49777 Cappi

49777 Cappi (provisional designation 1999 XS) is a stony background asteroid from the inner regions of the asteroid belt, approximately 2 kilometers in diameter.

49777 Cappi

Discovery[1]
Discovered by	P. G. Comba
Discovery site	Prescott Obs.
Discovery date	2 December 1999
Designations
MPC designation	(49777) Cappi
Named after	Margaret Comba (discoverer's wife)[2]
Alternative designations	1999 XS · 2001 KD31
Minor planet category	main-belt · (inner)[3] background[4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	24.96 yr (9,115 days)
Aphelion	2.5138 AU
Perihelion	2.1982 AU
Semi-major axis	2.3560 AU
Eccentricity	0.0670
Orbital period (sidereal)	3.62 yr (1,321 days)
Mean anomaly	183.85°
Mean motion	0° 16m 21s / day
Inclination	4.4688°
Longitude of ascending node	237.61°
Argument of perihelion	341.93°
Physical characteristics
Mean diameter	1.85 km (calculated)[3]
Synodic rotation period	5.9389±0.0018 h[5]
Geometric albedo	0.20 (assumed)[3]
Spectral type	S (assumed)[3]
Absolute magnitude (H)	15.6[1] · 15.92±0.23[6] · 15.575±0.010 (R)[5] · 16.02[3]

The asteroid was discovered on 2 December 1999, by Italian–American astronomer Paul Comba at the Prescott Observatory in Arizona, United States.^[7] It was named after the discoverer's wife, Margaret Capitola Sonntag Comba.^[2]

Orbit and classification

Cappi is a non-family from the main belt's background population.^[4] It orbits the Sun in the inner asteroid belt at a distance of 2.2–2.5 AU once every 3 years and 7 months (1,321 days; semi-major axis of 2.36 AU). Its orbit has an eccentricity of 0.07 and an inclination of 4° with respect to the ecliptic.^[1]

The asteroid's observation arc begins 8 years prior to its official discovery observation, with a precovery taken by the Steward Observatory's Spacewatch survey at Kitt Peak in September 1991.^[7]

Physical characteristics

Cappi is an assumed stony S-type asteroid.^[3]

Rotation and shape

In September 2013, a rotational lightcurve of Cappi was obtained from photometric observation taken in the R-band at the Palomar Transient Factory in California. It showed a rotation period of 5.9389 hours with a brightness amplitude of 0.78 magnitude (U=2), indicating a non-spheroidal shape.^[5]

Diameter and albedo estimate

The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 1.85 kilometers with an absolute magnitude of 16.02.^[3]

Naming

This minor planet was named after Margaret Capitola Sonntag Comba (born 1940), a psychologist and art therapist by profession, faculty member at Prescott College, and wife of the discoverer.^[7] The approved naming citation was published by the Minor Planet Center on 4 May 2004 (M.P.C. 51981).^[8]