Article · Wikipedia archive · Last revised Jun 19, 2026

391 Ingeborg

391 Ingeborg is an asteroid and second-largest Mars-crosser on an eccentric orbit from the asteroid belt. It was discovered by German astronomer Max Wolf on 1 November 1894, at the Heidelberg Observatory in southwest Germany. When discovered, it was observed for a couple of weeks, and follow-up observations were made in 1901 and 1904.

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391 Ingeborg
Modelled shape of Ingeborg from its lightcurve
Discovery1
Discovered byM. F. Wolf
Discovery siteHeidelberg Obs.
Discovery date1 November 1894
Designations
PronunciationGerman: [ˈɪŋəbɔʁk] ⓘ2
Named after
unknown (Ingeborg)3
1894 BE · 1934 AJ
A894 VB
Mars-crosser145
Orbital characteristics1
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc122.86 yr (44,875 days)
Aphelion3.0285 AU
Perihelion1.6120 AU
2.3203 AU
Eccentricity0.3052
3.53 yr (1,291 days)
292.16°
0° 16m 44.04s / day
Inclination23.202°
212.88°
147.06°
Mars MOID0.2350 AU
Physical characteristics
Dimensions15.75±3.05 km6
17.33±1.73 km7
18.15±0.19 km8
19.63 km (calculated)5
16 h9
26.39±0.02 h10
26.391±0.006 h11
26.4145±0.0005 h12
26.4146±0.0005 h13
26.4149±0.0001 h14
0.20 (assumed)5
0.282±0.0567
0.290±0.1106
0.34±0.166
0.495±0.0138
Tholen = S1
SMASS = S15
10.108 · 10.21±0.8115 · 10.80167 · 10.95 · 10.9±0.2169

391 Ingeborg (prov. designation: A894 VB or 1894 BE) is an asteroid and second-largest Mars-crosser on an eccentric orbit from the asteroid belt. It was discovered by German astronomer Max Wolf on 1 November 1894, at the Heidelberg Observatory in southwest Germany. When discovered, it was observed for a couple of weeks, and follow-up observations were made in 1901 and 1904.34

Among the many thousands of named minor planets, Ingeborg is one of 120 asteroids, for which no official naming citation has been published. All of these low-numbered asteroids have numbers between 164 Eva and 1514 Ricouxa and were discovered between 1876 and the 1930s, predominantly by astronomers Auguste Charlois, Johann Palisa, Max Wolf and Karl Reinmuth.17

Ingeborg orbits the Sun in the inner main-belt at a distance of 1.6–3.0 AU once every 3 years and 6 months (1,291 days). Its orbit has an eccentricity of 0.31 and an inclination of 23° with respect to the ecliptic.1 The stony S-type asteroid has a rotation period of 26.4 hours3

According to the surveys carried out by the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Ingeborg measures between 15.75 and 18.15 kilometers in diameter and its surface has an albedo between 0.282 and 0.495.678 The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.20 and calculates a diameter of 19.63 kilometers based on an absolute magnitude of 10.9.5 Other large Mars crossing minor planets include 132 Aethra (43 km), 323 Brucia (36 km), and 2204 Lyyli (25 km).

References

References

  1. "JPL Small-Body Database Browser: 391 Ingeborg (1894 BE)" (2017-09-30 last obs.). Jet Propulsion Laboratory. Retrieved 2 November 2017.
  2. (German Names)
  3. Schmadel, Lutz D. (2007). "(391) Ingeborg". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 47. doi:10.1007/978-3-540-29925-7_392. ISBN 978-3-540-00238-3.
  4. "391 Ingeborg (1894 BE)". Minor Planet Center. Retrieved 2 November 2017.
  5. "MinorPlanet.info: One Asteroid Information". Asteroid Lightcurve Database (LCDB). Retrieved 2 November 2017. Search using Number = "391"
  6. Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117.
  7. Alí-Lagoa, V.; Delbo', M. (July 2017). "Sizes and albedos of Mars-crossing asteroids from WISE/NEOWISE data". Astronomy and Astrophysics. 603: 8. arXiv:1705.10263. Bibcode:2017A&A...603A..55A. doi:10.1051/0004-6361/201629917.
  8. Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
  9. Wisniewski, W. Z.; Michalowski, T. M.; Harris, A. W.; McMillan, R. S. (March 1995). "Photoelectric Observations of 125 Asteroids". Abstracts of the Lunar and Planetary Science Conference. 26: 1511. Bibcode:1995LPI....26.1511W.
  10. Behrend, Raoul. "Asteroids and comets rotation curves – (391) Ingeborg". Geneva Observatory. Retrieved 2 November 2017.
  11. Koff, R. A.; Brincat, S. M.; Stephens, R. D.; Pravec, P. (September 2001). "Lightcurve Photometry of Asteroid 391 Ingeborg". The Minor Planet Bulletin. 28: 46–48. Bibcode:2001MPBu...28...46K.
  12. Hanus, J.; Broz, M.; Durech, J.; Warner, B. D.; Brinsfield, J.; Durkee, R.; et al. (November 2013). "An anisotropic distribution of spin vectors in asteroid families". Astronomy and Astrophysics. 559: 19. arXiv:1309.4296. Bibcode:2013A&A...559A.134H. doi:10.1051/0004-6361/201321993.
  13. Hanus, J.; Durech, 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.
  14. Durech, J.; Hanus, J.; Oszkiewicz, D.; Vanco, R. (March 2016). "Asteroid models from the Lowell photometric database". Astronomy and Astrophysics. 587: 6. arXiv:1601.02909. Bibcode:2016A&A...587A..48D. doi:10.1051/0004-6361/201527573.
  15. 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:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007.
  16. Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus. 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026.
  17. Schmadel, Lutz D. (2007). "Appendix 11 – Minor Planet Names with Unknown Meaning". Dictionary of Minor Planet Names – Fifth Revised and Enlarged revision. Springer Berlin Heidelberg. pp. 927–929. ISBN 978-3-540-00238-3.
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