1647 Menelaus (// men-ə-LAY-əs), provisional designation 1957 MK, is a mid-sized Jupiter trojan from the Greek camp, approximately 42 kilometers (26 miles) in diameter. It was discovered on 23 June 1957 by American astronomer Seth Nicholson at the Palomar Observatory in California, and later named after the Spartan King Menelaus from Greek mythology. The dark asteroid has a rotation period of 17.7 hours. It is the principle body of the proposed Menelaus cluster, which encompasses several, mostly tentative Jovian asteroid families.
|Discovered by||S. B. Nicholson|
|Discovery site||Palomar Obs.|
|Discovery date||23 June 1957|
|MPC designation||(1647) Menelaus|
|Jupiter trojan |
Greek  · background 
|Orbital characteristics |
|Epoch 23 March 2018 (JD 2458200.5)|
|Uncertainty parameter 0|
|Observation arc||65.57 yr (23,949 d)|
|11.90 yr (4,347 d)|
|0° 4m 58.08s / day|
|Jupiter MOID||0.1563 AU|
V–R = 0.428±0.043
V–I = 0.866±0.043
Orbit and classificationEdit
Menelaus is a dark Jovian asteroid in a 1:1 orbital resonance with Jupiter. It is located in the leading Greek camp at the Gas Giant's L4 Lagrangian point, 60° ahead on its orbit . Since the discovery of the first Jupiter trojan, 588 Achilles, by astronomer Max Wolf in 1906, more than 7000 Jovian asteroids have already been discovered.
It orbits the Sun at a distance of 5.1–5.3 AU once every 11 years and 11 months (4,347 days; semi-major axis of 5.21 AU). Its orbit has an eccentricity of 0.02 and an inclination of 6° with respect to the ecliptic. Menelaus was first imaged at Palomar in November 1951. This precovery extends the body's observation arc by more than 5 years prior to its official discovery observation.
In 1993, Andrea Milani suggested that Menelaus might be the parent body of an asteroid family based on a modified HCM-analysis.:78 The finding was also mentioned by David Jewitt in 2004,:12 who noted that the Menelaus family is the largest proposed dynamical family to exist among the Jupiter trojans, despite having only 8 members.[a]
In 2008, Fernando Roig and Ricardo Gil-Hutton described this particular aggregation of Jupiter trojans as the "Menelaus clan", which, similar to the Flora family in the inner asteroid belt, is composed of several families (or subfamilies).:9 In this publication, the Menelaus clan encompasses a dozen clusters, if the separation criteria used in the HCM analysis are sufficiently relaxed. The principal bodies of these proposed family-like clusters include: 1647 Menelaus, 3548 Eurybates, 1749 Telamon, 12973 Melanthios, 13062 Podarkes, 5436 Eumelos, 2148 Epeios, 4007 Euryalos, 4138 Kalchas, 3063 Makhaon and others.:10
With the exception of the Eurybates family, which was studies in more detail by Jakub Rozehnal and Miroslav Brož in 2011 (also see 3548 Eurybates § Eurybates family), all other proposed families with their principal bodies in the Menelaus clan, including Menelaus itself, are tentative and not listed neither on the Asteroids—Dynamic Site (Milani and Knežević), nor included in the robust HCM-analysis by Nesvorný (also see Asteroid family § All families).:23 Instead, these bodies are considered non-family asteroids of the Jovian background population.
This minor planet was named after the Greek mythological figure, Menelaus, husband of Helen of Troy, brother of Agamemnon, and king and leader of the Spartan contingent of the Greek army during the Trojan War. The discoverer followed the convention to name bodies located in the camp to the east of Jupiter after famous Greek heroes.
The Dictionary of Minor Planet Names also mentions that the lunar crater Menelaus was named after the Greek hero. However, based on the official International Astronomical Union–WGPSN nomenclature, it is named after Greek geometer and astronomer Menelaus of Alexandria (70–140). The official naming citation was published by the Minor Planet Center in June 1960 (M.P.C. 2019).
The Palomar Transient Factory in California obtained a rotational lightcurve of Menelaus from photometric observation in the R-band in October 2010. It gave a rotation period of 17.7390 hours with a brightness variation of 0.32 magnitude in the R-band (U=2). In February 2014, a refined period of 17.74±0.01 hours with an amplitude of 0.15 magnitude was determined by American astronomer Robert D. Stephens at the Center for Solar System Studies (U=3-).[b]
Diameter and albedoEdit
According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Menelaus measures 42.72 kilometers in diameter and its surface has an albedo of 0.056. The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 44.22 kilometers using an absolute magnitude of 10.5.
