| 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) |
| 2026-05-12 00:00 |
14:10:26.04 |
-12:01:00.3 |
HIP 69305 |
10.90 |
| 2026-05-12 12:00 |
14:10:07.38 |
-11:58:59.6 |
HIP 69305 |
14.88 |
| 2026-05-13 00:00 |
14:09:48.80 |
-11:56:59.3 |
HIP 69305 |
19.31 |
| 2026-05-13 12:00 |
14:09:30.31 |
-11:54:59.4 |
HIP 69092 |
15.89 |
| 2026-05-14 00:00 |
14:09:11.91 |
-11:53:00.1 |
HIP 69092 |
10.99 |
| 2026-05-14 12:00 |
14:08:53.60 |
-11:51:01.2 |
HIP 69092 |
6.15 |
| 2026-05-15 00:00 |
14:08:35.40 |
-11:49:02.8 |
HIP 69092 |
1.72 |
| 2026-05-15 12:00 |
14:08:17.28 |
-11:47:04.9 |
HIP 69092 |
3.93 |
| 2026-05-16 00:00 |
14:07:59.28 |
-11:45:07.6 |
HIP 69092 |
8.63 |
| 2026-05-16 12:00 |
14:07:41.37 |
-11:43:10.8 |
HIP 69092 |
13.39 |
| 2026-05-17 00:00 |
14:07:23.57 |
-11:41:14.6 |
HIP 69092 |
18.14 |
| 2026-05-17 12:00 |
14:07:05.88 |
-11:39:19.0 |
HIP 68861 |
16.07 |
| 2026-05-18 00:00 |
14:06:48.30 |
-11:37:23.9 |
HIP 68861 |
11.46 |
| 2026-05-18 12:00 |
14:06:30.84 |
-11:35:29.5 |
HIP 68861 |
7.02 |
| 2026-05-19 00:00 |
14:06:13.49 |
-11:33:35.7 |
HIP 68861 |
3.33 |
| 2026-05-19 12:00 |
14:05:56.26 |
-11:31:42.6 |
HIP 68861 |
4.00 |
| 2026-05-20 00:00 |
14:05:39.15 |
-11:29:50.1 |
HIP 68861 |
7.95 |
| 2026-05-20 12:00 |
14:05:22.17 |
-11:27:58.3 |
HIP 68861 |
12.32 |
| 2026-05-21 00:00 |
14:05:05.31 |
-11:26:07.1 |
HIP 68754 |
10.95 |
| 2026-05-21 12:00 |
14:04:48.57 |
-11:24:16.7 |
HIP 68754 |
8.27 |
| 2026-05-22 00:00 |
14:04:31.97 |
-11:22:27.0 |
HIP 68754 |
7.57 |
| 2026-05-22 12:00 |
14:04:15.49 |
-11:20:38.0 |
HIP 68754 |
9.25 |
| 2026-05-23 00:00 |
14:03:59.15 |
-11:18:49.7 |
HIP 68754 |
12.35 |
| 2026-05-23 12:00 |
14:03:42.95 |
-11:17:02.2 |
HIP 68754 |
16.03 |
| 2026-05-24 00:00 |
14:03:26.88 |
-11:15:15.4 |
HIP 68671 |
17.22 |
| 2026-05-24 12:00 |
14:03:10.95 |
-11:13:29.4 |
HIP 68671 |
15.96 |
| 2026-05-25 00:00 |
14:02:55.16 |
-11:11:44.2 |
HIP 68671 |
15.79 |
| 2026-05-25 12:00 |
14:02:39.51 |
-11:09:59.8 |
HIP 68671 |
16.72 |
| 2026-05-26 00:00 |
14:02:24.01 |
-11:08:16.2 |
HIP 68671 |
18.57 |
| 2026-05-26 12:00 |
14:02:08.65 |
-11:06:33.4 |
HIP 68671 |
21.07 |
| 2026-05-27 00:00 |
14:01:53.43 |
-11:04:51.4 |
HIP 68671 |
23.99 |
| 2026-05-27 12:00 |
14:01:38.37 |
-11:03:10.3 |
HIP 68671 |
27.19 |
| 2026-05-28 00:00 |
14:01:23.45 |
-11:01:30.0 |
HIP 68671 |
30.56 |
| 2026-05-28 12:00 |
14:01:08.69 |
-10:59:50.6 |
HIP 68671 |
34.03 |
| 2026-05-29 00:00 |
14:00:54.08 |
-10:58:12.0 |
HIP 68483 |
35.90 |
| 2026-05-29 12:00 |
14:00:39.62 |
-10:56:34.3 |
HIP 68376 |
32.96 |
| 2026-05-30 00:00 |
14:00:25.32 |
-10:54:57.5 |
HIP 68376 |
30.21 |
| 2026-05-30 12:00 |
14:00:11.18 |
-10:53:21.6 |
HIP 68376 |
27.75 |
| 2026-05-31 00:00 |
13:59:57.19 |
-10:51:46.6 |
HIP 68376 |
25.65 |
| 2026-05-31 12:00 |
13:59:43.36 |
-10:50:12.5 |
HIP 68376 |
23.98 |
| 2026-06-01 00:00 |
13:59:29.70 |
-10:48:39.3 |
HIP 68376 |
22.81 |
| 2026-06-01 12:00 |
13:59:16.19 |
-10:47:07.0 |
HIP 68376 |
22.20 |
| 2026-06-02 00:00 |
13:59:02.85 |
-10:45:35.7 |
HIP 68198 |
21.60 |