9969 Braille

Infobox Planet
minorplanet = yes
width = 25em
bgcolour = #FFFFC0
apsis =
name = 9969 Braille
symbol =


caption = 9969 Braille, as imaged by Deep Space 1
discovery = yes
discovery_ref =
discoverer = E. F. Helin & K. J. Lawrence
discovered = May 27, 1992
designations = yes
mp_name = 9969 Braille
alt_names = 1992 KD
mp_category =
orbit_ref =
epoch = April 10, 2007
aphelion = 3.355258248767612 AU
perihelion = 1.33334143409973 AU
semimajor = 2.34429984143367 AU
eccentricity = 0.431241085063454
period = 1311.046707341689 d
avg_speed =
inclination = 28.8950758886474°
asc_node = 242.0860869040194°
mean_anomaly = 53.44583107846355°
arg_peri = 355.6230995683221°
satellites =
physical_characteristics = yes
dimensions = 2.1 km × 1 km × 1 km
mass = 7.8×10¹⁵g
density = 3.9 g cm^-3 [cite journal|title = First Direct Magnetic Field Measurements of an Asteroidal Magnetic Field: DS1 at Braille|author = I. Richter, D.E. Brinza, M. Cassel, K.H. Glassmeier, F. Kuhnke, G. Mussmann, C. Othmer, K. Schwingenschuh and B.T. Tsurutani|journal = Geophysical Research Letters|volume = 28|number = 10|pages = 1913–1916|date = May 1, 2001|doi = 10.1029/2000GL012679]
surface_grav =
escape_velocity =
sidereal_day = 226.4 h
axial_tilt =
pole_ecliptic_lat =
pole_ecliptic_lon =
albedo = 0.34
temperatures=yes
temp_name1 = Kelvin
mean_temp_1 =
max_temp_1 = ~238
temp_name2 = Celsius
max_temp_2 =
spectral_type = Q-type asteroid
abs_magnitude = 15.8

9969 Braille is a small Mars crossing asteroid that orbits the Sun once every 3.58 years.cite journal|title = 9969 Braille: Deep Space 1 infrared spectroscopy, geometric albedo, and classification|author = Buratti, B. J.; Britt, D. T.; Soderblom, L. A.; Hicks, M. D.; Boice, D. C.; Brown, R. H.; Meier, R.; Nelson, R. M.; Oberst, J.; Owen, T. C.; Rivkin, A. S.; Sandel, B. R.; Stern, S. A.; Thomas, N.; Yelle, R. V.|journal = Icarus|volume = 167|issue = 1|pages = 129–135|url = http://adsabs.harvard.edu/abs/2004Icar..167..129B |month = January | year = 2004|accessdate = 2008-01-07|doi = 10.1016/j.icarus.2003.06.002] 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. [cite web|url = http://www.planetary.org/about/press/releases/1999/0728_Spacecraft_Target_Asteroid_Named_in.html|title = Spacecraft Target Asteroid Named in Planetary Society Contest|date = July 28, 1999|author = Susan Lendroth|publisher = The Planetary Society|accessdate = 2008-01-08] Later, it was renamed 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". ["MPC 35492" Minor Planet Center] [cite web|url = http://www.cnn.com/TECH/space/9907/26/space.briefs/|title = Asteroid target gets new name|date = July 26, 1999|publisher = Cable News Network|accessdate=2008-01-08]

Orbit

[
left|thumb|Orbit_of_9969_Braille_(blue),_planets_(red)_and_the_Sun (black). The outermost planet visible is Jupiter.]

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 sometime around 6000 CE. [cite web|url = http://www.solarviews.com/portug/braille.htm|title = Asteroid Braille|author = Calvin J. Hamilton] 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. 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.

Exploration

Detailed information about Braille comes primarily from the Deep Space 1 probe, which passed within 26 km of the asteroid on July 29, 1999, [cite web|url = http://nmp.nasa.gov/ds1/gen/gen3.html|title = A CLOSE-UP OF AN ASTEROID|publisher = National Aeronautics and Space Administration] and from extensive ground based observations done in conjunction with the mission. 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 000km, due to problems with the tracking system. [cite journal|title = Groundbased investigation of asteroid 9969 Braille, target of the spacecraft mission Deep Space 1|author = M. Lazzarin, S. Fornasier, M. A. Barucci and M. Birlan|journal = Astronomy & Astrophysics|date = 24 May 2001|accessdate = 2008-01-07|url = http://www.aanda.org/index.php?option=article&access=doi&doi=10.1051/0004-6361:20010789|volume = 375|pages = 281–284|doi = 10.1051/0004-6361:20010789]

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. [cite journal|title = A Model for Rotation and Shape of Asteroid 9969 Braille from Ground-Based Observations and Images Obtained during the Deep Space 1 (DS1) Flyby|author = Oberst, J.; Mottola, S.; di Martino, M.; Hicks, M.; Buratti, B.; Soderblom, L.; Thomas, N.|journal = Icarus|volume = 153|issue = 1|pages = 16–23|month = September | year = 2001|accessdate = 2008-01-07|url = http://adsabs.harvard.edu/abs/2001Icar..153...16O|doi = 10.1006/icar.2001.6648]

References

External links

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