1563 Noël

1563 Noël, provisional designation 1943 EG, is a stony Flora asteroid from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 7 March 1943, by Belgian astronomer Sylvain Arend at the Royal Observatory of Belgium in Uccle, and named after his son.^[2][6]

1563 Noël

Discovery[1]
Discovered by	S. Arend
Discovery site	Uccle Obs.
Discovery date	7 March 1943
Designations
MPC designation	(1563) Noël
Named after	Emanuel Arend (discoverer's son)[2]
Alternative designations	1943 EG · 1930 EF
Minor planet category	main-belt · Flora[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	87.06 yr (31,799 days)
Aphelion	2.3789 AU
Perihelion	2.0037 AU
Semi-major axis	2.1913 AU
Eccentricity	0.0856
Orbital period (sidereal)	3.24 yr (1,185 days)
Mean anomaly	347.57°
Mean motion	0° 18m 13.68s / day
Inclination	5.9829°
Longitude of ascending node	53.649°
Argument of perihelion	116.41°
Physical characteristics
Dimensions	7.23±0.51 km[4] 8.98 km (calculated)[3]
Synodic rotation period	3.5483±0.0003 h[a] 3.5486±0.0002 h[a] 3.5488±0.0001 h[a] 3.5495±0.0001 h[a] 3.550±0.002 h[5]
Geometric albedo	0.24 (assumed)[3] 0.370±0.051[4]
Spectral type	SMASS = Sa[1] · S[3]
Absolute magnitude (H)	12.4[1][3][4]

Orbit and classification

Noël is a member of the Flora family, one of the largest groups of stony asteroids in the main-belt. It orbits the Sun at a distance of 2.0–2.4 AU once every 3 years and 3 months (1,185 days). Its orbit has an eccentricity of 0.09 and an inclination of 6° with respect to the ecliptic.^[1] Noël was first identified as 1930 EF at the Crimean Simeiz Observatory in 1930, extending its observation arc by 13 years prior to its official discovery observation.^[6]

Physical characteristics

The S-type asteroid is characterized as a transitional Sa-subtype on the SMASS taxonomic scheme.^[1]

Rotation period

Between April 2008 and June 2015, five rotational lightcurves were obtained from photometric observations by Czech astronomer Petr Pravec at the Ondřejov Observatory near Prague. All lightcurves show a well-defined rotation period between 3.548 and 3.550 hours with a brightness variation of 0.15 to 0.18 in magnitude (U=3).^[a]

In April 2008, a photometric observation by astronomer Julian Oey at the Kingsgrove Observatory, Australia, gave a concurring period of 3.550±0.002 hours and an amplitude of 0.14 (U=3).^[5]

Diameter and albedo

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Noël measures 7.2 kilometers in diameter and its surface has a high albedo of 0.37,^[4] while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the family's principal body and namesake – and calculates a larger diameter of 9.0 kilometers.^[3]

Naming

This minor planet was named in honor of the discoverer's son, Emanuel Arend (H 138).^[2]

Notes

1. Pravec (2008, 2011, 2013, 2015) web: rotation period of 3.5495±0.0001, 3.5483±0.0003, 3.5488±0.0001 and 3.5486±0.0002 hours with a brightness amplitude of 0.15 mag. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (1563) Noel and Pravec, P.; Wolf, M.; Sarounova, L. (2011, 2013, 2015)