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Extreme Black Widow

June 4, 2021

A dead star about 4500 light-years from Earth is blasting away its companion. Before long, the companion may disappear completely — the victim of a black widow.

The “dead” star is a pulsar — the crushed core of a once mighty star. It spins hundreds of times per second, beaming energy in our direction with each turn. That makes the star appear to “pulse” on and off.

Its companion is a small ball of gas — mainly helium. It’s only about eight times as heavy as Jupiter, the largest planet in the solar system — roughly a tenth of the minimum mass of a star.

The object may well have been a true star in the past. But it’s so close to the pulsar that the pulsar blasts away the former star’s outer layers. That makes the pulsar a “black widow” — a star that devours its mate. It’s the most extreme black widow yet seen.

The pulsar continues to erode the tiny companion today. Some of the gas falls onto the pulsar, making it heavier. In fact, it’s the most massive pulsar yet discovered — at least 2.1 times the mass of the Sun. The rest of the companion’s gas simply blows out into space — the remnants of a disappearing star.

The system is known as J1311-3430. It’s in Centaurus, the centaur, which is low in the south as night falls. Although the system is much too faint to see without a big telescope, you can pick out its location. It’s at the centaur’s northern edge, above one of its brighter stars, Iota Centaurus.

Script by Damond Benningfield

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