Skip to main content

How the James Webb Space Telescope will look for life around dead stars

Looking for life around dead stars

When NASA’s James Webb Space Telescope launches next year, it may be able to find indications of life beyond our planet in an unexpected location — on planets which orbit dead stars called white dwarfs.

A recent study found an intact planet orbiting around a white dwarf, which surprised astronomers as in their death throes these stars usually destroy the planets around them when they swell before collapsing to form the white dwarf. But this planet somehow survived, giving a clue to a new type of location where we could search for habitable planets.

Rendering of a planet transiting a white dwarf star.
Rendering of a planet transiting a white dwarf star. Jack Madden, Carl Sagan Institute, Cornell University

“If rocky planets exist around white dwarfs, we could spot signs of life on them in the next few years,” Lisa Kaltenegger, one of the authors of the new study and associate professor of astronomy in the College of Arts and Sciences and director of the Carl Sagan Institute, said in a statement.

Her co-author Ryan MacDonald, also at the Carl Sagan Institute, agreed that planets orbiting white dwarf are a prime target for searches for life: “We know now that giant planets can exist around white dwarfs, and evidence stretches back over 100 years showing rocky material polluting light from white dwarfs. There are certainly small rocks in white dwarf systems,” he said. “It’s a logical leap to imagine a rocky planet like the Earth orbiting a white dwarf.”

To actually discover if there are habitable planets around these dead stars, researchers will make use of new tools like NASA’s upcoming James Web Space Telescope. This instrument is so sensitive it will be able to detect whether distant planets have an atmosphere, which is a key requirement for habitability, and even whether that atmosphere contains gases that could indicate life.

Rendering of a white dwarf star on the horizon of a mountainous planet.
Rendering of a white dwarf star on the horizon of a mountainous planet. Jack Madden, Carl Sagan Institute, Cornell University

“When observing Earth-like planets orbiting white dwarfs, the James Webb Space Telescope can detect water and carbon dioxide within a matter of hours,” MacDonald said. “Two days of observing time with this powerful telescope would allow the discovery of biosignature gases, such as ozone and methane.”

The telescope is set to launch in 2021, when it will be able to begin its search for habitable worlds. The recently discovered planet orbiting a white dwarf, WD 1856 b, is a gas giant like Jupiter and therefore couldn’t host life, but finding it has opened the door to a new range of possibilities of where life could be located.

“What if the death of the star is not the end for life?” Kaltenegger said. “Could life go on, even once our sun has died? Signs of life on planets orbiting white dwarfs would not only show the incredible tenacity of life, but perhaps also a glimpse into our future.”

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
James Webb captures stunning image of supernova remnant Cassiopeia A
Cassiopeia A (Cas A) is a supernova remnant located about 11,000 light-years from Earth in the constellation Cassiopeia. It spans approximately 10 light-years. This new image uses data from Webb’s Mid-Infrared Instrument (MIRI) to reveal Cas A in a new light.

A stunning new image from the James Webb Space Telescope shows a famous supernova remnant called Cassiopeia A, or Cas A. When a massive star comes to the end of its life and explodes in a huge outpouring of light and energy called a supernova, it leaves behind a dense core that can become a black hole or a neutron star. But that's not all that remains after a supernova: the explosion can leave its mark on nearby clouds of dust and gas that are formed into intricate structures.

The image of Cas A was taken using Webb's MIRI instrument, which looks in the mid-infrared range. Located 11,000 light-years away, Cassiopeia A is one of the brightest objects in the sky in the radio wavelength, and is also visible in the optical, infrared, and X-ray wavelengths. To see the different features picked up in different wavelengths, you can look at the slider comparison of the Webb infrared image alongside a Hubble visible light image of the same object.

Read more
James Webb captures the rarely-seen rings around Uranus
This zoomed-in image of Uranus, captured by Webb’s Near-Infrared Camera (NIRCam) on 6 February 2023, reveals stunning views of the planet’s rings. The planet displays a blue hue in this representative-colour image, made by combining data from two filters (F140M, F300M) at 1.4 and 3.0 microns, shown here as blue and orange, respectively.

The James Webb Space Telescope spends much of its time peering out into distant regions of space searching for some of the earliest galaxies to exist, but it also occasionally turns its sights onto targets a little closer to home. Following up on its image of Neptune released last year, astronomers using Webb have just released a brand-new image of Uranus as you've never seen it before.

As Webb looks in the infrared wavelength, unlike telescopes like Hubble which look in the visible light spectrum, its image of Uranus picks out some features of the planet which are hard to see otherwise like its dusty rings. Uranus' rings are almost invisible in the optical wavelength, but in this new image, they stand out proudly.

Read more
James Webb spots exoplanet with gritty clouds of sand floating in its atmosphere
This illustration conceptualises the swirling clouds identified by the James Webb Space Telescope in the atmosphere of the exoplanet VHS 1256 b. The planet is about 40 light-years away and orbits two stars that are locked in their own tight rotation. Its clouds, which are filled with silicate dust, are constantly rising, mixing, and moving during its 22-hour day.

One of the most exciting things about the James Webb Space Telescope is that not only can it detect exoplanets, but it can even peer into their atmospheres to see what they are composed of. Understanding exoplanet atmospheres will help us to find potentially habitable worlds, but it will also turn up some fascinating oddities -- like a recent finding of an exoplanet with an atmosphere full of gritty, sand clouds.

Exoplanet VHS 1256 b, around 40 light-years away, has a complex and dynamic atmosphere that shows considerable changes over a 22-hour day. Not only does the atmosphere show evidence of commonly observed chemicals like water, methane, and carbon monoxide, but it also appears to be dotted with clouds made up of silicate grains.

Read more