1580 Betulia

1580 Betulia

Lightcurve-based 3D-model of Betulia
Discovery[1]
Discovered by	E. L. Johnson
Discovery site	Johannesburg Obs.
Discovery date	22 May 1950
Designations
MPC designation	(1580) Betulia
Pronunciation	/bɛˈtjuːliə/
Named after	Betulia Toro Herrick (wife of astronomer S. Herrick)[2]
Alternative designations	1950 KA
Minor planet category	NEO · Amor[1][3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	66.64 yr (24,342 days)
Aphelion	3.2684 AU
Perihelion	1.1258 AU
Semi-major axis	2.1971 AU
Eccentricity	0.4876
Orbital period (sidereal)	3.26 yr (1,190 days)
Mean anomaly	252.41°
Mean motion	0° 18^m 9.36^s / day
Inclination	52.096°
Longitude of ascending node	62.291°
Argument of perihelion	159.50°
Earth MOID	0.1365 AU · 53.2 LD
Physical characteristics
Dimensions	3.82 km[4] 3.9 km[5] 4.2 km (CALL-LCDB)[6] 4.57 km[7] 5.37±0.04 km[8] 5.39±0.54 km[9] 5.8 km (Gehrels 1994)[1] 8.55±5.23 km[10]
Synodic rotation period	6.130 h[11] 6.1324±0.0002 h[12] 6.134 h[13] 6.135±0.005 h[14] 6.13836 h[9][15] 6.156 h[16] 6.48 h[17]
Geometric albedo	0.04±0.08[10] 0.05[18] 0.07±0.01[8] 0.077[7] 0.08 (Gehrels 1994)[1] 0.09 (CALL-LCDB)[6] 0.11[4] 0.17[5]
Spectral type	Tholen = C[1][6] · B[19] B–V = 0.656[1] U–B = 0.249[1]
Absolute magnitude (H)	14.00[19] · 14.5[10] · 14.53[7] · 14.58[5] · 14.8[1] · 14.8±0.3[12] · 14.90[8] · 15.1[4][6]

1580 Betulia, provisional designation 1950 KA, is an eccentric, carbonaceous asteroid, classified as near-Earth object of the Amor group, approximately 4.2 kilometers in diameter. It was discovered on 22 May 1950, by South African astronomer Ernest Johnson at the Union Observatory in Johannesburg.^[3] The asteroid was named for Betulia Toro, wife of astronomer Samuel Herrick.^[2]

Orbit and classification

Betulia orbits the Sun at a distance of 1.1–3.3 AU once every 3 years and 3 months (1,190 days). Its orbit has an eccentricity of 0.49 and an inclination of 52° with respect to the ecliptic.^[1] The body's observation arc begins with its official discovery observation at Johannesburg in 1950.^[3]

Close approaches

Betulia is a near-Earth asteroid with an Earth minimum orbital intersection distance of 0.1365 AU (20,400,000 km), which corresponds to 53.2 lunar distances.^[1] As an Amor asteroid, and contrary to the Apollo and Aten asteroids, it approaches Earth's orbit from beyond but does not cross it. Betulia is also a Mars-crosser due to its eccentric orbit.^[1]

Physical characteristics

In the Tholen classification, Betulia is an unusual C-type asteroid, as near-Earth objects are typically of stony rather than carbonaceous composition.^[1] Based on images taken by the Sloan Digital Sky Survey, the asteroid has also been characterized as a carbonaceous but "brighter" B-type asteroid.^[19]

Rotation period

Several rotational lightcurves of Betulia were obtained from photometric observations since the 1970s. Analysis of the best-rated lightcurve gave a rotation period of 6.1324 hours with a brightness variation of 0.70 magnitude (U=3), indicating that the body has a non-spheroidal shape.^[12] Other observations gave a period between 6.130 and 6.48 hours.^{[11][13][14][17]}

Poles

Photometric and radiometric observations of Betulia were also used to model the asteroid's lightcurve. It gave a concurring period of 6.13836 hours as well as a spin axis of (133.0°, 22.0°) and (136.0°, 22.0°) in ecliptic coordinates (λ, β), respectively.^[9][15] The results supersede previously determined rotational poles (also see LCDB summary).^[6][11][16]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Radar observations at the Arecibo Observatory in Puerto Rico, Tom Gehrels estimate from the Hazards due to Comets and Asteroids, and observations by Alan W. Harris using the NASA Infrared Telescope Facility on Mauna Kea, Hawaii, Betulia measures between 3.82 and 8.55 kilometers in diameter and its surface has an albedo between 0.04 and 0.17.^{[1][4][5][8][9][10][18]}

The Collaborative Asteroid Lightcurve Link takes an albedo of 0.09 and a diameter of 4.2 kilometers as best estimates and adopts an absolute magnitude of 15.1.^[6]

Naming

This minor planet was named after Betulia Toro Herrick, wife of Samuel Herrick (1911–1974), an American astronomer who specialized in celestial mechanics. Herrick had studied the asteroid's orbit, and requested the name, along with that of 1685 Toro.^[2][20] The official naming citation was published by the Minor Planet Center in May 1952 (M.P.C. 768).^[21]

Further reading

• Lebofsky, L. A.; Veeder, G. J.; Lebofsky, M. J.; Matson, D. L. (September 1978). "Visual and radiometric photometry of 1580 Betulia". Icarus. 35 (3): 336–343. Bibcode:1978Icar...35..336L. doi:10.1016/0019-1035(78)90086-6. Retrieved 12 September 2017.

