Gaia Satellite has discovered a rare Binary System where one star is ‘eating’ the other, but neither star has hydrogen, the most common element in the Universe

 

It is a type of 2-star system known as a Cataclysmic Variable, where one super dense white dwarf star is stealing gas from its companion star, effectively ‘cannibalising’ it.The system could also be an important laboratory for studying ultra-bright supernova explosions, which are a vital tool for measuring the expansion of the Universe. The system, named Gaia14aae, is 730 light years away in Draco constellation. It was discovered by the ESA’s Gaia satellite in August 2014 when it suddenly became 5 times brighter over the course of a single day.

>>Additional observations made by the Center for Backyard Astrophysics (CBA), a collaboration of amateur and professional astronomers, found the system is a rare eclipsing binary, where one star passes directly in front of the other, completely blocking it out when viewed from Earth. The 2 stars are tightly orbiting each other, so a total eclipse occurs roughly every 50 minutes. “It’s rare to see a binary system so well-aligned”…”Because of this, we can measure the system with great precision in order to figure out what these systems are made of and how they evolved.”

Using spectroscopy from William Herschel Telescope, Campbell’s team found Gaia14aae has large amounts of He, but no H. The lack of H allowed them to classify Gaia14aae as a very rare type of system known as AM Canum Venaticorum (AM CVn), a type of Cataclysmic Variable system where both stars have lost all of their H. This is the first known AM CVn system where one star totally eclipses the other.

AM CVn systems consist of a small and hot white dwarf star which is devouring its larger companion. The gravitational effects from the hot and superdense white dwarf are so strong that it has forced the companion star to swell up like a massive balloon and move towards it. The companion star is ~125X the volume of our sun, and towers over the tiny white dwarf, which is about the size of the Earth.

It’s not known whether the two stars will collide and cause a supernova explosion, or whether the white dwarf will completely devour its companion first. “This is an exquisite system: a very rare type of binary system in which the component stars complete orbits faster than the minute hand of a clock, oriented so that one eclipses the other,” said Professor Tom Marsh of the University of Warwick. “We will be able to measure their sizes and masses to a higher accuracy than any similar system.”

http://www.cam.ac.uk/research/news/gaia-satellite-and-amateur-astronomers-spot-one-in-a-billion-star