152830 Dinkinesh
First flyby target of NASA's Lucy mission.
152830 Dinkinesh, originally designated 1999 VD57, is a binary asteroid in the main belt, roughly 740 meters across. It was first spotted on 4 November 1999 by the LINEAR survey in Socorro, New Mexico. The asteroid gained attention as the initial flyby target for NASA's Lucy mission, which came within 425 kilometers of it on 1 November 2023. During that encounter, Lucy revealed that Dinkinesh has a small contact-binary moon, named Selam, about 220 meters in diameter. So far, Dinkinesh is the smallest main-belt asteroid any spacecraft has visited, though some near-Earth asteroids are smaller.
The discovery observations were published by the Minor Planet Center on 23 November 1999, earning the provisional designation 1999 VD57. After being tracked by LINEAR and Spacewatch through mid-November 1999, the asteroid was lost for years. It was rediscovered by Spacewatch in April 2004, but those sightings were mistakenly linked to another asteroid, 2004 GZ43. Then, in February 2007, the NEAT survey at Palomar Observatory spotted it again, leading to another provisional designation, 2007 CB63. Gareth V. Williams of the MPC connected the 1999 and 2007 observations in March 2007, which allowed the MPC to find additional detections from 2001 to 2007 and extend the observation arc to over seven years. This led to the permanent number 152830 on 2 April 2007. Later, pre-discovery LINEAR data from October 1999 was identified, pushing the arc back another five years. In March 2007, the MPC corrected the 2004 misidentification, labeling those observations as 2004 HJ78, but it wasn't until February 2009 that Williams linked that object to Dinkinesh.
The name Dinkinesh comes from the Amharic word for the Lucy fossil, after which the Lucy mission is named. It means "you are wonderful"—"dinkʼi" meaning "wonderful" and "nesh" meaning "you are" (feminine). The asteroid was unnamed when chosen for the mission, so the Lucy team proposed the name, which the IAU approved on 6 February 2023.
Dinkinesh orbits the Sun in the inner main belt on an elliptical path, averaging 2.19 astronomical units from the Sun and completing an orbit every 3.24 years. Its eccentricity of 0.112 brings it as close as 1.95 AU at perihelion and as far as 2.44 AU at aphelion, with an orbital inclination of 2.1 degrees. It may belong to the Flora family of asteroids.
- Provisional designation
- 1999 VD57
- Discovery date
- 4 November 1999
- Discovery survey
- Lincoln Near-Earth Asteroid Research (LINEAR)
- Discovery location
- Socorro, New Mexico
- Diameter
- about 740 meters (2,400 feet)
- Flyby date
- 1 November 2023
- Flyby distance
- 425 km (264 mi)
- Satellite name
- Selam
- Satellite diameter
- 220 meters (720 ft)
Lore & Background
Dinkinesh was discovered on 4 November 1999 by the LINEAR survey. After initial observations, the asteroid became lost and was reobserved multiple times under different provisional designations, including 2007 CB63. Gareth V. Williams of the Minor Planet Center linked these observations, enabling the asteroid to receive its permanent number 152830 on 2 April 2007. The name Dinkinesh, meaning 'you are wonderful' in Amharic, was proposed by the Lucy mission team and approved on 6 February 2023.
Dinkinesh orbits the Sun in the inner main asteroid belt with an average distance of 2.19 AU and an orbital period of 3.24 years. It is possibly a member of the Flora family. Visible light spectroscopy in 2022 showed it is an S-type asteroid, mainly composed of rocky silicates. Its rotation period is 3.7387 hours. During the Lucy flyby on 1 November 2023, the spacecraft discovered that Dinkinesh has a contact-binary natural satellite named Selam, about 220 meters in diameter. Dinkinesh is thought to have a rubble pile structure, similar to near-Earth asteroids Bennu and Ryugu.
Reader's Guide
Dinkinesh's significance stems from its role as the first flyby target of NASA's Lucy mission, which approached within 425 km on 1 November 2023. It is the smallest main-belt asteroid explored by spacecraft, though some smaller near-Earth asteroids have also been explored. The flyby revealed Dinkinesh to be a binary system with a contact-binary satellite, Selam—the first known contact-binary satellite of an asteroid. This discovery allows scientists to compare binary asteroid systems in different environments, as the Dinkinesh system resembles the near-Earth binary 65803 Didymos in size and composition but differs in distance from the Sun. The asteroid's name, borrowed from the Amharic name for the Lucy fossil, ties it directly to the mission's theme. Its surface composition and shape suggest it is an old, rubble-pile asteroid with an equatorial ridge, indicating past mass shedding. The Lucy spacecraft's observations also resolved earlier discrepancies in spectral data, which may indicate compositional variations across Dinkinesh's surface.
Did You Know?
- Dinkinesh is the smallest main-belt asteroid explored by spacecraft as of the article's writing.
- Its satellite Selam is a contact binary, the first known contact-binary satellite of an asteroid.
- The name Dinkinesh means 'you are wonderful' in the Amharic language.
- Dinkinesh was discovered by the LINEAR survey on 4 November 1999 and later became lost for several years.
Frequently Asked Questions
What is 152830 Dinkinesh?
Dinkinesh is a binary asteroid located in the main asteroid belt, measuring roughly 740 meters (about 2,400 feet) in diameter. It was originally catalogued under the provisional designation 1999 VD57 before receiving its permanent name.
Who discovered 152830 Dinkinesh and when?
The asteroid was first detected on 4 November 1999 by the Lincoln Near-Earth Asteroid Research (LINEAR) survey, operating out of Socorro, New Mexico.
What happened during NASA's Lucy flyby of Dinkinesh?
On 1 November 2023, the Lucy spacecraft made its first flyby of the asteroid, passing within roughly 425 kilometers of its surface. The encounter confirmed that Dinkinesh is a contact-binary system with a smaller companion orbiting it.
What is Selam, the moon of Dinkinesh?
Selam is a small contact-binary moon approximately 220 meters across that orbits Dinkinesh. It was identified during the November 2023 Lucy flyby, making it one of the smallest natural satellites ever characterized up close by a spacecraft.
Why is 152830 Dinkinesh considered notable among asteroids?
Dinkinesh holds the distinction of being the smallest main-belt asteroid that any spacecraft has visited to date. While a few near-Earth asteroids are smaller, none in the main belt had been flown past by a probe before Lucy's 2023 encounter.
More in Notable Asteroids 1-24
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