120P/Mueller

120P/Mueller
Discovery[1]
Discovered byJean E. Mueller
Discovery sitePalomar Observatory
Discovery date18 October 1987
Designations
P/1987 U2
P/1995 O2
Mueller 1
1987 XXXI, 1987a1
Orbital characteristics[3][4]
Epoch6 September 2007 (JD 2454349.5)
Observation arc34.14 years
Number of
observations
147
Aphelion5.527 AU
Perihelion2.744 AU
Semi-major axis4.136 AU
Eccentricity0.33654
Orbital period8.412 years
Inclination8.791°
4.443°
Argument of
periapsis
30.008°
Mean anomaly125.57°
Last perihelion7 May 2021
Next perihelion5 April 2029[2]
TJupiter2.917
Earth MOID1.754 AU
Jupiter MOID0.265 AU
Physical characteristics[3]
Mean radius
0.77 km (0.48 mi)[5]
Comet total
magnitude
(M1)
6.6
Comet nuclear
magnitude (M2)
16.4

120P/Mueller, also known as Mueller 1, is a Jupiter-family comet with an 8.4-year orbit around the Sun. It is one of 15 comets discovered by American astronomer, Jean Mueller.

Observational history

Jean Mueller first spotted the comet on photographic plates exposed from the Palomar Observatory on the night of 18 October 1987.[1] She described the new comet as a diffuse 17th-magnitude object within the constellation Pisces.[a] A condensation and an apparent tail about 20–30 arcseconds in length towards the south-southwest was also noted.[6] Orbital calculations using follow-up observations until 27 October 1987 helped Daniel W. E. Green to determine Mueller's comet as periodic, at the time having an orbital period of roughly 8.21 years.[7]

James V. Scotti recovered the comet from the Kitt Peak Observatory on 30 July 1995 as P/1995 O1.[8] It was a 22nd-magnitude object at the time of its recovery.[8] The comet was observed from every subsequent apparition since. It most recently came to perihelion in May 2021[4] and underwent a 1.4 magnitude outburst in August 2021.[9]

Physical characteristics

Initial estimates of the size of its nucleus in 2004 was approximately 3.0 km (1.9 mi) in diameter.[10] Optical photometry obtained in 2007 revised this to half of the previous estimate, currently about 1.54 km (0.96 mi) in diameter.[5]

Notes

  1. ^ Reported initial position upon discovery was: α = 1h 12m 47.4s, δ = 12° 25′ 50″[6]

References

  1. ^ a b J. E. Mueller; N. Reid; A. Maury (19 October 1987). D. W. Green (ed.). "Comet Mueller (1987a1)". IAU Circular. 4472 (2). Bibcode:1987IAUC.4472....2M.
  2. ^ "Horizons Batch for 120P/Mueller 1 on 2029-Apr-05" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Retrieved 13 September 2021. (JPL#20/Soln.date: 2021-Apr-15)
  3. ^ a b "120P/Mueller 1 – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 5 December 2025.
  4. ^ a b "120P/Mueller Orbit". Minor Planet Center. Retrieved 17 June 2014.
  5. ^ a b C. S. Snodgrass; S. C. Lowry; A. Fitzsimmons (2007). "Optical observations of 23 distant Jupiter Family Comets, including 36P/Whipple at multiple phase angles" (PDF). Monthly Notices of the Royal Astronomical Society. 385 (2): 737–756. arXiv:0712.4204. Bibcode:2008MNRAS.385..737S. doi:10.1111/j.1365-2966.2008.12900.x. S2CID 55536237.
  6. ^ a b G. W. Kronk; M. Meyer; D. A. J. Seargent (2017). Cometography: A Catalog of Comets. Vol. 6: 1983–1994. Cambridge: Cambridge University Press. pp. 320–322. ISBN 978-0-521-87216-4.
  7. ^ E. M. Shoemaker; C. S. Shoemaker; H. Holt; et al. (27 October 1987). D. W. Green (ed.). "Periodic Comet Mueller (1987a1)". IAU Circular. 4480 (1). Bibcode:1987IAUC.4480....1S.
  8. ^ a b J. V. Scotti; S. Nakano (3 August 1995). B. G. Marsden (ed.). "Comet P/1995 O1 (Mueller)". IAU Circular. 6199 (1). Bibcode:1995IAUC.6199....1S.
  9. ^ M. S. P. Kelley. "Small Apparent Outburst of Comet 120P/Mueller 1". The Astronomer's Telegram. 14876: 1. Bibcode:2021ATel14876....1K.
  10. ^ P. L. Lamy; I. Toth; Y. R. Fernández; H. A. Weaver (2004). "The Sizes, Shapes, Albedos, and Colors of Cometary Nuclei" (PDF). Comets II. University of Arizona Press. pp. 223–264. Bibcode:2004come.book..223L. doi:10.2307/j.ctv1v7zdq5.22. ISBN 978-0-8165-2450-1. JSTOR j.ctv1v7zdq5.22.