Why are planets in quadruple star systems part of discovery for astronomers?

Astronomers have discovered the second known case of a planet residing in a quadruple star system.This particular planet had been known before, but was thought to have only three stars, not four. By finding this planet within a quadruple star system, it helps astronomers better understand how multiple star systems can influence the development and fate of planets. This is because such systems can have a greater gravitational pull on the planet in comparison to a system with only one or two stars, potentially changing its orbit and other characteristics of the planet.

Growing up as a planet with more than one parent star has its challenges, but researchers are beginning to understand the complex influences of multiple stars on the planets they orbit. With the help of instruments fitted to telescopes at the Palomar Observatory in San Diego, two new case studies of multiple-star system planets have been identified: one with three parents and another with four. This is the second time a planet has been identified in a quadruple star system, with KIC 4862625 being the first, which was discovered in 2013 by citizen scientists using data from NASA’s Kepler Mission. Understanding how planets form and evolve in multiple-star systems can help astronomers learn more about the conditions that can foster the formation of planets, and ultimately, life.

The latest discovery suggests that planets in quadruple star systems might be less rare than once thought. Recent research has revealed that this type of star system, with two pairs of twin stars orbiting each other from great distances, is more common than previously believed. It has been estimated that around four percent of solar-type stars are in quadruple systems, up from earlier estimates due to improved observational techniques. The recently discovered four-star planetary system, 30 Ari, is located 136 light-years away in the constellation Aries. It has a large gaseous planet with ten times the mass of Jupiter, which orbits its primary star every 335 days. The primary star also has a close partner star, to which the planet does not orbit. This pair is further held in orbit with another pair of stars at a distance of 1,670 astronomical units. It is highly unlikely that this planet or any moons orbiting it can sustain life. These findings suggest that planets in quadruple star systems may not be as rare as once thought and present a potential new field of exploration for astronomers.

The possibility of seeing the sky from this world reveals four parent stars that look like one small sun and two very bright stars that can be seen in daylight. With a powerful enough telescope, one of those stars is revealed as a binary system consisting of two stars orbiting each other. This discovery is not too big of a surprise, as binary stars are more common in our galaxy than single stars. The new findings show that star systems come in many forms, such as single stars, binary stars, triple stars, and even quintuple star systems. This shows the vastness of nature and how creative it can be. As Lewis Roberts, the lead author of the new findings in the Astronomical Journal, said about the findings: “It’s amazing the way nature puts these things together.”

Roberts and his colleagues are looking to understand the effects that multiple parent stars have on developing planets. Evidence suggests that a stellar companion can alter a planet’s orbit, or even cause its mass to grow. One possible example of this is the “hot Jupiters” – planets around Jupiter’s mass that move quickly around their parent stars. It has been suggested that the gravitational pull of a stellar companion could influence these planets and move them closer to their primary parent star. To further investigate this idea, Roberts and his team conducted a study using the Robo-AO system on Palomar Observatory. By scanning hundreds of stars per night, they were able to find two exoplanetary candidates with multiple parent stars. The findings were confirmed by the higher-resolution PALM-3000 instrument also on Palomar Observatory, providing them with further evidence to support their hypothesis.

The new planet with a trio of stars is a hot Jupiter that circles its primary star tightly, completing one lap every three days. Scientists already knew this primary star was locked in a gravitational tango with another star located about 0.7 light-years away. The latest discovery is of a third star in the system, which orbits the primary star from a distance of 28 astronomical units. This close proximity is likely to have had an influence on the development and final orbit of the hot Jupiter. Furthermore, the discovery of a fourth star in the system, located at a distance of 23 astronomical units from the planet has also reinforced the connection between multiple star systems and massive planets. However, this newfound star does not appear to have impacted the orbit of the planet and thus the exact reason for this is unknown. To understand this complex system further, the team is planning further observations in order to uncover more details about its orbit and family dynamics.