Comet Finlay is a

periodic comet Periodic comets (also known as short-period comets) are comets with orbital periods of less than 200 years or that have been observed during more than a single perihelion passage (e.g. 153P/Ikeya–Zhang). "Periodic comet" is also sometimes us ...

with an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting pla ...

of 6 years discovered by William Henry Finlay ( Royal Observatory,

Cape of Good Hope The Cape of Good Hope ( af, Kaap die Goeie Hoop ) ;''Kaap'' in isolation: pt, Cabo da Boa Esperança is a rocky headland on the Atlantic coast of the Cape Peninsula in South Africa. A common misconception is that the Cape of Good Hope is ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...

) on September 26, 1886. The next

perihelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any elli ...

passage is July 13, 2021 when the comet will have a

solar elongation In astronomy, a planet's elongation is the angular separation between the Sun and the planet, with Earth as the reference point. The greatest elongation of a given inferior planet occurs when this planet's position, in its orbital path around t ...

of 54 degrees at approximately

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ...

10. It last came to perihelion on December 27, 2014, at around magnitude 10. Of the numbered periodic comets, the orbit of 15P/Finlay has one of the smallest

minimum orbit intersection distance Minimum orbit intersection distance (MOID) is a measure used in astronomy to assess potential close approaches and collision risks between astronomical objects. It is defined as the distance between the closest points of the osculating orbits o ...

s with the orbit of Earth (E-MOID). In October 2060 the comet will pass about 5 million km from Earth.

Description

When the first orbit calculations were made in 1886, there was a similarity between this orbit and that of Francesco de Vico's lost periodic comet of 1844 ( 54P/de Vico-Swift-NEAT).

Lewis Boss Lewis Boss (26 October 1846 – 5 October 1912) was an American astronomer. He served as the director of the Dudley Observatory in Schenectady, New York. Early life Boss was born in Providence, Rhode Island to Samuel P. and Lucinda (née J ...

( Dudley Observatory,

Schenectady Schenectady () is a city in Schenectady County, New York, United States, of which it is the county seat. As of the 2020 census, the city's population of 67,047 made it the state's ninth-largest city by population. The city is in eastern New Y ...

, United States) noted large discrepancies between the orbits and after further observations concluded that de Vico's comet could not be the same as Finlay's. During the 1906 apparition the comet brightened to magnitude 6. In 1910 a close pass with

Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousand ...

increased the

, in 1919 the path was off predictions and a new comet discovered by

Sasaki Sasaki () is the 13th most common Japanese surname. Less common variants are 佐咲, 佐佐木 and 笹木. Notable people with the surname include: Overview *, Japanese figure skater *, Japanese alpine skier *, Japanese idol and singer *, Japane ...

(Kyoto Observatory, Japan) on October 25, 1919, was discovered to be Finlay's. The magnitude of the comet declined after 1926, and it was not until 1953 that it has been observed on every return.

2014–2015

During the 2014 perihelion passage the comet outburst on 16 December 2014 from magnitude 11 to magnitude 9 becoming bright enough to be seen in common

binoculars Binoculars or field glasses are two refracting telescopes mounted side-by-side and aligned to point in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. Most binoculars are sized to be held ...

with a 50 mm

objective lens In optical engineering, the objective is the optical element that gathers light from the object being observed and focuses the light rays to produce a real image. Objectives can be a single lens or mirror, or combinations of several optical elem ...

. On December 23, 2014, 15P and Mars were only 1/6 of a degree apart in the sky after sunset. But by December 23, 2014, the comet had dimmed considerably since the outburst. On 16 January 2015, the comet outburst to magnitude 8.

2060

15P/Finlay currently has an Earth-

MOID Minimum orbit intersection distance (MOID) is a measure used in astronomy to assess potential close approaches and collision risks between astronomical objects. It is defined as the distance between the closest points of the osculating orbits of ...

of . The comet will come to perihelion six more times and then on October 22, 2060, the comet will pass roughly from Earth with an uncertainty region of about ±2300 km. This will be one of the closest comet approaches to Earth.Comet Close Approaches to the Earth
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Arids meteor shower

Debris ejected during the 1995 perihelion passage generated a meteor shower on 29-30 September 2021 radiating from the southern constellation of

Ara ARA may refer to: Media and the arts * American-Romanian Academy of Arts and Sciences * '' Artistička Radna Akcija'', compilation album released in former Yugoslavia * Associate of the Royal Academy, denoting membership in the British Royal Acad ...

. More outbursts are expected on 7 October 2021 from the 2008 and 2014 streams.

References

External links

Orbital simulation
from JPL (Java)
Horizons Ephemeris

Elements and Ephemeris for 15P/Finlay
–

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function T ...

15P at Kronk's Cometography

15P at CometBase database

2014 June 22 recovery at apmag 20
(comets-ml)
15P/Finlay on 18 Dec 2014
(200mm lens F5.6 / Rob Kaufman of Australia)
Animation of 15P/Finlay by FRAM (0.3-m f/10 reflector + CCD, MPC I47), 17th and 18th Dec 2014
(Martin Masek) {{DEFAULTSORT:Finlay, 015P Periodic comets 015P 0015 Comets in 2014 20210713 18860926