There is a new toy in town, an additional component to the called the Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE). SPHERE, the optics system used to collect data on planets that are outside of our own Solar System, has recently been used to look at the double star, V471 Tauri.
Very Large Telescope
What exactly is a double star? In short, it is a pair of stars that appear close to each other in the sky when viewed through an optical telescope. This effect can happen for a number of reasons – either the stars are orbiting around their common center of mass (binary star),or gravitationally bound to each other. They may also form an optical double (an alignment of stars that actually lie at different distances). In the case of V471 Tauri, its two stars happen to eclipse each other at irregular intervals. For some time, astronomers were thrown off by this, but the technology to investigate did not exist until the introduction of SPHERE.
The two stars in V471 Tauri are of slightly different masses – the larger of which has grown to become a red giant. During this state, it transferred material to the other star, until both were surrounded by a gaseous cloak. As the cloud dissipated, however, both stars eventually moved closer together, forming a tight pair comprised of one normal star and one white dwarf. Under normal circumstances, their orbits should be at regular intervals.
Astronomers confidently predicted that the cause of the irregular intervals could be a third smaller star, known as a brown dwarf, which was thought to be orbiting the two larger stars. Yet, detailed pictures from SPHERE actually revealed…nothing.
The European Space Agency, owners of the Very Large Telescope, has claimed that SPHERE is working just fine and the images are more than accurate enough to detect any brown dwarfs that may be lurking in the vicinity. It simply is not there.
“There are many papers suggesting the existence of such circumbinary objects, but the results here provide damaging evidence against this hypothesis,” remarks Adam Hardy of the Universidad Valparaíso, Valparaíso, Chile.
All is not lost, however. Professor Hardy and his team are rather optimistic about the new findings, or lack thereof. With hard proof that there is little chance of a brown dwarf to be throwing off the orbits of the two larger stars, astronomers are forced to abandon old ideas and begin afresh. One such theory is the idea that variations in the magnetic field of the larger star may be disrupting what should be a standard eclipse interval.
To view the full report, directly from the European Space Agency, click here.