Asteroid Bennu

Discoverer

LINEAR Project

Formal Name

101955 Bennu

Impact Risk

1-in-1,750 cumulative chance of impacting Earth between 2178 and 2290

Applications

Studying the formation of the early solar system and the origins of life on Earth

Mean Diameter

490 meters (approximately 1,610 feet)

Classification

Apollo group, Carbonaceous (B-type) asteroid, Potentially Hazardous Object (PHO)

Orbital Period

1.2 years

Semi-major Axis

1.126 astronomical units (AU)

Scientific Field

Planetary Science, Astrobiology

Provisional Designation

1999 RQ36

1999-09-11

2016-09-08

2018-12-03

2020-10-20

2025-08-01

2025-12-01

The asteroid Bennu was selected from over half a million known asteroids by the OSIRIS-REx selection committee. The primary constraint for selection was close proximity to Earth, since proximity implies low impulse (Δv) required to reach an object from Earth orbit. The criteria stipulated an asteroid in an orbit with low eccentricity, low inclination, and an orbital radius of 0.8–1.6 au. Furthermore, the candidate asteroid for a sample-return mission must have loose regolith on its surface, [...] 101955 Bennu (provisional designation 1999 RQ36) is a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999. It is a potentially hazardous object that is listed on the Sentry Risk Table "Sentry (monitoring system)") and has the second highest cumulative rating on the Palermo scale. It has a cumulative chance of around 1-in-1,750 of impacting Earth between 2178 and 2290 with the greatest risk being on 24 September 2182. It is named after Bennu, the [...] Bennu is an active asteroid, sporadically emitting plumes of particles and rocks as large as 10 cm (3.9 in), (not dust, defined as tens of micrometers). Scientists hypothesize the releases may be caused by thermal fracturing, volatile release through dehydration of phyllosilicates, pockets of subsurface water, and/or meteoroid impacts.

“Bennu is almost an intermediate between comets and asteroids,” Ashley says. “Comets form a tail behind them when they enter the solar system, as the materials in them sublimate when they get closer to the Sun.” “While Bennu’s rocky composition is more asteroid-like, OSIRIS-REx saw small particles being ejected from the surface when it first arrived. This behaviour is more similar to a comet than an asteroid, so studying more examples could help to clarify exactly how they are related.” [...] As part of ongoing research into Bennu, it was recently visited by NASA’s OSIRIS-REx mission. The robotic probe retrieved around 120 grams of pristine material from the rock which formed at the birth of the solar system. It is now being studied by scientists all over the world. [...] Some of the most basic building blocks of the solar system are missing from one of its most dangerous asteroids. Bennu has been the subject of intense scientific research over the past few years. Not only is the asteroid revealing more about the early years of the solar system, but it’s also one of the most likely to hit Earth. While the 0.06% risk of a collision is small, scientists are keeping a watchful eye on this space rock.

Bennu, is an asteroid located in our the asteroid belt of the solar system, formally known as 101955 Bennu, is a near-Earth asteroid that belongs to the Apollo group. It has become a focal point of study and exploration, particularly through NASA's OSIRIS-REx mission that went there in 2018. ## Physical Characteristics:[] [...] Bennu is a relatively small asteroid, with a mean diameter of approximately 490 meters (1,610 feet). This size is comparable to that of a few city blocks or the height of a skyscraper. It is categorized as a potentially hazardous asteroid (PHA) due to its proximity to Earth's orbit and its potential to impact our planet in the distant future. Bennu has a somewhat irregular shape, resembling a spinning top or a rough, rocky diamond. ## Orbit and Location:[] [...] Bennu follows an orbit that brings it relatively close to Earth, which is one of the reasons it has drawn so much attention. Its semi-major axis is about 1.126 astronomical units (AU), with an orbital period of approximately 1.2 years. Bennu is classified as a near-Earth object (NEO), and its orbit intersects with Earth's, making it accessible for study and potential future missions. ## OSIRIS-REx Mission:[]

Near-Earth asteroid Bennu could hit Earth in 157 years and set off a global ‘impact winter,’ study says [...] Bennu, with a name that name refers to an ancient Egyptian deity associated with the sun, creation and rebirth, stretches about one-third of a mile wide. The space rock likely represents a chunk that broke off of a much larger asteroid sometime between 2 billion and 700 million years ago. It probably formed in the main asteroid belt between Mars and Jupiter, and its chemical composition reflects the beginnings of the solar system, dating back about 4.5 billion years, according to NASA. [...] The asteroid has been orbiting close to Earth for about 1.75 million years. Data has shown it could hit our planet in the year 2182, potentially leading to a “global winter.” Scientists currently estimate the odds of impact to be 1 in 2,700, or 0.037% chance. Related article This mosaic image of asteroid Bennu is composed of 12 PolyCam images collected on Dec. 2 by the OSIRIS-REx spacecraft from a range of 15 miles (24 km). NASA/Goddard/University of Arizona