October 16, 2012 in Space
A new planet has been discovered that has four suns in its sky. It directly orbits two of the stars, which are in turn orbited by two distant stars. The circumbinary star is the first of its kind to be discovered, and was originally spotted not by professional researchers but by citizen scientists from the website Planethunters.org.
A Yale-led international team of researchers confirmed its discovery of the planet and then characterized it as a circumbinary planet in a four-star system.
So far, out of all the planets discovered, only six of them are known to orbit double stars, and until now none of them were orbited by other stars.
“Circumbinary planets are the extremes of planet formation,” said lead author Meg Schwamb of Yale.
“The discovery of these systems is forcing us to go back to the drawing board to understand how such planets can assemble and evolve in these dynamically challenging environments.”
“Named PH1, the planet was identified by citizen scientists who were participating in a Yale-based program called Planet Hunters. The program uses interested members of the public to sort through and review the huge quantities of astronomical data they receive from NASA’s Kepler spacecraft. This is the first planet found by the project.”
“The volunteers — Kian Jek of San Francisco and Robert Gagliano of Cottonwood, Arizona — spotted faint dips in light caused by the planet as it passed in front of its parent stars, a common method of finding extrasolar planets. Schwamb, a Yale postdoctoral researcher, led the team of professional astronomers that confirmed the discovery and characterized the planet, following observations from the Keck telescopes on Mauna Kea, Hawaii. PH1 is a gas giant with a radius about 6.2 times that of Earth, making it a bit bigger than Neptune.”
PH1 is currently following a 20-day orbit around a pair of eclipsing stars that are around 1.5 and 0.41 times the mass of the Sun. Its orbit takes around 138 days. That’s all remarkable on its own, but then just 1000 AU away there’s another pair of stars that orbit the planetary system. An AU is about the distance between the Earth and the Sun.
“The thousands of people who are involved with Planet Hunters are performing a valuable service,” said coauthor Jerome Orosz, who earned his Ph.D. at Yale in 1996 and is now associate professor of astronomy at San Diego State University. “Many of the automated techniques used to find interesting features in the Kepler data don’t always work as efficiently as we would like. The hard work of the Planet Hunters helps ensure that important discoveries are not falling through the cracks.”
The research has been submitted to the Astrophysical Journal.
Source: Yale University
Image Credits: Haven Giguere/Yale; David A. Aguilar (CfA)