Astronomers using the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) instrument on ESO’s Very Large Telescope have captured dramatic details of the turbulent stellar relationship in a binary star system called R Aquarii.
This image taken by ESO’s Very Large Telescope shows the binary system R Aquarii and the jets of material spewing from the stellar couple. Image credit: ESO / Schmid et al.
Located 650 light-years away, R Aquarii is a so-called symbiotic binary, comprising two stars surrounded by a large, dynamic cloud of gas (a nebula).
Such binaries contain two stars in an unequal and complex relationship — a white dwarf and a red giant.
In a disquieting act of stellar cannibalism, the white dwarf is stripping matter from its larger companion.
The tormented red giant and the unstable white dwarf occasionally eject matter in weird spurts, loops and trails.
“The red giant in the R Aquarii system is a type of star known as a Mira variable,” the astronomers said.
“At the end of their life, these stars start to pulsate, becoming 1,000 times as bright as the Sun as their outer envelopes expand and are cast into the interstellar void.”
“The death throes of this vast star are already dramatic, but the influence of the companion white dwarf star transforms this intriguing astronomical situation into a sinister cosmic spectacle.”
“The white dwarf is flaying material from the outer layers of its larger companion.”
“The jets of stellar material cast off by this dying giant and white dwarf pair can be seen here spewing outwards from R Aquarii.”
Occasionally, enough material collects on the surface of the white dwarf to trigger a thermonuclear nova explosion, a titanic event which throws a vast amount of material into space.
“The remnants of past nova events can be seen in the tenuous nebula of gas radiating from R Aquarii in the SPHERE image,” they said.
The research was published in the journal Astronomy & Astrophysics.
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H.M. Schmid et al. 2017. SPHERE/ZIMPOL observations of the symbiotic system R Aquarii. I. Imaging of the stellar binary and the innermost jet clouds. A&A 602, A53; doi: 10.1051/0004-6361/201629416
