Astronomers have discovered an Earth-size exoplanet, or world beyond our solar system, that may be carpeted with volcanoes. Called LP 791-18 d, the planet could undergo volcanic outbursts as often as Jupiter’s moon Io, the most volcanically active body in our solar system.
They found and studied the planet using
data from NASA’s TESS
(Transiting Exoplanet Survey Satellite) and retired Spitzer Space
Telescope, as well as a
suite of ground-based observatories.
A paper about the planet – led by Merrin
Peterson, a graduate of the Trottier Institute for Research on Exoplanets
(iREx) based at the University of Montreal – appears in the May 17 edition of
the scientific journal Nature.
LP 791-18 d, shown here in an artist's concept, is an Earth-size world about 90 light-years away. The gravitational tug from a more massive planet in the system, shown as a blue disk in the background, may result in internal heating and volcanic eruptions – as much as Jupiter’s moon Io, the most geologically active body in the solar system. Astronomers discovered and studied the planet using data from NASA’s Spitzer Space Telescope and TESS (Transiting Exoplanet Survey Satellite) along with many other observatories. Credits: NASA’s Goddard Space Flight Center/Chris Smith (KRBwyle)
Download
high-resolution video and images from NASA’s Scientific Visualization Studio
“LP 791-18 d is tidally locked, which
means the same side constantly faces its star,” said Björn Benneke, a co-author
and astronomy professor at iREx who planned and supervised the study. “The day
side would probably be too hot for liquid water to exist on the surface. But
the amount of volcanic activity we suspect occurs all over the planet could
sustain an atmosphere, which may allow water to condense on the night side.”
LP 791-18 d orbits a small red dwarf star
about 90 light-years away in the southern constellation Crater. The team
estimates it’s only slightly larger and more massive than Earth.
Astronomers already knew about two other
worlds in the system before this discovery, called LP 791-18 b and c. The inner
planet b is about 20% bigger than Earth. The outer planet c is about 2.5 times
Earth’s size and more than seven times its mass.
During each orbit, planets d and c pass
very close to each other. Each close pass by the more massive planet c produces
a gravitational tug on planet d, making its orbit somewhat elliptical. On this
elliptical path, planet d is slightly deformed every time it goes around the
star. These deformations can create enough internal friction to substantially
heat the planet’s interior and produce volcanic activity at its surface.
Jupiter and some of its moons affect Io in a similar way.
Planet d sits on the inner edge of the
habitable zone, the traditional range of distances from a star where scientists
hypothesize liquid water could exist on a planet’s surface. If the planet is as
geologically active as the research team suspects, it could maintain an
atmosphere. Temperatures could drop enough on the planet’s night side for water
to condense on the surface.
Planet c has already been approved for
observing time on the James Webb Space Telescope, and the team thinks planet d is also an
exceptional candidate for atmospheric studies by the mission.
“A big question in astrobiology, the field
that broadly studies the origins of life on Earth and beyond, is if tectonic or
volcanic activity is necessary for life,” said co-author Jessie Christiansen, a
research scientist at NASA’s Exoplanet Science Institute at the California Institute of
Technology in Pasadena. “In addition to potentially providing an atmosphere,
these processes could churn up materials that would otherwise sink down and get
trapped in the crust, including those we think are important for life, like
carbon.”
Spitzer’s observations of the system were
among the last the satellite collected before it was decommissioned in January 2020.
“It is incredible to read about the
continuation of discoveries and publications years beyond Spitzer’s end of
mission,” said Joseph Hunt, Spitzer project manager at NASA’s Jet Propulsion
Laboratory in
Southern California. “That really shows the success of our first-class
engineers and scientists. Together they built not only a spacecraft but also a
data set that continues to be an asset for the astrophysics community.”
TESS is a NASA Astrophysics Explorer
mission led and operated by MIT in Cambridge, Massachusetts, and managed by NASA's Goddard Space
Flight Center.
Additional partners include Northrop Grumman, based in Falls Church, Virginia; NASA’s Ames Research
Center in
California’s Silicon Valley; the Center for Astrophysics | Harvard &
Smithsonian in Cambridge, Massachusetts; MIT’s Lincoln Laboratory; and the
Space Telescope Science Institute in Baltimore. More than a dozen universities,
research institutes, and observatories worldwide are participants in the
mission.
The entire body of scientific data collected
by Spitzer during its lifetime is available to the public via the Spitzer data
archive, housed at the Infrared Science Archive at IPAC at Caltech in Pasadena,
California. NASA’s Jet Propulsion Laboratory, a division of Caltech, managed
Spitzer mission operations for the agency’s Science Mission Directorate in
Washington. Science operations were conducted at the Spitzer Science Center at
IPAC at Caltech. Spacecraft operations were based at Lockheed Martin Space in
Littleton, Colorado.
NASA's Goddard Space
Flight Center,
Greenbelt, Md.
Source: NASA’s Spitzer, TESS Find Potentially Volcano-Covered Earth-Size World | NASA
No comments:
Post a Comment