3581 Alvarez

3581 Alvarez, provisional designation 1985 HC, is a carbonaceous asteroid and a very large Mars-crosser on an eccentric orbit from the asteroid belt, approximately 13.7 kilometers (8.5 miles) in diameter. It was discovered on 23 April 1985, by American astronomer couple Carolyn and Eugene Shoemaker at the Palomar Observatory in California.[1] The likely spherical B-type asteroid has a rotation period of 33.4 hours.[3] It was named for scientists Luis Alvarez and his son Walter Alvarez.[1]

3581 Alvarez
Discovery [1]
Discovered byC. Shoemaker
E. Shoemaker
Discovery sitePalomar Obs.
Discovery date23 April 1985
Designations
(3581) Alvarez
Named after
Luis Alvarez
Walter Alvarez
(American scientists)[1]
1985 HC · 1962 JL
1971 KE · 1981 TG4
Mars crosser [1][2][3]
Orbital characteristics [2]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 0
Observation arc56.37 yr (20,590 d)
Aphelion3.9009 AU
Perihelion1.6506 AU
2.7757 AU
Eccentricity0.4053
4.62 yr (1,689 d)
79.224°
0° 12m 47.16s / day
Inclination28.858°
217.47°
107.59°
Mars MOID0.5301 AU
TJupiter3.0440
Physical characteristics
Mean diameter
13.69±1.37 km[4]
33.42±0.02 h[5][lower-alpha 1]
0.113[4]
SMASS = B [2][6][7]
12.10[8][6]
12.2[1][2]
12.30[4]
12.4[3][9][10]

    Orbit and classification

    Alvarez is a Mars-crossing asteroid, a dynamically unstable group between the main belt and the near-Earth populations, crossing the orbit of Mars at 1.66 AU.[1][2] However, due to the high inclination of its orbit, it never actually passes through the orbit of Mars since at perihelion it is well away from Mars' orbital plane.[11] It orbits the Sun at a distance of 1.7–3.9 AU once every 4 years and 7 months (1,689 days; semi-major axis of 2.78 AU). Its orbit has an eccentricity of 0.41 and an inclination of 29° with respect to the ecliptic.[2] The body's observation arc begins with its first observation as 1962 JL at Goethe Link Observatory in May 1962, almost 23 years prior to its official discovery observation at Palomar.[1]

    Naming

    This minor planet was named after planetary scientist Walter Alvarez (born 1940) and his Nobel-prize winning father, physicist Luis Walter Alvarez (1911–1988).[1] Both at University of California, Berkeley, they are best known for the discovery of a global geochemical anomaly of noble metals at the K-T boundary, which led to hypothesis that the dinosaurs were killed by an asteroid impact (also see Alvarez hypothesis). The official naming citation was published by the Minor Planet Center on 2 February 1988 (M.P.C. 12807),[12] just a few months after the naming was announcement on the occasion of the second Conference on Global Catastrophes in Earth History, held in October 1987 at Snowbird, Utah.[13]

    Physical characteristics

    In the SMASS classification, Alvarez is a carbonaceous B-type asteroid, somewhat "brighter" than the more common C-type asteroids.[2]

    Rotation period

    In September 2004, a rotational lightcurve of Alvarez was obtained from photometric observations by American photometrist William Koff at the Antelope Hills Observatory (H09) in Bennett, Colorado. Lightcurve analysis gave a longer-than-average rotation period of 33.42±0.02 hours with a small brightness amplitude of 0.06±0.02 magnitude (U=2), indicative of a spherical rather than elongated shape.[5][lower-alpha 1] The result supersedes a previous period determination by Wiesław Wiśniewski from 1990, which gave a period of at least 24 hours (U=1).[10]

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Alvarez measures 13.69 kilometers in diameter and its surface has an albedo of 0.113.[4] Previously published WISE data from 2013 and 2016 gave a concurring diameter of 14 and 13.7 kilometer with an albedo of 0.14 and 0.13, respectively.[8][6] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.057 and derives a diameter of 18.43 kilometers based on an absolute magnitude of 12.4.[3]

    With a diameter close to 14 kilometers, Alvarez is larger than most sizeable Mars-crossing asteroids such as 1065 Amundsenia (9.75 km), 1139 Atami (9.35 km), 1011 Laodamia (7.39 km), 1727 Mette (5.44 km), 1131 Porzia (7.13 km), 1235 Schorria (5.55 km), 985 Rosina (8.18 km) and 1468 Zomba (7 km), comparable with 1310 Villigera (15.24 km) and 1474 Beira (15.46 km), but still smaller than the largest members of this dynamical group, namely, 132 Aethra, 323 Brucia (former Mars-crosser), 1508 Kemi, 2204 Lyyli and 512 Taurinensis, which are larger than 20 kilometers in diameter in at least one of the publications.

    Notes
    1. Lightcurve plot of (3581) Alvarez, Antelope Hills Observatory (H09) rotation period 33.42±0.02 hours with a brightness amplitude of 0.06±0.02 mag. Quality code is. Summary figures for (3581) Alvarez at the LCDB

    References
    1. "3581 Alvarez (1985 HC)". Minor Planet Center. Retrieved 23 October 2018.
    2. "JPL Small-Body Database Browser: 3581 Alvarez (1985 HC)" (2018-09-18 last obs.). Jet Propulsion Laboratory. Retrieved 23 October 2018.
    3. "LCDB Data for (3581) Alvarez". Asteroid Lightcurve Database (LCDB). Retrieved 23 October 2018.
    4. 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.
    5. Koff, Robert A. (June 2005). "Lightcurve photometry of asteroids 212 Medea, 517 Edith, 3581 Alvarez 5682 Beresford, and 5817 Robertfrazer". The Minor Planet Bulletin. 32 (2): 32–34. Bibcode:2005MPBu...32...32K. ISSN 1052-8091.
    6. Alí-Lagoa, V.; de León, J.; Licandro, J.; Delbó, M.; Campins, H.; Pinilla-Alonso, N.; et al. (June 2013). "Physical properties of B-type asteroids from WISE data". Astronomy and Astrophysics. 554: 16. arXiv:1303.5487. Bibcode:2013A&A...554A..71A. doi:10.1051/0004-6361/201220680.
    7. "Asteroid 3581 Alvarez". Small Bodies Data Ferret. Retrieved 23 October 2018.
    8. Alí-Lagoa, V.; Licandro, J.; Gil-Hutton, R.; Cañ; ada-Assandri, M.; Delbo', M.; et al. (June 2016). "Differences between the Pallas collisional family and similarly sized B-type asteroids". Astronomy and Astrophysics. 591: 11. Bibcode:2016A&A...591A..14A. doi:10.1051/0004-6361/201527660.
    9. 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.
    10. Wisniewski, W. Z.; Michalowski, T. M.; Harris, A. W.; McMillan, R. S. (April 1997). "Photometric Observations of 125 Asteroids". Icarus. 126 (2): 395–449. Bibcode:1997Icar..126..395W. doi:10.1006/icar.1996.5665.
    11. de Leon, Julia; Campins, H.; Tsiganis, K.; Morbidelli, A.; Licandro, J. (October 2010). "Origin Of The Near-earth Asteroid Phaethon And The Geminids Meteor Shower". American Astronomical Society. 42: 1058. Bibcode:2010DPS....42.1327D.
    12. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 23 October 2018.
    13. Glen, William (December 1987). "Alvarez receives Astral Tribute". Eos. 69 (52): 1688. Bibcode:1988EOSTr..69.1688G. doi:10.1029/88EO01266.

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