9826 Ehrenfreund

9826 Ehrenfreund
Discovery [1]
Discovered by C. J. van Houten
I. van Houten
T. Gehrels
Discovery site Palomar Obs.
Discovery date 16 October 1977
Designations
MPC designation 9826 Ehrenfreund
Named after
 Pascale Ehrenfreund
(astrophysicist)[2]
2114 T-3 · 1993 VH2
main-belt · Eos [3]
Orbital characteristics [1]
Epoch 16 February 2017 (JD 2457800.5)
Uncertainty parameter 0
Observation arc 38.64 yr (14,113 days)
Aphelion 3.2584 AU
Perihelion 2.7325 AU
2.9954 AU
Eccentricity 0.0878
5.18 yr (1,894 days)
258.13°
0° 11m 24.36s / day
Inclination 8.9507°
215.57°
112.17°
Physical characteristics
Dimensions 6.94 km (calculated)[3]
8.378±0.267 km[4][5]
3.7484±0.0013 h[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 designation 2114 T-3, is a stony asteroid from the outer region of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 16 October 1977, by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Dutch–American astronomer Tom Gehrels at the U.S. Palomar Observatory in California.[8]

    The S-type asteroid is a member of the Eos family, an orbital group of more than 4,000 asteroids, which are well known for mostly being of stony composition. It orbits the Sun at a distance of 2.7–3.3 AU once every 5 years and 2 months (1,894 days). Its orbit has an eccentricity of 0.09 and an inclination of 9° with respect to the ecliptic.[1] The first used observation was taken at the discovering observatory on 7 October 1977, extending the asteroid's observation arc by just 9 days prior to its discovery.[8]

    A rotational light-curve for this asteroid was obtained from photometric observations taken at the U.S. Palomar Transient Factory in August 2013. It gave a rotation period of 3.7484±0.0013 hours with a brightness variation of 0.37 in magnitude (U=2).[6]

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, the asteroid measures 8.4 kilometers in diameter and its surface has an albedo of 0.19,[4] while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.14 – derived from the family's largest member and namesake, 221 Eos – and calculates a diameter of 6.9 kilometers.[3] Since 221 Eos, the parent of a collisional group is classified as a K-type asteroid on the SMASS taxonomy scheme, this may also apply for 9826 Ehrenfreund.

    The survey designation T-3 stands for the last of three Palomar–Leiden Trojan surveys, named after the fruitful collaboration of the Palomar and Leiden Observatory in the 1960s and 1970s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of several thousand minor planets.[9]

    The minor planet was named in honour of Austrian female astrophysicist and biochemist, Pascale Ehrenfreund (b. 1960), who has analyzed dust particles and circumstellar organic molecules on a number of space missions.[2] Naming citation was published on 11 November 2000 (M.P.C. 41570).[10] Ehrenfreund has been the lead investigator at NASA Astrobiology Institute and was elected CEO of the German Aerospace Center in 2015, the first woman to lead a major research facility in Germany.[11]

    References

    1. 1 2 3 4 "JPL Small-Body Database Browser: 9826 Ehrenfreund (2114 T-3)" (2016-05-28 last obs.). Jet Propulsion Laboratory. Retrieved 4 December 2016.
    2. 1 2 Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (9826) Ehrenfreund. Springer Berlin Heidelberg. p. 710. ISBN 978-3-540-00238-3. Retrieved 30 July 2016.
    3. 1 2 3 4 5 6 "LCDB Data for (9826) Ehrenfreund". Asteroid Lightcurve Database (LCDB). Retrieved 30 July 2016.
    4. 1 2 3 4 Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 30 July 2016.
    5. 1 2 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096Freely accessible. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 4 December 2016.
    6. 1 2 3 Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041Freely accessible. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 1 January 2016.
    7. ↑ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 30 July 2016.
    8. 1 2 "9826 Ehrenfreund (2114 T-3)". Minor Planet Center. Retrieved 30 July 2016.
    9. ↑ "Minor Planet Discoverers". Minor Planet Center. 22 June 2016. Retrieved 30 July 2016.
    10. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 30 July 2016.
    11. ↑ "First woman to head a major German research facility". DLR – German Aerospace Center. 18 June 2015. Retrieved 1 January 2016.

    External links

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