490 Veritas
Encyclopedia
490 Veritas is a large asteroid
, which may have been involved in one of the more massive asteroid-asteroid collisions of the past 100 million years.
At 115 and 125 km in diameter, Veritas and 92 Undina
are the largest of the 300-strong Veritas family
of asteroids. David Nesvorný of the Southwest Research Institute in Boulder
traced the orbits of these bodies back in time, and calculated that they formed in a collision of a body at least 150 km in diameter with a smaller asteroid some 8 million years ago. Veritas and Undina would have been the largest fragments of that collision.
Substantiating Nesvorný's estimate, Kenneth Farley
et al. found evidence in sea-floor sediments of a fourfold increase in the amount of cosmic dust
reaching Earth's surface, which began 8.2 million years ago and tapered off over the next million and a half years. This is one of the largest increases in dust deposits of the past 100 million years.
The suspected Veritas collision would have been too far from Jupiter
for the fragments to have been slung into a collision course with Earth. However, solar radiation would have caused the resulting dust to drift inward to Earth orbit over a time span consistent with the record of dust in the ocean sediment.
Today continuing collisions among Veritas-family asteroids are estimated to send five thousand tons of cosmic dust to Earth each year, 15% of the total.
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
, which may have been involved in one of the more massive asteroid-asteroid collisions of the past 100 million years.
At 115 and 125 km in diameter, Veritas and 92 Undina
92 Undina
92 Undina is a large main belt asteroid. It has an unusually high albedo and an M-type spectrum. It was discovered by C. H. F. Peters on July 7, 1867. It is named for the eponymous heroine of Undine, a popular novella by Friedrich de la Motte Fouqué. Undina is a member of the Veritas asteroid...
are the largest of the 300-strong Veritas family
Asteroid family
An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions...
of asteroids. David Nesvorný of the Southwest Research Institute in Boulder
Boulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...
traced the orbits of these bodies back in time, and calculated that they formed in a collision of a body at least 150 km in diameter with a smaller asteroid some 8 million years ago. Veritas and Undina would have been the largest fragments of that collision.
Substantiating Nesvorný's estimate, Kenneth Farley
Kenneth Farley
Kenneth A. Farley is a noble gas isotope geochemist, W. M. Keck Foundation professor of geochemistry and chairman of theDivision of Geological and Planetary Sciences at the California Institute of Technology...
et al. found evidence in sea-floor sediments of a fourfold increase in the amount of cosmic dust
Cosmic dust
Cosmic dust is a type of dust composed of particles in space which are a few molecules to 0.1 µm in size. Cosmic dust can be further distinguished by its astronomical location; for example: intergalactic dust, interstellar dust, interplanetary dust and circumplanetary dust .In our own Solar...
reaching Earth's surface, which began 8.2 million years ago and tapered off over the next million and a half years. This is one of the largest increases in dust deposits of the past 100 million years.
The suspected Veritas collision would have been too far from Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
for the fragments to have been slung into a collision course with Earth. However, solar radiation would have caused the resulting dust to drift inward to Earth orbit over a time span consistent with the record of dust in the ocean sediment.
Today continuing collisions among Veritas-family asteroids are estimated to send five thousand tons of cosmic dust to Earth each year, 15% of the total.
External links
- "Asteroid Smashup Yields Dust Shower on Earth" from SkyandTelescope.com, Jan. 20, 2006.