 Hubble Space Telescope image of Nessus taken in 2009 | |
| Discovery[1] | |
|---|---|
| Discovered by | Spacewatch (D. Rabinowitz uncredited)[2] |
| Discovery site | Kitt Peak National Obs. |
| Discovery date | 26 April 1993 |
| Designations | |
| (7066) Nessus | |
| Pronunciation | /ˈnɛsəs/[3] |
Named after | ΝέσσοςNessos(Greek mythology)[1] |
| 1993 HA2 | |
| centaur[4][5][6] · distant[1] | |
| Adjectives | Nessian/ˈnɛsiən/[7] |
| Symbol | .svg) (astrological) |
| Orbital characteristics[4] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 3 | |
| Observation arc | 11.08yr (4,048 d) |
| Aphelion | 37.423AU |
| Perihelion | 11.854 AU |
| 24.639 AU | |
| Eccentricity | 0.5189 |
| 122.30 yr (44,670 d) | |
| 80.046° | |
| 0° 0m 29.16s / day | |
| Inclination | 15.663° |
| 31.183° | |
| 170.96° | |
| Jupiter MOID | 6.400 AU |
| TJupiter | 3.793 |
| Physical characteristics | |
| 57±17 km[8] 60±16 km[5][9] | |
| 0.065[5][9] 0.086[8] | |
| RR(very red)[10] B–V =1.090±0.010[10] V–R =0.790±0.010[10] V–I =1.470±0.030[10] B–R =1.847[11] | |
| 24.31[12] | |
| 9.55[13][14] 9.6[1][4] | |
7066 Nessus/ˈnɛsəs/ is a very redcentaur on an eccentric orbit, located beyondSaturn in theouter Solar System. It was discovered on 26 April 1993, by astronomers of theSpacewatch program at theKitt Peak National Observatory inTucson, Arizona.[1] The dark and reddishminor planet is likely elongated and measures approximately 60 kilometers (37 miles) in diameter.[5][13] It was named afterNessus from Greek mythology.[1]
Nessus is acentaur, a dynamically unstable population ofminor planets between the classicalasteroids and thetrans-Neptunian objects. It orbits the Sun at a distance of 11.9–37.4 AU once every 122 years and 4 months (44,670 days;semi-major axis of 24.64 AU). Its orbit has aneccentricity of 0.52 and aninclination of 16° with respect to theecliptic. At itsperihelion (11.9 AU), it moves much closer to theSun thanUranus (19.2 AU) but not as close as Saturn (9.6 AU), while at itsaphelion (37.4 AU), it moves out well beyond the orbit ofNeptune (30.1 AU).[4]
The orbits of centaurs are unstable due toperturbations by thegiant planets. Nessus is an "SE object" because currently Saturn controls its perihelion and its aphelion is within theKuiper belt. It is estimated to have a relatively long orbital half-life of about 4.9 million years.[15] Fifty clones of the orbit of Nessus suggest that it will not pass within 1 AU (or 150 million kilometers) of any planet for at least 20,000 years.[16]
Nessus was discovered byDavid Rabinowitz (not officially credited), working with theSpacewatch program, atKitt Peak National Observatory on 26 April 1993.[1][2] The discovery was announced on 13 May 1993 in anIAU Circular (IAUC 5789) of theCentral Bureau for Astronomical Telegrams.[2] It was the third discovery of a centaur after2060 Chiron and5145 Pholus, discovered byCharles Kowal and David Rabinowitz in 1977 and 1992, respectively.[17] The body'sobservation arc begins with its official discovery observation atKitt Peak in April 1993.[1]
Thisminor planet was named afterNessus, acentaur fromGreek mythology, who poisoned and was killed by the divine heroHeracles.[1] The officialnaming citation was published by theMinor Planet Center on 22 April 1997 (M.P.C. 29671).[18]
A symbol derived from that for2060 Chiron,U+2BDC ⯜NESSUS (
), was devised in the late 1990s by German astrologer Robert von Heeren. It replaces Chiron's K with an N for Nessus.[19]
Nessus has a very red color (RR),[10] with aB–R magnitude of 1.847 and 1.88, respectively.[5][11]Color indices were also determined by Bauer (2003) and Hainaut (2002, 2012).[6][20][21][22]
As of 2018, no rotationallightcurve of Nessus has been obtained fromphotometric observations. However, a brightness variation of 0.5magnitude was measured in the 1990s, indicating that the body has a non-spherical, elongated shape.[14] The body'srotation period andpole remain unknown.[4][13]
According to theHerschel Space Observatory with itsPACS instrument, Nessus measures 57 kilometers in diameter and its surface has analbedo of 0.086,[8] while infrared observations with theSpitzer Space Telescope gave a diameter of 60 kilometers with an albedo of 0.065.[9] TheCollaborative Asteroid Lightcurve Link assumes acarbonaceous standard albedo of 0.057 and derives a diameter of 68.48 kilometers based on anabsolute magnitude of 9.55.[13]
Nessus is a playable destination in the 2017 video gameDestiny 2, after previously being referenced in the series' 2014 debut entryDestiny. Known simply as "Nessus," it is described as a planetoid that has beenterraformed by acybernetic species known as the Vex into a "machine world".[23]
