 Braille imaged byDeep Space 1 in 1999 | |
| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin K. J. Lawrence |
| Discovery site | Palomar Obs. |
| Discovery date | 27 May 1992 |
| Designations | |
| (9969) Braille | |
| Pronunciation | /ˈbreɪl/[2] |
Named after | Louis Braille (inventor ofbraille)[3] |
| 1992 KD | |
| Mars-crosser[1][4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 24.93 yr (9,107 days) |
| Aphelion | 3.3557AU |
| Perihelion | 1.3263 AU |
| 2.3410 AU | |
| Eccentricity | 0.4334 |
| 3.58yr (1,308 days) | |
| 16.880° | |
| Inclination | 28.999° |
| 241.95° | |
| 356.11° | |
| Earth MOID | 0.3154 AU · 122.9LD |
| Physical characteristics | |
| Dimensions | 1.600±0.511 km[5] 1.64 km(derived)[6] 2.1 km × 1 km × 1 km[1] |
| Mass | 7.8 trillion kg |
Meandensity | 3.9 g cm−3[7] |
| 226h[8] 226.4 h[9] | |
| 0.1289±0.2441[5] 0.18(assumed)[6] | |
| SMASS =Q[1] | |
| 15.8[1] | |
9969 Braille, provisional designation1992 KD, is an eccentric, rare-type and elongatedasteroid from the innermost regions of theasteroid belt, classified asMars-crosser andslow rotator, approximately 1–2 kilometers in diameter. It was discovered in 1992, by astronomers atPalomar Observatory and later named afterLouis Braille, the inventor of thewriting system for the blind. It was photographed in closeup by the spacecraftDeep Space 1 in 1999, but a malfunction resulted in indistinct images.
Discovered on May 27, 1992, byE. F. Helin andK. J. Lawrence working at thePalomar observatory as part ofNASA'sPlanet-Crossing Asteroid Survey, it was given the provisional designation1992 KD.[4][10] Later, it was named Braille in honour ofLouis Braille as suggested byKennedy Space Centersoftware engineer Kerry Babcock inThe Planetary Society's contest titled "Name That Asteroid".[3][11] The official naming citation was published by theMinor Planet Center on 28 July 1999 (M.P.C. 35492).[12]
Braille has an unusually inclined orbit, and belongs to the somewhat rare class of asteroids known asMars-crossing asteroids. Simulations of itsorbit by scientists of the Deep Space 1 project predict that it will evolve into anEarth-crossing orbit in about 4000 years.[13] Although its closest approach to theSun is closer thanMars orbit, its highly elliptical orbit takes it almost half-way toJupiter at its apoapsis, and as such itssemi-major axis is too large for it to be classified as anAmor asteroid.
Braille is aQ-type asteroid, composed mostly ofolivine andpyroxene.[1] Early ground-based observations had suggested that it could have been aV-type asteroid with similarities of composition between it and the much larger4 Vesta. The asteroid is irregularly shaped, measuring approximately 2.1 km × 1 km × 1 km.[1]
Detailed information about Braille comes primarily from theDeep 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, itsultravioletspectrometer had failed, but it did return twoCCD images of medium resolution and threeinfraredspectra during the encounter. However, although the probe came within 26 km of Braille, the images andspectra were taken from an approximate distance of14000 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]