- Members of the Menelaus cluster identified by Milani in 1993 are 1749 Telamon, 3548 Eurybates, (6053) 1993 BW3, 6076 Plavec, (6002) 1988 RO, 6051 Anaximenes and 6006 Anaximandros, some of which are main-belt or Amor asteroids (Milani 1993, p. 94). Besides the Menelaus family, Milani found four other potential families in the Greek camp, clustered around the Jovian asteroids 1437 Diomedes, 2456 Palamedes, 2797 Teucer and (4035) 1986 WD, as well as the asteroid pair 1583 Antilochus—3801 Thrasymedes.
- Lightcurve plots of (1647) Menelaus from Jan–Feb 2014 by Robert Stephens at the Center for Solar System Studies (U81). Quality code is 3- (lightcurve rating at CS3). Summary figures at the LCDB and CS3.
- "1647 Menelaus (1957 MK)". Minor Planet Center. Retrieved 22 June 2018.
- Schmadel, Lutz D. (2007). "(1647) Menelaus". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 131. doi:10.1007/978-3-540-29925-7_1648. ISBN 978-3-540-00238-3.
- "JPL Small-Body Database Browser: 1647 Menelaus (1957 MK)" (2017-06-03 last obs.). Jet Propulsion Laboratory. Retrieved 22 June 2018.
- "List of Jupiter Trojans". Minor Planet Center. 1 June 2018. Retrieved 22 June 2018.
- "Asteroid (1647) Menelaus – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 22 June 2018.
- Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R. (November 2012). "WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy". The Astrophysical Journal. 759 (1): 10. arXiv:1209.1549. Bibcode:2012ApJ...759...49G. doi:10.1088/0004-637X/759/1/49. Retrieved 22 June 2018. (Grav (2012) Grav (2011))
- Stephens, Robert D.; Coley, Daniel R.; Warner, Brian D.; French, Linda, M. (October 2016). "Lightcurves of Jovian Trojan Asteroids from the Center for Solar System Studies: L4 Greek Camp and Spies". The Minor Planet Bulletin. 43 (4): 323–331. Bibcode:2016MPBu...43..323S. ISSN 1052-8091. Retrieved 22 June 2018.
- "LCDB Data for (1647) Menelaus". Asteroid Lightcurve Database (LCDB). Retrieved 27 December 2016.
- Hainaut, O. R.; Boehnhardt, H.; Protopapa, S. (October 2012). "Colours of minor bodies in the outer solar system. II. A statistical analysis revisited". Astronomy and Astrophysics. 546: 20. arXiv:1209.1896. Bibcode:2012A&A...546A.115H. doi:10.1051/0004-6361/201219566.
- Milani, Andrea (October 1993). "The Trojan asteroid belt: Proper elements, stability, chaos and families". Celestial Mechanics and Dynamical Astronomy. 57 (1–2): 59–94. Bibcode:1993CeMDA..57...59M. doi:10.1007/BF00692462. ISSN 0923-2958. Retrieved 13 April 2017.
- Jewitt, David C.; Sheppard, Scott; Porco, Carolyn (2004). "Jupiter's Outer Satellites and Trojans – 12.4.2 Families" (PDF). In Bagenal, F.; Dowling, T.E.; McKinnon, W.B. (eds.). Jupiter: The planet, Satellites and Magnetosphere. Cambridge University Press. p. 12. Retrieved 13 April 2017.
- Roig, F.; Ribeiro, A. O.; Gil-Hutton, R. (June 2008). "Taxonomy of asteroid families among the Jupiter Trojans: comparison between spectroscopic data and the Sloan Digital Sky Survey colors". Astronomy and Astrophysics. 483 (3): 911–931. arXiv:0712.0046. Bibcode:2008A&A...483..911R. doi:10.1051/0004-6361:20079177.
- Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). Identification and Dynamical Properties of Asteroid Families. Asteroids IV. pp. 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131.
- "Gazetteer of Planetary Nomenclature – Planetary Names: Crater, craters: Menelaus on Moon". International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN). Retrieved 27 December 2016.
- 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.
- Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75.
- Center for Solar System Studies, homepage
- Asteroid Lightcurve Database (LCDB), query form (info)
- Dictionary of Minor Planet Names, Google books
- Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
- Asteroid 1647 Menelaus at the Small Bodies Data Ferret
- 1647 Menelaus at AstDyS-2, Asteroids—Dynamic Site
- 1647 Menelaus at the JPL Small-Body Database