Astronomers have discovered a new planet located in a system with three stars and another planet located in a system with not one, not two, not three, but four stars in the system.
This is only the second time a planet has been identified in a star system with four stars. While this planet has been known for some time, originally it was thought to have three stars, not four. The first four-star planet, KIC 4862625, was discovered by amateur scientists using public data from NASA's Kepler mission.
This latest discovery could mean that planets in quadruple star systems might be less rare than once believed. In fact, recent research indicates that this type of star system, which usually consists of two pairs of stars circling each other at great distances, is itself more common than previously thought.
"About four percent of solar-type stars are in quadruple systems, which is up from previous estimates because observational techniques are steadily improving," said co-author Andrei Tokovinin of the Cerro Tololo Inter-American Observatory in Chile.
The newfound planet in the four star system, called 30 Ari, is located approximately 136 light-years away in the constellation Aries. The planet is a gas giant that is enormous, with ten times the mass of our solar system's largest gas giant, Jupiter. Much like the Earth around our Sun, the gas giant planet orbits its primary star every 335 days. However unlike the Earth, astronomers don't believe that this planet or any moons could sustain life.
"Star systems come in myriad forms. There can be single stars, binary stars, triple stars, even quintuple star systems," said Lewis Roberts of JPL, lead author of the new findings appearing in the journal Astronomical Journal. "It's amazing the way nature puts these things together."
Roberts and his colleagues want to understand the types of effects multiple parent stars can have on the development of planets in their system. Current evidence suggests that stellar companions can change the orbits of the planets and even trigger some of the planets to grow more massive.
However, in the case of Ari 30, the newfound fourth star does not appear to have impacted the orbit of the planet. The exact reason for this is currently unknown, but the team is planning further observations to better understand the orbit of the star and its complicated family dynamics of the stars and the planets in the system.
