| Parameter |
Value |
| Designation |
P/2006 HR30 (Siding Spring) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2007-01-02T06:45:45.152640Z |
| Orbit solution date (soln_date, UTC) |
2026-08-07T12:42:15Z |
| Obs used |
3073 |
| NEO |
Yes |
| M1 |
13.900 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2006-11-26.0000000 |
| e |
0.84312358 |
| q (au) |
1.226429 |
| a (au) |
7.817805 |
| i (deg) |
31.884450 |
| Ω (om, deg) |
309.951881 |
| ω (w, deg) |
117.413801 |
| M (ma, deg) |
358.318978 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.237 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.237 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-0.665 |
| k |
0.800 |
| 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) |
| 2026-09-20 00:00 |
18:45:51.56 |
-36:40:51.9 |
HIP 91959 |
18.86 |
| 2026-09-20 12:00 |
18:45:49.71 |
-36:39:25.0 |
HIP 91959 |
19.58 |
| 2026-09-21 00:00 |
18:45:48.04 |
-36:37:57.9 |
HIP 91959 |
20.41 |
| 2026-09-21 12:00 |
18:45:46.57 |
-36:36:30.7 |
HIP 91901 |
20.85 |
| 2026-09-22 00:00 |
18:45:45.28 |
-36:35:03.3 |
HIP 91901 |
21.11 |
| 2026-09-22 12:00 |
18:45:44.18 |
-36:33:35.8 |
HIP 91901 |
21.52 |
| 2026-09-23 00:00 |
18:45:43.26 |
-36:32:08.2 |
HIP 91901 |
22.04 |
| 2026-09-23 12:00 |
18:45:42.54 |
-36:30:40.4 |
HIP 91901 |
22.69 |
| 2026-09-24 00:00 |
18:45:42.00 |
-36:29:12.4 |
HIP 91901 |
23.44 |
| 2026-09-24 12:00 |
18:45:41.64 |
-36:27:44.4 |
HIP 91901 |
24.28 |
| 2026-09-25 00:00 |
18:45:41.48 |
-36:26:16.2 |
HIP 92220 |
24.76 |
| 2026-09-25 12:00 |
18:45:41.50 |
-36:24:47.9 |
HIP 92220 |
25.18 |
| 2026-09-26 00:00 |
18:45:41.70 |
-36:23:19.5 |
HIP 92220 |
25.65 |
| 2026-09-26 12:00 |
18:45:42.09 |
-36:21:51.0 |
HIP 92220 |
26.16 |
| 2026-09-27 00:00 |
18:45:42.66 |
-36:20:22.4 |
HIP 92220 |
26.71 |
| 2026-09-27 12:00 |
18:45:43.41 |
-36:18:53.7 |
HIP 92220 |
27.30 |
| 2026-09-28 00:00 |
18:45:44.35 |
-36:17:24.9 |
HIP 92017 |
26.53 |
| 2026-09-28 12:00 |
18:45:45.48 |
-36:15:56.0 |
HIP 92017 |
25.12 |
| 2026-09-29 00:00 |
18:45:46.78 |
-36:14:27.1 |
HIP 92017 |
23.74 |
| 2026-09-29 12:00 |
18:45:48.27 |
-36:12:58.0 |
HIP 92108 |
22.23 |
| 2026-09-30 00:00 |
18:45:49.94 |
-36:11:28.9 |
HIP 92108 |
20.71 |
| 2026-09-30 12:00 |
18:45:51.79 |
-36:09:59.7 |
HIP 92108 |
19.18 |
| 2026-10-01 00:00 |
18:45:53.83 |
-36:08:30.4 |
HIP 92108 |
17.64 |
| 2026-10-01 12:00 |
18:45:56.04 |
-36:07:01.1 |
HIP 92108 |
16.08 |
| 2026-10-02 00:00 |
18:45:58.44 |
-36:05:31.7 |
HIP 92108 |
14.52 |
| 2026-10-02 12:00 |
18:46:01.02 |
-36:04:02.2 |
HIP 92108 |
12.94 |
| 2026-10-03 00:00 |
18:46:03.77 |
-36:02:32.7 |
HIP 92108 |
11.35 |
| 2026-10-03 12:00 |
18:46:06.71 |
-36:01:03.1 |
HIP 92108 |
9.75 |
| 2026-10-04 00:00 |
18:46:09.82 |
-35:59:33.5 |
HIP 92108 |
8.15 |
| 2026-10-04 12:00 |
18:46:13.12 |
-35:58:03.8 |
HIP 92108 |
6.55 |
| 2026-10-05 00:00 |
18:46:16.59 |
-35:56:34.1 |
HIP 92108 |
4.96 |
| 2026-10-05 12:00 |
18:46:20.24 |
-35:55:04.4 |
HIP 92108 |
3.44 |
| 2026-10-06 00:00 |
18:46:24.07 |
-35:53:34.6 |
HIP 92108 |
2.17 |
| 2026-10-06 12:00 |
18:46:28.07 |
-35:52:04.8 |
HIP 92108 |
1.84 |
| 2026-10-07 00:00 |
18:46:32.25 |
-35:50:35.0 |
HIP 92108 |
2.83 |
| 2026-10-07 12:00 |
18:46:36.61 |
-35:49:05.1 |
HIP 92108 |
4.34 |
| 2026-10-08 00:00 |
18:46:41.15 |
-35:47:35.2 |
HIP 92108 |
6.00 |
| 2026-10-08 12:00 |
18:46:45.86 |
-35:46:05.3 |
HIP 92108 |
7.73 |
| 2026-10-09 00:00 |
18:46:50.74 |
-35:44:35.3 |
HIP 92108 |
9.51 |
| 2026-10-09 12:00 |
18:46:55.80 |
-35:43:05.4 |
HIP 92108 |
11.31 |
| 2026-10-10 00:00 |
18:47:01.03 |
-35:41:35.4 |
HIP 92108 |
13.14 |
| 2026-10-10 12:00 |
18:47:06.43 |
-35:40:05.5 |
HIP 92234 |
13.70 |
| 2026-10-11 00:00 |
18:47:12.01 |
-35:38:35.5 |
HIP 92234 |
11.82 |