| Parameter |
Value |
| Designation |
C/1947 O1 (Wirtanen) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1947-07-16T20:09:37.615680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:07Z |
| Obs used |
3 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1948-03-29.0000000 |
| e |
1.01675158 |
| q (au) |
2.807881 |
| a (au) |
-167.618847 |
| i (deg) |
97.324802 |
| Ω (om, deg) |
311.764379 |
| ω (w, deg) |
8.848565 |
| M (ma, deg) |
0.116341 |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
09:18:58.62 |
+28:28:46.5 |
HIP 45617 |
15.15 |
| 2026-07-29 12:00 |
09:18:59.76 |
+28:28:40.8 |
HIP 45617 |
15.41 |
| 2026-07-30 00:00 |
09:19:00.89 |
+28:28:35.1 |
HIP 45617 |
15.68 |
| 2026-07-30 12:00 |
09:19:02.03 |
+28:28:29.4 |
HIP 45617 |
15.95 |
| 2026-07-31 00:00 |
09:19:03.17 |
+28:28:23.8 |
HIP 45767 |
16.20 |
| 2026-07-31 12:00 |
09:19:04.32 |
+28:28:18.2 |
HIP 45767 |
15.96 |
| 2026-08-01 00:00 |
09:19:05.46 |
+28:28:12.5 |
HIP 45767 |
15.71 |
| 2026-08-01 12:00 |
09:19:06.61 |
+28:28:07.0 |
HIP 45767 |
15.46 |
| 2026-08-02 00:00 |
09:19:07.75 |
+28:28:01.4 |
HIP 45767 |
15.21 |
| 2026-08-02 12:00 |
09:19:08.90 |
+28:27:55.9 |
HIP 45767 |
14.97 |
| 2026-08-03 00:00 |
09:19:10.05 |
+28:27:50.4 |
HIP 45767 |
14.72 |
| 2026-08-03 12:00 |
09:19:11.20 |
+28:27:44.9 |
HIP 45767 |
14.48 |
| 2026-08-04 00:00 |
09:19:12.35 |
+28:27:39.4 |
HIP 45767 |
14.23 |
| 2026-08-04 12:00 |
09:19:13.51 |
+28:27:34.0 |
HIP 45767 |
13.99 |
| 2026-08-05 00:00 |
09:19:14.66 |
+28:27:28.6 |
HIP 45767 |
13.75 |
| 2026-08-05 12:00 |
09:19:15.81 |
+28:27:23.2 |
HIP 45767 |
13.51 |
| 2026-08-06 00:00 |
09:19:16.97 |
+28:27:17.8 |
HIP 45767 |
13.27 |
| 2026-08-06 12:00 |
09:19:18.13 |
+28:27:12.5 |
HIP 45767 |
13.03 |
| 2026-08-07 00:00 |
09:19:19.28 |
+28:27:07.2 |
HIP 45767 |
12.80 |
| 2026-08-07 12:00 |
09:19:20.44 |
+28:27:01.9 |
HIP 45767 |
12.56 |
| 2026-08-08 00:00 |
09:19:21.60 |
+28:26:56.6 |
HIP 45767 |
12.33 |
| 2026-08-08 12:00 |
09:19:22.76 |
+28:26:51.4 |
HIP 45767 |
12.10 |
| 2026-08-09 00:00 |
09:19:23.91 |
+28:26:46.2 |
HIP 45767 |
11.87 |
| 2026-08-09 12:00 |
09:19:25.07 |
+28:26:41.1 |
HIP 45767 |
11.65 |
| 2026-08-10 00:00 |
09:19:26.23 |
+28:26:35.9 |
HIP 45767 |
11.42 |
| 2026-08-10 12:00 |
09:19:27.39 |
+28:26:30.8 |
HIP 45767 |
11.20 |
| 2026-08-11 00:00 |
09:19:28.55 |
+28:26:25.7 |
HIP 45767 |
10.98 |
| 2026-08-11 12:00 |
09:19:29.71 |
+28:26:20.7 |
HIP 45767 |
10.76 |
| 2026-08-12 00:00 |
09:19:30.87 |
+28:26:15.7 |
HIP 45767 |
10.55 |
| 2026-08-12 12:00 |
09:19:32.02 |
+28:26:10.7 |
HIP 45767 |
10.34 |
| 2026-08-13 00:00 |
09:19:33.18 |
+28:26:05.8 |
HIP 45767 |
10.13 |
| 2026-08-13 12:00 |
09:19:34.34 |
+28:26:00.8 |
HIP 45767 |
9.93 |
| 2026-08-14 00:00 |
09:19:35.50 |
+28:25:55.9 |
HIP 45767 |
9.73 |
| 2026-08-14 12:00 |
09:19:36.65 |
+28:25:51.1 |
HIP 45767 |
9.53 |
| 2026-08-15 00:00 |
09:19:37.81 |
+28:25:46.3 |
HIP 45767 |
9.34 |
| 2026-08-15 12:00 |
09:19:38.96 |
+28:25:41.5 |
HIP 45767 |
9.15 |
| 2026-08-16 00:00 |
09:19:40.12 |
+28:25:36.7 |
HIP 45767 |
8.96 |
| 2026-08-16 12:00 |
09:19:41.27 |
+28:25:32.0 |
HIP 45767 |
8.78 |
| 2026-08-17 00:00 |
09:19:42.42 |
+28:25:27.3 |
HIP 45767 |
8.61 |
| 2026-08-17 12:00 |
09:19:43.57 |
+28:25:22.7 |
HIP 45767 |
8.44 |
| 2026-08-18 00:00 |
09:19:44.72 |
+28:25:18.0 |
HIP 45767 |
8.28 |
| 2026-08-18 12:00 |
09:19:45.87 |
+28:25:13.5 |
HIP 45767 |
8.12 |
| 2026-08-19 00:00 |
09:19:47.02 |
+28:25:08.9 |
HIP 45767 |
7.97 |