| Discovery [1] | |
|---|---|
| Discovered by | C. Kowal |
| Discovery site | Palomar Obs. |
| Discovery date | 22 October 1976 |
| Designations | |
| (2340) Hathor | |
| Pronunciation | /ˈhæθɔːr,-ər/ |
Named after | Hathor(Egyptian deity)[2] |
| 1976 UA | |
| Aten · NEO · PHA [1][3] | |
| Orbital characteristics [1] | |
| Epoch 11 August 2004 (JD 2453228.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 38.00 yr (13,878 days) |
| Aphelion | 1.2235AU |
| Perihelion | 0.4642 AU |
| 0.8438 AU | |
| Eccentricity | 0.4499 |
| 0.78yr (283 days) | |
| 42.104° | |
| 1° 16m 17.4s / day | |
| Inclination | 5.8546° |
| 211.54° | |
| 39.926° | |
| Earth MOID | 0.0069 AU · 2.7LD |
| Physical characteristics | |
| Dimensions | 0.210±0.030 km[4] 0.3 km(dated)[1] |
| 3.350±0.002h[5] | |
| 0.15(dated)[1] 0.3331(derived)[6] | |
| CSU(Tholen)[1] Sq(SMASS)[1] · S [6] B–V = 0.770[1] U–B = 0.500[1] | |
| 20.2[1][6] | |
2340 Hathor (/ˈhæθɔːr,-ər/), provisional designation1976 UA, is an eccentric stonyasteroid, classified asnear-Earth object andpotentially hazardous asteroid. It belongs to theAten group of asteroids and measures approximately 210 meters in diameter. Discovered byCharles Kowal in 1976, it was later named after theancient Egyptian goddessHathor.
Hathor was discovered on 22 October 1976, by American astronomerCharles Kowal atPalomar Observatory, California, United States.[3] It was independently discovered byEleanor Helin and is named for the ancient Egyptian deityHathor.[2]
On 25 October 1976, Hathor was independently discovered by Eleanor Helin during thePalomar Planet-Crossing Asteroid Survey (PCAS), and byWilliam Lawrence Sebok, who photographed the same field almost simultaneously using Palomar's 1.22-meter Schmidt telescope. On the same day, the official discoverer Charles Kowal found thatHathor had already been imaged three days earlier by Palomar's 0.46-meter telescope (the same instrument used by PCAS). A fourth independent discovery was made several days later byNikolai Chernykh atCrAO on the Crimean peninsula.
The multiple discoveries were probably due to its very close approach distance to Earth.[7]: 20 After2062 Aten, Hathor was the second discovery of an Aten asteroid. In 1978, the third Aten,2100 Ra-Shalom was discovered. The Aten1954 XA was already identified at Palomar in 1954, but its discovery date was later assigned to a 2003 observation atLincoln Laboratory ETS, and is now known as(363505) 2003 UC20.[7]: 21
Being a member of theAten asteroids, Hathor orbits the Sun at a distance of 0.5–1.2 AU once every 0 years and 9 months (283 days). Its orbit has aneccentricity of 0.45 and aninclination of 6° with respect to theecliptic.[1] Itsobservation arc begins 3 days after its official discovery at Palomar, with noprecoveries taken and no prior identifications made.[3] Its orbital solution includes non-gravitational force (A2).[1]
Hathor has an EarthMinimum orbit intersection distance of 0.0069 AU (1,030,000 km), which corresponds to 2.7lunar distances (LD).[1]
When it was discovered in 1976, Hathor had one of its closest approaches to Earth at 0.007752 AU (1,160,000 km).[1] On 21 October 2014, when it passed Earth at 0.048 AU, or 18.8 LD, it was observed 22 times by theGoldstone Deep Space Network usingradar astronomy over a period of 21 days from 10 to 31 October.[8] It will pass Earth again at 0.00658 AU (984,000 km) on 21 October 2069.[1]
In theTholen andSMASS taxonomy, Hathor has a CSU and Sqspectral type, respectively.[1]
In the 1990s, Dutch–American astronomerTom Gehrels estimated Hathor's diameter to measure approximately 300 meters, assuming analbedo of 0.15.[1] During its close approach to Earth in October 2014, a team of astronomer published a revised estimate of210±30 meters for its diameter.[4] TheCollaborative Asteroid Lightcurve Link adopts this diameter and derives an albedo of 0.3331 with anabsolute magnitude of 20.2.[6]
In November 2014, American astronomerBrian Warner obtained a rotationallightcurve of Hathor from photometric observations taken at the Palmer Divide Station in Colorado(also see§ External links). Light-curve analysis gave a well-definedrotation period of 3.350 hours with a brightness variation of 0.11magnitude (U=3).[5]
In accordance with the custom to name all members of the Aten group afterAncient Egyptian deities, thisminor planet is named forHathor, sky-goddess and daughter ofRa, who personified the principles of joy, feminine love, and motherhood. The Ancient Greeks sometimes identified Hathor with the goddessAphrodite. Naming was proposed by Eleanor Helin who also participated in the 1981 recovery. The minor planet161 Athor is also named for Hathor.[2] The official naming citation was published by theMinor Planet Center on 1 June 1981 (M.P.C. 6060).[9]
