Comet Wirtanen
- Details
- Last Updated: 29 November 2018
by David Nakamoto
Nov 22nd, 2018
Comet Wirtanen, periodic comet 46P, will have a once in a lifetime passage close to earth in December of 2018. This is due to two events, a few days apart, that will make the comet brighter than it usually is.
December 12th -- Wirtanen will be closest to the Sun, perihelion. It will be as bright as it can get, if it follows its behavior during past perihelion passages.
December 16th -- Wirtanen will be closest to the earth, only 11.5 million km or 7.1 million miles away. This will also contribute to making it as bright as it can get, for observers on earth anyways.
This coincidence of a perihelion passage followed by a close approach mimics Mars’ opposition in July of this year. Now when Mars did this, a global dust storm conspired to make Mars' globe a bland featureless disk. However, we want Wirtanen to produce lots of dust and gas, which will make it reflect more sunlight, so the comet will become bright. Some estimates predict Wirtanen might reach magnitude 4. But comets are notoriously unpredictable, so it might become even brighter, or it might even fade. Since no one knows which way it goes, this is not a comet to miss. No other comet is predicted to be brighter than 8th mag in 2019.
Since no one knows what will happen, I urge observers to look frequently and often as the comet goes from the southern skies to the north. It actually becomes visible all night as it passes by the earth. Remember, nothing in the sky waits for anyone. Small scopes, binoculars, anything that is easy to use at a moment’s notice is better than nothing, so make the most of every chance you can get.
Below is a star chart showing the path of the comet. Notice that at perihelion Dec 12th and closest approach on the 16th, the comet is fairly high in the sky just west of Taurus the Bull. Late December and early January it passes Lynx and heads towares Ursa Major, going circumpolar in the process and so appearing all night.
Based to the light curve made up of observed magnitudes, Wirtanen is behaving according to predictions, so 4th mag appears to be possible.
What will we see ? Well, Wirtanen will travel alongside earth during the close encounter, and going in the same direction. This means the passage won't be a quick one, but will last for several weeks. Since the tails point away from the Sun, and the comet is almost opposite the Sun during the encounter, we’re looking at the part of the comet pointed towards the Sun and earth, with the tails trailing away from the earth. This might mean the dust tail might be short, and the plasma tail even shorter. On the other hand, before closest approach, we’ll be looking “down” on the comet, and after we’ll be “below” it looking “up” at it. Both tails might be long at these times. The only way to be sure is to look at Wirtanen with anything you have.
The ephemeris below was generated by <in-the-sky.org>. As with all comet magnitude estimates, your mileage may vary, but LOOK !
Happy Hunting !
David Nakamoto can be reached at .
|
Ephemeris for 46P/Wirtanen |
||||||||||
|
Date |
Age of |
