Artist’s concept of a white dwarf and a companion. Image via Helena Uthas/ Durham University.
White dwarf rapid brightness change
Astronomers in the U.K. said this week that, for the first time, they saw a white dwarf star abruptly switch on and off. The star is TW Pictoris – 1,400 light-years from Earth – already known as a variable star. But its previous brightness changes were seen to happen over days or months. This time, astronomers saw the star suddenly dim and brighten again over the course of just 30 minutes. What happened to cause such a rapid shift?
A white dwarf star is a main-sequence star (a star like our sun) that has shrunk because it’s at the end of its life. The TW Pictoris system includes a white dwarf, plus a small companion star that the white dwarf “feeds” on. The white dwarf pulls in material from the companion. It’s this gradual accretion (build up) of material that causes the dwarf to change its brightness.
The scientists, led by researchers from Durham University in the UK, used a planet-hunting satellite – NASA’s Transiting Exoplanet Survey Satellite (TESS) – to make their discovery. Lead author Simone Scaringi of ...