The white dwarfs, the bodies of stars like the Sun, are known to be able to host planets despite the particularly violent phase of the transition. However, the nature of these objects makes the most frequently used methods of detecting exoplanet ineffective. How can we find them? A team of astronomers proposes to use the James Webb telescope.
Planets around the white dwarfs
Of the more than 5,000 exoplanets found to date, most are located around stars similar to the Sun.
And all the stars that compare to the Sun end up like white dwarfs, and imagine carbon cores and oxygen the size of the Earth, so almost all the stars around which we found planets will eventually turn into white dwarfs.
We also know that these objects are able to host planets, despite a particularly violent process of transition. Toward the end of their lives, stars like the sun begin to swell into red giants. In addition to these stars growing in size, they are also subjected to severe spasms, which lift large plumes of matter into the surrounding system.
However, even after all this violence, planets far enough can still be saved. The interaction between these planets and any new discarded material can bring the stars closer together. New planets can also emerge from the wreckage of old planets, creating a new planetary system.
JWT for detection
The detection of these planets, however, is a difficult task. Since these objects are very small and relatively dark, the transit method commonly used in detecting an exoplanet does not work. In addition, the white dwarfs do not have many notable features in their spectrum. Thus, another popular method, radial speed, which includes observation of the red and blue displacement of the spectral features when an orbital planet draws to its parent star, also does not work.
Identifying earthlike planets around white dwarfs would be very interesting, which could help us understand the final fate of our own solar system, and by the way, it could also increase the number of targets in the search for extraterrestrial life.
A few days ago, a group of astronomers released a road map suggesting that we can detect these potential worlds using James Webb's telescope. All we need to do is look at them.
If the white dwarfs are relatively cold, then any orbital planet will be relatively warmer. This means that the infrared light from the white dwarf will also contain part of the infrared light from the orbital planet. By comparing this combined light with that of the white dwarf, which we know has no planets, we can assume that there is an exoplanet.
In their article, astronomers note that JWT can observe the 15 nearest white dwarfs and potentially detect planets in their liveable zones, provided that the planets are of appropriate size and temperature. Light from too small and cold worlds would be indistinguishable from the light of their white dwarf.