1845 Helewalda

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1845 Helewalda
Discovery
Synodic rotation period
7.2786±0.0002 h[7]
7.3985±0.0098 h[8]
7.399±0.004 h[9]
7.4±0.1 h[10]
0.057 (assumed)[3]
0.1289±0.0185[6]
0.134±0.014[5]
C (assumed)[3]
11.193±0.002[8] · 11.2[1][3] · 11.3[6] · 11.60±0.98[11]

1845 Helewalda (

provisional designation 1972 UC) is a carbonaceous Eoan asteroid in the outer regions of the asteroid belt, approximately 20 kilometers in diameter. It was discovered by Swiss astronomer Paul Wild at Zimmerwald Observatory near Bern, Switzerland, on 30 October 1972.[12] The asteroid was named after Helen Gachnang, a friend of the discoverer.[2]

Orbit and classification

Helewalda is a member of the

606), the largest asteroid family in the outer main belt consisting of nearly 10,000 asteroids.[4][13]: 23  It orbits the Sun in the outer main-belt at a distance of 2.8–3.1 AU once every 5 years and 1 month (1,868 days). Its orbit has an eccentricity of 0.06 and an inclination of 11° with respect to the ecliptic.[1] The first precovery was taken at Lowell Observatory in 1931, extending the asteroid's observation arc by 41 years prior to its discovery.[12]

Physical characteristics

Helewalda is an assumed carbonaceous C-type asteroid.[3]

Rotation period

Based on observations made by French astronomer

U=3-).[7]

Between 2009 and 2015, other

U=2/2+/2).[9][10][8]

Diameter and albedo

The Collaborative Asteroid Lightcurve Link calculates a diameter of 32.0 kilometers, based on an assumed standard albedo for carbonaceous

NEOWISE mission of NASA's Wide-field Infrared Survey Explorer measured a higher albedo of 0.134 and 0.129 and a corresponding diameter of 19.9 and 20.4 kilometers in diameter, respectively.[5][6]

Naming

The discoverer, Paul Wild, named a pair of asteroids after two of his former schoolmates, Susi and Helen, both from the small village of

M.P.C. 4156).[15]

References

  1. ^ a b c d "JPL Small-Body Database Browser: 1845 Helewalda (1972 UC)" (2017-05-05 last obs.). Jet Propulsion Laboratory. Retrieved 8 June 2017.
  2. ^
    ISBN 978-3-540-00238-3
    .
  3. ^ a b c d e f g "LCDB Data for (1845) Helewalda". Asteroid Lightcurve Database (LCDB). Retrieved 18 May 2016.
  4. ^ a b "Asteroid 1845 Helewalda – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 26 October 2019.
  5. ^
    doi:10.1088/0004-637X/791/2/121
    . Retrieved 8 December 2016.
  6. ^
    doi:10.1088/0004-637X/741/2/90
    . Retrieved 18 May 2016.
  7. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1845) Helewalda". Geneva Observatory. Retrieved 18 May 2016.
  8. ^
    doi:10.1088/0004-6256/150/3/75
    . Retrieved 18 May 2016.
  9. ^
    ISSN 1052-8091
    . Retrieved 18 May 2016.
  10. ^
    ISSN 1052-8091
    . Retrieved 18 May 2016.
  11. doi:10.1016/j.icarus.2015.08.007
    . Retrieved 18 May 2016.
  12. ^ a b "1845 Helewalda (1972 UC)". Minor Planet Center. Retrieved 18 May 2016.
  13. ISBN 9780816532131
    .
  14. ^ "Himmlischer Besuch auf der Sternwarte Eschenberg" (in German). Sternwarte Eschenberg. Retrieved 1 March 2016. Helen Gachnang and Susi Petit-Pierre visit the Eschenberg Observatory
  15. ISBN 978-3-642-01964-7
    .

External links
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