2061 Anza

2061 Anza, provisional designation 1960 UA, is an eccentric asteroid of the Amor group, a subtype of near-Earth objects, estimated to measure approximately 2.7 kilometers in diameter. It was discovered on 22 October 1960, by American astronomer Henry Giclas at Lowell's Flagstaff Observatory in Arizona, United States.[6] The asteroid was later named after Spanish explorer Juan Bautista de Anza.[2]

2061 Anza
Discovery [1]
Discovered byH. L. Giclas
Discovery siteFlagstaff (LO)
Discovery date22 October 1960
Designations
(2061) Anza
Named after
Juan Bautista de Anza
(Governor of Nuevo México)[2]
1960 UA
Amor · NEO [1]
Mars-crosser
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc56.56 yr (20,659 days)
Aphelion3.4824 AU
Perihelion1.0527 AU
2.2675 AU
Eccentricity0.5358
3.41 yr (1,247 days)
251.57°
0° 17m 19.32s / day
Inclination3.7970°
207.41°
156.95°
Earth MOID0.0570 AU · 22.2 LD
Physical characteristics
Dimensions2.6 km[3]
2.71 km (calculated)[4]
11.50 h[5]
0.057 (assumed)[4]
Tholen = TCG: [1][3][4]
B–V = 0.825[1]
U–B = 0.350[1]
16.56[1][3][4]

    Classification and orbit

    Anza is an Amor asteroid – a subgroup of near-Earth asteroids that approach the orbit of Earth from beyond, but do not cross it. Orbiting the Sun at a distance of 1.1–3.5 AU once every 3 years and 5 months (1,247 days), its orbit has an eccentricity of 0.54 and an inclination of 4° with respect to the ecliptic.[1] Due to its high eccentricity, Anza also classifies as a Mars-crosser. The body's observation arc begins with its official discovery observation.[6]

    Close approaches

    The asteroid has an Earth minimum orbit intersection distance (MOID) of 0.0570 AU (8,530,000 km) which correspond to 22.2 lunar distances. On 7 October 1960, it passed Earth at 0.0634 AU (9,480,000 km) and was tracked for a period of 3.5 months to determine a better orbit. It was not observed again until its next near-Earth approach of 1977.[6]

    Physical characteristics

    In the Tholen classification, Anza has a rare TCG: spectral type.[1]

    Lightcurves

    In the 1960s, a rotational lightcurve of Anza was obtained from photometric observations taken at the discovering observatory by Austrian astronomer Karl Rakos from Graz University Observatory (580). Lightcurve analysis gave a rotation period of 11.50 hours with a brightness amplitude of 0.3 magnitude (U=2).[5] No additional lightcurves have been obtained since.[4]

    Diameter and albedo

    According to Tom Gehrels publication in his book Hazards Due to Comets and Asteroids, Anza measures 2.6 kilometers in diameter,[1][3] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 2.71 kilometers based on an absolute magnitude of 16.56.[4]

    Naming

    This minor planet was named after Juan Bautista de Anza (1736–1788), Spanish explorer and Governor of Santa Fe de Nuevo México for the Spanish Empire in the 18th century, now the U.S state of New Mexico. He was born in Tucson, Arizona, then New Spain, and became the commander at the Spanish fortification Presidio San Ignacio de Tubac before he explored the first overland route from southern Arizona to California (Monterey).[2]

    The official naming citation was published by the Minor Planet Center on 1 August 1978 (M.P.C. 4420).[7]

    References
    1. "JPL Small-Body Database Browser: 2061 Anza (1960 UA)" (2017-05-15 last obs.). Jet Propulsion Laboratory. Retrieved 3 August 2017.
    2. Schmadel, Lutz D. (2007). "(2061) Anza". Dictionary of Minor Planet Names – (2061) Anza. Springer Berlin Heidelberg. p. 167. doi:10.1007/978-3-540-29925-7_2062. ISBN 978-3540002383.
    3. Tom Gehrels; Mildred Shapley Matthews; A. M. Schumann (1994). Hazards Due to Comets and Asteroids. University of Arizona Press. pp. 540–543. ISBN 978-0816515059.
    4. "LCDB Data for (2061) Anza". Asteroid Lightcurve Database (LCDB). Retrieved 3 August 2017.
    5. Rakos, Karl D. (December 1959). "Light variations of the fast moving minor planet : discovered on October 22, 1960, by H.L. Giclas". Bulletin of the Lowell Observatory. 5 (109): 28–29. Bibcode:1960LowOB...5...28R.
    6. "2061 Anza (1960 UA)". Minor Planet Center. Retrieved 3 August 2017.
    7. Schmadel, Lutz D. (2009). "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. Bibcode:2009dmpn.book.....S. doi:10.1007/978-3-642-01965-4. ISBN 978-3642019647.
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