730 Athanasia

730 Athanasia (prov. designation: A912 GG or 1912 OK) is a background asteroid from the inner regions of the asteroid belt, approximately 4.5 kilometers (2.8 miles) in diameter. It was discovered by Austrian astronomer Johann Palisa at the Vienna Observatory on 10 April 1912.^[1] The presumed stony S-type asteroid has a rotation period of 5.7 hours and is likely very elongated in shape. It was named Athanasia, the Greek word for "immortality".^[3]

730 Athanasia

Discovery[1]
Discovered by	J. Palisa
Discovery site	Vienna Obs.
Discovery date	10 April 1912
Designations
MPC designation	(730) Athanasia
Pronunciation	/ˌæθəˈneɪʒiə/[2]
Named after	Immortality (from Greek)[3]
Alternative designations	A912 GG · 2016 FP6 1912 OK
Minor planet category	main-belt[1][4] · (inner) background[5][6][7]
Orbital characteristics[4]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc	108.05 yr (39,464 d)
Aphelion	2.6429 AU
Perihelion	1.8450 AU
Semi-major axis	2.2440 AU
Eccentricity	0.1778
Orbital period (sidereal)	3.36 yr (1,228 d)
Mean anomaly	52.393°
Mean motion	0° 17m 35.52s / day
Inclination	4.2348°
Longitude of ascending node	95.073°
Argument of perihelion	123.60°
Physical characteristics
Mean diameter	4.497±0.734 km[4][8]
Synodic rotation period	5.7348±0.0001 h[9][a]
Geometric albedo	0.289±0.123[4][8]
Spectral type	S (assumed)[10]
Absolute magnitude (H)	13.7[1][4] 13.90[8]

Orbit and classification

Located in the region of the Flora family (402),^[10] a giant asteroid family and the largest family of stony asteroids in the main-belt, Athanasia is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements.^[5][6][7] It orbits the Sun in the inner asteroid belt at a distance of 1.8–2.6 AU once every 3 years and 4 months (1,228 days; semi-major axis of 2.24 AU). Its orbit has an eccentricity of 0.18 and an inclination of 4° with respect to the ecliptic.^[4] The body's observation arc begins at Vienna Observatory on 15 April 1912, or five nights after its official discovery observation.^[1]

Naming

This minor planet was named by friends of the discoverer after the Greek word for immortality, "athanasia". Any reference to a person or occurrence is unknown. The naming was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 73).^[3]

Physical characteristics

Athanasia is an assumed, stony S-type asteroid.^[10]

Rotation period

In February 2016, a rotational lightcurve of Athanasia was obtained from photometric observations by Frederick Pilcher at the Organ Mesa Observatory (G50) in New Mexico, United States. Analysis gave a classically shaped, well-defined bimodal lightcurve with a rotation period of 5.7348±0.0001 hours and a very high brightness variation of 0.63±0.04 magnitude, indicative of a highly elongated shape (U=3).^[9][a] In May 2013, Pilcher already observed the object and reported an ambiguous period of 5.7345 or 8.6016 hours with an amplitude of 0.14 magnitude (U=2+).^[11][b]

Diameter and albedo

According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Athanasia measures (4.497±0.734) kilometers in diameter and its surface has a high albedo of (0.289±0.123).^[8] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a Florian asteroid of 0.24 and calculates a diameter of 4.94 kilometers based on an absolute magnitude of 13.7.^[10]

Notes

1. Lightcurve-plot of (730) Athanasia, by Frederick Pilcher at the Organ Mesa Observatory (2016). Rotation period of 5.7348 hours with a brightness amplitude of 0.63 mag. Quality code is 3. Summary figures at the LCDB and ALSC websites.
2. Lightcurve-plot of (730) Athanasia, by Frederick Pilcher at the Organ Mesa Observatory (2013). Rotation period of 5.7345 hours with a brightness amplitude of 0.14 mag. Quality code is 2+. Summary figures at the LCDB and ALSC websites.