101 days ago
Dominic Ford, Editor
From the Comets feed
Comet C/2017 K2 (PANSTARRS) will make its closest approach to the Sun on 19 December, at a distance of 1.80 AU.
From Cambridge on the day of perihelion it will not be observable because it will lie so far south that it never rises above the horizon.
The events that comprise the 2022–2023 apparition of C/2017 K2 (PANSTARRS) are as follows:
|19 Dec 2022||Comet C/2017 K2 (PANSTARRS) passes perihelion|
The table below lists the times when C/2017 K2 (PANSTARRS) will be visible from Cambridge day-by-day through its apparition:
|28 Nov 2022||Ara||Not observable|
|30 Nov 2022||Ara||Not observable|
|02 Dec 2022||Ara||Not observable|
|04 Dec 2022||Ara||Not observable|
|06 Dec 2022||Ara||Not observable|
|08 Dec 2022||Ara||Not observable|
|10 Dec 2022||Ara||Not observable|
|12 Dec 2022||Ara||Not observable|
|14 Dec 2022||Pavo||Not observable|
|16 Dec 2022||Pavo||Not observable|
|18 Dec 2022||Pavo||Not observable|
|20 Dec 2022||Pavo||Not observable|
|22 Dec 2022||Pavo||Not observable|
|24 Dec 2022||Pavo||Not observable|
|26 Dec 2022||Pavo||Not observable|
|28 Dec 2022||Pavo||Not observable|
|30 Dec 2022||Pavo||Not observable|
|01 Jan 2023||Pavo||Not observable|
|03 Jan 2023||Pavo||Not observable|
|05 Jan 2023||Pavo||Not observable|
|07 Jan 2023||Pavo||Not observable|
A more detailed table of C/2017 K2 (PANSTARRS)'s position on each night is available here. A diagram of the orbit of C/2017 K2 (PANSTARRS) is available here.
The chart below shows the path of C/2017 K2 (PANSTARRS) over the course of its apparition, as calculated from the orbital elements published by the Minor Planet Center (MPC). It is available for download, either on dark background, in PNG, PDF or SVG formats, or on a light background, in PNG, PDF or SVG formats. It was produced using StarCharter.
Comets are intrinsically highly unpredictable objects, since their brightness depends on the scattering of sunlight from dust particles in the comet's coma and tail. This dust is continually streaming away from the comet's nucleus, and its density at any particular time is governed by the rate of sublimation of the ice in the comet's nucleus, as it is heated by the Sun's rays. It also depends on the amount of dust that is mixed in with that ice. This is very difficult to predict in advance, and can be highly variable even between successive apparitions of the same comet.
In consequence, while the future positions of comets are usually known with a high degree of confidence, their future brightnesses are not. For most comets, we do not publish any magnitude estimates at all. For the few comets where we do make estimates, we generally prefer the BAA's magnitude parameters to those published by the Minor Planet Center, since they are typically updated more often.
Based on the magnitude parameters published for this comet by the BAA Comet Section, we estimate that it may be around mag 9 on 19 December 2022. This estimate is based on observations that the BAA has received from amateur astronomers, assuming that its current level of activity will remain constant.
This comet is not expected to be visible to the naked eye, but might be visible through bird-watching binoculars.
The comet's position at perihelion will be:
|Comet C/2017 K2 (PANSTARRS)||17h57m10s||60°18'S||Pavo||8.8|
The coordinates are given in J2000.0.
The sky on 19 Dec 2022
|The sky on 19 December 2022|
26 days old
All times shown in EST.
This event was automatically generated on the basis of orbital elements published by the Minor Planet Center (MPC) , and is updated whenever new elements become available. It was last updated on 19 Feb 2023.
© Andy Roberts 1997. Pictured comet is C/1995 O1 Hale-Bopp.