_Kerstin.png) Modelled shape ofKerstin from itslightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | M. F. Wolf |
| Discovery site | Heidelberg Obs. |
| Discovery date | 1 October 1916 |
| Designations | |
| (842) Kerstin | |
| Pronunciation | German:[ˈkɛʁstiːn][2] |
Named after | unknown[3] |
| A916 TB · 1916 AM | |
| Orbital characteristics[4] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 103.12yr (37,664 d) |
| Aphelion | 3.6139AU |
| Perihelion | 2.8597 AU |
| 3.2368 AU | |
| Eccentricity | 0.1165 |
| 5.82 yr (2,127 d) | |
| 350.44° | |
| 0° 10m 9.48s / day | |
| Inclination | 14.496° |
| 5.4008° | |
| 352.49° | |
| Physical characteristics | |
| 18.716±0.002 h[11] | |
| (18.0°, 78.0°) (λ1/β1)[11][12] | |
| C(assumed)[12] | |
842 Kerstin (prov. designation:A916 TBor1916 AM) is a darkbackground asteroid from the outer regions of theasteroid belt. It was discovered on 1 October 1916, by German astronomerMax Wolf at theHeidelberg-Königstuhl State Observatory in southwest Germany.[1] The assumedC-type asteroid has arotation period of 18.7 hours and measures approximately 41 kilometers (25 miles) in diameter. Any reference of the origin of the asteroid's name is unknown.[3]
Kerstin is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[5][6] It orbits the Sun in theouter main-belt at a distance of 2.9–3.6 AU once every 5 years and 10 months (2,127 days;semi-major axis of 3.24 AU). Its orbit has aneccentricity of 0.12 and aninclination of 14° with respect to theecliptic.[4] The body'sobservation arc begins atHeidelberg Observatory with its official discovery observation on 1 October 1916.[1]
"Kerstin" is a German feminine first name. Any reference of this name to a person or occurrence is unknown.[3]
Among the many thousands ofnamed minor planets,Kerstin is one of 120 asteroids for which no official naming citation has been published. All of these asteroids have low numbers between164 Eva and1514 Ricouxa and were discovered between 1876 and the 1930s, predominantly by astronomersAuguste Charlois,Johann Palisa, Max Wolf andKarl Reinmuth.[13]
Kerstin is an assumedC-type asteroid, with a lowastronomical albedo(see below) comparable to fresh asphalt.[12]
In 2018, Czech astronomersJosef Ďurech andJosef Hanuš published a modeledlightcurve usingphotometric data from theGaia spacecraft's second data release. It showed a sidereal period of18.716±0.002 hours (U=2), and gave aspin axis at (18.0°, 78.0°) inecliptic coordinates (λ, β).[11][12]
According to the surveys carried out by the Infrared Astronomical SatelliteIRAS, the JapaneseAkari satellite, and theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE),Kerstin measures (39.16±2.8), (41.21±1.40) and (43.576±0.190) kilometers in diameter and its surface has analbedo of (0.0552±0.009), (0.050±0.004) and (0.041±0.009), respectively.[7][8][9][10] TheCollaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 42.23 kilometers based on anabsolute magnitude of 10.6.[12] Alternative mean-diameter measurements published by the WISE team include (36.87±11.73 km), (38.53±14.48 km), (44.602±0.680 km) and (45.536±0.186 km) with corresponding albedos of (0.06±0.04), (0.06±0.07), (0.051±0.005) and (0.0408±0.0082).[6][12]
