| Parameter |
Value |
| Designation |
253P/PANSTARRS |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2018-05-07T16:43:41.024640Z |
| Orbit solution date (soln_date, UTC) |
2025-10-28T16:12:55Z |
| Obs used |
936 |
| NEO |
- |
| M1 |
8.000 |
| K1 |
29.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-05-04.0000000 |
| e |
0.41304705 |
| q (au) |
2.036337 |
| a (au) |
3.469336 |
| i (deg) |
4.940807 |
| Ω (om, deg) |
146.875124 |
| ω (w, deg) |
230.708050 |
| M (ma, deg) |
55.106908 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.139 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.139 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.655 |
| k |
0.800 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2024-05-08 |
2025-02-03 |
+31.1826 |
-9.791 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
09:18:58.25 |
+15:58:50.8 |
HIP 45777 |
15.43 |
| 2026-06-01 12:00 |
09:19:21.20 |
+15:57:19.1 |
HIP 45777 |
9.75 |
| 2026-06-02 00:00 |
09:19:44.27 |
+15:55:46.7 |
HIP 45777 |
4.18 |
| 2026-06-02 12:00 |
09:20:07.44 |
+15:54:13.6 |
HIP 45777 |
2.47 |
| 2026-06-03 00:00 |
09:20:30.72 |
+15:52:39.8 |
HIP 45777 |
7.88 |
| 2026-06-03 12:00 |
09:20:54.10 |
+15:51:05.2 |
HIP 45777 |
13.65 |
| 2026-06-04 00:00 |
09:21:17.59 |
+15:49:30.0 |
HIP 45777 |
19.49 |
| 2026-06-04 12:00 |
09:21:41.18 |
+15:47:54.0 |
HIP 45989 |
15.69 |
| 2026-06-05 00:00 |
09:22:04.87 |
+15:46:17.3 |
HIP 45989 |
9.94 |
| 2026-06-05 12:00 |
09:22:28.67 |
+15:44:40.0 |
HIP 45989 |
4.64 |
| 2026-06-06 00:00 |
09:22:52.57 |
+15:43:01.9 |
HIP 45989 |
3.89 |
| 2026-06-06 12:00 |
09:23:16.56 |
+15:41:23.1 |
HIP 45989 |
8.99 |
| 2026-06-07 00:00 |
09:23:40.65 |
+15:39:43.7 |
HIP 45989 |
14.81 |
| 2026-06-07 12:00 |
09:24:04.84 |
+15:38:03.5 |
HIP 45989 |
20.77 |
| 2026-06-08 00:00 |
09:24:29.13 |
+15:36:22.6 |
HIP 45989 |
26.81 |
| 2026-06-08 12:00 |
09:24:53.51 |
+15:34:41.1 |
HIP 45989 |
32.89 |
| 2026-06-09 00:00 |
09:25:17.99 |
+15:32:58.9 |
HIP 46318 |
32.75 |
| 2026-06-09 12:00 |
09:25:42.56 |
+15:31:16.0 |
HIP 46318 |
28.03 |
| 2026-06-10 00:00 |
09:26:07.22 |
+15:29:32.4 |
HIP 46318 |
23.96 |
| 2026-06-10 12:00 |
09:26:31.98 |
+15:27:48.1 |
HIP 46318 |
20.94 |
| 2026-06-11 00:00 |
09:26:56.83 |
+15:26:03.2 |
HIP 46318 |
19.49 |
| 2026-06-11 12:00 |
09:27:21.76 |
+15:24:17.6 |
HIP 46318 |
19.98 |
| 2026-06-12 00:00 |
09:27:46.78 |
+15:22:31.3 |
HIP 46449 |
15.65 |
| 2026-06-12 12:00 |
09:28:11.90 |
+15:20:44.4 |
HIP 46449 |
11.28 |
| 2026-06-13 00:00 |
09:28:37.09 |
+15:18:56.8 |
HIP 46449 |
9.45 |
| 2026-06-13 12:00 |
09:29:02.38 |
+15:17:08.6 |
HIP 46449 |
11.48 |
| 2026-06-14 00:00 |
09:29:27.75 |
+15:15:19.7 |
HIP 46449 |
16.00 |
| 2026-06-14 12:00 |
09:29:53.20 |
+15:13:30.1 |
HIP 46635 |
10.37 |
| 2026-06-15 00:00 |
09:30:18.74 |
+15:11:39.9 |
HIP 46635 |
5.61 |
| 2026-06-15 12:00 |
09:30:44.35 |
+15:09:49.1 |
HIP 46635 |
6.19 |
| 2026-06-16 00:00 |
09:31:10.05 |
+15:07:57.6 |
HIP 46635 |
11.35 |
| 2026-06-16 12:00 |
09:31:35.83 |
+15:06:05.5 |
HIP 46635 |
17.43 |
| 2026-06-17 00:00 |
09:32:01.69 |
+15:04:12.7 |
HIP 46635 |
23.76 |
| 2026-06-17 12:00 |
09:32:27.62 |
+15:02:19.4 |
HIP 46635 |
30.19 |
| 2026-06-18 00:00 |
09:32:53.63 |
+15:00:25.4 |
HIP 46926 |
32.39 |
| 2026-06-18 12:00 |
09:33:19.71 |
+14:58:30.8 |
HIP 46969 |
27.66 |
| 2026-06-19 00:00 |
09:33:45.87 |
+14:56:35.6 |
HIP 46969 |
22.96 |
| 2026-06-19 12:00 |
09:34:12.10 |
+14:54:39.7 |
HIP 46969 |
19.39 |
| 2026-06-20 00:00 |
09:34:38.40 |
+14:52:43.3 |
HIP 46969 |
17.68 |
| 2026-06-20 12:00 |
09:35:04.78 |
+14:50:46.3 |
HIP 46969 |
18.37 |
| 2026-06-21 00:00 |
09:35:31.22 |
+14:48:48.7 |
HIP 46969 |
21.25 |
| 2026-06-21 12:00 |
09:35:57.73 |
+14:46:50.5 |
HIP 47096 |
24.09 |
| 2026-06-22 00:00 |
09:36:24.31 |
+14:44:51.7 |
HIP 47096 |
23.36 |