4435 Holt
Stony Mars-crosser asteroid with a small moon.
4435 Holt (provisional designation 1983 AG2) is a stony asteroid from the inner main belt, roughly 5 kilometers across. It is a sizable Mars-crosser and a binary system. American astronomer Carolyn Shoemaker discovered it on 13 January 1983 at Palomar Observatory in California. The asteroid was later named for American astronomer Henry E. Holt. The discovery of its moon was announced in January 2018.
Holt orbits the Sun at a distance of 1.5–3.1 AU, completing one revolution every 3 years and 6 months (1,288 days). Its orbit has an eccentricity of 0.34 and an inclination of 22° relative to the ecliptic. A precovery image from Crimea-Nauchnij in 1978 extended the observation arc by five years before its official discovery.
The minor planet honors Henry E. Holt (born 1929), an American planetary geologist and astronomer at NAU and USGS. He studied the Moon’s surface, geology, and photometric properties during the Apollo and Surveyor programs. After retiring, Holt was a key participant in the Palomar Asteroid and Comet Survey (PACS) from 1983 to 1993. He discovered or co-discovered six comets and 683 minor planets between 1989 and 1993, including 4581 Asclepius, a potentially hazardous asteroid that made the closest approach to Earth of any numbered asteroid. The naming citation was published by the Minor Planet Center on 30 January 1991 (M.P.C. 17656).
In the SMASS classification, Holt is a common S-type (stony) asteroid. NASA’s WISE/NEOWISE survey measured its diameter at 5.03 kilometers with an albedo of 0.28. The Collaborative Asteroid Lightcurve Link assumes a standard stony albedo of 0.20 and derives a diameter of 6.44 kilometers from an absolute magnitude of 13.32.
A rotational lightcurve obtained by Robert Stephens and collaborators in November 2017 gave a rotation period of 2.8670 ± 0.0002 hours, with a brightness variation of 0.15 magnitude. The observations also revealed a moon roughly 2 kilometers in size, which orbits the primary every 42.6 hours (1.777 days).
Quick Facts
- Minorplanet
- yes
- Background
- #FA8072
- Discoverer
- C. Shoemaker
- Discovery Site
- Palomar Obs.
- Discovered
- 13 January 1983
- Mpc Name
- (4435) Holt
- Pronounced
- ' · h · ou · l · t
- Named After
- Henry E. Holt / (American astronomer)
- Mp Category
- Mars-crosser
- Epoch
- 4 September 2017 (JD 2458000.5)
- Uncertainty
- 0
- Observation Arc
- 37.89 yr (13,840 days)
Facts from the source article.
Lore & Background
4435 Holt orbits the Sun in the inner main-belt at a distance of 1.5–3.1 AU once every 3 years and 6 months (1,288 days). Its orbit has an eccentricity of 0.34 and an inclination of 22° with respect to the ecliptic. The first precovery was taken at Crimea-Nauchnij in 1978, extending the asteroid's observation arc by 5 years prior to its discovery. In the SMASS classification, Holt is a common S-type asteroid. According to the survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Holt measures 5.03 kilometers in diameter and its surface has an albedo of 0.28, while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and derives a diameter of 6.44 kilometer with an absolute magnitude of 13.32. In November 2017, a rotational lightcurve of Holt was obtained from photometric observation by Robert Stephens and collaborators. Lightcurve analysis gave a rotation period of 2.8670±0.0002 hours with a brightness variation of 0.15 magnitude. During the observations, the presence of an approximately 2-kilometer sized minor-planet moon was detected. The satellite orbits its primary every 42.6 hours (1.777 d). The discovery of its companion was announced in January 2018.
Reader's Guide
4435 Holt is significant as a binary asteroid system, with a moon approximately 2 kilometers in diameter discovered in 2017 and announced in January 2018. Its stony composition (S-type) and Mars-crossing orbit make it a member of the inner main-belt population. The asteroid was named for American planetary geologist and astronomer Henry E. Holt, who explored the Moon's surface during the Apollo and Surveyor programs and later co-discovered many minor planets and comets. The naming citation was published by the Minor Planet Center on 30 January 1991. The asteroid's physical characteristics include a rotation period of 2.8670 hours and a diameter of about 5 kilometers (NEOWISE) or 6.44 kilometers (assumed albedo). Its orbit has a high eccentricity of 0.34 and inclination of 22°, and it was discovered by Carolyn Shoemaker at Palomar Observatory. The binary nature adds to its scientific interest for studying asteroid satellite systems.
Did You Know?
- 4435 Holt was discovered on 13 January 1983 by American astronomer Carolyn Shoemaker at Palomar Observatory.
- It has a small moon about 2 kilometers in diameter, discovered in November 2017 and announced in January 2018.
- The asteroid's rotation period is 2.8670 ± 0.0002 hours.
- It was named after American planetary geologist Henry E. Holt, who participated in the Apollo and Surveyor programs.
Frequently Asked Questions
Who discovered 4435 Holt and when?
American astronomer Carolyn Shoemaker spotted the asteroid on 13 January 1983 while observing from Palomar Observatory in California. It was initially catalogued under the provisional designation 1983 AG2 before receiving its permanent number.
Who is 4435 Holt named after?
The asteroid was named in honor of American astronomer Henry E. Holt, a fellow figure in the field of planetary science. The naming followed the standard practice of honoring contributors to astronomy.
Does 4435 Holt have a moon?
Yes—Holt is a binary asteroid system. The existence of its small companion was publicly announced in January 2018, confirming that the primary body is orbited by at least one satellite.
What are 4435 Holt's orbital characteristics?
As a Mars-crosser in the inner main belt, Holt travels between roughly 1.5 and 3.1 AU from the Sun with a period of about 3 years and 6 months (1,288 days). Its orbit is moderately elliptical (eccentricity 0.34) and tilted 22 degrees relative to the ecliptic plane.
How big is 4435 Holt and what is it made of?
NEOWISE thermal data places its diameter at approximately 5 kilometers, though an assumed-albedo estimate pushes that figure closer to 6.4 km. It is classified as a stony (S-type) body and rotates on its axis roughly every 2.87 hours.
More in Notable Asteroids, Part 3 1-24
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