Can life survive the death of a star? Web telescope can reveal answers


A planet orbiting a small star produces strong atmospheric signals when it passes through the front, or as in the picture above, crossing its host star. White dwarfs give astronomers a rare opportunity to characterize rocky planets. Sincerely: Carl Sagan Institute

When our sun-like stars die, all that remains is an exposed core – a white dwarf. According to researchers at the University of Corn, a planet that orbits a white dwarf presents a great opportunity to determine whether life can survive the death of its star.


In a study published in Astrophysical Journal Letters, They show how NASA’s upcoming James Webb Space Telescope orbiting white dwarfs on Earth-like planets can provide signs of life.

A planet that orbits a small star produces strong atmospheric signals when it passes through the front, or “crosses the host”. White dwarfs pushed it to extremes: they are 100 times smaller than our Sun, almost as small as the Earth, giving astronomers a rare opportunity to mark rocky planets.

“If rocky planets exist around white dwarfs, we can see traces of life over them over the next few years,” corresponding author Lisa Kalteniger, associate professor of astronomy at the College of Arts and Sciences and Carl Sagan Institute. The director said.

Co-author Ryan Macdonald, a research associate at the institute, said the James Webb Space Telescope, scheduled to launch in October 2021, is uniquely placed on rocky exoplanets to find signatures of life.

“When Earth-like planets orbit white dwarfs, the James Webb Space Telescope can detect water and carbon dioxide,” McDonald said. “Two days of observing time with this powerful telescope will allow the discovery of bio-gases, such as ozone and methane.”

The discovery of the first transit giant planet orbiting the white dwarf (WD 1856 + 534b), announced in a separate paper – led by co-author Andrew Vanderburg, assistant professor at the University of Wisconsin, Madison – on the existence of white all-around planets Proves it. Dwarfs. Kaltenegger is a co-author on this paper, as well.

This planet is a gas giant and therefore is not able to sustain life. But its existence suggests that small rocky planets, which can sustain life, may also exist in habitable areas of white dwarfs.

“We now know that giant planets may exist around white dwarfs,” said McDonald, and more than 100 years old evidence exists showing light polluted rocky matter from white dwarfs. “It’s a rocky planet like Earth Is a logical leap to imagine that orbiting a white dwarf. ”

The researchers used state-of-the-art analysis techniques, combined with the model atmosphere of white dwarf planets from previous Cornell research, to detect gases in the giant exoplanet atmosphere with the Hubble Space Telescope.

NASA’s Transiting Exoplanet Survey Satellite is now looking for such rocky planets around white dwarfs. If and when one of these worlds is found, Kalteniger and his team have developed models and tools to identify signs of life in the planet’s atmosphere. The web telescope may soon begin this search.

Kaltenager said the implications of finding signatures of life on a planet orbiting a white dwarf are profound. Most stars, including our sun, will one day end up as white dwarfs.

“What if the star’s death is not the end for life?” he said. “Can life go on, even once our sun has died. The signs of life on planets orbiting white dwarfs will not only show the incredible tenacity of life, but perhaps also a glimpse into our future.” ”


Astronomers can see signs of life orbiting long-dead stars


more information:
Lisa Kultenegger et al. The White Dwarf Occasion: Molecule Detection Robots in the Earth-like Exoplanet Atmosphere with the James Webb Space Telescope. The Astrophysical Journal Letters, Volume 901, Number 1. DOI: 10.3847 / 2041-8213 / aba9d3

Provided by Cornell University

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