Right |
Declination |
Rise |
Culm |
Set |
Approx |
Constellation |
||
|
|
Moon |
Ascension |
|
Mag. |
|
|||||
|
2018 |
Dec |
01 |
24 days |
02h25m08s |
-20°16'38" |
16:29 |
21:34 |
02:43 |
6.0 |
|
|
2018 |
Dec |
03 |
25 days |
02h28m16s |
-18°42'51" |
16:23 |
21:33 |
02:47 |
5.9 |
|
|
2018 |
Dec |
04 |
26 days |
02h31m39s |
-16°59'45" |
16:17 |
21:32 |
02:51 |
5.8 |
|
|
2018 |
Dec |
05 |
27 days |
02h35m19s |
-15°06'24" |
16:11 |
21:32 |
02:57 |
5.7 |
|
|
2018 |
Dec |
06 |
28 days |
02h39m18s |
-13°01'53" |
16:05 |
21:32 |
03:03 |
5.6 |
|
|
2018 |
Dec |
07 |
29 days |
02h43m38s |
-10°45'15" |
15:59 |
21:32 |
03:10 |
5.5 |
|
|
2018 |
Dec |
08 |
00 days |
02h48m19s |
-08°15'40" |
15:53 |
21:33 |
03:17 |
5.4 |
|
|
2018 |
Dec |
09 |
01 days |
02h53m24s |
-05°32'23" |
15:47 |
21:34 |
03:26 |
5.3 |
|
|
2018 |
Dec |
10 |
02 days |
02h58m55s |
-02°34'54" |
15:40 |
21:36 |
03:35 |
5.2 |
|
|
2018 |
Dec |
11 |
03 days |
03h04m53s |
+00°37'01" |
15:33 |
21:38 |
03:46 |
5.1 |
|
|
2018 |
Dec |
12 |
04 days |
03h11m22s |
+04°02'59" |
15:27 |
21:40 |
03:58 |
5.0 |
|
|
2018 |
Dec |
13 |
05 days |
03h18m23s |
+07°42'03" |
15:20 |
21:43 |
04:11 |
4.9 |
|
|
2018 |
Dec |
14 |
06 days |
03h25m58s |
+11°32'31" |
15:12 |
21:47 |
04:26 |
4.9 |
|
|
2018 |
Dec |
15 |
06 days |
03h34m10s |
+15°31'52" |
15:05 |
21:51 |
04:42 |
4.8 |
|
|
2018 |
Dec |
16 |
07 days |
03h43m01s |
+19°36'45" |
14:57 |
21:56 |
04:59 |
4.8 |
|
|
2018 |
Dec |
17 |
08 days |
03h52m31s |
+23°43'22" |
14:49 |
22:02 |
05:18 |
4.8 |
|
|
2018 |
Dec |
18 |
09 days |
04h02m44s |
+27°47'22" |
14:41 |
22:08 |
05:39 |
4.8 |
|
|
2018 |
Dec |
19 |
10 days |
04h13m38s |
+31°44'37" |
14:32 |
22:15 |
06:02 |
4.8 |
|
|
2018 |
Dec |
20 |
11 days |
04h25m13s |
+35°31'05" |
14:23 |
22:23 |
06:26 |
4.9 |
|
|
2018 |
Dec |
21 |
12 days |
04h37m29s |
+39°03'39" |
14:13 |
22:31 |
06:53 |
4.9 |
|
|
2018 |
Dec |
22 |
13 days |
04h50m21s |
+42°19'47" |
14:02 |
22:40 |
07:21 |
5.0 |
|
|
2018 |
Dec |
23 |
15 days |
05h03m47s |
+45°17'53" |
13:51 |
22:49 |
07:52 |
5.1 |
|
|
2018 |
Dec |
24 |
16 days |
05h17m41s |
+47°57'13" |
13:38 |
22:59 |
08:24 |
5.2 |
|
|
2018 |
Dec |
25 |
17 days |
05h31m54s |
+50°17'47" |
13:23 |
23:09 |
09:00 |
5.3 |
|
|
2018 |
Dec |
26 |
18 days |
05h46m20s |
+52°20'06" |
13:04 |
23:20 |
09:39 |
5.4 |
|
|
2018 |
Dec |
27 |
20 days |
06h15m14s |
+55°34'09" |
Circumpolar |
5.6 |
|
|
2018 |
Dec |
29 |
21 days |
06h29m24s |
+56°48'36" |
Circumpolar |
5.8 |
|
|
2018 |
Dec |
30 |
22 days |
06h43m12s |
+57°49'59" |
Circumpolar |
5.9 |
|
|
2018 |
Dec |
31 |
23 days |
06h56m29s |
+58°39'49" |
Circumpolar |
6.0 |
|
|
2019 |
Jan |
01 |
24 days |
07h09m13s |
+59°19'34" |
Circumpolar |
6.1 |
|
|
2019 |
Jan |
02 |
25 days |
07h21m16s |
+59°50'33" |
Circumpolar |
6.2 |
|
|
2019 |
Jan |
03 |
26 days |
07h32m38s |
+60°14'01" |
Circumpolar |
6.4 |
|
|
2019 |
Jan |
04 |
27 days |
07h43m17s |
+60°31'05" |
Circumpolar |
6.5 |
|
|
2019 |
Jan |
05 |
28 days |
07h53m12s |
+60°42'44" |
Circumpolar |
6.6 |
|
|
2019 |
Jan |
06 |
29 days |
08h02m23s |
+60°49'47" |
Circumpolar |
6.7 |
|
|
2019 |
Jan |
07 |
00 days |
08h10m53s |
+60°52'58" |
Circumpolar |
6.8 |
|
|
2019 |
Jan |
08 |
01 days |
