C/2018 V1 (Machholz–Fujikawa–Iwamoto)
A comet with a probable extrasolar origin, now escaping the Solar System.
C/2018 V1 (Machholz–Fujikawa–Iwamoto) is a comet on a slightly hyperbolic path. It was first spotted on 7 November 2018 by amateur astronomer Donald Machholz using an 18.5-inch reflecting telescope, and was independently found the same day by Shigehisa Fujikawa and Masayuki Iwamoto. The comet made its closest approach to the Sun on 3 December 2018. From mid-November to mid-December 2018, its brightness was estimated between magnitude 8 and 10, making it visible through a small telescope. The comet’s name honors its three discoverers: one observer in Colfax, California, and two in Japan. Its current orbit is based on 750 observations over a 37-day arc. There is a 72.6% chance that C/2018 V1 originated outside the Solar System, though an Oort Cloud origin remains possible. Because its barycentric orbital eccentricity now exceeds 1, the comet is currently leaving the Solar System and heading into interstellar space.
Quick Facts
- Discoverer
- Donald Machholz / Shigehisa Fujikawa / Masayuki Iwamoto
- Discovery Site
- Colfax, California / Japan
- Discovery Date
- 7 November 2018
- Orbit Ref
- jpl
- Epoch
- 16 November 2018 (JD 2458438.5)
- Observation Arc
- 37 days
- Obs
- 750
- Perihelion
- 0.387 AU
- Eccentricity
- 1.00039
- Inclination
- 143.988°
- Asc Node
- 128.722°
- Arg Peri
- 88.775°
Facts from the source article.
Lore & Background
C/2018 V1 was visually discovered on 7 November 2018 by Donald Machholz using an 18.5-inch reflecting telescope in Colfax, California, USA. It was independently co-discovered by Shigehisa Fujikawa and Masayuki Iwamoto, both observers in Japan. The comet's name reflects the three amateur astronomers who contributed to its discovery.
The comet was estimated to be between 8 and 10th magnitude from mid-November to mid-December 2018, making it visible in a small telescope. Its current orbit determination is based on 750 observations with a 37-day observation arc. The comet follows a slightly hyperbolic trajectory.
Notably, the comet has a significant probability (72.6%) of having an extrasolar provenance, although an origin in the Oort Cloud cannot be excluded. As the present-day value of its barycentric orbital eccentricity is greater than 1, this comet is currently escaping from the Solar System, aiming for interstellar space.
Reader's Guide
C/2018 V1 (Machholz–Fujikawa–Iwamoto) is significant as a comet discovered entirely by amateur astronomers, highlighting the continued contributions of non-professional observers to cometary science. Its discovery by three independent amateurs—one in the United States and two in Japan—underscores the global reach of amateur astronomy. The comet's slightly hyperbolic trajectory and barycentric eccentricity greater than 1 indicate it is on an escape path from the Solar System. The article notes a 72.6% probability of extrasolar provenance, meaning it likely originated outside the Solar System, though an Oort Cloud origin remains possible. This makes C/2018 V1 a rare example of a potentially interstellar object, adding to the legacy of comets like ʻOumuamua and Borisov. Its visibility in small telescopes from mid-November to mid-December 2018 allowed many amateur astronomers to observe it. The comet's orbit determination, based on 750 observations over 37 days, provided the data for these conclusions. The entry in the JPL Small-Body Database and related sky charts helped observers track it. The comet's name, combining the discoverers, follows the standard naming convention for comets with multiple co-discoverers.
Did You Know?
- The comet has a 72.6% probability of having an extrasolar provenance.
- Its barycentric orbital eccentricity is greater than 1, meaning it is escaping the Solar System.
Frequently Asked Questions
Who found C/2018 V1 (Machholz–Fujikawa–Iwamoto)?
Donald Machholz in Colfax, California, first detected it on 7 November 2018 with an 18.5-inch reflector, while Shigehisa Fujikawa and Masayuki Iwamoto in Japan made an independent discovery the very same night. The comet's designation honors all three observers.
What kind of orbit does C/2018 V1 follow, and where did it likely come from?
It travels on a slightly hyperbolic trajectory, meaning it is not gravitationally bound to the Sun and is on its way out of the Solar System permanently. Astronomers believe it most likely originated outside our solar system entirely, making it an interstellar visitor.
How bright was C/2018 V1 and when was the best time to see it?
Between mid-November and mid-December 2018 its apparent brightness hovered around 8th to 10th magnitude, so it was a small-telescope target rather than a naked-eye show. Its closest approach to the Sun came on 3 December 2018, bracketing the peak of its visibility window.
What happened to C/2018 V1 after it passed perihelion?
After swinging around the Sun in early December 2018, the comet continued on its hyperbolic escape trajectory and faded beyond practical detection within roughly 37 days of first observation. It is now receding into interstellar space and will not return to the Solar System.
Why is C/2018 V1 (Machholz–Fujikawa–Iwamoto) considered important in amateur astronomy?
It stands out as a rare interstellar interloper caught by backyard-scale equipment rather than a professional survey, giving amateur observers a genuine role in identifying an object from beyond the Sun's gravitational reach. Its short 37-day observation arc also made it a memorable 'here-today, gone-tomorrow' target for small-instrument owners.
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