Featured Research

from universities, journals, and other organizations

Hubble views an old and mysterious cluster

Date:
November 14, 2013
Source:
ESA/Hubble Information Centre
Summary:
The NASA/ESA Hubble Space Telescope has captured the best ever image of the globular cluster Messier 15, a gathering of very old stars that orbits the center of the Milky Way. This glittering cluster contains over 100 000 stars, and could also hide a rare type of black hole at its center.

New Hubble image of star cluster Messier 15.
Credit: NASA, ESA

The NASA/ESA Hubble Space Telescope has captured the best ever image of the globular cluster Messier 15, a gathering of very old stars that orbits the centre of the Milky Way. This glittering cluster contains over 100,000 stars, and could also hide a rare type of black hole at its centre.

This multi-coloured firework display is a cluster of stars known as Messier 15, located some 35,000 light-years away in the constellation of Pegasus (The Winged Horse). It is one of the oldest globular clusters [1] known, with an age of around 12 billion years.

Very hot blue stars and cooler golden stars are seen swarming together in this image, becoming more concentrated towards the cluster's bright centre. Messier 15 is one of the densest globular clusters known, with most of its mass concentrated at its core.

However, this sparkling bauble has hidden secrets. Astronomers studying the cluster with Hubble in 2002 found there to be something dark and mysterious lurking at its heart. It could either be a collection of dark neutron stars [2], or an intermediate-mass black hole. Of the two possibilities it is more likely that Messier 15 harbours a black hole at its centre, as does the massive globular cluster Mayall II.

Intermediate-mass black holes are thought to form either from the merging of several smaller, stellar-mass black holes, or as a result of a collision between massive stars in dense clusters. A third possibility is that they were formed during the Big Bang. In terms of mass they lie between the more commonly found stellar-mass and supermassive types of black hole [3], and could tell us about how black holes grow and evolve within clusters like Messier 15, and within galaxies.

As well as this black hole, Messier 15 is known to house a planetary nebula, Pease 1 [4] -- and it was the first globular known to contain one of these objects [5]. This nebula is visible as the bright blue object just to the left of the cluster's centre.

This new image is made up of observations from Hubble's Wide Field Camera 3 and Advanced Camera for Surveys in the ultraviolet, infrared and optical parts of the spectrum.

Notes

[1] A globular cluster is a roughly spherical group of stars that orbits the core of a galaxy. The Milky Way has over 150 of these starry satellites -- including Messier 15. However, other galaxies have many more than this; a staggering 160,000 were recently discovered by Hubble in the galaxy cluster Abell 1689 (heic1317). Globular clusters contain some of the most ancient stars in the Universe.

[2] A neutron star is formed from the collapse of a massive star. They are very hot and very dense, with an average mass of around two solar masses contained within a radius of tens of kilometres.

[3] Stellar-mass black holes have masses of a few to a few tens of times the mass of the Sun. Supermassive black holes have masses ranging from hundreds of thousands to billions of times the mass of the Sun.

[4] Pease 1 is also known as PN Ku 648, or Kόrster 648.

[5] Since the discovery of Pease 1, only three other globular clusters have been found to host planetary nebulae: Messier 22, NGC 6441, and Palomar 6. This number is so low because planetary nebulae are a very brief, short-lived phase at the end of the lives of low to moderate mass stars -- which are not common within globular clusters.


Story Source:

The above story is based on materials provided by ESA/Hubble Information Centre. Note: Materials may be edited for content and length.


Cite This Page:

ESA/Hubble Information Centre. "Hubble views an old and mysterious cluster." ScienceDaily. ScienceDaily, 14 November 2013. <www.sciencedaily.com/releases/2013/11/131114122206.htm>.
ESA/Hubble Information Centre. (2013, November 14). Hubble views an old and mysterious cluster. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2013/11/131114122206.htm
ESA/Hubble Information Centre. "Hubble views an old and mysterious cluster." ScienceDaily. www.sciencedaily.com/releases/2013/11/131114122206.htm (accessed April 24, 2014).

Share This



More Space & Time News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nuclear-Level Asteroids Might Be More Common Than We Realize

Nuclear-Level Asteroids Might Be More Common Than We Realize

Newsy (Apr. 23, 2014) — The B612 Foundation says asteroids strike Earth much more often than previously thought, and are hoping to build an early warning system. Video provided by Newsy
Powered by NewsLook.com
NASA Chief Outlines Plan for Human Mission to Mars

NASA Chief Outlines Plan for Human Mission to Mars

AFP (Apr. 22, 2014) — NASA administrator Charles Bolden, speaking at the 'Human to Mars Summit' in Washington, says that learning more about the Red Planet can help answer the 'fundamental question' of 'life beyond Earth'. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Nasa Gives You An Excuse to Post a Selfie on Earth Day

Nasa Gives You An Excuse to Post a Selfie on Earth Day

TheStreet (Apr. 22, 2014) — NASA is inviting all social media users to take a selfie of themselves alongside nature and to post it to Twitter, Facebook, Flickr, Instagram, or Google Plus with the hashtag #globalselfie. NASA's goal is to crowd-source a collection of snapshots of the earth, ground-up, that will be used to create one "unique mosaic of the Blue Marble." This image will be available to all in May. Since this is probably one of the few times posting a selfie to Twitter won't be embarrassing, we suggest you give it a go for a good cause. Video provided by TheStreet
Powered by NewsLook.com
SpaceX's Dragon Spacecraft Captured by International Space Station

SpaceX's Dragon Spacecraft Captured by International Space Station

Reuters - US Online Video (Apr. 20, 2014) — SpaceX's unmanned Dragon spacecraft makes a scheduled Easter Sunday rendezvous with the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
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