Hanny's Voorwerp

_nl. Hanny's Voorwerp, Dutch for "Hanny's object", [ [http://news.bbc.co.uk/1/hi/sci/tech/7543776.stm "Teacher finds new cosmic object"] , BBC, 5 August 2008] is an astronomical object discovered by a Dutchwoman, schoolteacher Hanny van Arkel, in 2007 while participating as an amateur volunteer in the Galaxy Zoo project. It is a strange blob close to spiral galaxy IC 2497 in the constellation Leo Minor. Recently appearing on the Astronomy Picture of the Day website in data taken by Daniel J.B. Smith (Liverpool John Moores University) and Peter Herbert (University of Hertfordshire) on the 2.5 metre Isaac Newton Telescope, it appears unusually green owing to the presence of several luminous emission lines. It has been shown to be the same distance from Earth as the galaxy, about 700 million light-years away.

One leading hypothesis suggests that the voorwerp is a small galaxy or dust cloud close to galaxy IC 2497 that is reflecting the light of a bright quasar event that occurred in the centre of IC 2497 about 100,000 years ago. [cite news | first= | last= | coauthors= | title=Stars in their eyes: An armchair astronomer discovers something very odd | date=2008-06-26 | publisher= | url =http://www.economist.com/science/displayStory.cfm?source=hptextfeature&story_id=11614176 | work =The Economist | pages = | accessdate = 2008-06-30 | language = ] The quasar event has receded but the light from the voorwerp is following a longer path to Earth via its reflection in the cloud and so shows the event as a "Ghost Image". [ [http://www.physorg.com/news137157808.html 'Cosmic ghost' discovered by volunteer astronomer] Physorg.com August 05, 2008]

The voorwerp itself doesn't contain any stars and has a huge central hole over 16,000 light years across. Astronomers are still puzzling over what brought it into existence in the first place.

References

* [http://antwrp.gsfc.nasa.gov/apod/ap080625.html What is Hanny's Voorwerp?] NASA Astronomy picture of the day June 25th, 2008.
* [http://www.sciencenews.org/view/generic/id/33403/title/Science_%2B_the_Public__Galaxy_Zoos_blue_mystery_(part_I) Galaxy Zoo's blue mystery (part I)] by Janet Raloff at Science News June 19th, 2008
* [http://www.sciencenews.org/view/generic/id/33436/title/Galaxy_Zoos_blue_mystery_%28part_2%29 Galaxy Zoo's blue mystery (part 2)] Janet Raloff June 20th, 2008
* [http://www.astr.ua.edu/keel/research/voorwerp.html Hanny's Voorwerp (SDSS J094103.80+344334.2)] Hanny's Voorwerp at Bill Keel's pages University of Alabama. Accessed June 2008
* [http://www.universetoday.com/2008/06/09/hannys-voorwerp-still-alive-and-kicking/ Hanny's Voorwerp - Still Alive and Kicking] by Tammy Plotner, Universe Today, June 9th, 2008