| Discovery[1] | |
|---|---|
| Discovered by | C. J. van Houten I. van Houten T. Gehrels |
| Discovery site | Palomar Obs. |
| Discovery date | 16 October 1977 |
| Designations | |
| (9826) Ehrenfreund | |
Named after | Pascale Ehrenfreund (Austrianastrophysicist)[2] |
| 2114 T-3 · 1993 VH2 | |
| main-belt · Eos[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 39.66 yr (14,486 days) |
| Aphelion | 3.2560AU |
| Perihelion | 2.7308 AU |
| 2.9934 AU | |
| Eccentricity | 0.0877 |
| 5.18yr (1,892 days) | |
| 295.74° | |
| 0° 11m 25.08s / day | |
| Inclination | 8.9529° |
| 215.57° | |
| 112.60° | |
| Physical characteristics | |
| Dimensions | 6.94 km(calculated)[3] 8.378±0.267 km[4][5] |
| 3.7484±0.0013h[6] | |
| 0.14(assumed)[3] 0.191±0.024[4][5] | |
| S[3] | |
| 12.8[4] · 13.096±0.002(R)[6] · 13.1[1] · 13.38±0.26[7] · 13.55[3] | |
9826 Ehrenfreund, provisional designation2114 T-3, is a stony Eoanasteroid from the outer region of theasteroid belt, approximately 7 kilometers in diameter.
The asteroid was discovered on 16 October 1977, by Dutch astronomer coupleIngrid andCornelis van Houten at Leiden, on photographic plates taken by Dutch–American astronomerTom Gehrels at thePalomar Observatory in California, United States.[8] It was later named for Austrian astrophysicist and biochemistPascale Ehrenfreund.[2]
Ehrenfreund is a member of theEos family, an orbital group of more than 4,000 asteroids, which are well known for mostly being ofstony composition. It orbits the Sun in theouter main-belt at a distance of 2.7–3.3 AU once every 5 years and 2 months (1,892 days). Its orbit has aneccentricity of 0.09 and aninclination of 9° with respect to theecliptic.[1]
The first used observation was taken at the discovering observatory on 7 October 1977, extending the body'sobservation arc by just 9 days prior to its official discovery observation.[8]
Thesurvey designation "T-3" stands for the last of threePalomar–Leiden Trojan surveys, named after the fruitful collaboration of the Palomar andLeiden Observatory in the 1960s and 1970s. Gehrels used Palomar'sSamuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped thephotographic plates to Ingrid and Cornelis van Houten at Leiden Observatory whereastrometry was carried out. The trio are credited with the discovery of several thousand minor planets.[9]
Since221 Eos, the parent of the collisional Eos family, has been characterized as a rareK-type asteroid in theSMASS classification,Ehrenfreund may as well reveal suchspectral type.
A rotationallightcurve for this asteroid was obtained from photometric observations taken at the U.S.Palomar Transient Factory in August 2013. It gave arotation period of3.7484±0.0013 hours with a brightness variation of 0.37 inmagnitude (U=2).[6]
According to the survey carried out by theNEOWISE mission of NASA'sWide-field Infrared Survey Explorer,Ehrenfreund measures 8.4 kilometers in diameter and its surface has analbedo of 0.19,[4] while theCollaborative Asteroid Lightcurve Link assumes an albedo of 0.14 – derived from221 Eos the family's largest member and namesake – and calculates a diameter of 6.9 kilometers with anabsolute magnitude of 13.55.[3]
Thisminor planet was named in honour of Austrian astrophysicist and biochemist,Pascale Ehrenfreund (born 1960), who has analyzeddust particles andcircumstellar organic molecules on a number of space missions.[2] Ehrenfreund has been the lead investigator atNASA Astrobiology Institute and was elected CEO of theGerman Aerospace Center in 2015, the first woman to lead a major research facility in Germany.[10] The approved naming citation was published by theMinor Planet Center on 11 November 2000 (M.P.C. 41570).[11]
