T Pyxidis

Image credit: NASA, ESA, A. Crotts, J. Sokoloski, H. Uthas (Columbia University), and S. Lawrence (Hofstra University)

Colleagues and I used a flash of light from a stellar outburst to probe for the first time the 3-D structure of material ejected by an erupting nova. We used NASA's Hubble Space Telescope to observe the light emitted by the close double-star system T Pyxidis, or T Pyx, a recurrent nova, during its latest outburst in April 2011. Contrary to some predictions, we were surprised to find that the ejecta from earlier outbursts formed a disk of debris around the nova. The discovery suggests that material expands outward along the system's orbital plane.

A nova erupts when a white dwarf, the burned-out core of a Sun-like star, has siphoned enough hydrogen off a companion star to trigger a thermonuclear runaway. As hydrogen builds up on the surface of the white dwarf, it becomes hotter and denser until it detonates like a colossal hydrogen bomb, leading to a 10,000-fold increase in brightness in a little more than one day. Nova explosions are extremely powerful, equal to a blast of one million billion tons of dynamite. T Pyx erupts every 12 to 50 years.

These data indicate that the companion star plays an important role in shaping how material is ejected, presumably along the system's orbital plane, creating the pancake-shaped disk, or ring. The disk is tilted about 30 degrees from face-on toward Earth.

The team also used the light echo to refine estimates of the nova's distance from Earth. The new distance is 15,600 light-years from Earth. Previous estimates were between 6,500 light-years to 16,000 light-years. T Pyx is located in the southern constellation Pyxis, the Mariner's Compass.

Press coverage:

Although the story was picked up by CBS, NBS, Fox New, and the Huffington Post, the best place to read about it is right here at Columbia:

Last modified: Fri Jun 14 2013