| Discovery[1] | |
|---|---|
| Discovered by | S. Arend |
| Discovery site | Uccle Obs. |
| Discovery date | 24 August 1933 |
| Designations | |
| (1313) Berna | |
Named after | Bern[2] (capital of Switzerland) |
| 1933 QG · 1926 EA A911 OA | |
| main-belt[1][3] · (middle) background[4][5] | |
| Orbital characteristics[3] | |
| Epoch 27 April 2019 (JD 2458600.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 84.74yr (30,953 d) |
| Aphelion | 3.2074AU |
| Perihelion | 2.1112 AU |
| 2.6593 AU | |
| Eccentricity | 0.2061 |
| 4.34 yr (1,584 d) | |
| 241.65° | |
| 0° 13m 38.28s / day | |
| Inclination | 12.545° |
| 298.14° | |
| 99.773° | |
| Knownsatellites | 1(see 2nd infobox)[a] |
| Physical characteristics | |
| 13.12±2.44 km[6] 13.504±0.311 km[7][8][9] 13.93±0.64 km[10] 14.27±0.36 km[11] 19.96±4.97 km[12] | |
| Mass | (2.25±2.00)×1015 kg[10] |
Meandensity | 1.21±0.14 cm3[10] |
| 25.46 h[13][14][15][16] | |
| 0.13[12] 0.169[11] 0.185[7][8][9] 0.212[17] 0.245[6] | |
| S(assumed)[13] | |
| 11.55[6] 11.6[1][3][13] 11.69±0.12[17] 11.75[12] 11.80[7][9][11] | |
1313 Berna, provisional designation1933 QG, is a backgroundasteroid and synchronousbinary system from theEunomian region in the centralasteroid belt, approximately 14 kilometers (8.7 miles) in diameter. It was discovered on 24 August 1933, by Belgian astronomerSylvain Arend at theUccle Observatory in Belgium.[1] The assumedS-type asteroid has a longer-than averagerotation period of 25.5 hours and is likely elongated in shape.[13] It was named for the Swiss capital ofBern.[1] The discovery of an 11-kilometer-sizedsatellite was announced in February 2004.[a]
According to modernHCM-analyses byNesvorný, as well as byMilani andKnežević,Berna is a non-family asteroid from the main belt'sbackground population.[4][5]
Based on osculating Keplerianorbital elements, it is located in the region of theEunomia family (502), a prominent family of stony asteroids.[13] It orbits the Sun in thecentral asteroid belt at a distance of 2.1–3.2 AU once every 4 years and 4 months (1,584 days;semi-major axis of 2.66 AU). Its orbit has aneccentricity of 0.21 and aninclination of 13° with respect to theecliptic.[3] In 1911,Berna was first identified asA911 OA atJohannesburg. Itsobservation arc begins with its official discovery observation at Uccle.[1]
Thisminor planet was named after the Swiss capital city ofBern. The name was proposed by Sigmund Mauderli (1876–1962), astronomer and director of the Astronomical Institute at theUniversity of Bern, after whom1748 Mauderli is named. He computed the definitive orbit of the body, and also insisted to rename the minor planet to its current name, after it had been originally published as "Bernia".[2] The officialnaming citation was first mentioned inThe Names of the Minor Planets byPaul Herget in 1955 (H 120).[2]
A network of astronomers at several observatories includingRaoul Behrend atGeneva Observatory, Switzerland, obtained the so-far best rated rotationallight-curve ofBerna. Light-curve analysis gave arotation period of25.464 hours with a brightness variation of 0.28magnitude (U=3).[15] In November 2007, photometric observations atCerro Tololo, Chile, using its 0.9-meterPrompt5 telescope in combination with theSpitzer Space Telescope gave a concurring period of 25.46 hours with an amplitude of 0.5 magnitude (U=n.a.).[17]: 40 Other light-curves were also obtained by several amateur astronomers giving a period of 6, 25.4 and 25.45 hours, respectively (U=1/2-/3-).[16]
| Discovery[a] | |
|---|---|
| Discovered by | R. Behrend,R. Roy S. Sposetti |
| Discovery date | 6 February 2004 |
| Light-curve | |
| Orbital characteristics | |
| 25 km | |
| 25.464±0.001h[17][14] | |
| 30mas(maximum) | |
| Satellite of | 1313 Berna |
| Physical characteristics | |
| Dimensions | 8.37 km[18] |
| Δ0.51fainter than prim. | |
| 12.8–13.0 | |
In February 2004, asatellite orbiting the asteroid was discovered. The moon, which does not have a provisional designation,[3] measures about 11 kilometers in diameter and orbitsBerna at a distance of 35 kilometer once every 25 hours and 28 minutes. Since the lightcurve is synchronized with the eclipse events, at least one body of the binary system rotates synchronously with the orbital motion. It was identified based onlight-curve observations taken in February 2004 by several astronomers, including Raoul Behrend at Geneva Observatory,Stefano Sposetti,René Roy,Donald Pray,Christophe Demeautis,Daniel Matter,Alain Klotz and others.[a][14] Although theIAUC was released on 23 February 2004, the announcement was already made on 12 February 2004. There are several hundreds of asteroids known to have satellites(also seeCategory:Binary asteroids).[19]
According to the surveys carried out by the JapaneseAkari satellite, NASA's Spitzer Space Telescope and theWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Berna measures between 13.12 and 19.96 kilometers in diameter and its surface has analbedo between 0.13 and 0.25.[6][17][9][8][11][12] TheCollaborative Asteroid Lightcurve Link assumes an albedo of 0.21 – derived from15 Eunomia, the parent body of the Eunomia family – and calculates a diameter of 13.88 kilometers based on anabsolute magnitude of 11.6.[13]
