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965 Angelica (prov. designation: A921 VB or 1921 KT), is a large background asteroid from the outer regions of the asteroid belt, approximately 60 kilometers (37 miles) in diameter. It was discovered on 4 November 1921, by astronomer Johannes F. Hartmann at the La Plata Astronomical Observatory in Argentina. The dark X-type asteroid (Xc) with a low T_Jupiter has a rotation period of 26.8 hours and is likely spherical in shape. It was named after the discoverer's wife, Angelica Hartmann.

Orbit and classification

Angelica is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. It orbits the Sun in the outer asteroid belt at a distance of 2.3–4.0 AU once every 5 years and 7 months (2,049 days; semi-major axis of 3.16 AU). Its orbit has an eccentricity of 0.28 and an inclination of 21° with respect to the ecliptic. Due to this relatively high inclination and eccentricity, Angelica has a Jupiter Tisserand's parameter just barely above 3, which is commonly used as the threshold to distinguish between the populations of asteroids and Jupiter-family comets. The body's observation arc begins at Heidelberg Observatory in December 1927, or six years after its official discovery observation at the La Plata Astronomical Observatory.

Naming

This minor planet was named after Angelica Hartmann, wife of German astronomer Johannes F. Hartmann, who discovered this asteroid. The naming was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 92).

Physical characteristics

In the Bus–Binzel SMASS classification, Angelica is a Xc subtype, that transitions from the X-types to the carbonaceous C-type asteroids.

Rotation period

During five nights in December 2017, a rotational lightcurve of Angelica was obtained from photometric observations by Tom Polakis at the Command Module Observatory (V02) in Tempe, Arizona. Lightcurve analysis gave a rotation period of 26.752±0.035 hours with a very low brightness variation of 0.08±0.01 magnitude (U=3−), which is indicative of regular, spherical shape.

Another observation from January 2018, by Brigitte Montminy and Katherine McDonald at Minnetonka High School, and Russell Durkee at the Shed of Science Observatory (H39) in Minnetonka, Minnesota, determined a concurring period of 26.63±0.03 hours with an amplitude of 0.12±0.02 magnitude (U=2+). Federico Manzini at the Sozzago Astronomical Station (A12) obtained the object's first lightcurve in December 2006, measuring a period of 17.772±0.007 hours and an amplitude 0.06±0.01 magnitude (U=2).

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), and the Japanese Akari satellite, Angelica measures 53.63±1.3, 60.857±0.198 and 64.11±0.74 kilometers in diameter, and its surface has an albedo of 0.0739±0.004, 0.058±0.007 and 0.052±0.002, respectively. Earlier published measurements by the WISE team gives larger mean diameter of 71.59±0.55 km and 76.741±0.994 km. The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0515 and a diameter of 53.39 km based on an absolute magnitude of 10.2.

References

1. ^ "965 Angelica (A921 VB)". Minor Planet Center. Retrieved 12 February 2020.
2. ^ Schmadel, Lutz D. (2007). "(965) Angelica". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 84. doi:10.1007/978-3-540-29925-7_966. ISBN 978-3-540-00238-3.
3. ^ "JPL Small-Body Database Browser: 965 Angelica (A921 VB)" (2019-08-17 last obs.). Jet Propulsion Laboratory. Retrieved 12 February 2020.
4. ^ "Asteroid 965 Angelica – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 12 February 2020.
5. ^ "Asteroid 965 Angelica". Small Bodies Data Ferret. Retrieved 12 February 2020.
6. ^ Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 12 February 2020.
7. ^ 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.
8. ^ 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. (online, AcuA catalog p. 153)
9. ^ "LCDB Data for (965) Angelica". Asteroid Lightcurve Database (LCDB). Retrieved 12 February 2020.
10. ^ Polakis, Tom (April 2018). "Lightcurve Analysis for Eleven Main-belt Asteroids" (PDF). The Minor Planet Bulletin. 45 (2): 199–203. Bibcode:2018MPBu...45..199P. ISSN 1052-8091. Archived from the original (PDF) on 12 February 2020. Retrieved 12 February 2020.
11. Montminy, Brigitte; McDonald, Katherine; Durkee, Russell I. (October 2018). "Five Lightcurves from the Shed of Science: 2017 November - 2018 April" (PDF). The Minor Planet Bulletin. 45 (4): 331–333. Bibcode:2018MPBu...45..331M. ISSN 1052-8091. Retrieved 12 February 2020.
12. Behrend, Raoul. "Asteroids and comets rotation curves – (965) Angelica". Geneva Observatory. Retrieved 12 February 2020.

External links

• Lightcurve Database Query (LCDB), at www.minorplanet.info
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Geneva Observatory, Raoul Behrend
• Discovery Circumstances: Numbered Minor Planets (1)-(5000) – Minor Planet Center
• 965 Angelica at AstDyS-2, Asteroids—Dynamic Site
  • Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info
• 965 Angelica at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters

• Minor planet object articles (numbered)
• Background asteroids
• Discoveries by Johannes Franz Hartmann
• Named minor planets
• Xc-type asteroids (SMASS)
• Astronomical objects discovered in 1921