Texas Tech University

Space Photo from Texas Tech Researcher’s Project Chosen by TIME Magazine

Glenys Young

December 22, 2015

Paul Sell’s work was included in a list of the Best Space Photos of 2015.


An image from a Texas Tech University astrophysicist's research has been included in TIME Magazine's list of the Best Space Photos of 2015.

Paul Sell, a postdoctoral research fellow in astrophysics and astronomy instructor, was intimately involved with multiple studies of Circinus X-1, a binary star system, which has a neutron star feeding on gas from its orbiting companion star. The neutron star was formed from the leftover core of a star that exploded in a supernova.

“This TIME image was focused on the large ring features created by scattered X-rays from Circinus X-1,” Sell said. “This is an image made from observations with very different telescopes that help tell a more complete story and show all three main features we have discovered, which I have been heavily involved in.”

From the center of the image outward, these three features are:

Paul Sell
Paul Sell
  • The two-sided jets seen in blue. Sell led this work, which measured the size and brightness of the jets to determine their power. “This work shows neutron stars can be as effective as black holes in launching powerful jets into space.”
  • The filled-in red circle is the remnant of the supernova that created the neutron star, seen currently as expanding shockwaves glowing in X-rays. “By discovering and measuring its properties, we can figure out how old the neutron star is. This happens to explain quite well some unusual properties of the system, such as how elliptical or elongated the orbit of the neutron star and its companion star is.”
  • The colorful rings of the dust-scattering halo. “The X-rays bounce off dust preferentially forward toward us just off the line of sight to the neutron star. By studying the dust-scattering halo, we can find out the distance to the source much more accurately than before. It also tells us about the dust and clouds in the direction of the neutron star.”

Sell said studying this system could help scientists to better understand how binary star systems behave when the lives of their constituent stars end. This is important because a large percentage of stars live in such systems, rather than living alone like the Sun.

“The most basic takeaway is these new observations have helped us put together a more complete picture to much better understand how this system evolves and maybe how other such systems evolve,” Sell said.