Astrophysicist predicts detached, eclipsing white dwarfs to merge into exotic star

OU astrophysicist predicts detached, eclipsing white dwarfs to merge into exotic star
Mukremin Kilic, OU astrophysicist, and team have discovered two detached, eclipsing double white dwarf binaries with orbital periods of 40 and 46 minutes, respectively. Only a handful of white dwarf binaries are know with orbital periods less than one hour in our galaxy and most were discovered by Kilic and colleagues. Credit: University of Oklahoma

A University of Oklahoma astrophysicist, Mukremin Kilic, and his team have discovered two detached, eclipsing double white dwarf binaries with orbital periods of 40 and 46 minutes, respectively. White dwarfs are the remnants of Sun-like stars, many of which are found in pairs, or binaries. However, only a handful of white dwarf binaries are known with orbital periods less than one hour in the Milky Way—a galaxy made up of two hundred billion stars—and most have been discovered by Kilic and his colleagues.

"Short-period white dwarf binaries are interesting because they generate gravitational waves. One of the new discoveries emits so much that it is a new verification source for the upcoming Laser Interferometer Space Antenna—a gravitational wave satellite," Kilic said.

Kilic, an astrophysics professor in the Homer L. Dodge Department of Physics and Astronomy, with OU graduate students Alekzander Kosakowski and A. Gianninas, and collaborator Warren R. Brown, Smithsonian Astrophysical Observatory, discovered the two white dwarf binaries using the MMT 6.5-meter telescope, a joint facility of the Smithsonian Institution and the University of Arizona. Observations at the Apache Point Observatory 3.5-meter telescope revealed that one of the binaries is eclipsing, only the seventh known eclipsing white dwarf binary.

In the future, Kilic and his team will watch in real time as the eclipse to measure how they are getting closer and closer—a sign they will likely merge. What occurs when the make contact continues to be a mystery at this point. One possibility is an explosion—a phenomenon known as a supernova. Kilic predicts these two stars will come together and create an "exotic star," known as R Coronae Borealis. These stars are often identified for their spectacular declines in brightness at irregular intervals. There are only about 65 R Coronae Borealis stars known in our galaxy.

"The existence of double white dwarfs that merge in 20 to 35 million years is remarkable," Brown said. "It implies that many more such systems must have formed and merged over the age of the Milky Way."


Explore further

Binary white dwarf stars

Citation: Astrophysicist predicts detached, eclipsing white dwarfs to merge into exotic star (2017, August 18) retrieved 17 June 2019 from https://phys.org/news/2017-08-astrophysicist-detached-eclipsing-white-dwarfs.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
576 shares

Feedback to editors

User comments

Aug 19, 2017
From article:
"Short-period white dwarf binaries are interesting because they generate gravitational waves. One of the new discoveries emits so much gravitational waves that it is a new verification source for the upcoming Laser Interferometer Space Antenna—a gravitational wave satellite," Kilic said.
The same can be said for Hulse-Taylor Neutron-Star Binary System dynamics.

Yet gravitational waves from these relatively nearby grav-wave sources have yet to be detected. Why?

That is the question that should be answered by those claiming to have detected grav-waves from sources BILLION(s) of lightyears distance but have not detected any from THESE MUCH CLOSER sources.

So, would anyone 'believing' a-LIGO claims care to 'do the maths' and post it here to explain how grav-waves can remain 'detectable' over 'background noise' after BILLION(s) of lightyears propagation, yet NO grav-waves detected from these Binary NS/WD sources close to/within our MW galaxy?

Thanks. :)

Aug 21, 2017

Good Point.
In May of 2014 I experienced an exceptional calmness and was surprised to find that the imaginary 'gravity waves' were claimed to have been identified on that day. Nope. Magnetic solitons must be the responsible party.

Aug 21, 2017
As an answer to why some are not detected and some are, it is not just the magnitude of the waves, it also is the frequency of the waves. If you have something with a longer wavelength (lower frequency) then you have to have legs of the interferometer longer. If you notice, they could only detect the waves as they were entering the audible frequency range. That is a much shorter wavelength than something like a binary with a frequency in the per/hour range. Look up the "chirp" for the detected waves to see how their frequency changed as the black holes collided. If it was two white dwarfs that were closer that collided they could have detected that. The space interferometers will have legs that are hundreds of kilometers long and they will be able to detect lower frequency waves such as the orbiting white dwarf stars.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more