Violent events leading to the death of the stars will drive out all planets. Newly discovered JupiterObjects of the size may have arrived long after the star died.
International astronomer team using NASA‘s Transiting Exoplanet Survey Satellite (TESS) And the retired Spitzer Space Telescope White dwarf, A dense remnant of a sun-like star that is 40% larger than Earth.
A Jupiter-sized object called WD 1856 b is about 7 times larger than a white dwarf called WD 1856 + 534. It orbits this stellar cinder every 34 hours at a rate more than 60 times faster than Mercury orbiting our Sun.
How did the giant planet survive the violent process of turning its parent star into a white dwarf? Astronomers have some ideas after discovering the astronomical object WD 1856 b the size of Jupiter. Credits: NASA /JPL-Caltech/NASA’s Goddard Space Flight Center
Andrew Vanderburg, assistant professor of astronomy at the University of Wisconsin-Madison, said, “WD 1856 b somehow got very close to that white dwarf star and managed to stay on a piece. “The white dwarf formation process destroys nearby planets, and getting too close later is usually torn by the star’s enormous gravity. There are still many questions as to how the WD 1856 b got to its current location without meeting one of those fates.”
A paper on the system, led by Vanderburg and including several NASA co-authors, appeared in the September 16, 2020 issue. nature.
TESS monitors a wide sky called a sector for almost a month at a time. This long line of sight allows satellites to locate extraterrestrial planets or worlds beyond the solar system by capturing changes in star brightness that occur when planets cross or pass in front of the stars.
The satellite discovered WD 1856 b, about 80 light-years away from the northern constellation Draco. It orbits about 18,000 km (11,000 miles) of cool, quiet white dwarfs, and is a distant member of the triple star system, reaching up to 10 billion years old.
When a star like the sun runs out of fuel, it swells hundreds to thousands of times its original size, forming a cooler red giant. After all, it releases an outer layer of gas that loses up to 80% of its mass. The remaining thermonuclears become white dwarfs. All surrounding objects are usually swallowed and incinerated during this process, and in this system the current orbit would have included WD 1856 b. Vanderburg and his colleagues estimate that possible planets were at least 50 times further away from their current location.
“After the birth of a white dwarf, we have known for a long time that distant small objects such as asteroids and comets can scatter inward towards this star. They are usually separated by the strong gravitational force of white dwarfs and turn into debris disks,” said Siyi Xu, assistant astronomer at the International Gemini Observatory in Hilo, Hawaii, the National Science Foundation’s NOIRLab program. . “So when Andrew talked about this system, I was so excited. We saw hint The planet may be scattered inside, but this seems to be the first time I’ve seen a planet that hasn’t damaged the entire itinerary.”
The team proposes several scenarios that could push the WD 1856 b into an elliptical path around a white dwarf. This trajectory would have become more circular over time as the star’s gravitational force stretched the object, creating a massive tide that dissipates the orbital energy.
Juliette Becker, 51 Pegasi b Fellow of Planetary Sciences at Caltech, Pasadena, said, “The most likely examples involve several other Jupiter-sized objects close to the original orbit of WD 1856 b. “The gravitational effects of large objects can easily allow for the instability needed to knock the planet inward. But at this point we still have more theories than data points.”
Other possible scenarios include the flight of a rogue star in which two other stars in the system, the red dwarf stars G229-20 A and B, gradually gravitate over billions of years and disturb the system. Vanderburg’s team believes these and other explanations are less likely because they require fine-tuned conditions to achieve the same effect as a potential giant companion planet.
Jupiter-sized objects can occupy a huge range of mass, but only on planets Several times larger than Earth Even low-mass stars thousands of times the mass of the Earth. Others are brown dwarfs that span between planets and stars. In general, scientists can imply their composition and properties by turning to observations of the rate of radiation to measure the mass of an object. This method works by studying how orbiting objects attract stars and change the color of light. However, in this case, the white dwarf is so old that its light is too dim and featureless for scientists to detect noticeable changes.
