In 185 AD, astronomers recorded the appearance of a new star in
the Nanmen asterism - a part of the sky identified with Alpha
and Beta Centauri on modern star charts. The new star was
visible for months and is thought to be the earliest composite
image from orbiting telescopes of the 21st century, XMM-Newton
and Chandra in X-rays, and Spitzer and WISE in infrared,
supernova remnant RCW 86, understood to be the remnant of that
The false-color view shows interstellar gas heated by the
expanding supernova shock wave at X-ray energies (blue and
green) and interstellar dust radiating at cooler temperatures in
infrared light (yellow and red). An abundance of the element
iron and lack of a neutron star or pulsar in the remnant suggest
that the original supernova was Type Ia. supernovae are
thermonuclear explosions that a white dwarf star as it accretes
material from a companion in a binary star system. the X-ray
emitting shell and infrared dust temperatures indicate that the
remnant is expanding extremely rapidly in