The first dark comet — a celestial object that looks like an asteroid but moves through space like a comet — was reported less than two years ago. Soon after, six more were found. In a new paper, researchers announced the discovery of seven more, doubling the number of known dark comets, and showing that they fall into two distinct populations: the larger ones that live in the outer Solar System; and smaller ones that live in the inner solar system. Various other traits that set them apart.
The findings were published Monday, Dec. 9, in the Proceedings of the National Academy of Sciences.
Scientists got their first evidence that dark comets exist when they noticed a March 2016 study that the trajectory of “asteroid” 2003 RM had deviated slightly from its expected orbit by now. This deviation cannot be explained by the specific acceleration of the asteroid, such as the small acceleration Yarkowski effect.
“When you see this kind of turbulence on a celestial object, it usually means it’s a comet,” said study co-author David Fernuccia of NASA’s Jet Propulsion Laboratory in Southern California. The volatile material from the surface gives it a slight thrust.” “But try as we might, we couldn’t find any sign of the comet’s tail. It looked like any other asteroid — just a point of light. So, for a while, we had this strange celestial object. There was something we couldn’t quite figure out.
Farnocchia and the astronomical community didn’t have to wait long for another piece of the puzzle. The following year, in 2017, a NASA-sponsored telescope discovered the first-ever documented celestial object that exited our solar system. Not only did 1I/2017 U1 (‘Oumuamua) Appearing as a point of light, like an asteroid, its speed changes as it ejects volatile material from its surface like a comet.
“‘Oumuamua was surprising in many ways,” Farnocchia said. “The fact that the first object we detected from interstellar space exhibited similar behavior to 2003 RM made 2003 RM even more interesting.”
By 2023, researchers had identified seven solar system objects that looked like asteroids but acted like comets. It was enough for the astronomical community to award them their own celestial object category: “The black cometNow, with seven more of these objects found, researchers can begin a new set of questions.
“We had such a large number of dark comets that we could begin to ask if there is such a thing,” said lead author Darrell Seligman, a postdoctoral fellow in the Department of Physics at Michigan State University, East Lansing. which can differentiate them.” New paper. “By analyzing the reflectivity, or albedo, and the orbits, we found that there are two different types of dark comets in our solar system.”
The study’s authors found that one type, which they call outer dark comets, has similar properties. Jupiter family comets: They have a lot. eccentric (or elliptical) orbits and are large (hundreds of meters or more across).
The second group, the inner dark comets, reside in the inner Solar System (which includes Mercury, Venus, Earth, and Mars), travel in nearly circular orbits, and are on the small side (tens of meters or less).
Like many astronomical discoveries, Seligman and Farnocchia’s research not only expands our knowledge of dark comets, but also raises several additional questions: Where did dark comets originate? What is the reason for their extraordinary speed? Can they contain ice?
“Deep comets are a new potential means of delivering materials to Earth that were essential for the development of life,” Seligman said. “The more we can learn about them, the better we can understand their role in the origin of our planet.”
For more information on asteroids and comets, visit:
https://www.jpl.nasa.gov/topics/asteroids/
Ian J. O’Neill
Jet Propulsion Laboratory, Pasadena, California
818-354-2649
ian.j.oneill@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
Bethany Mager
Michigan State University, East Lansing
maugerbe@msu.edu
2024-168