C/2002 E2 (Snyder-Murakami)
| Parameter |
Value |
| Designation |
C/2002 E2 (Snyder-Murakami) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2002-02-21T19:01:43.622400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:15Z |
| Obs used |
905 |
| NEO |
- |
| M1 |
10.600 |
| K1 |
7.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2002-05-22.0000000 |
| e |
1.00078903 |
| q (au) |
1.466445 |
| a (au) |
-1858.536843 |
| i (deg) |
92.544982 |
| Ω (om, deg) |
244.582842 |
| ω (w, deg) |
9.034141 |
| M (ma, deg) |
0.001097 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.648 + 4.589\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.648 |
| n |
4.589 |
| gf |
0.980 |
| gb |
-1.000 |
| k |
0.992 |
| δ90 |
9.688 |
| 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) |
| 2026-02-03 00:00 |
03:57:11.01 |
+32:31:13.9 |
HIP 18558 |
20.35 |
| 2026-02-03 12:00 |
03:57:10.10 |
+32:31:02.1 |
HIP 18558 |
20.62 |
| 2026-02-04 00:00 |
03:57:09.21 |
+32:30:50.3 |
HIP 18558 |
20.89 |
| 2026-02-04 12:00 |
03:57:08.35 |
+32:30:38.6 |
HIP 18558 |
21.16 |
| 2026-02-05 00:00 |
03:57:07.51 |
+32:30:26.9 |
HIP 18558 |
21.42 |
| 2026-02-05 12:00 |
03:57:06.70 |
+32:30:15.3 |
HIP 18558 |
21.68 |
| 2026-02-06 00:00 |
03:57:05.92 |
+32:30:03.7 |
HIP 18558 |
21.93 |
| 2026-02-06 12:00 |
03:57:05.16 |
+32:29:52.2 |
HIP 18558 |
22.18 |
| 2026-02-07 00:00 |
03:57:04.43 |
+32:29:40.7 |
HIP 18558 |
22.42 |
| 2026-02-07 12:00 |
03:57:03.73 |
+32:29:29.3 |
HIP 18558 |
22.66 |
| 2026-02-08 00:00 |
03:57:03.05 |
+32:29:18.0 |
HIP 18558 |
22.90 |
| 2026-02-08 12:00 |
03:57:02.40 |
+32:29:06.7 |
HIP 18558 |
23.13 |
| 2026-02-09 00:00 |
03:57:01.78 |
+32:28:55.4 |
HIP 18397 |
23.31 |
| 2026-02-09 12:00 |
03:57:01.18 |
+32:28:44.2 |
HIP 18397 |
23.09 |
| 2026-02-10 00:00 |
03:57:00.61 |
+32:28:33.1 |
HIP 18397 |
22.87 |
| 2026-02-10 12:00 |
03:57:00.07 |
+32:28:22.1 |
HIP 18397 |
22.65 |
| 2026-02-11 00:00 |
03:56:59.55 |
+32:28:11.1 |
HIP 18397 |
22.44 |
| 2026-02-11 12:00 |
03:56:59.06 |
+32:28:00.1 |
HIP 18397 |
22.23 |
| 2026-02-12 00:00 |
03:56:58.59 |
+32:27:49.2 |
HIP 18397 |
22.02 |
| 2026-02-12 12:00 |
03:56:58.15 |
+32:27:38.4 |
HIP 18397 |
21.82 |
| 2026-02-13 00:00 |
03:56:57.74 |
+32:27:27.7 |
HIP 18397 |
21.62 |
| 2026-02-13 12:00 |
03:56:57.36 |
+32:27:17.0 |
HIP 18397 |
21.43 |
| 2026-02-14 00:00 |
03:56:57.00 |
+32:27:06.3 |
HIP 18397 |
21.24 |
| 2026-02-14 12:00 |
03:56:56.67 |
+32:26:55.8 |
HIP 18397 |
21.06 |
| 2026-02-15 00:00 |
03:56:56.37 |
+32:26:45.3 |
HIP 18397 |
20.88 |
| 2026-02-15 12:00 |
03:56:56.09 |
+32:26:34.8 |
HIP 18397 |
20.71 |
| 2026-02-16 00:00 |
03:56:55.84 |
+32:26:24.5 |
HIP 18397 |
20.54 |
| 2026-02-16 12:00 |
03:56:55.62 |
+32:26:14.2 |
HIP 18397 |
20.37 |
| 2026-02-17 00:00 |
03:56:55.42 |
+32:26:03.9 |
HIP 18397 |
20.21 |
| 2026-02-17 12:00 |
03:56:55.26 |
+32:25:53.8 |
HIP 18397 |
20.05 |
| 2026-02-18 00:00 |
03:56:55.11 |
+32:25:43.7 |
HIP 18397 |
19.90 |
| 2026-02-18 12:00 |
03:56:55.00 |
+32:25:33.7 |
HIP 18397 |
19.75 |
| 2026-02-19 00:00 |
03:56:54.91 |
+32:25:23.7 |
HIP 18397 |
19.61 |
| 2026-02-19 12:00 |
03:56:54.85 |
+32:25:13.9 |
HIP 18397 |
19.47 |
| 2026-02-20 00:00 |
03:56:54.81 |
+32:25:04.1 |
HIP 18397 |
19.33 |
| 2026-02-20 12:00 |
03:56:54.80 |
+32:24:54.3 |
HIP 18397 |
19.21 |
| 2026-02-21 00:00 |
03:56:54.82 |
+32:24:44.7 |
HIP 18397 |
19.08 |
| 2026-02-21 12:00 |
03:56:54.87 |
+32:24:35.1 |
HIP 18397 |
18.96 |
| 2026-02-22 00:00 |
03:56:54.94 |
+32:24:25.6 |
HIP 18397 |
18.85 |
| 2026-02-22 12:00 |
03:56:55.04 |
+32:24:16.1 |
HIP 18397 |
18.74 |
| 2026-02-23 00:00 |
03:56:55.16 |
+32:24:06.8 |
HIP 18397 |
18.64 |
| 2026-02-23 12:00 |
03:56:55.31 |
+32:23:57.5 |
HIP 18397 |
18.54 |
| 2026-02-24 00:00 |
03:56:55.49 |
+32:23:48.3 |
HIP 18397 |
18.45 |