Discovering exoplanets with gravitational waves

Discovering exoplanets with gravitational waves
Artistic representation of gravitational waves produced by a compact binary white dwarf system with a jovian mass planetary companion. Credit: Simonluca Definis

In a recent paper in Nature Astronomy, researchers from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) in Potsdam and from the French Alternative Energies and Atomic Energy Commission (CEA) in Saclay, Paris suggest how the planned space-based gravitational-wave observatory LISA can detect exoplanets orbiting white dwarf binaries everywhere in the Milky Way and in the nearby Magellanic Clouds. This new method will overcome certain limitations of current electromagnetic detection techniques and might allow LISA to detect planets down to 50 Earth masses.

In the past two decades, the knowledge of exoplanets has grown significantly, and more than 4000 planets orbiting a large variety of stars have been discovered. Up to now, the techniques used to find and characterize these systems are based on electromagnetic radiation and are limited to the solar neighborhood and some parts of the galaxy.

In a recent paper published in Nature Astronomy, Dr. Nicola Tamanini, researcher at the AEI in Potsdam and his colleague Dr. Camilla Danielski, researcher at the CEA/Saclay (Paris) show how these limitations may be overcome by gravitational-wave astronomy. "We propose a method which uses to find exoplanets that orbit binary white dwarf stars," says Nicola Tamanini. White dwarfs are very old and small remnants of stars once similar to the sun. "LISA will measure gravitational waves from thousands of white dwarf binaries. When a planet is orbiting such a pair of white dwarfs, the observed gravitational-wave pattern will look different compared to the one of a binary without a planet. This characteristic change in the gravitational waveforms will enable us to discover exoplanets."

The new method exploits the Doppler shift modulation of the gravitational-wave signal caused by the gravitational attraction of the planet on the white dwarf binary. This technique is the gravitational-wave analogue of the radial velocity method, a well-known technique used to find exoplanets with standard electromagnetic telescopes. The advantage, however, of gravitational waves is that they are not affected by stellar activity, which can hamper electromagnetic discoveries.

In their paper, Tamanini and Danielski show that the upcoming ESA mission LISA (Laser Interferometer Space Antenna), scheduled for launch in 2034, can detect Jupiter-mass exoplanets around white dwarf binaries everywhere in the galaxy, overcoming the limitations in distance of electromagnetic telescopes. Furthermore, they point out that LISA will have the potential to detect those exoplanets also in nearby galaxies, possibly leading to the discovery of the first extragalactic bound .

"LISA is going to target an exoplanet population yet completely unprobed," explains Tamanini. "From a theoretical perspective nothing prevents the presence of exoplanets around compact binary ." If these systems exist and are found by LISA, scientists will obtain new data to further develop planetary evolution theory. They will better understand the conditions under which a planet can survive the stellar red-giant phase(s) and will also test the existence of a second generation of planets, i.e., planets that form after the red-giant phase. On the other hand, if LISA does not detect exoplanets orbiting white dwarf binaries, the scientists will be able to set constraints on the final stage of planetary evolution in the Milky Way.

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More information: Nicola Tamanini et al. The gravitational-wave detection of exoplanets orbiting white dwarf binaries using LISA, Nature Astronomy (2019). DOI: 10.1038/s41550-019-0807-y
Journal information: Nature Astronomy

Provided by Max Planck Society
Citation: Discovering exoplanets with gravitational waves (2019, July 9) retrieved 21 July 2019 from
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Jul 09, 2019
"Gravitational waves – a great discovery or a great scandal (a plagiarism)? ...
A question could be asked here: how is it possible that gravity, as a force of attraction, creates the reverse force at the same time? These waves should be moving towards the center of gravity and not away from it; therefore, there should be nothing to be measured.

It seems that this is only a too much of a hussle (even the president Obama praised the discovery) and only an attempt to disguise the next American plagiarism by creating such a great machination." Now the new players who deepen lies. https://www.svemi...#scandal

(A new article suddenly appeared on February 25th, and all of a sudden, a new change of the already new paradigm occurred again. Gravitational waves could be created by pulsars that have a fast rotation!
This utter "shift" seems to be at the core of the discovery, as well

Jul 09, 2019
I don't think you understand what the work plagiarism actually means.

