1126 Otero

1126 Otero, provisional designation 1929 AC, is a rare-type Florian asteroid from the inner regions of the asteroid belt, approximately 10 kilometers in diameter. It was discovered on 11 January 1929, by German astronomer Karl Reinmuth at Heidelberg Observatory in southwest Germany.^[8] It was named after Spanish courtesan Carolina Otero.^[2]

1126 Otero

A lightcurve-based 3D-model of Otero
Discovery[1]
Discovered by	K. Reinmuth
Discovery site	Heidelberg Obs.
Discovery date	11 January 1929
Designations
MPC designation	(1126) Otero
Named after	Carolina Otero (Spanish courtesan)[2]
Alternative designations	1929 AC · 1926 GD 1948 RN1 · 1949 YO
Minor planet category	main-belt · Flora[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc	90.71 yr (33,133 days)
Aphelion	2.6052 AU
Perihelion	1.9394 AU
Semi-major axis	2.2723 AU
Eccentricity	0.1465
Orbital period (sidereal)	3.43 yr (1,251 days)
Mean anomaly	291.09°
Mean motion	0° 17m 15.72s / day
Inclination	6.5045°
Longitude of ascending node	1.0892°
Argument of perihelion	136.08°
Physical characteristics
Dimensions	8.87±1.56 km[4] 10.974±0.892 km[5] 11.74 km (derived)[3]
Synodic rotation period	3.648±0.002 h[6] 3.64808±0.00014 h[a]
Geometric albedo	0.1994 (derived)[3] 0.37±0.13[4] 0.399±0.320[5]
Spectral type	SMASS = A[1] · A[3]
Absolute magnitude (H)	11.41[5] · 11.57±0.05 (R)[a] · 11.9[1] · 12.098±0.071[3][7] · 12.10[4]

Classification and orbit

Otero is a member of the Flora family, one of the largest families of stony asteroids in the main belt. It orbits the Sun in the inner main-belt at a distance of 1.9–2.6 AU once every 3 years and 5 months (1,251 days). Its orbit has an eccentricity of 0.15 and an inclination of 7° with respect to the ecliptic.^[1] It was first identified as 1926 GD at Uccle/Heidelberg in 1926, extending the asteroid's observation arc by 3 years prior to its official discovery at Heidelberg.^[8]

Physical parameters

In the SMASS classification, Otero is a rare A-type asteroid.^[1]

Lightcurves

Two rotational lightcurve of Otero were obtained from photometric observations by astronomers Petr Pravec and Robert Stepens in February 2008. Lightcurve analysis gave a concurring, well-defined rotation period of 3.648 hours with a brightness variation of 0.69 and 0.70 magnitude, respectively (U=3/3).^[6][a]

Diameter and albedo

According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Otero measures 8.87 and 10.974 kilometers in diameter and its surface has an albedo of 0.37 and 0.399, respectively.^[4][5] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.1994 and a diameter of 11.74 kilometers with an absolute magnitude of 12.098 from Petr Pravec's revised WISE-data.^[3][7]

Naming

This minor planet was named by the discoverer for Galician-born Spanish courtesan, dancer and actress Carolina Otero (1868–1965), who was also known as "La Belle Otero". During the Belle Époque, she was the most sought after woman in all of Europe and led an excessive life thanks to her numerous rich and famous lovers. The official naming citation was first published by the Astronomical Calculation Institute (RI 803).^[2]

Observations

Otero was observed by ESA's mission Hera from a distance of 2.8 millions km on May 11th 2025 as the spacecraft was heading toward Didymos^[9].

Hera observation of Otero on May 11th 2025.

Notes

1. Pravec (2008) web: lightcurve plot of (1126) Otero by Petr Pravec of the Ondrejov Asteroid Photometry Project, with rotation period 3.64808±0.00014 hours and a brightness amplitude of 0.69 mag. Summary figures at Collaborative Asteroid Lightcurve Link and Pravec, P.; Wolf, M.; Sarounova, L. (2008)