| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
13:58:49.67 |
-10:44:05.4 |
HIP 68198 |
19.62 |
| 2026-06-03 00:00 |
13:58:36.66 |
-10:42:35.9 |
HIP 68198 |
18.14 |
| 2026-06-03 12:00 |
13:58:23.82 |
-10:41:07.5 |
HIP 68198 |
17.28 |
| 2026-06-04 00:00 |
13:58:11.14 |
-10:39:40.0 |
HIP 68198 |
17.10 |
| 2026-06-04 12:00 |
13:57:58.63 |
-10:38:13.5 |
HIP 68198 |
17.59 |
| 2026-06-05 00:00 |
13:57:46.29 |
-10:36:48.0 |
HIP 68123 |
17.35 |
| 2026-06-05 12:00 |
13:57:34.13 |
-10:35:23.4 |
HIP 68123 |
15.90 |
| 2026-06-06 00:00 |
13:57:22.13 |
-10:34:00.0 |
HIP 68123 |
15.06 |
| 2026-06-06 12:00 |
13:57:10.31 |
-10:32:37.4 |
HIP 68123 |
14.91 |
| 2026-06-07 00:00 |
13:56:58.66 |
-10:31:15.9 |
HIP 68123 |
15.42 |
| 2026-06-07 12:00 |
13:56:47.18 |
-10:29:55.4 |
HIP 68123 |
16.52 |
| 2026-06-08 00:00 |
13:56:35.89 |
-10:28:35.9 |
HIP 68123 |
18.08 |
| 2026-06-08 12:00 |
13:56:24.77 |
-10:27:17.5 |
HIP 68123 |
19.96 |
| 2026-06-09 00:00 |
13:56:13.82 |
-10:26:00.1 |
HIP 68123 |
22.07 |
| 2026-06-09 12:00 |
13:56:03.06 |
-10:24:43.8 |
HIP 68107 |
24.14 |
| 2026-06-10 00:00 |
13:55:52.47 |
-10:23:28.5 |
HIP 68107 |
24.03 |
| 2026-06-10 12:00 |
13:55:42.07 |
-10:22:14.3 |
HIP 68107 |
24.24 |
| 2026-06-11 00:00 |
13:55:31.84 |
-10:21:01.1 |
HIP 68107 |
24.77 |
| 2026-06-11 12:00 |
13:55:21.80 |
-10:19:49.0 |
HIP 68107 |
25.58 |
| 2026-06-12 00:00 |
13:55:11.94 |
-10:18:38.0 |
HIP 68107 |
26.62 |
| 2026-06-12 12:00 |
13:55:02.27 |
-10:17:28.1 |
HIP 68107 |
27.86 |
| 2026-06-13 00:00 |
13:54:52.78 |
-10:16:19.3 |
HIP 68107 |
29.26 |
| 2026-06-13 12:00 |
13:54:43.47 |
-10:15:11.5 |
HIP 68107 |
30.78 |
| 2026-06-14 00:00 |
13:54:34.35 |
-10:14:04.9 |
HIP 68107 |
32.39 |
| 2026-06-14 12:00 |
13:54:25.42 |
-10:12:59.3 |
HIP 68107 |
34.08 |
| 2026-06-15 00:00 |
13:54:16.67 |
-10:11:54.9 |
HIP 67763 |
35.47 |
| 2026-06-15 12:00 |
13:54:08.11 |
-10:10:51.6 |
HIP 67763 |
35.21 |
| 2026-06-16 00:00 |
13:53:59.74 |
-10:09:49.4 |
HIP 67763 |
35.10 |
| 2026-06-16 12:00 |
13:53:51.56 |
-10:08:48.3 |
HIP 67763 |
35.15 |
| 2026-06-17 00:00 |
13:53:43.57 |
-10:07:48.3 |
HIP 67763 |
35.33 |
| 2026-06-17 12:00 |
13:53:35.76 |
-10:06:49.4 |
HIP 67763 |
35.65 |
| 2026-06-18 00:00 |
13:53:28.15 |
-10:05:51.7 |
HIP 67619 |
35.73 |
| 2026-06-18 12:00 |
13:53:20.73 |
-10:04:55.1 |
HIP 67619 |
34.61 |
| 2026-06-19 00:00 |
13:53:13.49 |
-10:03:59.6 |
HIP 67619 |
33.61 |
| 2026-06-19 12:00 |
13:53:06.45 |
-10:03:05.3 |
HIP 67619 |
32.73 |
| 2026-06-20 00:00 |
13:52:59.60 |
-10:02:12.0 |
HIP 67619 |
31.96 |
| 2026-06-20 12:00 |
13:52:52.94 |
-10:01:19.9 |
HIP 67619 |
31.31 |
| 2026-06-21 00:00 |
13:52:46.46 |
-10:00:29.0 |
HIP 67619 |
30.78 |
| 2026-06-21 12:00 |
13:52:40.18 |
-09:59:39.2 |
HIP 67619 |
30.37 |
| 2026-06-22 00:00 |
13:52:34.09 |
-09:58:50.5 |
HIP 67619 |
30.06 |