their close proximity to the star can be inferred by the shadows they cast and how fast they move across the nebula. Because the nebula is around a light year in size, the shadows appear to flow outward, which demonstrates to us the speed of light (or the speed of darkness?) in a way that I find profoundly beautiful. Wouldn't it be wonderful if the telescope could observe this object many more times so we could watch the light flow lazily through the Universe?

I found a ground-based animation of the nebula's variation here: www.umanitoba.ca/faculties/science/astronomy/cbrown/imagi...

Some more information and the original news release is here: hubblesite.org/image/904/news_release/1999-35

An APOD is here: apod.nasa.gov/apod/ap991020.html

Data collected for Proposal 5574 made this image possible. WF/PC2 Cycle 4: Polarization Proposal

Red: F814W;POLQ Green: F675W;POLQ Blue: F555W;POLQ

North is 120° clockwise from up.