Astronomers have spotted a fourth star in a planetary system called 30 Ari, bringing the number of known planet-harboring quadruple-sun systems to two.
"Star systems come in myriad forms. There can be single stars, binary stars, triple stars, even quintuple star systems," study lead author Lewis Roberts, of NASA's Jet Propulsion Laboratory, said in a statement. "It's amazing the way nature puts these things together."
30 Ari lies 136 light-years from the sun in the constellation Aries. Astronomers discovered a giant planet in the system in 2009; the world is about 10 times more massive than Jupiter and orbits its primary star every 335 days. There's also a pair of stars that lie approximately 1,670 astronomical units away. (One AU is the distance between Earth and the sun — about 93 million miles, or 150 million kilometers).
The newfound star circles its companion once every 80 years, at a distance of just 22 AU, but it does not appear to affect the exoplanet's orbit despite such proximity. This is a surprising result that will require further observations to understand, researchers said.
To a hypothetical observer cruising through the giant planet's atmosphere, the sky would appear to host one small sun and two bright stars visible in daylight. With a large enough telescope, one of the bright stars could be resolved into a binary pair.
The discovery marks just the second time a planet has been identified in a four-star system. The first four-star planet, PH1b or Kepler-64b, was spotted in 2012 by citizen scientists using publicly available data from NASA's Kepler mission.
Planets with multiple suns have become less of a novelty in recent years, as astronomers have found a number of real worlds that resemble Tatooine, Luke Skywalker's home planet in the Star Wars films.
The research was published online this month in the Astronomical Journal.