Jul 09, 2019
"the practice of taking someone else's work or ideas and passing them off as one's own.
"there were accusations of plagiarism"
synonyms: copying, infringement of copyright, piracy, theft, stealing, poaching, appropriation; informalcribbing

Definition: In an instructional setting, plagiarism occurs when a writer deliberately uses someone else's language, ideas, or other original (not common-knowledge) material without acknowledging its source.
"In 1936, Einstein and Nathan Rosen submitted a work in the Physical Review claiming that gravity waves can not exist in the full general relativity theory because any such field equation solution has singularity."
"2008: "... Celestial objects rotate around their axes; the rotation creates waves, which travel away from an object and in that way create repulsion forces, which prevent the objects, captured in the orbits around them, from falling onto them." http://www.svemir...-Univers

Jul 09, 2019
If you having difficulty understanding this article because you aren't familiar with the relevant sciences, you can first read about the planned space-based gravitational-wave observatory LISA here;


One of there things LISA should be able to detect is gravitational waves from stars rotating very close to each other because, as it says in the link below, "according to general relativity, two masses orbiting each other will necessarily emit energy in the form of gravitational waves, coupled with a loss of angular momentum"


Jul 09, 2019
wduckss - you obviously do not understand a great many things. One of those things is the nature of gravitational waves.

Gravitational waves do not refer to waves of gravitation. They refer to waves in space caused by gravitation. As Einstein explained so well, the attraction caused by gravitation is caused by the way gravity warps spce. When objects travel in a path in warped space, it appears they are attracted to each other, but they are merely following a least time path along warped space.

Jul 09, 2019
A ~15 Earth years wait for LISA. Why take so long to do this? It's not like they will be sending humans out there.
In any case, binary white dwarfs aren't likely to cultivate any life forms on their planet(s). If such planets exist, they likely would be rocked by ongoing tremors and quakes. If they want to find living creatures, they would be better off looking for a solar system with only one Star in the centre that has planets orbiting the Star. Never mind exotic 2 Star systems that can only be verified of its existence, but no one will ever go there.

Jul 09, 2019
I don't think you understand what the work plagiarism actually means.
says 691Boat

LOL Mind your spelling. I think you meant "word" instead of "work".

Jul 09, 2019
waiting for the Gravitational Wave double slit experiment.

Jul 10, 2019
@wduckss "A question could be asked here: how is it possible that gravity, as a force of attraction, creates the reverse force at the same time? "

One example is solar wind/CME sending mass or 'anti-gravity' waves (at the speed of ultra sound vs speed of light) to LIGO mirrors in opposite direction to Sun's gravity attraction. It causes motion of receiver mirrors in local Sun direction. This direction is usually not perpendicular to local ECI x,y plane of two GW receiver vacuum tubes causing directional pre-cursor and echo correlations of strain (x,y-scale change/ms) residuals after interferometric side-band circulations reach DU c=C4 deceleration resolution of -1.15 10^-21/ms. Removal of these correlations would require costly 3rd vacuum tube for LISA - to little or no avail for GW detection from distant binary sources: Local binary merging motion & global gravitational energies got mostly balanced at GW source - faster than Eddington thought or by DU principles.

Jul 10, 2019
Hypothetical manipulations with hypothetical (fictitious) bodies need to be differentiated with real evidence, processes and bodies within the Universe.
There are more binary bodies in our system that "rotate very close to each other".
Why do not we measure the first body that is there, instead of measuring the body, there "God behind the leg"? ("Rotation can be analyzed in the broader way, too. Just like with the magnets, it is not only an object that rotates – but its gravitational forces rotate, too. For example, if there is an eruption that makes a large emission of radiation (waves), which last equally or more than a single rotation, then radiation also rotates in the direction of rotation and its constant blows correct the movement direction of an object. This needs to be analyzed also in the relation of the size differences of two objects. Sun possesses 99.86% of..") http://www.scienc...80603.13

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