| Parameter |
Value |
| Designation |
46P/Wirtanen |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2018-12-12T22:20:53.010240Z |
| Orbit solution date (soln_date, UTC) |
2024-02-21T09:51:41Z |
| Obs used |
4224 |
| NEO |
Yes |
| M1 |
16.600 |
| K1 |
4.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-12-13.0000000 |
| e |
0.65875501 |
| q (au) |
1.055355 |
| a (au) |
3.092662 |
| i (deg) |
11.747549 |
| Ω (om, deg) |
82.157634 |
| ω (w, deg) |
356.341072 |
| M (ma, deg) |
0.012474 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.091 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.091 |
| n |
2.000 |
| gf |
0.997 |
| gb |
-0.785 |
| k |
1.000 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
15:46:47.58 |
-16:51:45.5 |
HIP 77203 |
14.65 |
| 2026-07-29 12:00 |
15:46:44.36 |
-16:52:14.5 |
HIP 77203 |
13.76 |
| 2026-07-30 00:00 |
15:46:41.36 |
-16:52:44.1 |
HIP 77203 |
12.91 |
| 2026-07-30 12:00 |
15:46:38.57 |
-16:53:14.3 |
HIP 77203 |
12.12 |
| 2026-07-31 00:00 |
15:46:35.99 |
-16:53:45.0 |
HIP 77203 |
11.37 |
| 2026-07-31 12:00 |
15:46:33.62 |
-16:54:16.4 |
HIP 77203 |
10.69 |
| 2026-08-01 00:00 |
15:46:31.47 |
-16:54:48.4 |
HIP 77203 |
10.06 |
| 2026-08-01 12:00 |
15:46:29.52 |
-16:55:21.0 |
HIP 77203 |
9.49 |
| 2026-08-02 00:00 |
15:46:27.79 |
-16:55:54.2 |
HIP 77203 |
9.00 |
| 2026-08-02 12:00 |
15:46:26.27 |
-16:56:27.9 |
HIP 77203 |
8.58 |
| 2026-08-03 00:00 |
15:46:24.95 |
-16:57:02.3 |
HIP 77203 |
8.25 |
| 2026-08-03 12:00 |
15:46:23.85 |
-16:57:37.2 |
HIP 77203 |
8.00 |
| 2026-08-04 00:00 |
15:46:22.95 |
-16:58:12.8 |
HIP 77203 |
7.85 |
| 2026-08-04 12:00 |
15:46:22.27 |
-16:58:48.9 |
HIP 77203 |
7.81 |
| 2026-08-05 00:00 |
15:46:21.79 |
-16:59:25.6 |
HIP 77203 |
7.86 |
| 2026-08-05 12:00 |
15:46:21.52 |
-17:00:02.8 |
HIP 77203 |
8.01 |
| 2026-08-06 00:00 |
15:46:21.46 |
-17:00:40.7 |
HIP 77203 |
8.25 |
| 2026-08-06 12:00 |
15:46:21.60 |
-17:01:19.1 |
HIP 77203 |
8.58 |
| 2026-08-07 00:00 |
15:46:21.95 |
-17:01:58.1 |
HIP 77297 |
8.55 |
| 2026-08-07 12:00 |
15:46:22.51 |
-17:02:37.6 |
HIP 77297 |
8.10 |
| 2026-08-08 00:00 |
15:46:23.27 |
-17:03:17.8 |
HIP 77297 |
7.63 |
| 2026-08-08 12:00 |
15:46:24.24 |
-17:03:58.4 |
HIP 77297 |
7.16 |
| 2026-08-09 00:00 |
15:46:25.41 |
-17:04:39.7 |
HIP 77297 |
6.67 |
| 2026-08-09 12:00 |
15:46:26.79 |
-17:05:21.5 |
HIP 77297 |
6.19 |
| 2026-08-10 00:00 |
15:46:28.37 |
-17:06:03.8 |
HIP 77297 |
5.72 |
| 2026-08-10 12:00 |
15:46:30.15 |
-17:06:46.7 |
HIP 77297 |
5.28 |
| 2026-08-11 00:00 |
15:46:32.14 |
-17:07:30.2 |
HIP 77297 |
4.90 |
| 2026-08-11 12:00 |
15:46:34.32 |
-17:08:14.2 |
HIP 77297 |
4.61 |
| 2026-08-12 00:00 |
15:46:36.71 |
-17:08:58.7 |
HIP 77297 |
4.45 |
| 2026-08-12 12:00 |
15:46:39.30 |
-17:09:43.7 |
HIP 77297 |
4.45 |
| 2026-08-13 00:00 |
15:46:42.09 |
-17:10:29.3 |
HIP 77297 |
4.65 |
| 2026-08-13 12:00 |
15:46:45.08 |
-17:11:15.4 |
HIP 77297 |
5.03 |
| 2026-08-14 00:00 |
15:46:48.27 |
-17:12:02.1 |
HIP 77297 |
5.59 |
| 2026-08-14 12:00 |
15:46:51.66 |
-17:12:49.2 |
HIP 77297 |
6.30 |
| 2026-08-15 00:00 |
15:46:55.24 |
-17:13:36.9 |
HIP 77297 |
7.13 |
| 2026-08-15 12:00 |
15:46:59.02 |
-17:14:25.1 |
HIP 77297 |
8.06 |
| 2026-08-16 00:00 |
15:47:03.00 |
-17:15:13.8 |
HIP 77297 |
9.08 |
| 2026-08-16 12:00 |
15:47:07.16 |
-17:16:02.9 |
HIP 77297 |
10.17 |
| 2026-08-17 00:00 |
15:47:11.53 |
-17:16:52.6 |
HIP 77297 |
11.34 |
| 2026-08-17 12:00 |
15:47:16.08 |
-17:17:42.8 |
HIP 77297 |
12.56 |
| 2026-08-18 00:00 |
15:47:20.83 |
-17:18:33.4 |
HIP 77297 |
13.84 |
| 2026-08-18 12:00 |
15:47:25.77 |
-17:19:24.6 |
HIP 77343 |
14.48 |
| 2026-08-19 00:00 |
15:47:30.90 |
-17:20:16.2 |
HIP 77343 |
13.75 |