_Seraphina.png) Shape ofSeraphina from modeledlightcurve | |
| Discovery[1] | |
|---|---|
| Discovered by | M. F. Wolf |
| Discovery site | Heidelberg Obs. |
| Discovery date | 24 September 1916 |
| Designations | |
| (838) Seraphina | |
Named after | unknown[2] |
| A916 SL · 1916 AH 2019 FC5 | |
| Orbital characteristics[3] | |
| Epoch 31 May 2020 (JD 2459000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 103.28yr (37,724 d) |
| Aphelion | 3.2777AU |
| Perihelion | 2.5189 AU |
| 2.8983 AU | |
| Eccentricity | 0.1309 |
| 4.93 yr (1,802 d) | |
| 15.248° | |
| 0° 11m 59.28s / day | |
| Inclination | 10.423° |
| 240.05° | |
| 117.10° | |
| Physical characteristics | |
| 15.67±0.02 h[9] | |
| (18.0°, 4.0°) (λ1/β1)[10][11] (192.0°, 32.0°) (λ2/β2)[10][11] | |
| 10.1[1][3] | |
838 Seraphina (prov. designation:A916 SLor1916 AH) is a dark and largebackground asteroid, approximately 58 kilometers (36 miles) in diameter, located in the outer regions of theasteroid belt. It was discovered by German astronomerMax Wolf at theHeidelberg-Königstuhl State Observatory on 24 September 1916.[1] The primitiveP-type asteroid has arotation period of 15.7 hours and is rather spherical in shape. Any reference to the origin of the asteroid's name is unknown.[2]
Seraphina is a non-family asteroid of the main belt'sbackground population when applying thehierarchical clustering method to itsproper orbital elements.[4][5] It orbits the Sun in theouter asteroid belt at a distance of 2.5–3.3 AU once every 4 years and 11 months (1,802 days;semi-major axis of 2.9 AU). Its orbit has aneccentricity of 0.13 and aninclination of 10° with respect to theecliptic.[3] The body'sobservation arc begins with its official discovery observation atHeidelberg Observatory on 24 September 1916.[1]
Any reference of thisminor planet's name to a person or occurrence is unknown.[2]
Among the manythousands of named minor planets,Seraphina is one of 120 asteroids for which no official naming citation has been published. All of these asteroids have low numbers in between164 Eva and1514 Ricouxa and were discovered from 1876 up to the 1930s, predominantly by astronomersAuguste Charlois,Johann Palisa, Max Wolf andKarl Reinmuth.[13]
In theTholen classification,Seraphina is a very dark, primitiveP-type asteroid, that falls into the wider group of the carbonaceous C-Complex.[3] In both the Tholen- and SMASS-like taxonomy of theSmall Solar System Objects Spectroscopic Survey (S3OS2), it is anX-type asteroid.[5][12] P-type asteroids are common in the outer asteroid belt and among theJupiter trojans.
In November 2005, a rotationallightcurve ofSeraphina was obtained fromphotometric observations by French amateur astronomer Raymond Poncy. Lightcurve analysis gave arotation period of15.67±0.02 hours with a low brightness variation of0.07±0.01magnitude, indicative of a rather spherical shape (U=2).[9] Other observations include a period of16.2 hours with an amplitude of0.30 magnitude byRichard Binzel from June 1984 (U=2),[14] and a period of17.62±0.01 hours with an amplitude of0.13±0.03 magnitude by the Spanish group of asteroid observers, OBAS, in November 2015 (U=2).[15]
In 2018, Czech astronomersJosef Ďurech andJosef Hanuš published a modeled lightcurve using photometric data from theGaia spacecraft's second data release. It showed a sidereal period of11.7245±0.0002 hours (U=2), and gave twospin axes at (18.0°, 4.0°) and (192.0°, 32.0°) inecliptic coordinates (λ, β).[10][11]
According to the surveys carried out by the JapaneseAkari satellite, theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer (WISE), and the Infrared Astronomical SatelliteIRAS,Seraphina measures (49.36±0.78), (58.095±0.496) and (59.81±2.3) kilometers in diameter and its surface has analbedo of (0.068±0.002), (0.048±0.008) and (0.0455±0.004), respectively.[6][7][8] TheCollaborative Asteroid Lightcurve Link derives an albedo of 0.0427 and a diameter of 59.75 kilometers based on anabsolute magnitude of 10.16.[11] Alternative mean-diameter measurements published by the WISE team include (43.24±13.99 km), (48.861±11.16 km) and (65.33±0.24 km) with corresponding albedos of (0.04), (0.062±0.081) and (0.0820±0.0418).[5][11]
Twoasteroid occultations ofSeraphina gave a best-fit ellipse dimension of (60.0 km × 60.0 km) and (49.0 km × 49.0 km) for their respective observation on 5 February 2007 and on 20 July 2014. These timed observations are taken when the asteroid passes in front of a distant star. However, these two observations have received a poor quality rating.[5]
