Extragalactic planets? Gravitational waves could help us find them.


Oct 22, 2019
Very interesting report on possibly detecting exoplanets using gravity waves around binary white dwarfs. The NASA ADS Abstract has a six page arXiv report, Will Gravitational Waves Discover the First Extra-Galactic Planetary System? https://ui.adsabs.harvard.edu/abs/2020arXiv200707010D/abstract, July 2020.

My observation, there are a number of exoplanets reported now found orbiting white dwarf stars, these are like brown dwarf sizes in some cases. An example is, WD 0837+185 B, see http://exoplanet.eu/catalog/wd_0837+185_b/, also https://arxiv.org/abs/1210.0446

In the future, if LISA detects the postulated exoplanets around binary white dwarfs, it will add to the inventory of the exoplanet zoo :). From the NASA ADS Abstract arXiv report attached, "Nowadays exoplanets and GWs are experiencing an exceptionally fast development and are possibly the two subjects in the field of astrophysics that most spark the imagination and expectations of people. On the one hand, the information provided by more than four thousand discovered exoplanets changed the place that our Solar System occupies in the galactic context. Before realizing the huge diversity that the exoplanet population could offer, the Solar System used to be our reference case to develop planet formation theories. Now, the picture has been revolutionized: our Solar System is only one example, out of thousands, of all possible outcomes of the planetary formation and migration processes. Last but not least we are closer than ever to detect the Earth's twin in the habitable zone [3, 4].…Among this plethora of sources, LISA will be able to individually resolve tens of thousands of compact double white dwarf (DWD) binaries within and around the Milky Way [13,14]. Binary white dwarfs are the objects that will allow us to expand our understanding on planetary formation and planetary evolution, since they constitute a mean for detecting massive circumbinary exoplanets, as we recently demonstrated [15, 16]."