References

1. "JPL Small-Body Database Browser: 1580 Betulia (1950 KA)" (2017-01-12 last obs.). Jet Propulsion Laboratory. Retrieved 12 September 2017.
2. Schmadel, Lutz D. (2007). "(1580) Betulia". Dictionary of Minor Planet Names – (1580) Betulia. Springer Berlin Heidelberg. p. 125. doi:10.1007/978-3-540-29925-7_1581. ISBN 978-3-540-00238-3.
3. "1580 Betulia (1950 KA)". Minor Planet Center. Retrieved 12 September 2017.
4. Harris, Alan W.; Mueller, Michael; Delbó, Marco; Bus, Schelte J. (December 2005). "The surface properties of small asteroids: Peculiar Betulia---A case study". Icarus. 179 (1): 95–108. Bibcode:2005Icar..179...95H. doi:10.1016/j.icarus.2005.05.010. Retrieved 12 September 2017.
5. Harris, Alan W. (February 1998). "A Thermal Model for Near-Earth Asteroids". Icarus. 131 (2): 291–301. Bibcode:1998Icar..131..291H. doi:10.1006/icar.1997.5865. Retrieved 12 September 2017.
6. "LCDB Data for (1580) Betulia". Asteroid Lightcurve Database (LCDB). Retrieved 12 September 2017.
7. "1580 Betulia". ERAN – European Asteroid Research Node. Archived from the original on 8 February 2012. Retrieved 12 September 2017.
8. Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63.
9. Magri, Christopher; Ostro, Steven J.; Scheeres, Daniel J.; Nolan, Michael C.; Giorgini, Jon D.; Benner, Lance A. M.; et al. (January 2007). "Radar observations and a physical model of Asteroid 1580 Betulia". Icarus. 186 (1): 152–177. Bibcode:2007Icar..186..152M. doi:10.1016/j.icarus.2006.08.004. Retrieved 12 September 2017.
10. Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. S2CID 9341381. Retrieved 12 September 2017.
11. Tedesco, E.; Drummond, J.; Candy, M.; Birch, P.; Nikoloff, I.; Zellner, B. (September 1978). "1580 Betulia - an unusual asteroid with an extraordinary lightcurve". Icarus. 35 (3): 344–359.NASA–supportedresearch. Bibcode:1978Icar...35..344T. doi:10.1016/0019-1035(78)90087-8. Retrieved 12 September 2017.
12. Wisniewski, W. Z.; Michalowski, T. M.; Harris, A. W.; McMillan, R. S. (March 1995). "Photoelectric Observations of 125 Asteroids". Abstracts of the Lunar and Planetary Science Conference. 26: 1511. Bibcode:1995LPI....26.1511W. Retrieved 12 September 2017.
13. Austin, Rodney R. D. (December 1976). "Asteroid 1580 Betulia during the 1976 opposition". South. Stars. 26: 228–230. Bibcode:1976SouSt..26..228A. Retrieved 12 September 2017.
14. Warner, Brian D. (October 2015). "Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 March-June". The Minor Planet Bulletin. 42 (4): 256–266. Bibcode:2015MPBu...42..256W. ISSN 1052-8091. PMC 7244091. PMID 32455361.
15. Kaasalainen, Mikko; Pravec, Petr; Krugly, Yurij N.; Sarounová, Lenka; Torppa, Johanna; Virtanen, Jenni; et al. (January 2004). "Photometry and models of eight near-Earth asteroids". Icarus. 167 (1): 178–196. Bibcode:2004Icar..167..178K. doi:10.1016/j.icarus.2003.09.012. Retrieved 12 September 2017.
16. Drummond, J. D.; Wisniewski, W. Z. (February 1990). "The rotational poles and shapes of 1580 Betulia and 3908 (1980PA) from one apparition". Icarus. 83 (2): 349–359. Bibcode:1990Icar...83..349D. doi:10.1016/0019-1035(90)90072-H. ISSN 0019-1035. Retrieved 12 September 2017.
17. Lagerkvist, Claes-Ingvar (October 1977). "A Photographic Lightcurve of the Amor Asteroid 1580 Betulia". Icarus. 32 (2): 233–234. Bibcode:1977Icar...32..233L. doi:10.1016/0019-1035(77)90063-X. Retrieved 12 September 2017.
18. Rivkin, A. S.; Binzel, R. P.; Bus, S. J. (May 2005). "Constraining near-Earth object albedos using near-infrared spectroscopy". Icarus. 175 (1): 175–180. Bibcode:2005Icar..175..175R. doi:10.1016/j.icarus.2004.11.005. Retrieved 12 September 2017.
19. Carry, B.; Solano, E.; Eggl, S.; DeMeo, F. E. (April 2016). "Spectral properties of near-Earth and Mars-crossing asteroids using Sloan photometry". Icarus. 268: 340–354. arXiv:1601.02087. Bibcode:2016Icar..268..340C. doi:10.1016/j.icarus.2015.12.047. S2CID 119258489. Retrieved 12 September 2017.
20. "Samuel Herrick (1911–1974), Engineering; Astronomy: Los Angeles". University of California. March 1976. p. 135. Retrieved 12 September 2017.
21. 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 978-3-642-01964-7.

External links

• IAUC 1268 - Initial discovery
• Asteroid Lightcurve Database (LCDB), query form (info Archived 16 December 2017 at the Wayback Machine)
• Dictionary of Minor Planet Names, Google books
• Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
• 1580 Betulia at NeoDyS-2, Near Earth Objects—Dynamic Site
  • Ephemerides · Observation prediction · Orbital info · MOID · Proper elements · Observational info · Close approaches · Physical info · Orbit animation
• 1580 Betulia at ESA–space situational awareness
  • Ephemerides · Observations · Orbit · Physical properties · Summary
• 1580 Betulia at the JPL Small-Body Database
  • Close approach · Discovery · Ephemeris · Orbit viewer · Orbit parameters · Physical parameters