101955 Bennu

101955 Bennu
Mosaic image of Bennu after two years of observation by OSIRIS-REx
Discovery[1]
Discovered byLINEAR
Discovery siteLincoln Lab's ETS
Discovery date11 September 1999
Designations
(101955) Bennu
Pronunciation/ˈbɛnuː/[2]
Named after
Bennu
Alternative designations
1999 RQ36
Minor planet category
Apollo · NEO · PHA · risk listed
Orbital characteristics[1]
Epoch 1 January 2011 (JD 2455562.5)
Uncertainty parameter 0
Observation arc21.06 yr (7693 days)
Aphelion1.3559 au (202.84 Gm)
Perihelion0.8969 au (134.17 Gm)
1.1264 au (168.51 Gm)
Eccentricity0.2038
1.1955 yr (436.65 d)
Average orbital speed
28.0 km/s (63,000 mph)
101.7039°
Mean motion
0° 49m 28.056s / day
Inclination6.0349°
2.0609°
Argument of perihelion
66.2231°
Earth MOID0.0032228 au (482,120 km)
Venus MOID0.194 au (29,000,000 km)[3]
Mars MOID0.168 au (25,100,000 km)[3]
Jupiter MOID3.877 au (580.0 Gm)
TJupiter5.525
Proper orbital elements[4]
0.21145
5.0415°
Proper mean motion
301.1345 deg / yr
1.19548 yr
(436.649 d)
Physical characteristics[5]
Dimensions565 m × 535 m × 508 m (1854 ft × 1755 ft × 1667 ft)[1]
Mean radius
245.03±0.08 m (804±0.262 ft)
Equatorial radius
282.37±0.06 m (926.4±0.197 ft)
Polar radius
249.25±0.06 m (817.74±0.197 ft)
0.782±0.004 km2 (0.302±0.002 sq mi)
Volume0.0615±0.0001 km3
Mass(7.329±0.009)×1010 kg
Mean density
1.190±0.013 g/cm3
Equatorial surface gravity
6.27 micro-g[6] (61.5 μm/s2)
Equatorial escape velocity
20 cm/s
Synodic rotation period
4.296057±0.000002 h
177.6±0.11°
North pole right ascension
+85.65±0.12°
North pole declination
−60.17±0.09°
Geometric albedo
0.044±0.002
Surface temp. min mean max
Kelvin[7] 236 259 279
Fahrenheit -34.6 6.8 42.8
Celsius -37 -14 6
B[1][5]
F[8]
20.9

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 and has the second highest cumulative rating on the Palermo scale.[9] It has a cumulative 1-in-1,750 chance of impacting Earth between 2178 and 2290 with the greatest risk being on 24 September 2182.[10][11] It is named after Bennu, the ancient Egyptian mythological bird associated with the Sun, creation, and rebirth.

101955 Bennu has a mean diameter of 490 m (1,610 ft; 0.30 mi) and has been observed extensively by the Arecibo Observatory planetary radar and the Goldstone Deep Space Network.[5][12][13]

Bennu was the target of the OSIRIS-REx mission that returned samples of the asteroid to Earth.[14][15][16] The spacecraft, launched in September 2016, arrived at the asteroid two years later and mapped its surface in detail, seeking potential sample collection sites.[17] Analysis of the orbits allowed calculation of Bennu's mass and its distribution.[18] In October 2020, OSIRIS-REx briefly touched down and collected a sample of the asteroid's surface.[19][20][21] A capsule containing the sample was returned and landed on Earth in September 2023, with distribution and analysis of the sample ongoing.[22][23][24] On 15 May 2024, an overview of preliminary analytical studies on the returned samples was reported.[25]

  1. ^ a b c d Cite error: The named reference jpldata was invoked but never defined (see the help page).
  2. ^ "Bennu". Dictionary.com Unabridged (Online). n.d.
  3. ^ a b Cite error: The named reference mpc was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference neodys was invoked but never defined (see the help page).
  5. ^ a b c Lauretta, D.S. (19 March 2019). "The unexpected surface of asteroid (101955) Bennu". Nature. 568 (7750): 55–60. Bibcode:2019Natur.568...55L. doi:10.1038/s41586-019-1033-6. PMC 6557581. PMID 30890786.
  6. ^ Barnouin, O.S. (19 March 2019). "Shape of (101955) Bennu indicative of a rubble pile with internal stiffness". Nature Geoscience. 12 (4): 247–252. Bibcode:2019NatGe..12..247B. doi:10.1038/s41561-019-0330-x. PMC 6505705. PMID 31080497.
  7. ^ Cite error: The named reference PHL was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Cellino2018 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference risk-table was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Sentry was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Farnocchia2021 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference GDSCC-img was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Hudson et al. 2000 was invoked but never defined (see the help page).
  14. ^ Corum, Jonathan (8 September 2016). "NASA Launches the Osiris-Rex Spacecraft to Asteroid Bennu". The New York Times. Retrieved 9 September 2016.
  15. ^ Chang, Kenneth (8 September 2016). "The Osiris-Rex Spacecraft Begins Chasing an Asteroid". The New York Times. Retrieved 9 September 2016.
  16. ^ Cite error: The named reference NASA-20150331-db was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference NYT-20181203 was invoked but never defined (see the help page).
  18. ^ Plait, Phil (4 December 2018). "Welcome to Bennu!". SYFY Wire. Retrieved 5 December 2018.
  19. ^ Chang, Kenneth (20 October 2020). "Seeking Solar System's Secrets, NASA's OSIRIS-REX Mission Touches Bennu Asteroid". The New York Times. Retrieved 12 February 2021.
  20. ^ Hautaluoma, Grey; Johnson, Alana; Jones, Nancy Neal; Morton, Erin (29 October 2020). "Release 20-109 – NASA's OSIRIS-REx Successfully Stows Sample of Asteroid Bennu". NASA. Retrieved 30 October 2020.
  21. ^ Chang, Kenneth (29 October 2020). "NASA's Asteroid Mission Packs Away Its Cargo. Next Stop: Earth". The New York Times. Retrieved 12 February 2021.
  22. ^ Miller, Katrina (24 September 2023). "A NASA Spacecraft Comes Home With an Asteroid Gift for Earth – The seven-year OSIRIS-REX mission ended on Sunday [9/23/2023] with the return of regolith from the asteroid Bennu, which might hold clues about the origins of our solar system and life. + comment". The New York Times. Archived from the original on 25 September 2023. Retrieved 25 September 2023.
  23. ^ Chang, Kenneth (10 May 2021). "Bye-Bye, Bennu: NASA Heads Back to Earth With Asteroid Stash in Tow – The OSIRIS-REX mission will spend two years cruising home with space rock samples that could unlock secrets of the early solar system". The New York Times. Retrieved 11 May 2021.
  24. ^ Marcia Dunn, Associated Press (10 May 2021). "NASA spacecraft begins 2-year trip home with asteroid rubble". WJHL. Retrieved 10 May 2021.
  25. ^ Cite error: The named reference AST-20240515 was invoked but never defined (see the help page).
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