| Discovery[1] | |
|---|---|
| Discovered by | C. S. Shoemaker E. M. Shoemaker |
| Discovery site | Palomar Obs. |
| Discovery date | 5 May 1986 |
| Designations | |
| (14827) Hypnos | |
| Pronunciation | /ˈhɪpnɒs/ |
Named after | Hypnos[2] (Greek god of sleep) |
| 1986 JK | |
| Apollo · NEO · PHA[1][3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 19.32 yr (7,058 days) |
| Aphelion | 4.7318AU |
| Perihelion | 0.9491 AU |
| 2.8405 AU | |
| Eccentricity | 0.6659 |
| 4.79yr (1,749 days) | |
| 206.81° | |
| 0° 12m 21.24s / day | |
| Inclination | 1.9808° |
| 57.976° | |
| 238.09° | |
| Earth MOID | 0.0147 AU · 5.7LD |
| Jupiter MOID | 0.5249 AU |
| Physical characteristics | |
| 0.520±0.260 km[4] >0.74 km[5] 0.9 km(Gehrels 1994)[1] 0.907 km(derived)[6] | |
| 0.057(assumed)[6] <0.067(radar)[5] 0.22±0.17[4] | |
| C[5][6] B–V = 0.684[1] U–B = 0.492[1] | |
| 18.3[1] · 18.65±0.22[4] · 18.94[6][7] | |
14827 Hypnos (provisional designation:1986 JK) is a highly eccentric, sub-kilometer-sized carbonaceousasteroid that is thought to be anextinct comet. It is classified asnear-Earth object andpotentially hazardous asteroid of theApollo group.
The asteroid was discovered by American astronomer coupleCarolyn andEugene Shoemaker at thePalomar Observatory in California on 5 May 1986.[3] It was named afterHypnos, the Greek god of sleep.[2]
Hypnos orbits the Sun at a distance of 0.9–4.7 AU once every 4 years and 9 months (1,749 days). Its orbit has a higheccentricity of 0.67 and aninclination of 2° with respect to theecliptic.[1] It is frequentlyperturbed byJupiter.[8]
The body'sobservation arc begins atAnderson Mesa Station the night prior to its official discovery observation at Palomar.[3]
As anear-Earth object andpotentially hazardous asteroid Hypnos has an Earthminimum orbital intersection distance of 0.0147 AU (2,200,000 km), which corresponds to 5.7lunar distances.[1]
In 1958, Hypnos passed less than 0.03 AU from both Earth and Mars.[9] Neither planet has been approached so closely by Hypnos since the 862 AD pass of Earth, or will be until the 2214 pass of Earth.[citation needed] It is also aMars-crosser.
Hypnos may be thenucleus of anextinct comet that is covered by a crust several centimeters thick that prevents any remainingvolatiles fromoutgassing.[10]
Hypnos is an assumed carbonaceousC-type asteroid.[6][5]
As of 2018, no rotationallightcurve of Hypnos has been obtained from photometric observations. The asteroidsrotation period andspin axis remains unknown.[6] It has a low brightness amplitude of 0.05magnitude which indicates that the body has a ratherspheroidal shape.[7]
According to the NEOSurvey carried out by NASA'sSpitzer Space Telescope, Hypnos measures 520 meters in diameter and its surface has analbedo of 0.22 based on anabsolute magnitude of 18.65,[4] while infrared radiometry gave a radar albedo of no more than 0.067 and a diameter of at least 740 meters.[5]
TheCollaborative Asteroid Lightcurve Link assumes a standard optical albedo for carbonaceous asteroids 0.057 and derives a diameter of 907 meters with anabsolute magnitude of 18.94.[6] The diameter agrees withTom Gehrels 1994-publicationHazards due to Comets and Asteroids in which he estimated amean diameter of 900 meters for Hypnos.[1]
Thisminor planet was named afterHypnos fromGreek mythology. He is the god of sleep, son ofNyx andErebus and twin brother ofThanatos. He enters the sleep of mortals and gives them dreams of foolishness or inspiration.[2] The English word "hypnosis" is derived from his name. The official naming citation was published by theMinor Planet Center on 6 January 2003 (M.P.C. 47301).[11]
Hypnos was a potential target for theLICIACube extended mission,[12] but contact was lost shortly after completion of the primary mission.
