Featured Research

from universities, journals, and other organizations

'Stellar Cannibalism' Is Key To Formation Of Overweight Stars

Date:
January 15, 2009
Source:
University of Southampton
Summary:
Astronomical researchers have discovered evidence that blue stragglers in globular clusters, whose existence has long puzzled astronomers, are the result of 'stellar cannibalism' in binary stars.

Blue stragglers in globular cluster 47 Tucanae.
Credit: NASA Goddard Space Flight Center (NASA-GSFC)

Astronomical researchers have discovered evidence that blue stragglers in globular clusters, whose existence has long puzzled astronomers, are the result of 'stellar cannibalism' in binary stars.

Dr Christian Knigge, Reader in the School of Physics and Astronomy at the University of Southampton, Alison Sills, associate professor in physics and astronomy at McMaster University, and Nathan Leigh, PhD student in physics and astronomy at McMaster, have published their findings in the journal Nature.

Globular clusters are collections of about 100,000 stars, tightly bound by gravity, giving them a spherical shape. Blue stragglers are stars within these clusters that are more massive, and appear younger, than the bulk of their counterparts. This violates standard theories of stellar evolution, in which all stars in a cluster are born at the same time. Stars as massive as blue stragglers should have died long ago according to these theories, yet virtually every observed cluster contains some of these overweight stars.

Dr Knigge, who led the study, comments: "The origin of blue stragglers has been a long-standing mystery. The only thing that was clear is that at least two stars must be involved in the creation of every single blue straggler, because isolated stars this massive simply should not exist in these clusters."

Professor Sills explains further: "We've known of these stellar anomalies for 55 years now. Over time two main theories have emerged: that blue stragglers were created through collisions with other stars; or that one star in a binary system was 'reborn' by pulling matter off its companion."

The researchers looked at blue stragglers in 56 globular clusters. They examined the number of stars in each cluster and how that number scales with some key parameters of the cluster.

They found the total number of blue stragglers in a given cluster did not seem to correlate with the predicted collision rate - dispelling theory number one.

They did, however, discover a connection with the mass of the cluster core, and inferred a connection to the number of binary stars in a cluster core. This connection is supported by preliminary observations of binary stars in clusters, and points to 'stellar cannibalism' as the primary mechanism for blue straggler formation.

Dr Knigge says: "This is the strongest and most direct evidence to date that most blue stragglers, even those found in the cluster cores, are the offspring of binary stars transferring matter. In our future work we will want to determine whether the binary parents of blue stragglers evolve mostly in isolation, or whether dynamical encounters with other stars in the clusters are required somewhere along the line in order to explain our results."


Story Source:

The above story is based on materials provided by University of Southampton. Note: Materials may be edited for content and length.


Journal Reference:

  1. A binary origin for 'blue stragglers' in globular clusters. Nature, 15 January, 2009

Cite This Page:

University of Southampton. "'Stellar Cannibalism' Is Key To Formation Of Overweight Stars." ScienceDaily. ScienceDaily, 15 January 2009. <www.sciencedaily.com/releases/2009/01/090114095103.htm>.
University of Southampton. (2009, January 15). 'Stellar Cannibalism' Is Key To Formation Of Overweight Stars. ScienceDaily. Retrieved April 19, 2014 from www.sciencedaily.com/releases/2009/01/090114095103.htm
University of Southampton. "'Stellar Cannibalism' Is Key To Formation Of Overweight Stars." ScienceDaily. www.sciencedaily.com/releases/2009/01/090114095103.htm (accessed April 19, 2014).

Share This



More Space & Time News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

A Hoax? Cosmetics Company Wants To Brighten The Moon

A Hoax? Cosmetics Company Wants To Brighten The Moon

Newsy (Apr. 19, 2014) FOREO, a Swedish cosmetics company, says it wants to brighten the moon to lower electricity costs. Video provided by Newsy
Powered by NewsLook.com
Raw: Space X Launches to Space Station

Raw: Space X Launches to Space Station

AP (Apr. 18, 2014) On it's second attempt this week, The Space X company launched Friday from Cape Canaveral to ferry supplies to the International Space Station. (April 18) Video provided by AP
Powered by NewsLook.com
Unmanned Falcon 9 Rocket Blasts Off from Cape Canaveral Air Force Station in Florida

Unmanned Falcon 9 Rocket Blasts Off from Cape Canaveral Air Force Station in Florida

Reuters - US Online Video (Apr. 18, 2014) The rocket, built and operated by Space Exploration Technologies, carries a Dragon cargo ship loaded with supplies and equipment destined for the International Space Station. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Earth's Near-Twin Found Orbiting Red Dwarf

Earth's Near-Twin Found Orbiting Red Dwarf

Newsy (Apr. 17, 2014) The newly-discovered planet is roughly the size of Earth and could have liquid water on its surface. 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