_Bruce_Helin.png) Bruce Helin modeled from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | E. F. Helin E. Shoemaker |
| Discovery site | Palomar Obs. |
| Discovery date | 8 November 1977 |
| Designations | |
| (2430) Bruce Helin | |
Named after | Bruce Helin[2] (son ofEleanor Helin) |
| 1977 VC · 1976 JU1 A908 WC | |
| main-belt · Phocaea[3][4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 40.44 yr (14,772 days) |
| Aphelion | 2.8697AU |
| Perihelion | 1.8555 AU |
| 2.3626 AU | |
| Eccentricity | 0.2146 |
| 3.63yr (1,326 days) | |
| 21.845° | |
| 0° 16m 17.04s / day | |
| Inclination | 23.459° |
| 45.854° | |
| 309.89° | |
| Physical characteristics | |
| 128 h[a] 129.4163±0.3970 h[7] 129.75 h[8] | |
| 11.693±0.003(R)[7] · 11.70[6] · 11.8[1][3] · 12.24[5] | |
2430 Bruce Helin (prov. designation:1977 VC) is a stonyPhocaea asteroid andslow rotator from the inner regions of theasteroid belt. It was discovered by American astronomersEleanor Helin andEugene Shoemaker at the U.S.Palomar Observatory in California, on 8 November 1977.[9] It was later named after Bruce Helin, son of the first discoverer.[2] TheS-type asteroid (Sl) has an exceptionally longrotation period of 128 hours and measures approximately 12 kilometers (7.5 miles) in diameter.
Bruce Helin is a member of thePhocaea family (701).[4] It orbits the Sun in theinner main-belt at a distance of 1.9–2.9 AU once every 3 years and 8 months (1,326 days). Its orbit has aneccentricity of 0.21 and aninclination of 23° with respect to theecliptic.[1] It was first observed atA908 WC atHeidelberg Observatory in 1908. The body'sobservation arc begins with aprecovery taken atCrimea–Nauchnij in 1976, or one year prior to its official discovery observation at Palomar.[9]
Thisminor planet was named after Bruce Helin, son of the first discoverEleanor Helin, in an expression of gratitude for "the many years he tolerated his mother's preoccupation with extraterrestrial objects".[2] The discoverer has also honoured her daughter-in-law and wife of Bruce, Nancy Coker Helin, by the minor planet4222 Nancita.[10] The officialnaming citation was published by theMinor Planet Center on 13 October 1981 (M.P.C. 6421).[11]
In theTholen classification,Bruce Helin is a common, stonyS-type asteroid, while in the Bus–BinzelSMASS taxonomy, it is an Sl-subtype, which transitions from the S-type to the uncommonL-type asteroid.[1]
The first rotationallightcurve ofBruce Helin was obtained from photometric observations by Czech astronomerPetr Pravec in September 2006. The lightcurve showed arotation period of128 hours with a brightness variation of 0.60 inmagnitude (U=2).[a] Later observations rendered a similar rotation period of 129.75 and129.4163±0.3970 hours, respectively (U=n.a./2).[8][7]
According to the surveys carried out by the JapaneseAkari satellite and NASA'sWide-field Infrared Survey Explorer with itsNEOWISE mission,Bruce Helin measures 11.8 and 12.5 kilometers in diameter, and its surface has analbedo of 0.18 and 0.24, respectively.[5][6] TheCollaborative Asteroid Lightcurve Link (CALL) assumes an albedo of 0.23 and calculates a diameter of 12.1 kilometers with anabsolute magnitude of 11.8.[3]
