12 min orbit white dwarfs found Best target for gravitational waves

[MTd2]

I'd like to share with you people this great discovery!

http://arxiv.org/abs/1107.2389

A 12 minute Orbital Period Detached White Dwarf Eclipsing Binary

Warren R. Brown (1), Mukremin Kilic (1), J. J. Hermes (2), Carlos Allende Prieto (3), Scott J. Kenyon (1), D. E. Winget (2) ((1) SAO, (2) UT Austin, (3) IAC)
(Submitted on 12 Jul 2011)
We have discovered a detached pair of white dwarfs (WDs) with a 12.75 min orbital period and a 1,315 km/s radial velocity amplitude. We measure the full orbital parameters of the system using its light curve, which shows ellipsoidal variations, Doppler boosting, and primary and secondary eclipses. The primary is a 0.25 Msun tidally distorted helium WD, only the second tidally distorted WD known. The unseen secondary is a 0.55 Msun carbon-oxygen WD. The two WDs will come into contact in 0.9 Myr due to loss of energy and angular momentum via gravitational wave radiation. Upon contact the systems may merge yielding a rapidly spinning massive WD, form a stable interacting binary, or possibly explode as an underluminous supernova type Ia. The system currently has a gravitational wave strain of 10^-22, about 10,000 times larger than the Hulse-Taylor pulsar; this system would be detected by the proposed LISA gravitational wave mission in the first week of operation. This system's rapid change in orbital period will provide a fundamental test of general relativity.
Comments: 5 pages, accepted to ApJ Letters

 

[Nik_2213]

D'uh, by the time LISA's budget is approved, those two white-dwarfs will have gone supernova...

 

[Gestahl]

Maybe this will help to get LISA's budget approved!

 

[Drakkith]

Is there any way to detect this on earth? I'm assuming no for now.

 

[Gestahl]

In the future, we plan to use multi-passband photometry to directly measure the nature of the secondary WD and to detect the change in orbital period predicted by general relativity.

As the paper suggests, there are other ways to make these detections. LISA on the other hand searches for low-frequency gravitational waves that will never be detectable by any terrestrial detectors, existing or planned. These low-frequency gravitational waves cannot be detected on Earth because Earth's gravitational field is constantly changing (due to atmospheric effects and ground motions). These changes cause motion of proof masses in a way which is indistinguishable from the motion caused by gravitational waves. Ground-based detectors like the Laser Interferometer Gravitational-Wave Observatory (LIGO) view the high-frequency waves from transient phenomena, like supernovae and the final minutes of in-spiraling neutron-star binaries.