Researchers seeking to study the complexities of exoplanets with multiple stars have found a new system with four. Called 30 Ari, the system has been discovered earlier actually but at the time it was thought to only have three parent stars.
The truth about 30 Ari was realized with help from instruments installed on telescopes at San Diego's Palomar Observatory, detailed in a study published in the Astronomical Journal. These instruments include the PALM-3000 and the Robo-AO adaptive optics systems by NASA's Jet Propulsion Laboratory and Caltech and the California Institute of Technology and the Inter-University Center for Astronomy and Astrophysics, respectively. The only other four-star exoplanet on record is the KIC 4862625 discovered in 2013.
The discovery of 30 Ari hints at the possibility that four-star planets might not be as rare as previously believed. In fact, research has shown that the four-star systems these planets are in are also more common than thought of before. According to Andrei Tokovinin from the Cerro Tololo Inter-American Observatory and one of the co-authors for the study, around 4 percent of solar stars are found in quadruple systems.
The four-star system 30 Ari is situated 136 light-years away in the Aries constellation. It features a massive gaseous planet 10 times Jupiter's mass orbiting its primary star every 335 days. This primary star has a partner star close by but the exoplanet does not orbit the partner. The primary star and its pair are in turn locked in long-distance orbit with another star pair some 1,670 astronomical units away. One astronomical unit is equivalent to the distance between the sun and the Earth.
If one were to stand on 30 Ari's exoplanet and look up at the sky, the parent stars will look like a small sun flanked by two bright stars visible during daylight.
In recent years, exoplanets with two or three stars as parents have been discovered, including some with Tatooine-like sunsets. The fact that a lot of binary stars exist in the galaxy makes it unsurprising that so many exoplanets are being discovered with multiple parent stars.
"It's amazing the way nature puts these things together," said Lewis Roberts from JPL, the lead author for the study.
The researchers want to further understand how having several parent stars can affect a developing exoplanet. Evidence from previous research suggests that accompanying stars can have an effect on exoplanets by changing planetary orbits or triggering further growth for the planet.
