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T Pyxidis

April 14, 2021

A star in the system known as T Pyxidis isn’t a good neighbor. It’s taking gas from a companion star. And every few decades, it erupts, blasting away more of the companion. So the companion could soon disappear.

T Pyxidis is a recurrent nova. That means it sometimes flares thousands of times brighter than normal. The first known outburst took place as early as 1866. And the most recent was first seen 10 years ago today.

The system’s main star is a white dwarf — the dead core of a once-normal star. It appears to be more massive than the Sun, but only about as big as Earth.

The companion star is larger but less massive. The white dwarf pulls gas from its surface, which then settles on the white dwarf. This gas is squeezed tightly, so it gets hotter and hotter. When it gets hot enough, it explodes like a giant H-bomb. A new blast takes place roughly every two to four decades.

A study a few years ago found that the system gets a little fainter after each outburst. That could mean that the white dwarf is blasting more material into space than it’s taking from the companion. The strong outbursts could be eroding the companion. So in a couple of hundred thousand years, the companion star could vanish.

T Pyxidis is in Pyxis, the compass, which is low in the south at nightfall. The star is too faint to see without a telescope. It may be biding its time — building up to another eruption in a decade or so.

Script by Damond Benningfield

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