110P/Hartley
Periodic comet discovered by Malcolm Hartley, with a 6.85-year orbit.
110P/Hartley is a short-period comet that orbits the Sun once every six years. It belongs to a group of ten comets found by Australian astronomer Malcolm Hartley.
The comet was first spotted as a faint, 16.5-magnitude streak near the edge of photographic plates taken at the UK Schmidt Telescope at Siding Spring Observatory. Hartley confirmed the sighting with the same telescope on February 22, noting a tail roughly 10 arcminutes long. Later, Carolyn and Eugene Shoemaker uncovered two precovery images from Palomar Observatory, taken about 4.8 hours before the official discovery, which helped confirm it as a short-period comet.
In March 1988, six observatories worldwide tracked the comet, including observations by Tsutomu Seki, Robert H. McNaught, James V. Scotti, and David H. Levy. Revised orbital calculations by Brian G. Marsden that April showed the comet follows an elliptical orbit with a period of 6.85 years. James V. Scotti successfully recovered the comet on June 23, 1993, using the Spacewatch telescope at Kitt Peak Observatory.
Studies of the comet’s nucleus by the Hubble Space Telescope in 2004 and 2011 gave an effective radius of about 2.15 ± 0.04 km and a rotation period of 9.4 ± 1.0 hours. Later ground-based observations from Pan-STARRS and other surveys refined these values to a radius of 2.31 ± 0.03 km and a rotation period of 10.153 ± 0.001 hours.
Quick Facts
- Discovery Ref
- IAUC_4553
- Discoverer
- Malcolm Hartley
- Discovery Site
- UK Schmidt Telescope
- Discovery Date
- 19 February 1988
- Mpc Name
- P/1988 D1 / P/1993 M1
- Designations
- Hartley 3 · 1987 XII, 1994 XII · 1988d, 1993m
- Orbit Ref
- jpldata · MPC
- Epoch
- 25 February 2023 (JD 2460000.5)
- Observation Arc
- 35.23 years
- Obs
- 3,998
- Perihelion
- 2.455 AU
- Aphelion
- 4.752 AU
Facts from the source article.
Lore & Background
Comet Hartley 3 was discovered as a weak trail at magnitude 16.5 on plates taken from the UK Schmidt Telescope of the Siding Spring Observatory. By 22 February, Hartley confirmed his discovery using the same telescope, finding a tail about 10 arcminutes in length. From the Palomar Observatory, Carolyn and Eugene Shoemaker found two precovery images of the comet about 4.8 hours before its official discovery, confirming it as a short-period comet.
Six observatories made follow-up observations in March 1988, including those by Tsutomu Seki, Robert H. McNaught, James V. Scotti, and David H. Levy. By April 1988, revised orbital calculations by Brian G. Marsden indicated the comet completes an elliptical orbit once every 6.85 years. The comet was successfully recovered by James V. Scotti using the Spacewatch telescope of the Kitt Peak Observatory on 23 June 1993.
Physical characteristics from Hubble Space Telescope observations in 2004 and 2011 gave an effective nucleus radius of 2.15±0.04 km and a rotation period of 9.4±1.0 hours. Later ground observations from Pan-STARRS and other sky surveys revised these to 2.31±0.03 km and 10.153±0.001 hours, respectively.
Reader's Guide
110P/Hartley is notable as one of ten comets discovered by Australian astronomer Malcolm Hartley, and its discovery was confirmed by precovery images from Carolyn and Eugene Shoemaker. The comet's orbital period was refined by Brian G. Marsden to 6.85 years, and it was successfully recovered in 1993 by James V. Scotti. Its physical properties—nucleus radius and rotation period—were measured by the Hubble Space Telescope and later revised by Pan-STARRS, showing slight discrepancies that reflect ongoing refinement in cometary science. The comet's observational history, involving multiple observatories and astronomers, underscores the collaborative nature of comet tracking. Its legacy lies in the detailed characterization of a short-period comet, contributing to the understanding of such objects' sizes and rotation rates.
More in Periodic Comets 1-24
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