| Parameter |
Value |
| Designation |
258P/PANSTARRS |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2020-06-18T01:33:18.210240Z |
| Orbit solution date (soln_date, UTC) |
2021-10-18T22:42:54Z |
| Obs used |
80 |
| NEO |
- |
| M1 |
16.300 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2016-06-01.0000000 |
| e |
0.21036720 |
| q (au) |
3.478121 |
| a (au) |
4.404733 |
| i (deg) |
6.745233 |
| Ω (om, deg) |
126.294862 |
| ω (w, deg) |
26.014329 |
| M (ma, deg) |
202.413786 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.051 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.051 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-0.500 |
| k |
1.000 |
| 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) |
| 2026-09-25 00:00 |
01:32:52.70 |
+01:09:32.4 |
HIP 7149 |
15.63 |
| 2026-09-25 12:00 |
01:32:38.90 |
+01:07:42.0 |
HIP 7149 |
14.94 |
| 2026-09-26 00:00 |
01:32:24.98 |
+01:05:51.5 |
HIP 7149 |
15.24 |
| 2026-09-26 12:00 |
01:32:10.96 |
+01:04:00.7 |
HIP 7149 |
16.51 |
| 2026-09-27 00:00 |
01:31:56.82 |
+01:02:09.9 |
HIP 7149 |
18.56 |
| 2026-09-27 12:00 |
01:31:42.58 |
+01:00:18.8 |
HIP 7149 |
21.18 |
| 2026-09-28 00:00 |
01:31:28.24 |
+00:58:27.7 |
HIP 7149 |
24.20 |
| 2026-09-28 12:00 |
01:31:13.80 |
+00:56:36.4 |
HIP 7025 |
27.09 |
| 2026-09-29 00:00 |
01:30:59.25 |
+00:54:45.1 |
HIP 7025 |
27.68 |
| 2026-09-29 12:00 |
01:30:44.61 |
+00:52:53.7 |
HIP 7025 |
28.84 |
| 2026-09-30 00:00 |
01:30:29.88 |
+00:51:02.2 |
HIP 7025 |
30.51 |
| 2026-09-30 12:00 |
01:30:15.05 |
+00:49:10.7 |
HIP 7025 |
32.62 |
| 2026-10-01 00:00 |
01:30:00.13 |
+00:47:19.2 |
HIP 7025 |
35.10 |
| 2026-10-01 12:00 |
01:29:45.13 |
+00:45:27.7 |
HIP 7025 |
37.89 |
| 2026-10-02 00:00 |
01:29:30.04 |
+00:43:36.2 |
HIP 7025 |
40.92 |
| 2026-10-02 12:00 |
01:29:14.87 |
+00:41:44.7 |
HIP 7025 |
44.16 |
| 2026-10-03 00:00 |
01:28:59.61 |
+00:39:53.3 |
HIP 6790 |
43.60 |
| 2026-10-03 12:00 |
01:28:44.29 |
+00:38:02.0 |
HIP 6790 |
40.00 |
| 2026-10-04 00:00 |
01:28:28.88 |
+00:36:10.8 |
HIP 6790 |
36.54 |
| 2026-10-04 12:00 |
01:28:13.41 |
+00:34:19.7 |
HIP 6790 |
33.26 |
| 2026-10-05 00:00 |
01:27:57.86 |
+00:32:28.7 |
HIP 6790 |
30.24 |
| 2026-10-05 12:00 |
01:27:42.25 |
+00:30:37.9 |
HIP 6790 |
27.56 |
| 2026-10-06 00:00 |
01:27:26.58 |
+00:28:47.3 |
HIP 6790 |
25.33 |
| 2026-10-06 12:00 |
01:27:10.85 |
+00:26:56.9 |
HIP 6790 |
23.71 |
| 2026-10-07 00:00 |
01:26:55.05 |
+00:25:06.7 |
HIP 6790 |
22.81 |
| 2026-10-07 12:00 |
01:26:39.21 |
+00:23:16.7 |
HIP 6790 |
22.73 |
| 2026-10-08 00:00 |
01:26:23.31 |
+00:21:27.0 |
HIP 6629 |
20.64 |
| 2026-10-08 12:00 |
01:26:07.36 |
+00:19:37.6 |
HIP 6629 |
16.34 |
| 2026-10-09 00:00 |
01:25:51.37 |
+00:17:48.5 |
HIP 6629 |
12.08 |
| 2026-10-09 12:00 |
01:25:35.33 |
+00:15:59.7 |
HIP 6629 |
7.96 |
| 2026-10-10 00:00 |
01:25:19.26 |
+00:14:11.2 |
HIP 6629 |
4.40 |
| 2026-10-10 12:00 |
01:25:03.14 |
+00:12:23.1 |
HIP 6629 |
3.76 |
| 2026-10-11 00:00 |
01:24:47.00 |
+00:10:35.4 |
HIP 6629 |
6.92 |
| 2026-10-11 12:00 |
01:24:30.82 |
+00:08:48.1 |
HIP 6629 |
10.99 |
| 2026-10-12 00:00 |
01:24:14.62 |
+00:07:01.3 |
HIP 6629 |
15.25 |
| 2026-10-12 12:00 |
01:23:58.39 |
+00:05:14.9 |
HIP 6629 |
19.59 |
| 2026-10-13 00:00 |
01:23:42.15 |
+00:03:28.9 |
HIP 6629 |
23.96 |
| 2026-10-13 12:00 |
01:23:25.88 |
+00:01:43.5 |
HIP 6629 |
28.35 |
| 2026-10-14 00:00 |
01:23:09.60 |
-00:00:01.5 |
HIP 6429 |
28.32 |
| 2026-10-14 12:00 |
01:22:53.31 |
-00:01:45.9 |
HIP 6429 |
25.63 |
| 2026-10-15 00:00 |
01:22:37.01 |
-00:03:29.8 |
HIP 6429 |
23.49 |
| 2026-10-15 12:00 |
01:22:20.70 |
-00:05:13.1 |
HIP 6429 |
22.04 |
| 2026-10-16 00:00 |
01:22:04.40 |
-00:06:55.8 |
HIP 6429 |
21.44 |