2006 Polonskaya
Stony Flora asteroid with an asynchronous binary satellite.
2006 Polonskaya, originally designated 1973 SB3, is a stony asteroid from the inner main belt, about 5 kilometers across. It belongs to the Flora family, though some classification methods list it as a background object. Discovered on 22 September 1973 by Soviet astronomer Nikolai Chernykh at the Crimean Astrophysical Observatory, it was named for Ukrainian astronomer Elena Kazimirchak-Polonskaïa, known for her work on comet motion and orbital evolution. The asteroid orbits the Sun at distances between 1.9 and 2.8 AU, completing one orbit every 3 years and 7 months, with an eccentricity of 0.19 and an inclination of 5 degrees. Its observation arc extends back to April 1950, with a first recorded sighting at the Finnish Turku Observatory in 1941.
In November 2005, an international team of astronomers detected a satellite roughly 1 kilometer in diameter, making Polonskaya an asynchronous binary system. However, the moon has not been fully confirmed, and some lightcurve data suggest the system might actually be a triple asteroid. The primary body is a stony S-type asteroid with a high albedo, typical of the Flora family. Lightcurve observations between 2005 and 2010 yielded a rotation period of about 3.118 hours, with brightness variations of 0.10 to 0.18 magnitude. A later proposed period of 6.69 hours was retracted. Follow-up observations in September 2019 confirmed the 3.1181-hour rotation period. According to NEOWISE data, Polonskaya measures 4.625 kilometers in diameter with an albedo of 0.354, while revised calculations give a diameter of 4.80 kilometers and an albedo of 0.3498.
Quick Facts
- Minorplanet
- yes
- Background
- #D6D6D6
- Discoverer
- N. Chernykh
- Discovered
- 22 September 1973
- Discovery Site
- Crimean Astrophysical Obs.
- Mpc Name
- (2006) Polonskaya
- Named After
- Elena Polonskaïa / (Russian astronomer)
- Mp Category
- main-beltFlora
- Epoch
- 17 December 2020 (JD 2459200.5)
- Uncertainty
- 0
- Observation Arc
- 70.93 yr (25,909 d)
- Aphelion
- 2.7721 AU
Facts from the source article.
Lore & Background
2006 Polonskaya is a member of the Flora family, one of the largest collisional populations of stony asteroids, according to the synthetic hierarchical clustering method by Nesvorný. However, another HCM-analysis by Milani and Knežević classifies it as a background asteroid, as the Flora clan is not recognized in that analysis. It orbits the Sun in the inner main-belt at a distance of 1.9–2.8 AU once every 3 years and 7 months, with an eccentricity of 0.19 and an inclination of 5°.
The asteroid was first observed on 16 September 1941 at the Finnish Turku Observatory, and its observation arc begins in April 1950 at Palomar Mountain. It was named after Russian astronomer Elena Ivanovna Kazimirchak-Polonskaya, who researched the motion and orbital evolution of comets and was awarded the F. A. Bredikhin prize. The official naming citation was published on 1 September 1978.
In 2005, lightcurve observations indicated a small moon about 0.99 km in diameter, but the non-synchronously rotating binary still needs to be fully resolved to confirm the satellite. Alternatively, the presence of another body has been suggested, which would make it a triple asteroid. Polonskaya is considered a stony S-type asteroid with a typically high albedo due to its Flora family membership.
Reader's Guide
2006 Polonskaya is notable as an asynchronous binary system, with a satellite discovered in November 2005 by an international collaboration of astronomers. Its classification is disputed: it is either a member of the Flora family or a background asteroid, depending on the hierarchical clustering method used. The asteroid's physical characteristics are derived from multiple lightcurve observations between 2005 and 2010, yielding a consistent rotation period near 3.118 hours, though an alternative period of 6.69 hours was later retracted. Its diameter is measured at 4.625 km by NEOWISE, with a high albedo of 0.354, while revised WISE-data gives 4.80 km and an albedo of 0.3498. The satellite, about 0.99 km in diameter, remains unconfirmed as a binary system, with a triple-asteroid possibility also suggested. The naming honors Elena Kazimirchak-Polonskaya for her comet research. The asteroid's legacy lies in its unresolved binary nature and the ongoing need for further observations to confirm its satellite and clarify its classification.
Did You Know?
- Its one-kilometer-sized satellite was discovered in November 2005 by an international collaboration of astronomers.
- The asteroid is named after Ukrainian astronomer Elena Kazimirchak-Polonskaïa, who studied comet orbital evolution.
- It has a rotation period of 3.1181 ± 0.0005 hours, as measured in September 2019.
Frequently Asked Questions
What is 2006 Polonskaya?
It is a stony asteroid in the inner main belt, roughly five kilometers across, that is generally grouped with the Flora family (though some taxonomic schemes treat it as a background object). It was first catalogued under the provisional label 1973 SB3 before receiving its permanent name.
Who discovered 2006 Polonskaya and where?
Soviet astronomer Nikolai Chernykh first observed it on 22 September 1973 from the Crimean Astrophysical Observatory at Nauchnij on the Crimean peninsula.
Who is 2006 Polonskaya named after?
The asteroid honors Ukrainian astronomer Elena Kazimirchak-Polonskaïa, who was recognized for her research into the motion and orbital evolution of comets.
Does 2006 Polonskaya have a moon?
Yes, it hosts a small satellite roughly one kilometer in diameter, making the system an asynchronous binary. The satellite's orbital period does not match the primary's rotation period.
How does 2006 Polonskaya orbit the Sun?
It follows an elliptical path between about 1.9 and 2.8 astronomical units from the Sun, with an eccentricity near 0.1. One complete revolution takes roughly three years and seven months.
More in Notable Asteroids, Part 2 1-24
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