Featured Research

from universities, journals, and other organizations

Gemini Observatory Welcomes The New Year With Galactic Fireworks

Date:
January 19, 2005
Source:
Particle Physics & Astronomy Research Council
Summary:
Astronomers at Gemini Observatory are ushering in the New Year with a striking image that dazzles the eye with stellar pyrotechnics. The image of the face-on spiral galaxy NGC 6946 is ablaze with a colourful galactic fireworks display fuelled by the births and deaths of multitudes of brilliant, massive stars.

Gemini North GMOS image of the 'Fireworks Galaxy' NGC 6946 in the Constellation of Cepheus.
Credit: Gemini Observatory

Astronomers at Gemini Observatory are ushering in the New Year with a striking image that dazzles the eye with stellar pyrotechnics.

The image of the face-on spiral galaxy NGC 6946 is ablaze with a colourful galactic fireworks display fuelled by the births and deaths of multitudes of brilliant, massive stars. Astronomers suspect that massive stars have been ending their lives in supernova explosions throughout NGC 6946 in rapid-fire fashion for tens of millions of years.

"If you could make a time-lapse movie that compressed millions of years into seconds, this galaxy would resemble a sparkler," said Dr Rachel Johnson, UK Gemini Spokesperson from the University of Oxford. "New stars would flare into view as old stars expired in huge explosions of light and energy called supernovae - this galaxy is literally a gigantic multi-coloured light show, but definitely not on human timescales!"

"In order to sustain this rate of supernova activity, massive, quickly evolving stars must form or be born at an equally rapid rate in NGC 6946," said Gemini North Associate Director, Jean-Renι Roy. "Its stars are exploding like a string of firecrackers!"

It is speculated that if just a million years of this galaxy's history were compressed into a time-lapse movie lasting a few seconds, there would be nearly constant outbursts of light as new stars flare into view, while old ones expire in spectacular explosions. Over the past century, eight supernovae have exploded in the arms of this stellar metropolis, occurring in 1917, 1939, 1948, 1968, 1969, 1980, 2002, and 2004.

"In order to sustain this rate of supernova activity, massive, quickly evolving stars must form or be born at an equally rapid rate. Stars in this galaxy are exploding like popcorn!" added Dr Johnson. But it is this extreme stellar birth-rate, not the supernovae, which lends the galaxy its blazingly colourful appearance.

By comparison, the average rate for such catastrophic stellar outbursts in the Milky Way is about one per century, and only four have been recorded over the last thousand years. The last known supernova went off in our galaxy in the constellation Ophiuchus in 1604.

Yet, it is the ubiquitous occurrence of starbirth throughout NGC 6946 and not its supernovae that lend this galaxy its blazingly colourful appearance. For reasons not completely understood, this galaxy experiences a much higher rate of star formation than all the large galaxies in our local neighbourhood. The prodigious output of stellar nurseries in this galactic neighbour eventually lead to accelerated numbers of supernova explosions.

Starbirth regions exist in most galaxies, particularly in spirals, and are obvious as clouds of predominantly hydrogen gas call H II regions. These areas coalesce over millions of years to form stars. Young, hot, massive stars formed in these regions emit copious amounts of ultraviolet radiation, which strips the electrons from hydrogen atoms in which they are embedded. When these ionized hydrogen atoms re-associate with electrons they radiate in a deep red colour (at a wavelength of 656.3 nanometres) as the electrons transition back to lower energy levels.

This Gemini image of NGC 6946 utilizes a selective filter specifically designed to detect the radiation emanating from the starbirth regions. Additional filters help to distinguish other details in the galaxy, including clusters of massive blue stars, dust lanes, and a yellowish core where older more evolved stars dominate.

NGC 6946 lies between 10 and 20 million light-years away in the constellation Cepheus, and was discovered by Sir William Herschel (1738-1822) on September 9, 1798. It continues to fascinate astronomers, who estimate that it contains about half as many stars as the Milky Way. They often use it to study and characterize the evolution of massive stars and the properties of interstellar gas. As viewed in the new Gemini optical image, we see only the "tip of the iceberg" of this galaxy. Its optical angular diameter is about 13 arcminutes, but viewed at radio wavelength at the frequency of neutral hydrogen (1420 Mhz or 21-cm line), it extends considerably more than the angular diameter of the Moon.


Story Source:

The above story is based on materials provided by Particle Physics & Astronomy Research Council. Note: Materials may be edited for content and length.


Cite This Page:

Particle Physics & Astronomy Research Council. "Gemini Observatory Welcomes The New Year With Galactic Fireworks." ScienceDaily. ScienceDaily, 19 January 2005. <www.sciencedaily.com/releases/2005/01/050111181528.htm>.
Particle Physics & Astronomy Research Council. (2005, January 19). Gemini Observatory Welcomes The New Year With Galactic Fireworks. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2005/01/050111181528.htm
Particle Physics & Astronomy Research Council. "Gemini Observatory Welcomes The New Year With Galactic Fireworks." ScienceDaily. www.sciencedaily.com/releases/2005/01/050111181528.htm (accessed July 31, 2014).

Share This




More Space & Time News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Supply Ship Takes Off for International Space Station

Supply Ship Takes Off for International Space Station

AFP (July 30, 2014) — The European Space Agency's fifth Automated Transfer Vehicle (ATV-5) is takes off to the International Space Station on an Ariane 5 rocket from French Guiana. Duration: 00:34 Video provided by AFP
Powered by NewsLook.com
Raw: Rocket Launches Into Space With Cargo Ship

Raw: Rocket Launches Into Space With Cargo Ship

AP (July 30, 2014) — Arianespace launched a rocket Tuesday from French Guiana carrying a robotic cargo ship to deliver provisions to the International Space Station. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) — Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Russia Saves Gecko Sex Satellite, Media Has Some Fun With It

Newsy (July 27, 2014) — The satellite is back under ground control after a tense few days, but with a gecko sex experiment on board, the media just couldn't help themselves. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins