258P/PANSTARRS
| 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 |
-0.606 |
| 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) |
| 2026-02-03 00:00 |
23:39:10.12 |
-07:23:50.6 |
HIP 116834 |
39.47 |
| 2026-02-03 12:00 |
23:39:31.85 |
-07:21:23.8 |
HIP 116834 |
38.49 |
| 2026-02-04 00:00 |
23:39:53.65 |
-07:18:56.6 |
HIP 116834 |
38.41 |
| 2026-02-04 12:00 |
23:40:15.51 |
-07:16:29.1 |
HIP 116834 |
39.23 |
| 2026-02-05 00:00 |
23:40:37.43 |
-07:14:01.3 |
HIP 116834 |
40.92 |
| 2026-02-05 12:00 |
23:40:59.43 |
-07:11:33.2 |
HIP 117052 |
41.41 |
| 2026-02-06 00:00 |
23:41:21.48 |
-07:09:04.8 |
HIP 117052 |
36.75 |
| 2026-02-06 12:00 |
23:41:43.60 |
-07:06:36.0 |
HIP 117052 |
32.52 |
| 2026-02-07 00:00 |
23:42:05.79 |
-07:04:07.0 |
HIP 117052 |
28.93 |
| 2026-02-07 12:00 |
23:42:28.03 |
-07:01:37.7 |
HIP 117052 |
26.23 |
| 2026-02-08 00:00 |
23:42:50.34 |
-06:59:08.1 |
HIP 117052 |
24.75 |
| 2026-02-08 12:00 |
23:43:12.71 |
-06:56:38.2 |
HIP 117131 |
23.49 |
| 2026-02-09 00:00 |
23:43:35.14 |
-06:54:08.0 |
HIP 117131 |
18.04 |
| 2026-02-09 12:00 |
23:43:57.62 |
-06:51:37.5 |
HIP 117131 |
13.16 |
| 2026-02-10 00:00 |
23:44:20.17 |
-06:49:06.8 |
HIP 117131 |
9.79 |
| 2026-02-10 12:00 |
23:44:42.78 |
-06:46:35.8 |
HIP 117131 |
9.67 |
| 2026-02-11 00:00 |
23:45:05.44 |
-06:44:04.5 |
HIP 117131 |
12.93 |
| 2026-02-11 12:00 |
23:45:28.16 |
-06:41:33.0 |
HIP 117131 |
17.81 |
| 2026-02-12 00:00 |
23:45:50.94 |
-06:39:01.2 |
HIP 117131 |
23.33 |
| 2026-02-12 12:00 |
23:46:13.77 |
-06:36:29.2 |
HIP 117131 |
29.14 |
| 2026-02-13 00:00 |
23:46:36.66 |
-06:33:57.0 |
HIP 117420 |
30.85 |
| 2026-02-13 12:00 |
23:46:59.60 |
-06:31:24.5 |
HIP 117420 |
24.62 |
| 2026-02-14 00:00 |
23:47:22.60 |
-06:28:51.7 |
HIP 117420 |
18.38 |
| 2026-02-14 12:00 |
23:47:45.64 |
-06:26:18.8 |
HIP 117420 |
12.15 |
| 2026-02-15 00:00 |
23:48:08.75 |
-06:23:45.6 |
HIP 117420 |
5.97 |
| 2026-02-15 12:00 |
23:48:31.90 |
-06:21:12.2 |
HIP 117420 |
1.63 |
| 2026-02-16 00:00 |
23:48:55.10 |
-06:18:38.6 |
HIP 117420 |
7.00 |
| 2026-02-16 12:00 |
23:49:18.35 |
-06:16:04.8 |
HIP 117420 |
13.24 |
| 2026-02-17 00:00 |
23:49:41.65 |
-06:13:30.8 |
HIP 117420 |
19.55 |
| 2026-02-17 12:00 |
23:50:05.00 |
-06:10:56.6 |
HIP 117420 |
25.88 |
| 2026-02-18 00:00 |
23:50:28.40 |
-06:08:22.2 |
HIP 117420 |
32.23 |
| 2026-02-18 12:00 |
23:50:51.85 |
-06:05:47.6 |
HIP 117736 |
27.71 |
| 2026-02-19 00:00 |
23:51:15.34 |
-06:03:12.9 |
HIP 117736 |
21.47 |
| 2026-02-19 12:00 |
23:51:38.88 |
-06:00:38.0 |
HIP 117736 |
15.35 |
| 2026-02-20 00:00 |
23:52:02.46 |
-05:58:02.9 |
HIP 117736 |
9.59 |
| 2026-02-20 12:00 |
23:52:26.08 |
-05:55:27.6 |
HIP 117736 |
5.49 |
| 2026-02-21 00:00 |
23:52:49.75 |
-05:52:52.2 |
HIP 117736 |
7.13 |
| 2026-02-21 12:00 |
23:53:13.46 |
-05:50:16.7 |
HIP 117736 |
12.43 |
| 2026-02-22 00:00 |
23:53:37.22 |
-05:47:41.0 |
HIP 117736 |
18.48 |
| 2026-02-22 12:00 |
23:54:01.01 |
-05:45:05.1 |
HIP 117736 |
24.74 |
| 2026-02-23 00:00 |
23:54:24.84 |
-05:42:29.2 |
HIP 117780 |
29.46 |
| 2026-02-23 12:00 |
23:54:48.72 |
-05:39:53.1 |
HIP 118026 |
30.85 |
| 2026-02-24 00:00 |
23:55:12.63 |
-05:37:16.9 |
HIP 118026 |
28.30 |