January 23, 2014
New, Neptune-Sized Exoplanet Discovered Around Bright Star
redOrbit Staff & Wire Reports - Your Universe Online
An international group of astronomers has discovered a new, roughly Neptune-sized exoplanet orbiting the brightest star in a binary system more than 400 light years from Earth, according to a study appearing in the most recent edition of The Astrophysical Journal.The study authors, who were working out of the Stellar Astrophysics Centre in Denmark, found the new planet by studying the star around which it revolves. They discovered the star’s rotation appeared to be in strong alignment with the planet’s movement, and the relative brightness of the star made the planet easy to study.
The exoplanet, which has a radius of approximately 2.8 times that of Earth, can be observed using strong binoculars. It its much closer to its star than our planet is to the sun, with a period of about 18 days, and is therefore too hot in order to sustain life. The planet has been named “Kepler-410A b” by the astronomers.
The star orbited by Kepler-410A b appears to be one-half of a two-star system, and in their research, 15 investigators representing seven different institutions described the orbit as slightly eccentric. Furthermore, they noted that perturbations on the newly-discovered exoplanet hint at the existence of a second world in the system.
Following the discovery of Kepler-410A b, the number of exoplanets discovered and identified by researchers around the world has increased to roughly 1,000. However, this particular specimen is intriguing because it can be studied in great detail, and already has been analyzed for over four years using NASA’s Kepler space telescope.
“Ultimately, to understand anything about exoplanets, we need to understand the stars they revolve around. In this case, asteroseismology has even allowed us to measure the inclination angle of the star,” lead author Vincent Van Eylen, a doctoral student at Aarhus University in Denmark, told the Stellar Astrophysics Centre's Peter F. Gammelby.
“We now know we are looking at the equator of the star, not at the pole,” he added. “This can be compared with the orbit of the planet to learn about planetary formation. The star is around 2.7 giga-years old and is a little larger than the Sun. We will never be able to go there, as it is located at around 425 light years from Earth.”
Thanks to the brightness of the star, Kepler-410A b has been deemed a suitable target for additional future observations. The astronomers have measured its transit times and found that it does not precisely cross the star every 17.8 days; rather, it can sometimes be up to 15 minutes earlier or later due to perturbations.
Those perturbations suggest that a second exoplanet could be present, slightly pulling Kepler-410A b closer or pushing it further way, Van Eylen explained. He added that he and his colleagues “are confident that there is another planet, but because it doesn't move in front of the star, we don't yet know what it is like.”
Vincent Van Eyen also regularly blogs at Scilogs.be, a blog portal by the magazine EOS.