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HST Reveals Debris Disk Around T Pyxidis
by Ivan Adamin in July-August 2013 (#1)
T Pyx is a recurrent nova, erupting every 12 to 50 years and ejecting material that has formed the disk around the bright star. Hubble Space Telescope photographed T Pyx's latest outburst in April 2011, giving a rare look at stellar eruption in details.
The light echo after explosion in the double-star system reveals that material ejected by previous T Pyx outbursts is sticking around the star and form a debris disk. The study represents the first time the area around an erupting star has been mapped in three dimensions, researchers said. According to their measurements, the debris disk is about 1 light-year wide.
Debris disk around T Pyxidis star
Image Credit: NASA, ESA, A. Crotts, J. Sokoloski, and
H. Uthas (Columbia University), and
S. Lawrence (Hofstra University)
The erupting T Pyx star is a white dwarf, the burned-out core of a star much like our own sun. White dwarfs are small but dense objects. Imagine the mass of the sun packed into a volume the size of Earth.
The system is binary, hence has a companion star. The believed reason of the explosion is a high volume of hydrogen on the white dwarf's surface built up by accretion from a companion star. Typical outbursts increase T Pyx's brightness ten thousand times over a single day. Apart from the 2011 event, eruptions were registered in 1890, 1902, 1920, 1944, and 1966 The new HST observations also help refine the distance to the star: about 15600 light-years from Earth.
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