| Discovery[1] | |
|---|---|
| Discovered by | G. Neujmin |
| Discovery site | Simeiz Obs. |
| Discovery date | 28 April 1913 |
| Designations | |
| (751) Faïna | |
Named after | Faina Neujmina[2] (Wife of the discoverer) |
| A913 HE · 1913 RK | |
| main-belt[1][3] · (middle) Faïna[4] · background[5][6] | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 106.97yr (39,072 d) |
| Aphelion | 2.9387AU |
| Perihelion | 2.1657 AU |
| 2.5522 AU | |
| Eccentricity | 0.1514 |
| 4.08 yr (1,489 d) | |
| 293.41° | |
| 0° 14m 30.12s / day | |
| Inclination | 15.600° |
| 78.849° | |
| 302.26° | |
| Physical characteristics | |
| Dimensions | 132.0 km × 88.2 km[6] |
| Mass | (3.27±0.58)×1018 kg[11] |
Meandensity | 5.05±0.92 g/cm3[11] |
| 23.678 h[12] | |
751 Faïna (prov. designation:A913 HEor1913 RK) is a very largebackground asteroid from the central regions of theasteroid belt, approximately 110 kilometers (68 miles) in diameter. It was discovered on 28 April 1913, by Russian astronomerGrigory Neujmin at theSimeiz Observatory on the Crimean peninsula.[1] The elongatedC-type asteroid (Ch) has arotation period of 23.7 hours. It was named after Faina Mikhajlovna Neujmina, colleague and first wife of the discoverer.[2]
Located close to the region of the stonyEunomia family (502),[13]Faïna is a non-family asteroid of the main belt'sbackground population when applying the modern synthetichierarchical clustering method (HCM) byNesvorný as well asMilani andKnežević (AstDys).[5][6] However, in the 1995 HCM-analysis byZappalà,[4]Faïna is the parent body of the tinyFaïna family,[4] which is not recognized by modern analysis. The HCM-method is based on an object'sproper orbital elements to group asteroids into families.
Faïna orbits the Sun in thecentral asteroid belt at a distance of 2.2–2.9 AU once every 4 years and 1 month (1,489 days;semi-major axis of 2.55 AU). Its orbit has aneccentricity of 0.15 and aninclination of 16° with respect to theecliptic.[3] The body'sobservation arc begins atVienna Observatory on 8 May 2013, or two weeks after its official discovery observation byGrigory Neujmin atSimeiz.[1]
Thisminor planet was named after Faina Mikhajlovna Neujmina, the first wife of the discoverer. AstronomerLutz Schmadel compiled thisnaming citation, based on his private communication with "N. S. Samojlova-Yakhontova", as neither theMinor Planet Circulars norThe Names of the Minor Planets give any information about this asteroid's name.[2][14]
In theTholen classification,Faïna is a common, carbonaceousC-type asteroid, while in the Bus–BinzelSMASS classification, it is a hydrated carbonaceous Ch-type.[3][6]
In late 1988, a rotationallightcurve ofFaïna was obtained fromphotometric observations by Richard Miles at the Manley Observatory nearChester in northwest England. Lightcurve analysis gave a well-definedrotation period of23.678 hours with a brightness variation of0.36magnitude (U=3).[12] Alternative observations by Roberto Crippa, Federico Manzini (2006) as well as by Bruno Christmann (2019) determined a period of10+ and (11.846±0.007) hours (or half the period) with an amplitude of0.02 and0.18±0.01 magnitude (U=1/2).[13][15]
According to the surveys carried out by the JapaneseAkari satellite, the Infrared Astronomical SatelliteIRAS, and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE),Faïna measures (106.81±1.28), (110.50±4.3) and (113.699±2.449) kilometers in diameter and its surface has a lowalbedo of (0.055±0.002), (0.0497±0.004) and (0.047±0.013), respectively.[7][8][9][10]
TheCollaborative Asteroid Lightcurve Link adopts the results from IRAS, that is, an albedo of 0.0497 and a diameter of 110.50 kilometers based on anabsolute magnitude of 8.66.[13] The WISE team also published several alternative mean-diameters of (102.25±33.63 km), (106.289±1.633 km), (123.69±43.48 km), (125.664±33.78 km) and (139.146±33.78 km), with a corresponding albedo of (0.04±0.02), (0.0537±0.0138), (0.03±0.02), (0.0327±0.0263), and (0.027±0.013).[6][13]
On 28 March 2007, anasteroid occultation ofFaïna gave a best-fit ellipse dimension of (132.0 km × 88.2 km) with a quality rating of 2, indicating its irregular, elongated shape. Another occultation on 21 October 2012, gave an ellipse of (125.0 km × 125.0 km). These timed observations are taken when the asteroid passes in front of a distant star.[6]
