C/1988 A1 (Liller)
Non-periodic comet discovered in 1988, namesake of the Liller family.
C/1988 A1 (Liller) is a non-periodic comet discovered by William Liller on 11 January 1988. It gives its name to the Liller family of comets, which also includes C/1996 Q1 (Tabur), C/2015 F3 (SWAN), C/2019 Y1 (ATLAS), and C/2023 V5 (Leonard).
Liller spotted the comet on two photographic plates taken half an hour apart during the PROBLICOM survey. He noted it appeared diffuse, with a coma roughly one arcminute wide and faint condensation. T. Cragg and R. H. McNaught later confirmed the sighting, estimating a visual magnitude of 10.2 and a coma spanning 6 arcminutes. At discovery, the comet lay in Sculptor, 1.62 AU from the Sun, at a solar elongation of 60°.
Brightening from magnitude 10 to 9 by late January, the comet continued to gain in brightness through February and March, reaching magnitude 7 by the end of March. It reached its smallest elongation—25°—on 13 March. Peak brightness came in April. Jacobson saw it with the naked eye on 18 April, and David H. Levy reported a naked-eye magnitude of 4.7 on 24 April. By late April, the tail stretched 2–3 degrees, and an antitail 0.2 degrees long appeared from 21 to 23 April. The comet faded in May. Its closest approach to Earth occurred on 12 May 1988, at a distance of 1.22 AU. By the end of May, its magnitude had dropped to 7–7.4.
Come July, the comet had grown very faint and diffuse. It was last observed on 12 August 1988, at magnitude 12, with a coma 1.3–1.4 arcminutes across.
Brian G. Marsden calculated a parabolic orbit on 17 January 1988 using positions available up to that day, yielding a perihelion date of 31.61 March 1988—a prediction that proved quite accurate. Daniel Green published the first orbit covering the full visibility period in August 1988, accounting for planetary perturbations. That orbit set perihelion at 31.11 March and gave a period of roughly 3833 years.
After the orbit of C/1996 Q1 (Tabur) was computed, Jost Jahn noticed its striking similarity to that of C/1988 A1, suggesting the two split at a previous perihelion. Zdenek Sekanina proposed that non-tidal forces might have caused the separation. Three more comets—C/2015 F3 (SWAN), C/2019 Y1 (ATLAS), and C/2023 V5 (Leonard)—were later linked to the Liller family.
Quick Facts
- Discoverer
- William Liller
- Discovery Site
- Vina del Mar, Chile
- Discovery Date
- 11 January 1988
- Designations
- 1988a, 1988 V
- Orbit Ref
- jpl
- Epoch
- 26 April 1988 (JD 2447277.5)
- Observation Arc
- 184 days
- Obs
- 427
- Aphelion
- 489 AU
- Perihelion
- 0.841 AU
- Semimajor
- 245 AU
- Eccentricity
- 0.9988
Facts from the source article.
Lore & Background
The comet was discovered by William Liller in two images exposed 30 minutes apart on 11 January 1988. He described it as diffuse with a coma about one arcminute across and with faint condensation. Confirmation came from T. Cragg and R. H. McNaught, who estimated a visual apparent magnitude of 10.2 and a coma 6 arcminutes across. At discovery the comet was in Sculptor, at a solar elongation of 60°, and 1.62 AU from the Sun. It brightened from magnitude 10 to 9 by late January, reached magnitude 7 by late March, and peaked in April. Jacobson spotted it with the naked eye on 18 April; David H. Levy reported magnitude 4.7 with the naked eye on 24 April. The tail reached 2–3 degrees long in late April, and an antitail 0.2 degrees long was reported from 21 to 23 April. The comet faded in May; closest approach to Earth was on 12 May at 1.22 AU. By late May its magnitude was 7–7.4. It became very faint and diffuse by July and was last observed on 12 August 1988 at magnitude 12 with a coma 1.3–1.4 arcminutes across.
Reader's Guide
C/1988 A1 (Liller) is notable as the first recognized member of the Liller family, a group of comets with strikingly similar orbits. Brian G. Marsden calculated a parabolic orbit on 17 January 1988 that proved quite accurate, and Daniel Green published a refined orbit in August 1988 with a perihelion date of 31.11 March 1988 and a period of about 3833 years. After the orbit of C/1996 Q1 (Tabur) was calculated, Jost Jahn noted its striking similarity to Liller's orbit, suggesting they separated at a previous perihelion. Zdenek Sekanina proposed that non-tidal forces could have caused the separation. Three more comets—C/2015 F3 (SWAN), C/2019 Y1 (ATLAS), and C/2023 V5 (Leonard)—were later associated with the Liller family. The comet's legacy lies in establishing this dynamical family, which provides insight into the fragmentation and evolution of cometary nuclei over multiple orbits.
Did You Know?
- The comet was discovered during the PROBLICOM survey.
- It reached naked-eye visibility, with magnitude 4.7 reported on 24 April 1988.
- An antitail 0.2 degrees long was observed from 21 to 23 April 1988.
More in Named Comets, Part 4 1-24
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