Life on a planet ruled by two suns might be a little complicated. Two sunrises, two sunsets. Twice the radiation field.
In a paper published in the December 2008 issue of Astronomy and Astrophysics, astronomer Joel Kastner and his team suggest that planets may easily form around certain types of twin (or “binary”) star systems. A disk of molecules discovered orbiting a pair of twin young suns in the constellation Sagittarius strongly suggests that many such binary systems also host planets.
“We think the molecular gas orbiting these two stars almost literally represents ‘smoking gun’ evidence of recent or possibly ongoing ‘giant’ (Jupiter-like) planet formation around the binary star system,” says Kastner, professor at Rochester Institute of Technology’s Chester F. Carlson Center for Imaging Science.
Kastner used the 30-meter radiotelescope operated by the Institut de Radio Astronomie Millimetrique (IRAM) to study radio molecular spectra emitted from the vicinity of the two stars in a binary system called V4046 Sgr, which lies about 210 light-years away from our solar system. (V4046 Sgr is the 4046th brightest variable-brightness star in the constellation Sagittarius.) The scientists found “in large abundance” raw materials for planet formation around the nearby stars, including circumstellar carbon monoxide and hydrogen cyanide, in the noxious molecular gas cloud.
The young stars, approximately 10 million years old, are close in proximity to each other—only 10 solar diameters apart—and orbit each other once every 2.5 days.
“In this case the stars are so close together, and the profile of the gas in terms of the types of molecules that are there is so much like the types of gaseous disks that we see around single stars, that it’s a real link between planets forming around single stars and planets forming around double stars,” Kastner says.
Planets that have just formed around young stars like the V4046 Sgr twins might leave leftover gas, a potential clue for astronomers who hunt planets.