The possibility of violent events leading up to the death of a star kills any planet. The newly discovered Jupiter-shaped object must have arrived long after the star died.
An international team of astronomers using NASA’s Transiting Exoplanet Survey Satellite (TESS) and the retired Spitzer Space Telescope have revealed what may be the first intact planet to closely orbit a white dwarf, a remnant of a Sun-like star. Can, Earth is larger than only 40%.
The Jupiter-shaped object, called WD 1856B, is about seven times larger than the white dwarf, named WD 1856 or 534. It resolves this stellar cycle every 34 hours, which is 60 times faster than Mercury and orbits our Sun.
How could a giant planet survive the violent process of turning its parent star into a white dwarf? Astronomers have some ideas after the discovery of Jupiter-shaped object WD 1856 b. Credit: NASA / JPL-Caltech / NASA’s Goddard Space Flight Center
Andrew Wanderberg, assistant professor of astronomy at the University of Wisconsin-Madison, said, “WD 1856B somehow got close to its white dwarf and managed to live in one piece.” “The white dwarf formation process destroys nearby planets, and anything that gets too close later is usually burst by the star’s immense gravity. We still have many questions about how WD 1856 b Arrived at the current location without completing any gatelets. ”
A paper about the system, led by Vanderburg and including several NASA co-authors, appears in issue 17 of Nature and is now available online.
TESS monitors large areas of the sky, called sectors, for about a month in a month. This long gaze allows the satellite to find exoplanets or worlds beyond our solar system, capturing changes in constellation brightness, when a planet passes or crosses the front of its star.
The satellite spotted WT 1856B about 80 light-years away in the northern constellation Draco. It orbits a quiet, calm white dwarf that is about 11,000 miles (18,000 kilometers) across, may be 10 billion years old, and is a distant member of a triple star system.
When a sun-like star runs out of fuel, it swells to hundreds to thousands of times its original size, forming a red giant star. Eventually, it removes its outer layers of gas, losing up to 80% of its mass. The remaining hot core becomes a white dwarf. During this process any nearby objects are usually entangled and stirred, which in this system incorporates the WD 1856 b into its current class. Vanderburg and his colleagues estimate that the possible planet would have originated at least 50 times away from its current location.
“We have known for a long time that after white dwarfs are born, distant small objects such as asteroids and comets can scatter inward toward these stars. They are usually separated by the strong gravity of a white dwarf and debris. Let’s turn to disk. “Said co-author Siyi Xu, an assistant astronomer at the International Gemini Observatory in Hilo, Hawaii, a program of the National Science Foundation’s NOIRAB. “That’s why I was so excited when Andrew told me about this system. We have seen signs that planets can also break inwards, but this seems to be the first time we’ve seen a planet that has Has retained the entire journey. ”
The team suggested several scenarios that the WD 1856 b could be undressed on the elliptical path around the white dwarf. This trajectory became more spherical over time as the star’s gravity propagated the object, propagating its orbiting energy.
“The most likely case involves several other Jupiter-shaped bodies that are close to the original orbit of WD 1856b,” said co-author Juliet Baker, a 51 Pegasi B fellow in planetary science at Caltech in Pasadena. “The gravitational effect of objects that can easily allow for instability. You have to knock a planet in. But at this point, we still have more theories than data points.”
Other possible scenarios include the gradual gravitational tug of two other stars in the system, the red dwarf G229-20 A and B, for billions of years and reversing a flybyte system from a rogue star. Vanderburg’s team feels that these and other explanations are less likely because they require finely tuned positions to achieve the same effects as possible giant companion planets.
Jupiter-sized objects can occupy massive amounts of mass, however, from planets that are thousands of times larger than Earth’s mass than low-mass stars from Earth. Others are brown dwarfs, which span the line between the planet and the star. Scientists usually turn to observations of radial velocity to measure the mass of an object, which can hint at its structure and nature. This method works by studying how a orbiting object tugs on its star and changes the color of its light. But in this case, the white dwarf is so old that its light is too faded and too featureless for scientists to detect noticeable changes.
Instead, the team observed the system in infrared using Spitzer, a telescope disbanded just a few months earlier. If WD 1856 b was a brown dwarf or low-mass star, it would emit its own infrared glow. This means that Spitzer will record a brighter transit, if the object is a planet, which will block instead of emitting light. When researchers compared the Spitzer data with the light transit observations shown with the Gran Telescopio Canaria in the Canary Islands, Spain, no differences were noted. Combined with other information about the star’s age and system, it led him to conclude that WD 1856b is most likely no more than 14 times the size of Jupiter. Future research and observations may be able to confirm this conclusion.
Exploring a possible world revolving around a white dwarf prompts co-authors Lisa Kultenegger, Vanderburgh, and others to consider the implications of studying the atmosphere of small rocky worlds under similar conditions. For example, suppose that the Earth-sized planet WD was located around 1856 at a range of orbital distances, where water could exist on its surface. Using simulated observations, researchers point out that NASA’s upcoming James Webb Space Telescope can detect water and carbon dioxide over imaginary worlds by looking at just five transits.
The results of these calculations, led by Kultinagar and Ryan Macdonald at Cornell University in Ithaca, New York, have been published in The Astrophysical Journal Letters and are available online.
“More impressively, the web can detect coincidences that have 25 transits indicating biological activity in such a world,” said Kultenegger, director of Cornell’s Carl Sagan Institute. “WD 1856b suggests that planets may survive the chaotic histories of white dwarfs. Under the right conditions, they could maintain favorable conditions for life for longer than the time scale fixed for world earth. Are. Now we can explore many new intriguing possibilities for the world, orbiting these dead stars. Cor. ”
There is currently no evidence that there are other worlds in the system, but it is possible that additional planets exist and have not yet been detected. They can revolve around the orbit when TESS inspects a field or is tipped as if there is no transit. The white dwarf is also so small that it is very unlikely to catch infection from outside planets in the system.
TESS is a NASA Astrophysics Explorer mission conducted and operated by MIT in Cambridge, Massachusetts, and managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Additional partners include Northrop Grumman, Falls Church, NASA’s Ames Research Center in Silicon Valley, Virginia, California, Cambridge in Massachusetts, Harvard-Smithsonian Center for Astrophysics in Massachusetts, and the Space Telescope Science Institute in Baltimore. More than a dozen universities, research institutes and observatories are participating in the mission.
NASA’s Jet Propulsion Laboratory in Southern California managed the Spitzer mission for the agency’s Science Mission Directorate in Washington. Spitzer Science data are analyzed through the Spitzer Data Archive, which is housed at the Infrared Science Archive housed at the Infrared Processing and Analysis Center (IPAC) in Caltech. Science operations were conducted at the Spitzer Science Center in Caltech. The spacecraft operation was based at the Lockheed Martin Space in Littleton, Colorado. Caltech manages JPL for NASA.
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Written by Zeenat Kazmirsk
NASA’s Goddard Space Flight Center, Greenbelt, MD.