| Parameter |
Value |
| Designation |
238P/Read |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-06-05T10:21:50.189760Z |
| Orbit solution date (soln_date, UTC) |
2024-05-30T15:51:09Z |
| Obs used |
119 |
| NEO |
- |
| M1 |
8.300 |
| K1 |
29.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-09-15.0000000 |
| e |
0.25167358 |
| q (au) |
2.369349 |
| a (au) |
3.166197 |
| i (deg) |
1.264088 |
| Ω (om, deg) |
51.625454 |
| ω (w, deg) |
324.206807 |
| M (ma, deg) |
17.768666 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.645 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.645 |
| n |
6.000 |
| gf |
0.980 |
| gb |
-0.872 |
| k |
1.000 |
| δ90 |
9.541 |
| 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 |
| 2021-06-11 |
2021-11-26 |
+2.0338 |
+0.530 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
16:13:47.12 |
-21:48:10.6 |
HIP 79524 |
24.23 |
| 2026-09-20 12:00 |
16:14:16.92 |
-21:49:26.2 |
HIP 79644 |
21.64 |
| 2026-09-21 00:00 |
16:14:46.91 |
-21:50:42.0 |
HIP 79644 |
17.34 |
| 2026-09-21 12:00 |
16:15:17.08 |
-21:51:57.9 |
HIP 79644 |
15.28 |
| 2026-09-22 00:00 |
16:15:47.43 |
-21:53:13.9 |
HIP 79644 |
16.36 |
| 2026-09-22 12:00 |
16:16:17.97 |
-21:54:30.0 |
HIP 79644 |
20.13 |
| 2026-09-23 00:00 |
16:16:48.70 |
-21:55:46.2 |
HIP 79839 |
13.65 |
| 2026-09-23 12:00 |
16:17:19.60 |
-21:57:02.5 |
HIP 79839 |
7.05 |
| 2026-09-24 00:00 |
16:17:50.69 |
-21:58:18.8 |
HIP 79839 |
4.37 |
| 2026-09-24 12:00 |
16:18:21.95 |
-21:59:35.2 |
HIP 79839 |
9.82 |
| 2026-09-25 00:00 |
16:18:53.39 |
-22:00:51.6 |
HIP 79839 |
16.83 |
| 2026-09-25 12:00 |
16:19:25.01 |
-22:02:08.1 |
HIP 80085 |
21.59 |
| 2026-09-26 00:00 |
16:19:56.81 |
-22:03:24.6 |
HIP 80085 |
16.87 |
| 2026-09-26 12:00 |
16:20:28.78 |
-22:04:41.1 |
HIP 80130 |
12.27 |
| 2026-09-27 00:00 |
16:21:00.92 |
-22:05:57.7 |
HIP 80130 |
4.72 |
| 2026-09-27 12:00 |
16:21:33.24 |
-22:07:14.2 |
HIP 80130 |
2.89 |
| 2026-09-28 00:00 |
16:22:05.73 |
-22:08:30.8 |
HIP 80130 |
10.51 |
| 2026-09-28 12:00 |
16:22:38.39 |
-22:09:47.3 |
HIP 80130 |
18.18 |
| 2026-09-29 00:00 |
16:23:11.23 |
-22:11:03.8 |
HIP 80130 |
25.89 |
| 2026-09-29 12:00 |
16:23:44.23 |
-22:12:20.3 |
HIP 80440 |
26.21 |
| 2026-09-30 00:00 |
16:24:17.41 |
-22:13:36.8 |
HIP 80440 |
21.72 |
| 2026-09-30 12:00 |
16:24:50.75 |
-22:14:53.2 |
HIP 80440 |
19.41 |
| 2026-10-01 00:00 |
16:25:24.26 |
-22:16:09.6 |
HIP 80440 |
20.13 |
| 2026-10-01 12:00 |
16:25:57.93 |
-22:17:25.9 |
HIP 80587 |
20.00 |
| 2026-10-02 00:00 |
16:26:31.78 |
-22:18:42.2 |
HIP 80587 |
14.68 |
| 2026-10-02 12:00 |
16:27:05.79 |
-22:19:58.3 |
HIP 80587 |
12.52 |
| 2026-10-03 00:00 |
16:27:39.96 |
-22:21:14.4 |
HIP 80632 |
14.69 |
| 2026-10-03 12:00 |
16:28:14.30 |
-22:22:30.4 |
HIP 80632 |
14.28 |
| 2026-10-04 00:00 |
16:28:48.80 |
-22:23:46.3 |
HIP 80632 |
17.95 |
| 2026-10-04 12:00 |
16:29:23.46 |
-22:25:02.1 |
HIP 80810 |
10.18 |
| 2026-10-05 00:00 |
16:29:58.29 |
-22:26:17.7 |
HIP 80810 |
2.04 |
| 2026-10-05 12:00 |
16:30:33.27 |
-22:27:33.3 |
HIP 80810 |
6.15 |
| 2026-10-06 00:00 |
16:31:08.42 |
-22:28:48.7 |
HIP 80810 |
14.37 |
| 2026-10-06 12:00 |
16:31:43.73 |
-22:30:03.9 |
HIP 80937 |
18.07 |
| 2026-10-07 00:00 |
16:32:19.19 |
-22:31:19.0 |
HIP 80937 |
19.34 |
| 2026-10-07 12:00 |
16:32:54.82 |
-22:32:34.0 |
HIP 81093 |
21.20 |
| 2026-10-08 00:00 |
16:33:30.60 |
-22:33:48.8 |
HIP 81093 |
16.37 |
| 2026-10-08 12:00 |
16:34:06.53 |
-22:35:03.4 |
HIP 81169 |
8.38 |
| 2026-10-09 00:00 |
16:34:42.62 |
-22:36:17.8 |
HIP 81169 |
0.71 |
| 2026-10-09 12:00 |
16:35:18.87 |
-22:37:32.0 |
HIP 81169 |
8.56 |
| 2026-10-10 00:00 |
16:35:55.26 |
-22:38:46.0 |
HIP 81169 |
17.03 |
| 2026-10-10 12:00 |
16:36:31.81 |
-22:39:59.8 |
HIP 81169 |
25.55 |
| 2026-10-11 00:00 |
16:37:08.51 |
-22:41:13.4 |
HIP 81464 |
20.45 |