| 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) |
| 2026-07-29 00:00 |
01:40:54.83 |
+03:23:46.9 |
HIP 7747 |
18.04 |
| 2026-07-29 12:00 |
01:41:01.11 |
+03:23:34.4 |
HIP 7860 |
19.30 |
| 2026-07-30 00:00 |
01:41:07.23 |
+03:23:20.8 |
HIP 7860 |
19.47 |
| 2026-07-30 12:00 |
01:41:13.17 |
+03:23:06.2 |
HIP 7860 |
19.78 |
| 2026-07-31 00:00 |
01:41:18.93 |
+03:22:50.4 |
HIP 7860 |
20.21 |
| 2026-07-31 12:00 |
01:41:24.53 |
+03:22:33.6 |
HIP 7860 |
20.74 |
| 2026-08-01 00:00 |
01:41:29.95 |
+03:22:15.6 |
HIP 7860 |
21.36 |
| 2026-08-01 12:00 |
01:41:35.20 |
+03:21:56.6 |
HIP 7860 |
22.05 |
| 2026-08-02 00:00 |
01:41:40.27 |
+03:21:36.4 |
HIP 7860 |
22.80 |
| 2026-08-02 12:00 |
01:41:45.16 |
+03:21:15.2 |
HIP 7860 |
23.60 |
| 2026-08-03 00:00 |
01:41:49.88 |
+03:20:52.9 |
HIP 7860 |
24.44 |
| 2026-08-03 12:00 |
01:41:54.43 |
+03:20:29.5 |
HIP 7860 |
25.30 |
| 2026-08-04 00:00 |
01:41:58.79 |
+03:20:04.9 |
HIP 7860 |
26.18 |
| 2026-08-04 12:00 |
01:42:02.98 |
+03:19:39.3 |
HIP 7860 |
27.08 |
| 2026-08-05 00:00 |
01:42:06.98 |
+03:19:12.6 |
HIP 7860 |
27.99 |
| 2026-08-05 12:00 |
01:42:10.81 |
+03:18:44.7 |
HIP 7860 |
28.90 |
| 2026-08-06 00:00 |
01:42:14.45 |
+03:18:15.8 |
HIP 8090 |
29.75 |
| 2026-08-06 12:00 |
01:42:17.92 |
+03:17:45.8 |
HIP 8090 |
29.35 |
| 2026-08-07 00:00 |
01:42:21.20 |
+03:17:14.6 |
HIP 8090 |
29.02 |
| 2026-08-07 12:00 |
01:42:24.30 |
+03:16:42.4 |
HIP 8090 |
28.77 |
| 2026-08-08 00:00 |
01:42:27.21 |
+03:16:09.0 |
HIP 8090 |
28.59 |
| 2026-08-08 12:00 |
01:42:29.94 |
+03:15:34.6 |
HIP 8090 |
28.48 |
| 2026-08-09 00:00 |
01:42:32.49 |
+03:14:59.0 |
HIP 8090 |
28.45 |
| 2026-08-09 12:00 |
01:42:34.85 |
+03:14:22.4 |
HIP 8090 |
28.50 |
| 2026-08-10 00:00 |
01:42:37.02 |
+03:13:44.6 |
HIP 8090 |
28.61 |
| 2026-08-10 12:00 |
01:42:39.01 |
+03:13:05.8 |
HIP 8090 |
28.78 |
| 2026-08-11 00:00 |
01:42:40.81 |
+03:12:25.9 |
HIP 8134 |
28.76 |
| 2026-08-11 12:00 |
01:42:42.42 |
+03:11:44.8 |
HIP 8134 |
28.39 |
| 2026-08-12 00:00 |
01:42:43.85 |
+03:11:02.7 |
HIP 8134 |
28.09 |
| 2026-08-12 12:00 |
01:42:45.08 |
+03:10:19.5 |
HIP 8134 |
27.85 |
| 2026-08-13 00:00 |
01:42:46.13 |
+03:09:35.2 |
HIP 8134 |
27.68 |
| 2026-08-13 12:00 |
01:42:46.99 |
+03:08:49.8 |
HIP 8134 |
27.59 |
| 2026-08-14 00:00 |
01:42:47.66 |
+03:08:03.3 |
HIP 8134 |
27.56 |
| 2026-08-14 12:00 |
01:42:48.14 |
+03:07:15.8 |
HIP 8134 |
27.61 |
| 2026-08-15 00:00 |
01:42:48.43 |
+03:06:27.1 |
HIP 8134 |
27.73 |
| 2026-08-15 12:00 |
01:42:48.53 |
+03:05:37.5 |
HIP 8134 |
27.93 |
| 2026-08-16 00:00 |
01:42:48.44 |
+03:04:46.7 |
HIP 8134 |
28.20 |
| 2026-08-16 12:00 |
01:42:48.16 |
+03:03:54.9 |
HIP 8134 |
28.54 |
| 2026-08-17 00:00 |
01:42:47.69 |
+03:03:02.0 |
HIP 8134 |
28.96 |
| 2026-08-17 12:00 |
01:42:47.03 |
+03:02:08.1 |
HIP 8134 |
29.44 |
| 2026-08-18 00:00 |
01:42:46.19 |
+03:01:13.2 |
HIP 8134 |
30.00 |
| 2026-08-18 12:00 |
01:42:45.15 |
+03:00:17.2 |
HIP 8134 |
30.63 |
| 2026-08-19 00:00 |
01:42:43.92 |
+02:59:20.1 |
HIP 8134 |
31.32 |