| Parameter |
Value |
| Designation |
185P/Petriew |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-08-13T01:18:02.707200Z |
| Orbit solution date (soln_date, UTC) |
2024-02-22T12:37:21Z |
| Obs used |
715 |
| NEO |
Yes |
| M1 |
13.600 |
| K1 |
10.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-04-17.0000000 |
| e |
0.69879499 |
| q (au) |
0.933837 |
| a (au) |
3.100337 |
| i (deg) |
13.997316 |
| Ω (om, deg) |
214.100822 |
| ω (w, deg) |
181.937558 |
| M (ma, deg) |
176.384777 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.159 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.159 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.827 |
| k |
0.988 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
14:18:32.58 |
-11:42:31.5 |
HIP 69945 |
21.65 |
| 2026-09-20 12:00 |
14:18:52.29 |
-11:44:00.0 |
HIP 69945 |
19.81 |
| 2026-09-21 00:00 |
14:19:12.07 |
-11:45:28.6 |
HIP 69945 |
19.15 |
| 2026-09-21 12:00 |
14:19:31.94 |
-11:46:57.5 |
HIP 69945 |
19.82 |
| 2026-09-22 00:00 |
14:19:51.88 |
-11:48:26.6 |
HIP 69945 |
21.70 |
| 2026-09-22 12:00 |
14:20:11.90 |
-11:49:56.0 |
HIP 69945 |
24.52 |
| 2026-09-23 00:00 |
14:20:31.99 |
-11:51:25.6 |
HIP 69945 |
28.02 |
| 2026-09-23 12:00 |
14:20:52.16 |
-11:52:55.4 |
HIP 70153 |
29.60 |
| 2026-09-24 00:00 |
14:21:12.40 |
-11:54:25.3 |
HIP 70281 |
24.51 |
| 2026-09-24 12:00 |
14:21:32.72 |
-11:55:55.5 |
HIP 70281 |
19.34 |
| 2026-09-25 00:00 |
14:21:53.11 |
-11:57:25.9 |
HIP 70281 |
14.17 |
| 2026-09-25 12:00 |
14:22:13.57 |
-11:58:56.5 |
HIP 70281 |
9.02 |
| 2026-09-26 00:00 |
14:22:34.10 |
-12:00:27.3 |
HIP 70281 |
4.07 |
| 2026-09-26 12:00 |
14:22:54.71 |
-12:01:58.2 |
HIP 70281 |
2.60 |
| 2026-09-27 00:00 |
14:23:15.38 |
-12:03:29.4 |
HIP 70281 |
7.25 |
| 2026-09-27 12:00 |
14:23:36.12 |
-12:05:00.7 |
HIP 70281 |
12.43 |
| 2026-09-28 00:00 |
14:23:56.94 |
-12:06:32.1 |
HIP 70281 |
17.69 |
| 2026-09-28 12:00 |
14:24:17.82 |
-12:08:03.8 |
HIP 70432 |
17.30 |
| 2026-09-29 00:00 |
14:24:38.77 |
-12:09:35.5 |
HIP 70432 |
15.69 |
| 2026-09-29 12:00 |
14:24:59.79 |
-12:11:07.5 |
HIP 70432 |
15.82 |
| 2026-09-30 00:00 |
14:25:20.88 |
-12:12:39.6 |
HIP 70432 |
17.66 |
| 2026-09-30 12:00 |
14:25:42.03 |
-12:14:11.8 |
HIP 70432 |
20.78 |
| 2026-10-01 00:00 |
14:26:03.25 |
-12:15:44.2 |
HIP 70432 |
24.71 |
| 2026-10-01 12:00 |
14:26:24.53 |
-12:17:16.7 |
HIP 70432 |
29.13 |
| 2026-10-02 00:00 |
14:26:45.88 |
-12:18:49.3 |
HIP 70432 |
33.86 |
| 2026-10-02 12:00 |
14:27:07.30 |
-12:20:22.1 |
HIP 70634 |
33.84 |
| 2026-10-03 00:00 |
14:27:28.77 |
-12:21:55.0 |
HIP 70634 |
33.24 |
| 2026-10-03 12:00 |
14:27:50.32 |
-12:23:28.0 |
HIP 70634 |
33.53 |
| 2026-10-04 00:00 |
14:28:11.92 |
-12:25:01.1 |
HIP 70634 |
34.70 |
| 2026-10-04 12:00 |
14:28:33.59 |
-12:26:34.3 |
HIP 70634 |
36.67 |
| 2026-10-05 00:00 |
14:28:55.31 |
-12:28:07.6 |
HIP 70975 |
32.50 |
| 2026-10-05 12:00 |
14:29:17.10 |
-12:29:41.1 |
HIP 70975 |
28.14 |
| 2026-10-06 00:00 |
14:29:38.95 |
-12:31:14.6 |
HIP 70975 |
24.26 |
| 2026-10-06 12:00 |
14:30:00.86 |
-12:32:48.1 |
HIP 70975 |
21.13 |
| 2026-10-07 00:00 |
14:30:22.83 |
-12:34:21.8 |
HIP 70975 |
19.13 |
| 2026-10-07 12:00 |
14:30:44.86 |
-12:35:55.6 |
HIP 70975 |
18.66 |
| 2026-10-08 00:00 |
14:31:06.94 |
-12:37:29.4 |
HIP 70975 |
19.83 |
| 2026-10-08 12:00 |
14:31:29.08 |
-12:39:03.2 |
HIP 70975 |
22.39 |
| 2026-10-09 00:00 |
14:31:51.28 |
-12:40:37.2 |
HIP 71113 |
22.06 |
| 2026-10-09 12:00 |
14:32:13.53 |
-12:42:11.1 |
HIP 71113 |
18.64 |
| 2026-10-10 00:00 |
14:32:35.84 |
-12:43:45.2 |
HIP 71113 |
16.49 |
| 2026-10-10 12:00 |
14:32:58.20 |
-12:45:19.2 |
HIP 71113 |
16.15 |
| 2026-10-11 00:00 |
14:33:20.62 |
-12:46:53.3 |
HIP 71113 |
17.73 |