3682 Welther

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3682 Welther
Discovery [1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date12 July 1923
MPC designation(3682) Welther
Named after
Barbara Welther[1]
(American historian of science)
A923 NB · 1951 YO
1978 NP3 · 1984 AA
main-belt[1][2] · (middle)
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc94.79 yr (34,621 d)
Aphelion3.6413 AU
Perihelion1.8769 AU
2.7591 AU
4.58 yr (1,674 d)
0° 12m 54.36s / day
Physical characteristics
Mean diameter
11.13±3.57 km[4]
16.83±4.95 km[5]
19.087±0.229 km[6]
19.24 km (derived)[7]
19.257±0.110 km[8]
19.32±0.7 km[9]
19.34±0.30 km[10]
3.595±0.003 h[11]
3.597 h[12]
3.5973±0.0001 h[11]
3.5973±0.0003 h[13][a]
3.599±0.003 h[14]
0.0997 (derived)[7]
C (assumed)[7]

3682 Welther, provisional designation A923 NB, is a background asteroid from the central regions of the asteroid belt, approximately 19 kilometers (12 miles) in diameter. It was discovered on 12 July 1923, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany.[1] The asteroid has a rotation period of 3.6 hours.[7] It was named after Barbara Welther, an American historian of science at CfA.[1]

Orbit and classification[edit]

Welther is a non-family asteroid from the main belt's background population.[3] It orbits the Sun in the central main-belt at a distance of 1.9–3.6 AU once every 4 years and 7 months (1,674 days; semi-major axis of 2.76 AU). Its orbit has an eccentricity of 0.32 and an inclination of 14° with respect to the ecliptic.[2]

The body's observation arc begins at Heidelber and Vienna Observatory in August 1928, or four weeks after its official discovery observation at Heidelberg.[1]

Physical characteristics[edit]

Welther is an assumed C-type asteroid.[7]

Rotation period[edit]

Several rotational lightcurves of Welther have been obtained from photometric observations since 2001.[11][12][13][14] Analysis of the best-rated lightcurves gave a rotation period of 3.5973 hours with a brightness amplitude of 0.22 and 0.21 magnitude, respectively (U=3-/3).[11][13][a] The observing French amateur astronomers also suspected the asteroid to be a binary system.[11]

Diameter and albedo[edit]

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Welther measures between 11.13 and 19.34 kilometers in diameter and its surface has an albedo between 0.1189 and 0.26.[4][5][6][8][9][10]

The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0997 and a diameter of 19.24 kilometers based on an absolute magnitude of 11.7.[7]


This minor planet was named after American Barbara Welther (born 1938), a historian of science at the Harvard–Smithsonian Center for Astrophysics (CfA).[1] The official naming citation was proposed by CfA's Planetary Sciences division and published by the Minor Planet Center on 1 September 1993 (M.P.C. 22499).[16]


  1. ^ a b Lightcurve plot of 3682 Welther, Palmer Divide Observatory, B. D. Warner (2001); Collaboration with R.D. Stephens (lead), P. Pravec, P. Kusnirak, et al. Only PDO data are shown. Rotation period 3.5973 hours with a brightness amplitude of 0.21±0.01 mag. Also see summary at the LCDB


  1. ^ a b c d e f g "3682 Welther (A923 NB)". Minor Planet Center. Retrieved 9 May 2018.
  2. ^ a b c d "JPL Small-Body Database Browser: 3682 Welther (A923 NB)" (2018-04-25 last obs.). Jet Propulsion Laboratory. Retrieved 9 May 2018.
  3. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 9 May 2018.
  4. ^ a b c d Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63.
  5. ^ a b c d Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8.
  6. ^ a b c Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.
  7. ^ a b c d e f g "LCDB Data for (3682) Welther". Asteroid Lightcurve Database (LCDB). Retrieved 9 May 2018.
  8. ^ a b c d 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. (catalog)
  9. ^ a b c d Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Archived from the original on 3 June 2016. Retrieved 9 May 2018.
  10. ^ a b c d 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. Retrieved 9 May 2018. Online catalog
  11. ^ a b c d e Behrend, Raoul. "Asteroids and comets rotation curves – (3682) Welther". Geneva Observatory. Retrieved 9 May 2018.
  12. ^ a b Székely, P.; Kiss, L. L.; Szabó, Gy. M.; Sárneczky, K.; Csák, B.; Váradi, M.; et al. (August 2005). "CCD photometry of 23 minor planets". Planetary and Space Science. 53 (9): 925–936. arXiv:astro-ph/0504462. Bibcode:2005P&SS...53..925S. doi:10.1016/j.pss.2005.04.006.
  13. ^ a b c Stephens, R. D.; Warner, B.; Pravec, P.; Kusnirak, P.; Sarounova, L.; Wolf, M.; et al. (September 2002). "Lightcurves of 3682 Welther". The Minor Planet Bulletin. 29: 41–46. Bibcode:2002MPBu...29...41S.
  14. ^ a b Klinglesmith, Daniel A., III; Hendrickx, Sebastian; Madden, Karl; Montgomery, Samuel (April 2016). "Lightcurves for Shape/Spin Models". The Minor Planet Bulletin. 43 (2): 123–128. Bibcode:2016MPBu...43..123K. ISSN 1052-8091.
  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. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 9 May 2018.

External links[edit]