C/2013 R1 (Lovejoy)
Fourth comet discovered by Terry Lovejoy, visible to the naked eye.
C/2013 R1 (Lovejoy) is a non-periodic comet first spotted on 7 September 2013 through a 0.2 m Schmidt–Cassegrain telescope. It marks the fourth comet found by Terry Lovejoy. On 14 October 2013, the comet crossed the celestial equator, improving its visibility for observers in the Northern Hemisphere.
By 1 November 2013, the comet could be seen without optical aid near the Beehive Cluster (M44), lying roughly halfway between Jupiter and Regulus. At that time, it outshone C/2012 S1 (ISON). Through binoculars, it appeared as a green, unresolved globular cluster. The comet made its closest pass to Earth on 19 November 2013, coming within 0.3967 AU (about 59.35 million km) and reaching an apparent magnitude near 4.5. On 27 November 2013, it sat in Canes Venatici, close to the bottom of the Big Dipper’s handle. From 28 November to 4 December 2013, it moved through Boötes, passing the star Beta Boötis on 1 December. It then traveled through Corona Borealis from 4 to 12 December 2013. From 12 December 2013 until 14 January 2014, the comet resided in Hercules, passing the star Zeta Herculis on 14 December. It reached perihelion on 22 December 2013 at a distance of 0.81 AU (roughly 121 million km) from the Sun, with an elongation of 51 degrees. By September 2014, its brightness had dropped to magnitude 18.
Narrow-band spectroscopy in December 2013 showed that the comet’s coma contained relatively high levels of H2O and CO2. Photometry from TRAPPIST through July 2014 indicated that organic compounds detected in the coma—OH, NH, CN, C3, and C2—partly resulted from the breakdown of outgassing HCN. Infrared observations from the Keck Observatory revealed enriched CO and hydrocarbons such as CH4, C2H6, and CH3OH, reflecting chemical variability seen in other Oort cloud comets. Additional complex organics, including HCOOH, CH3CHO, (CH2OH)2, and NH2CHO, were also identified.
The comet’s nucleus has an estimated radius of 1.266±0.10 km and a low bulk density of about 480±70 kg/m³. Measurements of dust emission structures around the comet suggest a rotation period of roughly 47.8±1.2 hours.
Quick Facts
- Discovery Ref
- CBET_3649 · MPEC_2013-R72
- Discoverer
- Terry Lovejoy
- Discovery Site
- Thornlands, Australia
- Discovery Date
- 7 September 2013
- Designations
- CK13R010MPEC_2013-R72
- Orbit Ref
- barycenter · jpldata
- Epoch
- 29 December 2013 (JD 2456655.5)
- Observation Arc
- 372 days (1.02 years)
- Obs
- 3,894
- Perihelion
- 0.812 AU
- Aphelion
- ~830 AU (outbound)
- Eccentricity
- 0.99843
Facts from the source article.
Lore & Background
By 1 November 2013, the comet was visible to the naked eye near the Beehive Cluster (M44), about halfway between Jupiter and Regulus, and became more impressive than C/2012 S1 (ISON). In binoculars, it appeared as a green, unresolved globular cluster. It crossed the celestial equator on 14 October 2013, making it better observed from the Northern Hemisphere. The comet made its closest approach to Earth on 19 November 2013 at a distance of 0.3967 AU, reaching an apparent magnitude of about 4.5. On 27 November 2013 it was in Canes Venatici near the bottom of the Big Dipper handle, then moved through Boötes (28 November–4 December), passing Beta Boötis on 1 December, and through Corona Borealis (4–12 December). From 12 December 2013 to 14 January 2014 it was in Hercules, passing Zeta Herculis on 14 December. It reached perihelion on 22 December 2013 at 0.81 AU from the Sun, with an elongation of 51 degrees. By September 2014, it had faded to magnitude 18.
Reader's Guide
C/2013 R1 (Lovejoy) is significant as the fourth comet discovered by amateur astronomer Terry Lovejoy, and for its unexpected brightness that made it a naked-eye object in November 2013, outshining the much-anticipated comet ISON. Its observational history provides a detailed record of its path through northern constellations, allowing for extensive study. Spectroscopic and photometric observations in December 2013 revealed a coma rich in H2O and CO2, with organic compounds such as OH, NH, CN, C3, and C2 partly resulting from HCN breakdown. Infrared observations from the Keck Observatory detected enriched CO and hydrocarbons including CH4, C2H6, and CH3OH, as well as complex organics like HCOOH, CH3CHO, (CH2OH)2, and NH2CHO, indicating chemical variability typical of Oort cloud comets. The nucleus radius is estimated at 1.266±0.10 km with a low bulk density of about 480±70 kg/m³, and dust emission structures suggest a rotation period of 47.8±1.2 hours. These measurements contribute to understanding the composition and physical properties of long-period comets from the Oort cloud.
Did You Know?
- Discovered on 7 September 2013 using a 0.2 m Schmidt–Cassegrain telescope.
- Crossed the celestial equator on 14 October 2013, improving visibility from the Northern Hemisphere.
- Closest approach to Earth was on 19 November 2013 at 0.3967 AU.
- Nucleus radius is about 1.266±0.10 km with a rotation period of 47.8±1.2 hours.
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