3905 Doppler
Stony binary asteroid from the central main belt.
3905 Doppler (provisional designation 1984 QO) is a stony asteroid and binary system located in the central main belt, with a diameter of roughly 8 kilometers. Czech astronomer Antonín Mrkos discovered it on 28 August 1984 at Kleť Observatory, and it was later named for physicist Christian Doppler.
The asteroid follows an orbit around the Sun at distances between 1.9 and 3.2 AU, completing one revolution every 4 years and 1 month (1,496 days). Its orbit has an eccentricity of 0.26 and an inclination of 14° relative to the ecliptic. Classified as a common S-type asteroid, Doppler is also a binary system: a minor-planet moon was detected in 2013, orbiting the primary every 50.8 hours (2 days, 2 hours, and 48 minutes). This orbital period is notably long for a moon of an asteroid of this size, and it matches the primary’s rotation period, indicating an F-type binary.
Measurements from NASA’s Wide-field Infrared Survey Explorer (NEOWISE mission) give Doppler a diameter of 8.021 kilometers and a surface albedo of 0.228. In contrast, the Collaborative Asteroid Lightcurve Link assumes a standard albedo of 0.20 for stony asteroids, yielding a diameter of 8.97 kilometers based on an absolute magnitude of 12.6.
The asteroid was named for Christian Doppler (1803–1853), the Austrian physicist in Vienna who first described the Doppler effect in his 1842 book *Ueber das farbige Licht der Doppelsterne*. Jana Tichá and M. Šolc proposed the name, and the Minor Planet Center published the approved citation on 28 August 1996 (M.P.C. 27734).
Quick Facts
- Minorplanet
- yes
- Background
- #D6D6D6
- Discovered
- 28 August 1984
- Discoverer
- A. Mrkos
- Discovery Site
- Kleť Obs.
- Mpc Name
- (3905) Doppler
- Pronounced
- ˈ · d · ɒ · p · l · ər
- Named After
- Christian Doppler / (Austrian physicist)
- Mp Category
- main-belt
- Epoch
- 4 September 2017 (JD 2458000.5)
- Uncertainty
- 0
- Observation Arc
- 35.81 yr (13,078 days)
Facts from the source article.
Lore & Background
3905 Doppler orbits the Sun in the central main-belt at a distance of 1.9–3.2 AU once every 4 years and 1 month (1,496 days). Its orbit has an eccentricity of 0.26 and an inclination of 14° with respect to the ecliptic. It has been characterized as a common S-type asteroid. A minor-planet moon orbiting Doppler every 50.8 hours (or 2 days, 2 hours, and 48 minutes) was found orbiting the asteroid in 2013. This is fairly long orbital period for a moon of an asteroid of this size. The satellite's orbital period is identical to the primary's rotation period (F-type binary). According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Doppler measures 8.021 kilometers in diameter and its surface has an albedo of 0.228, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 8.97 kilometers with an absolute magnitude of 12.6.
Reader's Guide
3905 Doppler is notable as a binary asteroid system discovered in the central main belt, with a satellite that has an orbital period identical to the primary's rotation period, classifying it as an F-type binary. This synchrony is relatively rare among asteroid moons. The asteroid's diameter is given with two values depending on the measurement method: 8.021 kilometers from NEOWISE data and 8.97 kilometers from an assumed albedo of 0.20, reflecting typical uncertainties in asteroid size estimation. Its naming honors Christian Doppler, the Austrian physicist famous for the Doppler effect, which he described in 1842. The naming was proposed by Jana Tichá and M. Šolc, and the citation was published by the Minor Planet Center on 28 August 1996. The asteroid's discovery by Antonín Mrkos at Kleť Observatory adds to the catalog of main-belt objects studied for their physical and orbital properties.
Did You Know?
- 3905 Doppler was discovered on 28 August 1984 by Czech astronomer Antonín Mrkos at Kleť Observatory.
- It has a minor-planet moon discovered in 2013 that orbits every 50.8 hours, identical to the asteroid's rotation period.
- The asteroid's diameter is estimated at 8.021 kilometers by NEOWISE or 8.97 kilometers using an assumed albedo of 0.20.
- It was named after physicist Christian Doppler, known for the Doppler effect, with the naming citation published on 28 August 1996.
More in Notable Asteroids, Part 2 1-24
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced