| Parameter |
Value |
| Designation |
162P/Siding Spring |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2010-03-08T10:33:48.648960Z |
| Orbit solution date (soln_date, UTC) |
2025-07-31T12:12:41Z |
| Obs used |
3224 |
| NEO |
Yes |
| M1 |
15.200 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2010-12-01.0000000 |
| e |
0.59607784 |
| q (au) |
1.233274 |
| a (au) |
3.053246 |
| i (deg) |
27.817056 |
| Ω (om, deg) |
31.236338 |
| ω (w, deg) |
356.327515 |
| M (ma, deg) |
49.429050 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.651 + 2.493\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.651 |
| n |
2.493 |
| gf |
0.924 |
| gb |
-0.877 |
| k |
0.998 |
| δ90 |
1.000 |
| 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) |
| 2026-03-26 00:00 |
00:04:13.49 |
-11:49:13.7 |
HIP 266 |
14.97 |
| 2026-03-26 12:00 |
00:05:36.36 |
-11:35:04.0 |
HIP 609 |
26.23 |
| 2026-03-27 00:00 |
00:06:59.22 |
-11:20:52.2 |
HIP 609 |
16.96 |
| 2026-03-27 12:00 |
00:08:22.07 |
-11:06:38.6 |
HIP 639 |
8.33 |
| 2026-03-28 00:00 |
00:09:44.91 |
-10:52:22.9 |
HIP 899 |
19.54 |
| 2026-03-28 12:00 |
00:11:07.74 |
-10:38:05.4 |
HIP 899 |
14.60 |
| 2026-03-29 00:00 |
00:12:30.58 |
-10:23:45.9 |
HIP 899 |
35.82 |
| 2026-03-29 12:00 |
00:13:53.41 |
-10:09:24.6 |
HIP 1117 |
24.87 |
| 2026-03-30 00:00 |
00:15:16.23 |
-09:55:01.5 |
HIP 1191 |
21.53 |
| 2026-03-30 12:00 |
00:16:39.06 |
-09:40:36.5 |
HIP 1274 |
15.29 |
| 2026-03-31 00:00 |
00:18:01.89 |
-09:26:09.8 |
HIP 1274 |
30.21 |
| 2026-03-31 12:00 |
00:19:24.72 |
-09:11:41.4 |
HIP 1607 |
13.23 |
| 2026-04-01 00:00 |
00:20:47.56 |
-08:57:11.2 |
HIP 1626 |
7.55 |
| 2026-04-01 12:00 |
00:22:10.40 |
-08:42:39.4 |
HIP 1682 |
29.27 |
| 2026-04-02 00:00 |
00:23:33.25 |
-08:28:05.8 |
HIP 2038 |
35.17 |
| 2026-04-02 12:00 |
00:24:56.12 |
-08:13:30.7 |
HIP 2038 |
15.89 |
| 2026-04-03 00:00 |
00:26:18.99 |
-07:58:54.0 |
HIP 2143 |
13.64 |
| 2026-04-03 12:00 |
00:27:41.87 |
-07:44:15.7 |
HIP 2143 |
11.84 |
| 2026-04-04 00:00 |
00:29:04.77 |
-07:29:35.9 |
HIP 2275 |
12.57 |
| 2026-04-04 12:00 |
00:30:27.68 |
-07:14:54.6 |
HIP 2275 |
34.00 |
| 2026-04-05 00:00 |
00:31:50.61 |
-07:00:11.8 |
HIP 2302 |
47.26 |
| 2026-04-05 12:00 |
00:33:13.57 |
-06:45:27.6 |
HIP 2710 |
23.81 |
| 2026-04-06 00:00 |
00:34:36.54 |
-06:30:42.0 |
HIP 2710 |
2.36 |
| 2026-04-06 12:00 |
00:35:59.53 |
-06:15:55.0 |
HIP 2785 |
10.22 |
| 2026-04-07 00:00 |
00:37:22.55 |
-06:01:06.7 |
HIP 2919 |
8.39 |
| 2026-04-07 12:00 |
00:38:45.59 |
-05:46:17.2 |
HIP 2980 |
18.21 |
| 2026-04-08 00:00 |
00:40:08.66 |
-05:31:26.3 |
HIP 2980 |
43.40 |
| 2026-04-08 12:00 |
00:41:31.76 |
-05:16:34.2 |
HIP 3222 |
43.54 |
| 2026-04-09 00:00 |
00:42:54.89 |
-05:01:41.0 |
HIP 3549 |
36.22 |
| 2026-04-09 12:00 |
00:44:18.05 |
-04:46:46.6 |
HIP 3552 |
18.77 |
| 2026-04-10 00:00 |
00:45:41.24 |
-04:31:51.0 |
HIP 3552 |
7.29 |
| 2026-04-10 12:00 |
00:47:04.47 |
-04:16:54.4 |
HIP 3645 |
10.53 |
| 2026-04-11 00:00 |
00:48:27.74 |
-04:01:56.8 |
HIP 3746 |
20.12 |
| 2026-04-11 12:00 |
00:49:51.04 |
-03:46:58.1 |
HIP 3746 |
27.06 |
| 2026-04-12 00:00 |
00:51:14.38 |
-03:31:58.5 |
HIP 4021 |
23.83 |
| 2026-04-12 12:00 |
00:52:37.77 |
-03:16:57.9 |
HIP 4021 |
18.28 |
| 2026-04-13 00:00 |
00:54:01.20 |
-03:01:56.5 |
HIP 4260 |
21.66 |
| 2026-04-13 12:00 |
00:55:24.67 |
-02:46:54.2 |
HIP 4260 |
17.17 |
| 2026-04-14 00:00 |
00:56:48.19 |
-02:31:51.0 |
HIP 4439 |
11.94 |
| 2026-04-14 12:00 |
00:58:11.76 |
-02:16:47.1 |
HIP 4609 |
16.51 |
| 2026-04-15 00:00 |
00:59:35.37 |
-02:01:42.5 |
HIP 4676 |
7.09 |
| 2026-04-15 12:00 |
01:00:59.04 |
-01:46:37.2 |
HIP 4726 |
8.50 |
| 2026-04-16 00:00 |
01:02:22.76 |
-01:31:31.2 |
HIP 4944 |
15.84 |