Instead, the team used Spitzer to observe the infrared system just a few months before the telescope was dismantled. If WD 1856 b is a brown dwarf star or a star of low mass, it will emit its own infrared light. This means that Spitzer records a brighter movement than when the object is a planet that blocks it instead of emitting light. The researchers confirmed that there were no distinct differences when comparing Spitzer data with visible light passage observations taken with Gran Telescopio Canarias in the Spanish Canary Islands. It, combined with the age of the stars and other information about the system, came to the conclusion that WD 1856 b is most likely a planet less than 14 times the size of Jupiter. Future studies and observations can confirm this conclusion.
Co-authors Lisa Kaltenegger, Vanderburg, and others, who discovered possible worlds orbiting closely with white dwarf stars, came to consider the implications of studying the atmosphere of a small rocky world under similar circumstances. For example, suppose an Earth-sized planet was located in the range of orbital distances around WD 1856, and water may exist on the surface. Using simulated observations, researchers say that NASA will soon James webb space telescope You can detect water and carbon dioxide in a virtual world by observing just 5 passes.
The results of these calculations, led by Kaltenegger and Ryan MacDonald, were published at Cornell University in Ithaca, New York. Astrophysics Journal Letter And Available online.
“More impressively, Webb was able to detect combinations of gases that could potentially exhibit biological activity in such a world,” said Carl Tenneger, director of the Carl Sagan Institute at Cornell. “WD 1856 b suggests that the planet could survive the chaotic history of white dwarfs. In the right conditions, the world can maintain favorable conditions for life Longer than the predicted timescale for Earth. Now we can explore many new and exciting possibilities for a world orbiting this dead star core.”
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 may have trajectories that exceed the time TESS observes the sector, or they may be skewed in such a way that no passage occurs. The white dwarf is also so small that it is very unlikely to catch a passage on a planet further away from the system.
References: Andrew Vanderburg, Saul A. Rappaport, Siyi Xu, Ian JM Crossfield, Juliette C. Becker, Bruce Gary, Felipe Murgas, Simon Blouin, Thomas G. Kaye, “Giant Planetary Candidate Through the White Dwarf” Carl Melis, Brett M. Morris, Laura Kreidberg, Varoujan Gorjian, Caroline V. Morley, Andrew W. Mann, Hannu Parviainen, Logan A. Pearce, Elisabeth R. Newton, Andreia Carrillo, Ben Zuckerman, Lorne Nelson, Greg Zeimann, Warren R Brown, René Tronsgaard, Beth Klein, George R. Ricker, Roland K. Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Fred C. Adams, Björn Benneke, David Berardo, Lars A Buchhave, Douglas A. Caldwell, Jessie L. Christiansen, Karen A. Collins, Knicole D. Colón, Tansu Daylan, John Doty, Alexandra E. Doyle, Diana Dragomir, Courtney Dressing, Patrick Dufour, Akihiko Fukui, Ana Glidden, Natalia M. Guerrero, Xueying Guo, Kevin Heng, Andreea I. Henriksen, Chelsea X. Huang, Lisa Kaltenegger, Stephen R. Kane, John A. Lewis, Jack J. L issauer, Farisa Morales, Norio Narit a, Joshua Pepper, Mark E. Rose, Jeffrey C. Smith, Keivan G. Stassun and Liang Yu, September 16, 2020, nature.
TESS is a NASA Astrophysics Explorer mission. Wow It is located in Cambridge, Massachusetts and is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Additional partners include Northrop Grumman in Falls Church, Virginia, NASA’s Ames Research Center in Silicon Valley, California, Harvard-Smithsonian Astrophysics Center in Cambridge, Massachusetts, Lincoln Institute at MIT, and Space Telescope Science Institute in Baltimore. . Worldwide, more than a dozen universities, research institutions and observatories are involved in the mission.
NASA’s Jet Propulsion Lab in Southern California managed the Spitzer Mission for the institution’s Scientific Mission Directory in Washington. Spitzer scientific data continues to be analyzed by the scientific community through the Spitzer data archive at Caltech’s Infrared Science Archive at the Infrared Processing and Analysis Center (IPAC). Scientific work was done at Caltech’s Spitzer Science Center. The spacecraft operation took place at Lockheed Martin Space in Littleton, Colorado. Caltech manages NASA’s JPL.