2001 Einstein

2001 Einstein (prov. designation: 1973 EB) is a bright Hungaria asteroid from the innermost region of the asteroid belt. It was discovered by Swiss astronomer Paul Wild at Zimmerwald Observatory near Bern, Switzerland, on 5 March 1973.[3] The X-type asteroid (Xe) has a rotation period of 5.5 hours and measures approximately 5 kilometers (3.1 miles) in diameter. It is named after physicist Albert Einstein (1879–1955).[2]

2001 Einstein
002001-asteroid shape model (2001) Einstein.png
Shape model of Einstein from its lightcurve
Discovered byP. Wild
Discovery siteZimmerwald Obs.
Discovery date5 March 1973
(2001) Einstein
Named after
Albert Einstein (physicist)[2]    
1973 EB
main-belt · Hungaria[3][4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc43.43 yr (15,864 days)
Aphelion2.1242 AU
Perihelion1.7430 AU
1.9336 AU
2.69 yr (982 days)
0° 21m 59.76s / day
Physical characteristics
Mean diameter
3.975±0.154 km[5][6]
5.66 km (calculated)[7]
5.4846±0.0001 h[8]
5.485±0.002 h[9]
5.48503±0.00005 h (S)[10]
5.487±0.001 h[11]
0.40 (assumed)[7]
X (Tholen), Xe (SMASS)[1]
X[7] · E[5]
B–V = 0.720[1]
U–B = 0.261[1]

Orbit and classificationEdit

Einstein is a member of the Hungaria family, which form the innermost dense concentration of asteroids in the Solar System. It orbits the Sun in the inner main-belt at a distance of 1.7–2.1 AU once every 2 years and 8 months (982 days). Its orbit has an eccentricity of 0.10 and an inclination of 23° with respect to the ecliptic.[1] As no precoveries were taken, the asteroid's observation arc begins with its discovery in 1973.[3]


This minor planet was named in honour of the German-born, Swiss–American physicist and Nobelist Albert Einstein (1879–1955). It is considered suitable, that the body discovered at Bern is named after the 1921 Nobel prize for physics laureate, since it was the place where he had his golden years while working as a clerk at the Swiss Patent Office in Bern. He is also honored by the lunar crater Einstein.[2] The official naming citation was published by the Minor Planet Center on 15 October 1977 (M.P.C. 4237).[12] Arthur C. Clarke joked in the postscript of his novel 3001: The Final Odyssey that he was hoping asteroid 2001 would be named after him, but it was named for Einstein first. Asteroid 3001 was named 3001 Michelangelo. Clarke was later honoured with asteroid 4923 Clarke, named together with 5020 Asimov.

Physical characteristicsEdit

The Tholen classification, Einstein is an X-type asteroid, while in the SMASS classification, it is an Xe-subtype which transitions from the X-type to the very bright E-type asteroid.

Rotation periodEdit

Several rotational lightcurves for this asteroid were obtained from photometric observations. In December 2004, the first lightcurve by American astronomer Brian Warner at his Palmer Divide Observatory (PDS) in Colorado, gave a rotation period of 5.487 hours with a brightness variation of 0.66 in magnitude (U=3).[11] Between 2008 and 2012, three additional lightcurves at the PDS gave an almost identical period of 5.485 hours with an amplitude of 0.67, 0.74 and 1.02, respectively (U=3/3/3).[9][13][14] Other lightcurves were obtained by Hanuš at the French CNES and other institutions, which gave a period of 5.48503 hours (U=n.a.),[10] and by Italian astronomer Federico Manzini at SAS observatory in Novara, Jean Strajnic and Raoul Behrend from December 2012, which rendered a period of 5.4846 hours with an amplitude of 0.66 in magnitude (U=2+).[8]

Diameter and albedoEdit

According to the survey carried out by the NEOWISE mission of NASA's space-based Wide-field Infrared Survey Explorer (WISE), the asteroid measures 4.0 km in diameter and its surface has an exceptionally high albedo of 0.81, for which WISE assigns an E-type.[5] The Collaborative Asteroid Lightcurve Link assumes a lower, yet still high albedo of 0.40 and hence calculates a larger diameter of 5.7 kilometers, as the lower the albedo, the larger the body's diameter for a constant absolute magnitude.[7]


  1. ^ a b c d e f g "JPL Small-Body Database Browser: 2001 Einstein (1973 EB)" (2016-08-10 last obs.). Jet Propulsion Laboratory. Retrieved 3 July 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(2001) Einstein". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 162. doi:10.1007/978-3-540-29925-7_2002. ISBN 978-3-540-00238-3.
  3. ^ a b c "2001 Einstein (1973 EB)". Minor Planet Center. Retrieved 1 April 2016.
  4. ^ Spratt, Christopher E. (April 1990). "The Hungaria group of minor planets". Journal of the Royal Astronomical Society of Canada. 84 (2): 123–131. Bibcode:1990JRASC..84..123S. ISSN 0035-872X. Retrieved 1 April 2016.
  5. ^ a b c d e 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:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 20 May 2016.
  6. ^ a b 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:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 8 December 2016.
  7. ^ a b c d e "LCDB Data for (2001) Einstein". Asteroid Lightcurve Database (LCDB). Retrieved 1 April 2016.
  8. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (2001) Einstein". Geneva Observatory. Retrieved 20 May 2016.
  9. ^ a b Warner, Brian D. (April 2010). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2009 September-December" (PDF). Minor Planet Bulletin. 37 (2): 57–64. Bibcode:2010MPBu...37...57W. ISSN 1052-8091. Retrieved 18 March 2020.
  10. ^ a b Hanuš, J.; Ďurech, J.; Oszkiewicz, D. A.; Behrend, R.; Carry, B.; Delbo, M.; et al. (February 2016). "New and updated convex shape models of asteroids based on optical data from a large collaboration network". Astronomy and Astrophysics. 586: 24. arXiv:1510.07422. Bibcode:2016A&A...586A.108H. doi:10.1051/0004-6361/201527441. Retrieved 20 May 2016.
  11. ^ a b Warner, Brian D. (September 2005). "Asteroid lightcurve analysis at the Palmer Divide Observatory - winter 2004-2005" (PDF). Minor Planet Bulletin. 32 (3): 54–58. Bibcode:2005MPBu...32...54W. ISSN 1052-8091. Retrieved 18 March 2020.
  12. ^ Schmadel, Lutz D. "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.
  13. ^ Warner, Brian D. (October 2008). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: February-May 2008" (PDF). Minor Planet Bulletin. 35 (4): 163–166. Bibcode:2008MPBu...35..163W. ISSN 1052-8091. Retrieved 18 March 2020.
  14. ^ Warner, Brian D. (April 2013). "Asteroid Lightcurve Analysis at the Palmer Divide Observatory: 2012 September - 2013 January" (PDF). Minor Planet Bulletin. 40 (2): 71–80. Bibcode:2013MPBu...40...71W. ISSN 1052-8091. Retrieved 18 March 2020.

External linksEdit