9969 Braille
Braille imaged by Deep Space 1 in 1999
Discovery [1]
Discovered byE. F. Helin
K. J. Lawrence
Discovery sitePalomar Obs.
Discovery date27 May 1992
Designations
(9969) Braille
Pronunciation/ˈbreɪl/[2]
Named after
Louis Braille
(inventor of braille)[3]
1992 KD
Mars-crosser [1][4]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc24.93 yr (9,107 days)
Aphelion3.3557 AU
Perihelion1.3263 AU
2.3410 AU
Eccentricity0.4334
3.58 yr (1,308 days)
16.880°
Inclination28.999°
241.95°
356.11°
Earth MOID0.3154 AU · 122.9 LD
Physical characteristics
Dimensions1.600±0.511 km[5]
1.64 km (derived)[6]
2.1 km × 1 km × 1 km[1]
Mass7.8×1012kg
Mean density
3.9 g cm−3[7]
226 h[8]
226.4 h[9]
0.1289±0.2441[5]
0.18 (assumed)[6]
SMASS = Q[1]
15.8[1]

9969 Braille, provisional designation 1992 KD, is an eccentric, rare-type and elongated asteroid from the innermost regions of the asteroid belt, classified as Mars-crosser and slow rotator, approximately 1–2 kilometers in diameter. It was discovered in 1992, by astronomers at Palomar Observatory and later named after Louis Braille, the inventor of the writing system for the blind. It was photographed in closeup by the spacecraft Deep Space 1 in 1999, but a malfunction resulted in indistinct images.

Discovery and naming

Discovered on May 27, 1992, by E. F. Helin and K. J. Lawrence working at the Palomar observatory as part of NASA's Planet-Crossing Asteroid Survey, it was given the provisional designation 1992 KD.[4][10] Later, it was named Braille in honour of Louis Braille as suggested by Kennedy Space Center software engineer Kerry Babcock in The Planetary Society's contest titled "Name That Asteroid".[3][11] The official naming citation was published by the Minor Planet Center on 28 July 1999 (M.P.C. 35492).[12]

Orbit of Braille (blue), with the inner planets and Jupiter

Orbit

Braille has an unusually inclined orbit, and belongs to the somewhat rare class of asteroids known as Mars-crossing asteroids. Simulations of its orbit by scientists of the Deep Space 1 project predict that it will evolve into an Earth-crossing orbit in about 4000 years.[13] Although its closest approach to the Sun is closer than Mars orbit, its highly elliptical orbit takes it almost half-way to Jupiter at its apoapsis, and as such its semi-major axis is too large for it to be classified as an Amor asteroid.

Physical characteristics

Braille is a Q-type asteroid, composed mostly of olivine and pyroxene.[1] Early ground-based observations had suggested that it could have been a V-type asteroid with similarities of composition between it and the much larger 4 Vesta. The asteroid is irregularly shaped, measuring approximately 2.1 km × 1 km × 1 km.[1]

Exploration

Animation of Deep Space 1's trajectory from 24 October 1998 to 31 December 2003
   Deep Space 1 ·   9969 Braille ·   Earth ·   19P/Borrelly

Detailed information about Braille comes primarily from the Deep Space 1 probe, which passed within 26 km of the asteroid on July 29, 1999,[14] and from extensive ground based observations done in conjunction with the mission.[15] By the time Deep Space 1 reached Braille, its ultraviolet spectrometer had failed, but it did return two CCD images of medium resolution and three infrared spectra during the encounter. However, although the probe came within 26 km of Braille, the images and spectra were taken from an approximate distance of 14 000 km, due to problems with the tracking system.[16]

The main purpose of the Deep Space 1 mission was technology testing, but the encounter with Braille was of strong scientific value. No lone asteroid as small as Braille had previously been observed from such a short distance.[9]

References

  1. ^ a b c d e f g h "JPL Small-Body Database Browser: 9969 Braille (1992 KD)" (2017-05-03 last obs.). Jet Propulsion Laboratory. Retrieved June 22, 2017.
  2. ^ "Braille". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  3. ^ a b Schmadel, Lutz D. (2007). "(9969) Braille". Dictionary of Minor Planet Names – (9969) Braille. Springer Berlin Heidelberg. p. 715. doi:10.1007/978-3-540-29925-7_7775. ISBN 978-3-540-00238-3.
  4. ^ a b "9969 Braille (1992 KD)". Minor Planet Center. Retrieved March 17, 2017.
  5. ^ a b Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved August 30, 2016.
  6. ^ a b "LCDB Data for (9969) Braille". Asteroid Lightcurve Database (LCDB). Retrieved August 30, 2016.
  7. ^ Richter, I.; Brinza, D. E.; Cassel, M.; Glassmeier, K.-H.; Kuhnke, F.; Musmann, G.; et al. (December 2000). "First direct magnetic field measurements of an asteroidal magnetic field: DS1 at Braille". Geophysical Research Letters. 28 (10): 1913–1916. Bibcode:2001GeoRL..28.1913R. doi:10.1029/2000GL012679. Retrieved August 30, 2016.
  8. ^ di Martino, M.; Oberst, J.; Mottola, S. (September 1999). "Lightcurve studies of asteroid 9969 (1992 KD), fly-by target of the Deep Space 1 spacecraft". Bulletin of the Astronomical Society. 31 (4): 1131–37.01. Bibcode:1999BAAS...31.1131D. Retrieved August 30, 2016.
  9. ^ a b Oberst, J.; Mottola, S.; Di Martino, M.; Hicks, M.; Buratti, B.; Soderblom, L.; et al. (September 2001). "A Model for Rotation and Shape of Asteroid 9969 Braille from Ground-Based Observations and Images Obtained during the Deep Space 1 (DS1) Flyby". Icarus. 153 (1): 16–23. Bibcode:2001Icar..153...16O. doi:10.1006/icar.2001.6648. Retrieved June 22, 2017.
  10. ^ Susan Lendroth (July 28, 1999). "Spacecraft Target Asteroid Named in Planetary Society Contest". The Planetary Society. Retrieved January 8, 2008.
  11. ^ "Asteroid target gets new name". Cable News Network. July 26, 1999. Archived from the original on February 8, 2008. Retrieved January 8, 2008.
  12. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved March 17, 2017.
  13. ^ Calvin J. Hamilton. "Asteroid Braille".
  14. ^ "A CLOSE-UP OF AN ASTEROID". National Aeronautics and Space Administration. Archived from the original on March 20, 2009.
  15. ^ Buratti, B. J.; Britt, D. T.; Soderblom, L. A.; Hicks, M. D.; Boice, D. C.; Brown, R. H.; et al. (January 2004). "9969 Braille: Deep Space 1 infrared spectroscopy, geometric albedo, and classification". Icarus. 167 (1): 129–135. Bibcode:2004Icar..167..129B. doi:10.1016/j.icarus.2003.06.002.
  16. ^ Lazzarin, M.; Fornasier, S.; Barucci, M. A.; Birlan, M. (August 2001). "Groundbased investigation of asteroid 9969 Braille, target of the spacecraft mission Deep Space 1" (PDF). Astronomy and Astrophysics. 375: 281–284. Bibcode:2001A&A...375..281L. doi:10.1051/0004-6361:20010789. Retrieved June 22, 2017.

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