Brent Miszalski is a SALT Astronomer (SA) at the South African Astronomical Observatory (SAAO) and is part of the Astronomy Operations Team at the Southern African Large Telescope (SALT). Together with colleagues he has discovered the majority of known binary central stars of PNe (see below). He enjoys fine tea, naartjies, photography, jazz and occasionally posts to the SALT Astronomy blog. He can be contacted via email using his first name (lowercase) at saao dot ac dot za.
Planetary Nebula Binaries
When low mass stars like our Sun reach the end of their lives they eject their atmospheres in one last hurrah, creating a short-lived object known as a planetary nebula (PN). Named after their similar appearance to planets like Neptune and Uranus through small telescopes, they are not actually planets.
Planetary nebulae (PNe) are clouds of hot gas and dust being ionized, like a neon sign, by a very hot star, soon to become a white dwarf. PNe are best known for their weird and wonderful shapes, as the Hubble Space Telescope has particularly well captured.
In the past few years, astronomers have become increasingly interested in the role that the interaction of two stars, a binary system, has to play in the formation of PNe. It turns out that many of the more peculiar shapes of PNe are difficult, if not impossible, to explain without two stars. This especially goes for collimated outflows or jets, thought to be launched from an accretion disk around a companion star. An excellent example of jets is seen in ETHOS1 (PN G068.1+11.0):
Stellar evolution is certainly more interesting with two stars.