By Definition
High Definition
Standard Definition
By Length
Full (4-12 min)
Short (1-4 min)
By Date
2018 | 2017 | 2016 | 2015 |
2014 | 2013 | 2012 | 2011 |
2010 | 2009 | 2008 | 2007 | 2006
By Category
Solar System
White Dwarfs
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Groups of Galaxies
Cosmology/Deep Field
Space Scoop for Kids!
Chandra Sketches
Quick Look
How To
Apple iTunes
RSS Reader
Web Shortcuts
Chandra Blog
RSS Feed
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
Recent Podcast
A Quick Look at Abell 1033
A Quick Look at Abell 1033
Hidden in a distant galaxy cluster collision are wisps of gas resembling the starship Enterprise, an iconic spaceship from the "Star Trek" franchise. (2018-11-15)

A Tour of X9 in 47 Tucanae

Narrator (April Hobart, CXC): In astronomy, a binary system is one where two objects are close enough that they orbit each other because they are gravitationally bound to one another. There are many possible combinations of binary systems: stars like the Sun orbiting each other, two neutron stars, a massive star and a smaller one, and so on. Binary systems are useful to astronomers for many reasons, including being useful laboratories to measure the masses of stars.

Recently, astronomers have found a particularly interesting binary. This pair has a white dwarf star in orbit around a black hole. While scientists have found this configuration many times before, this binary, known as X9, is special. That's because it has the closest orbit ever seen between a black hole and a companion star.

The X9 system is located in 47 Tucanae, a dense star cluster in the outskirts of the Milky Way. Using NASA's Chandra X-ray Observatory along with data from other telescopes, researchers determined that the white dwarf makes one complete orbit around the black hole in less than a half an hour. This means that the separation between the white dwarf and the black hole is about two and half times the distance between the Earth and the Moon. In cosmic terms, these two objects are extremely close together.

What does this close pairing mean for the objects in X9? The extreme proximity likely spells a bleak future for the white dwarf. Although scientists don't expect the white dwarf to fall into the black hole, they do think so much material will be pulled from the star that it will one day become some sort of exotic planet or even evaporate all together. In the short term, astronomers are going to watch this system very closely, because they don't know exactly how such an extreme system will behave.

Return to Podcasts