7066 Nessus
Encyclopedia
7066 Nessus is a centaur
(a type of icy planetoid) that was discovered by David L. Rabinowitz
, working with Spacewatch
, at Kitt Peak
on 26 April 1993. It was the second centaur found by him (5145 Pholus
being his previous find), and the third centaur discovery (2060 Chiron
, discovered by Charles Kowal in 1977, was the first). Nessus was officially announced on May 13, 1993, in IAUC 5789 with designation .
of 15.6 degrees. At perihelion
, it moves much closer to the Sun
than Uranus
, while at aphelion it moves out well beyond the orbit of Neptune
.
The orbits of centaurs are unstable due to perturbations
by the giant planets. Nessus is a SE object since currently Saturn controls the perihelion
and the Edgeworth–Kuiper belt controls the aphelion. Nessus is estimated to have a relatively long orbital half-life of about 4.9 Myr
. Fifty clones of the orbit of Nessus suggest that Nessus will not pass within 1AU (150Gm) of a planet for at least twenty thousand years.
were independently studying to see if it had any astrological significance. These were Zane B. Stein
in the USA, and Dieter Koch and Robert Von Heeren in Germany. In separate letters to astronomers David L. Rabinowitz
, Alan Stern
, Jim Scotti and Dr. Brian Marsden, these astrologers suggested naming the body after the mythological centaur
Nessus
.
Dr. Marsden gave his support to the suggested name, and recommended it to the IAU. This name was approved, and was officially named 7066 Nessus on April 22, 1997. This naming was an unprecedented cooperation between astrologers and astronomers.
Centaur (planetoid)
Centaurs are an unstable orbital class of minor planets that behave with characteristics of both asteroids and comets. They are named after the mythological race of beings, centaurs, which were a mixture of horse and human...
(a type of icy planetoid) that was discovered by David L. Rabinowitz
David L. Rabinowitz
David Lincoln Rabinowitz is a researcher at Yale University. He has built CCD cameras and software for the detection of near-Earth asteroids and Kuiper Belt Objects, and his research has helped reduce the assumed number of near-Earth asteroids by half, from 1,000-2,000 to 500-1,000 He has also...
, working with Spacewatch
Spacewatch
Spacewatch is a project at the University of Arizona led by Robert S. McMillan that specializes in the study of minor planets, including various types of asteroids and comets...
, at Kitt Peak
Kitt Peak
Kitt Peak is a mountain in the U.S. state of Arizona. It is the location of the Kitt Peak National Observatory. The radio telescope at the Observatory is one of ten dishes comprising the Very Long Baseline Array ....
on 26 April 1993. It was the second centaur found by him (5145 Pholus
5145 Pholus
5145 Pholus is a centaur in an eccentric orbit, with a perihelion less than Saturn's and aphelion greater than Neptune's. Pholus has not come within one astronomical unit of a planet since 764 BC, and will not until 5290. It is believed that Pholus originated as a Kuiper belt object.It was...
being his previous find), and the third centaur discovery (2060 Chiron
2060 Chiron
2060 Chiron is a minor planet in the outer Solar System. Discovered in 1977 by Charles T. Kowal , it was the first-known member of a new class of objects now known as centaurs, with an orbit between Saturn and Uranus.Although it was initially classified as an asteroid, it was later found to...
, discovered by Charles Kowal in 1977, was the first). Nessus was officially announced on May 13, 1993, in IAUC 5789 with designation .
Orbit
7066 Nessus has an orbital period of 122.4 years, an eccentricity of 0.52 and an inclination to the eclipticEcliptic
The ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...
of 15.6 degrees. At perihelion
Apsis
An apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...
, it moves much closer to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
than Uranus
Uranus
Uranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. It is named after the ancient Greek deity of the sky Uranus , the father of Cronus and grandfather of Zeus...
, while at aphelion it moves out well beyond the orbit of Neptune
Neptune
Neptune is the eighth and farthest planet from the Sun in the Solar System. Named for the Roman god of the sea, it is the fourth-largest planet by diameter and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times...
.
The orbits of centaurs are unstable due to perturbations
Perturbation (astronomy)
Perturbation is a term used in astronomy in connection with descriptions of the complex motion of a massive body which is subject to appreciable gravitational effects from more than one other massive body....
by the giant planets. Nessus is a SE object since currently Saturn controls the perihelion
Apsis
An apsis , plural apsides , is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system...
and the Edgeworth–Kuiper belt controls the aphelion. Nessus is estimated to have a relatively long orbital half-life of about 4.9 Myr
Myr
The symbol myr was formerly used in English-language geology, and remains as the standard usage in astronomy, as a unit of one million years.It is an abbreviation for 'million years' and lower case is used in geology, while upper case is used in astronomy....
. Fifty clones of the orbit of Nessus suggest that Nessus will not pass within 1AU (150Gm) of a planet for at least twenty thousand years.
Name
The naming of Nessus is an interesting break from tradition. Three astrologersAstrology
Astrology consists of a number of belief systems which hold that there is a relationship between astronomical phenomena and events in the human world...
were independently studying to see if it had any astrological significance. These were Zane B. Stein
Zane B. Stein
Zane B. Stein is an American astrologer and researcher, and is known as the world's leading astrological authority on Chiron. For his work in this field, he received the Canopus Award For Excellence in 1998.-Biography:...
in the USA, and Dieter Koch and Robert Von Heeren in Germany. In separate letters to astronomers David L. Rabinowitz
David L. Rabinowitz
David Lincoln Rabinowitz is a researcher at Yale University. He has built CCD cameras and software for the detection of near-Earth asteroids and Kuiper Belt Objects, and his research has helped reduce the assumed number of near-Earth asteroids by half, from 1,000-2,000 to 500-1,000 He has also...
, Alan Stern
Alan Stern
S. Alan Stern is an American planetary scientist. He is the principal investigator of the New Horizons mission to Pluto....
, Jim Scotti and Dr. Brian Marsden, these astrologers suggested naming the body after the mythological centaur
Centaur
In Greek mythology, a centaur or hippocentaur is a member of a composite race of creatures, part human and part horse...
Nessus
Nessus (mythology)
In Greek mythology, Nessus was a famous centaur who was killed by Heracles, and whose tainted blood in turn killed Heracles. He was the son of Centauros. He fought in the battle with the Lapiths. He became a ferryman on the river Euenos....
.
Dr. Marsden gave his support to the suggested name, and recommended it to the IAU. This name was approved, and was officially named 7066 Nessus on April 22, 1997. This naming was an unprecedented cooperation between astrologers and astronomers.
External links
- Orbital simulation from JPL (Java)
- Ephemeris
- Spacewatch
- Asteroid/Comet connection
- The Centaur Research Project
- an account of the naming