The Palomar Planet-Crossing Asteroid Survey (PCAS) was an
astronomical survey
An astronomical survey is a general map or image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of images, spectra, or other observations of obje ...
, initiated by American astronomers
Eleanor Helin
Eleanor Francis "Glo" Helin (née Francis, 19 November 1932 – 25 January 2009) was an American astronomer. She was principal investigator of the Near-Earth Asteroid Tracking (NEAT) program of NASA's Jet Propulsion Laboratory. (Some sources gi ...
and
Eugene Shoemaker
Eugene Merle Shoemaker (April 28, 1928 – July 18, 1997) was an American geologist. He co-discovered Comet Shoemaker–Levy 9 with his wife Carolyn S. Shoemaker and David H. Levy. This comet hit Jupiter in July 1994: the impact was televise ...
at the U.S
Palomar Observatory
Palomar Observatory is an astronomical research observatory in San Diego County, California, United States, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...
, California, in 1973.
The program is responsible for the discovery of 95
near-Earth Object
A near-Earth object (NEO) is any small Solar System body whose orbit brings it into proximity with Earth. By convention, a Solar System body is a NEO if its closest approach to the Sun (perihelion) is less than 1.3 astronomical units (AU). ...
s including 17
comet
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
s,
while the
Minor Planet Center
The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory.
Function
...
directly credits PCAS with the discovery of 20 numbered
minor planet
According to the International Astronomical Union (IAU), a minor planet is an astronomical object in direct orbit around the Sun that is exclusively classified as neither a planet nor a comet. Before 2006, the IAU officially used the term ''minor ...
s during 1993–1994.
PCAS ran for nearly 25 years until June 1995. It had an international extension,
INAS
Indium arsenide, InAs, or indium monoarsenide, is a narrow-bandgap semiconductor composed of indium and arsenic. It has the appearance of grey cubic crystals with a melting point of 942 °C.
Indium arsenide is similar in properties to galli ...
, and was the immediate predecessor of the outstandingly successful
NEAT program.
Notable discoveries
The first NEO discovered by PACS was
(5496) 1973 NA, an
Apollo asteroid
The Apollo asteroids are a group of near-Earth asteroids named after 1862 Apollo, discovered by German astronomer Karl Reinmuth in the 1930s. They are Earth-crossing asteroids that have an orbital semi-major axis greater than that of the Earth ...
with an exceptional
orbital inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object.
For a satellite orbiting the Earth ...
of 68
°, the
most highly inclined minor planet known until 1999. In 1976, Eleanor Helin discovered
2062 Aten,
the first of a new class of asteroids called the
Aten asteroid
The Aten asteroids are a dynamical group of asteroids whose orbits bring them into proximity with Earth. By definition, Atens are Earth-crossing asteroids . The group is named after 2062 Aten, the first of its kind, discovered on 7 January ...
s with small orbits that are never far from Earth's orbit. As a result, these objects have a particularly high probability of
colliding with the Earth. In 1979, Helin discovered an Apollo-type asteroid, that they later identified with the comet
4015 Wilson–Harrington
4015 Wilson–Harrington is an active asteroid known both as comet 107P/Wilson–Harrington and as asteroid 4015 Wilson–Harrington. It will pass from Earth on 20 July 2022 and then pass perihelion (closest approach to the Sun) on 24 August 20 ...
.
It was the first confirmation that a comet can evolve into an asteroid after it has degassed.
List of discovered minor planets
See also
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Brian P. Roman
Brian P. Roman is an American astronomer.
He has co-discovered the periodic comets 111P/Helin–Roman–Crockett, 117P/Helin–Roman–Alu and 132P/Helin–Roman–Alu. Brian Roman is also credited by the Minor Planet Center with the discove ...
*
*
Spacewatch
The Spacewatch Project is an astronomical survey that specializes in the study of minor planets, including various types of asteroids and comets at University of Arizona telescopes on Kitt Peak near Tucson, Arizona, in the United States. The Sp ...
*
List of near-Earth object observation projects
List of near-Earth object observation projects is a list of projects that observe Near-Earth objects. Most are astronomical surveys intended to find undiscovered asteroids. They sometimes find comets.
Neo-chart.png, Annual NEA discoveries by s ...
References
Publications
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{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System
1973 in science
Asteroid surveys
Astronomical surveys
Near-Earth Asteroid Tracking
Astronomical discoveries by institution
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