08h18m43s |
+60°52'56" |
Circumpolar |
6.9 |
|
|
2019 |
Jan |
09 |
02 days |
08h25m55s |
+60°50'09" |
Circumpolar |
7.0 |
|
|
2019 |
Jan |
10 |
03 days |
08h32m31s |
+60°45'06" |
Circumpolar |
7.1 |
|
|
2019 |
Jan |
11 |
04 days |
08h38m33s |
+60°38'08" |
Circumpolar |
7.3 |
|
|
2019 |
Jan |
12 |
05 days |
08h44m05s |
+60°29'33" |
Circumpolar |
7.4 |
|
|
2019 |
Jan |
13 |
06 days |
08h49m08s |
+60°19'36" |
Circumpolar |
7.5 |
|
|
2019 |
Jan |
14 |
07 days |
08h53m44s |
+60°08'31" |
Circumpolar |
7.6 |
|
|
2019 |
Jan |
15 |
08 days |
08h57m56s |
+59°56'28" |
Circumpolar |
7.7 |
|
|
2019 |
Jan |
16 |
09 days |
09h01m45s |
+59°43'35" |
Circumpolar |
7.8 |
|
|
2019 |
Jan |
17 |
10 days |
09h05m14s |
+59°30'01" |
Circumpolar |
7.9 |
|
|
2019 |
Jan |
18 |
11 days |
09h08m25s |
+59°15'49" |
Circumpolar |
8.0 |
|
|
2019 |
Jan |
19 |
12 days |
09h11m18s |
+59°01'06" |
Circumpolar |
8.1 |
|
|
2019 |
Jan |
20 |
13 days |
09h13m55s |
+58°45'56" |
Circumpolar |
8.2 |
|
|
2019 |
Jan |
21 |
14 days |
09h16m17s |
+58°30'21" |
Circumpolar |
8.3 |
|
2019 |
Jan |
22 |
16 days |
09h20m23s |
+57°58'10" |
Circumpolar |
8.5 |
|||
|
2019 |
Jan |
24 |
17 days |
09h22m09s |
+57°41'38" |
Circumpolar |
8.6 |
|||
|
2019 |
Jan |
25 |
19 days |
09h23m45s |
+57°24'48" |
Circumpolar |
8.7 |
|||
|
2019 |
Jan |
26 |
20 days |
09h25m11s |
+57°07'45" |
Circumpolar |
8.8 |
|||
|
2019 |
Jan |
27 |
21 days |
09h26m29s |
+56°50'27" |
Circumpolar |
8.9 |
|||
|
2019 |
Jan |
28 |
22 days |
09h27m40s |
+56°32'55" |
Circumpolar |
9.0 |
|||
|
2019 |
Jan |
29 |
23 days |
09h28m43s |
+56°15'11" |
Circumpolar |
9.0 |
|||
|
2019 |
Jan |
30 |
24 days |
09h29m40s |
+55°57'13" |
Circumpolar |
9.1 |
|||
|
2019 |
Jan |
31 |
25 days |
09h30m31s |
+55°39'04" |
Circumpolar |
9.2 |
|||
|
2019 |
Feb |
01 |
26 days |
09h31m17s |
+55°20'42" |
Circumpolar |
9.3 |
|||
|
2019 |
Feb |
02 |
26 days |
09h31m59s |
+55°02'10" |
13:07 |
00:39 |
12:08 |
9.4 |
|
|
2019 |
Feb |
03 |
27 days |
09h32m36s |
+54°43'26" |
13:19 |
00:36 |
11:50 |
9.5 |
|
|
2019 |
Feb |
04 |
28 days |
09h33m10s |
+54°24'32" |
13:27 |
00:33 |
11:35 |
9.6 |
|
|
2019 |
Feb |
05 |
00 days |
09h33m41s |
+54°05'27" |
13:33 |
00:29 |
11:22 |
9.7 |
|
|
2019 |
Feb |
06 |
00 days |
09h34m09s |
+53°46'12" |
13:38 |
00:26 |
11:10 |
9.8 |
|
|
2019 |
Feb |
07 |
01 days |
09h34m34s |
+53°26'48" |
13:42 |
00:22 |
10:59 |
9.9 |
|
|
2019 |
Feb |
08 |
02 days |
09h34m58s |
+53°07'15" |
13:45 |
00:19 |
10:49 |
10.0 |
|
|
2019 |
Feb |
09 |
03 days |
09h35m20s |
+52°47'33" |
13:48 |
00:15 |
10:39 |
10.1 |
|
|
2019 |
Feb |
10 |
04 days |
09h35m40s |
+52°27'44" |
13:50 |
00:12 |
10:29 |
10.2 |
|
|
2019 |
Feb |
11 |
05 days |
09h36m00s |
+52°07'46" |
13:52 |
00:08 |
10:20 |
10.2 |
|
|
2019 |
Feb |
12 |
06 days |
09h36m18s |
+51°47'42" |
13:53 |
00:04 |
10:11 |
10.3 |
|
|
2019 |
Feb |
13 |
07 days |
09h36m35s |
+51°27'31" |
13:55 |
23:57 |
10:03 |
10.4 |
|
|
2019 |
Feb |
14 |
08 days |
09h36m52s |
+51°07'14" |
13:56 |
23:53 |
09:54 |
10.5 |
|
|
2019 |
Feb |
15 |
09 days |
09h37m09s |
+50°46'52" |
13:57 |
23:50 |
09:46 |
10.6 |
|
|
2019 |
Feb |
16 |
10 days |
09h37m25s |
+50°26'25" |
13:57 |
23:46 |
09:38 |
10.7 |
|
