| Parameter |
Value |
| Designation |
C/2020 J1 (SONEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-04-18T14:32:05.205120Z |
| Orbit solution date (soln_date, UTC) |
2023-05-24T21:12:29Z |
| Obs used |
1423 |
| NEO |
- |
| M1 |
8.000 |
| K1 |
7.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-05-01T06:33:40.896000Z |
| Discovery magnitude (MPC) |
17.00 R |
| Discovery observatory (MPC) |
Y00 · SONEAR Observatory, Oliveira |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-10-28.0000000 |
| e |
1.00036308 |
| q (au) |
3.355156 |
| a (au) |
-9240.744312 |
| i (deg) |
142.295628 |
| Ω (om, deg) |
226.582890 |
| ω (w, deg) |
341.755563 |
| M (ma, deg) |
0.000213 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.505 + 3.369\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.505 |
| n |
3.369 |
| gf |
0.833 |
| gb |
-0.500 |
| k |
0.921 |
| δ90 |
2.649 |
| 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 |
| 2020-04-19 |
2021-04-17 |
+0.2477 |
+0.184 |
| 2021-04-19 |
2021-12-01 |
-7.4917 |
+3.560 |
| 2021-12-01 |
2023-05-23 |
+6.0369 |
-4.382 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
08:42:04.51 |
+57:29:56.4 |
HIP 42875 |
17.71 |
| 2026-03-26 12:00 |
08:41:52.93 |
+57:29:02.7 |
HIP 42875 |
19.39 |
| 2026-03-27 00:00 |
08:41:41.50 |
+57:28:08.3 |
HIP 42875 |
21.08 |
| 2026-03-27 12:00 |
08:41:30.20 |
+57:27:13.4 |
HIP 42875 |
22.76 |
| 2026-03-28 00:00 |
08:41:19.04 |
+57:26:18.0 |
HIP 42875 |
24.44 |
| 2026-03-28 12:00 |
08:41:08.03 |
+57:25:22.0 |
HIP 42875 |
26.11 |
| 2026-03-29 00:00 |
08:40:57.16 |
+57:24:25.5 |
HIP 42875 |
27.78 |
| 2026-03-29 12:00 |
08:40:46.43 |
+57:23:28.4 |
HIP 42875 |
29.45 |
| 2026-03-30 00:00 |
08:40:35.85 |
+57:22:30.8 |
HIP 42875 |
31.10 |
| 2026-03-30 12:00 |
08:40:25.40 |
+57:21:32.7 |
HIP 42875 |
32.75 |
| 2026-03-31 00:00 |
08:40:15.10 |
+57:20:34.1 |
HIP 42449 |
32.58 |
| 2026-03-31 12:00 |
08:40:04.94 |
+57:19:35.1 |
HIP 42449 |
31.31 |
| 2026-04-01 00:00 |
08:39:54.93 |
+57:18:35.5 |
HIP 42449 |
30.07 |
| 2026-04-01 12:00 |
08:39:45.05 |
+57:17:35.4 |
HIP 42449 |
28.87 |
| 2026-04-02 00:00 |
08:39:35.32 |
+57:16:34.9 |
HIP 42449 |
27.72 |
| 2026-04-02 12:00 |
08:39:25.74 |
+57:15:33.9 |
HIP 42449 |
26.62 |
| 2026-04-03 00:00 |
08:39:16.29 |
+57:14:32.4 |
HIP 42449 |
25.56 |
| 2026-04-03 12:00 |
08:39:06.99 |
+57:13:30.5 |
HIP 42449 |
24.56 |
| 2026-04-04 00:00 |
08:38:57.84 |
+57:12:28.2 |
HIP 42449 |
23.63 |
| 2026-04-04 12:00 |
08:38:48.83 |
+57:11:25.4 |
HIP 42449 |
22.76 |
| 2026-04-05 00:00 |
08:38:39.96 |
+57:10:22.2 |
HIP 42449 |
21.96 |
| 2026-04-05 12:00 |
08:38:31.23 |
+57:09:18.5 |
HIP 42449 |
21.25 |
| 2026-04-06 00:00 |
08:38:22.65 |
+57:08:14.5 |
HIP 42449 |
20.61 |
| 2026-04-06 12:00 |
08:38:14.21 |
+57:07:10.1 |
HIP 42449 |
20.07 |
| 2026-04-07 00:00 |
08:38:05.91 |
+57:06:05.2 |
HIP 42449 |
19.63 |
| 2026-04-07 12:00 |
08:37:57.76 |
+57:05:00.0 |
HIP 42449 |
19.29 |
| 2026-04-08 00:00 |
08:37:49.76 |
+57:03:54.3 |
HIP 42449 |
19.05 |
| 2026-04-08 12:00 |
08:37:41.89 |
+57:02:48.3 |
HIP 42449 |
18.91 |
| 2026-04-09 00:00 |
08:37:34.17 |
+57:01:42.0 |
HIP 42449 |
18.89 |
| 2026-04-09 12:00 |
08:37:26.59 |
+57:00:35.2 |
HIP 42449 |
18.97 |
| 2026-04-10 00:00 |
08:37:19.16 |
+56:59:28.2 |
HIP 42449 |
19.15 |
| 2026-04-10 12:00 |
08:37:11.87 |
+56:58:20.7 |
HIP 42449 |
19.43 |
| 2026-04-11 00:00 |
08:37:04.72 |
+56:57:13.0 |
HIP 42449 |
19.79 |
| 2026-04-11 12:00 |
08:36:57.72 |
+56:56:04.9 |
HIP 42449 |
20.25 |
| 2026-04-12 00:00 |
08:36:50.85 |
+56:54:56.4 |
HIP 42449 |
20.78 |
| 2026-04-12 12:00 |
08:36:44.14 |
+56:53:47.7 |
HIP 42046 |
20.78 |
| 2026-04-13 00:00 |
08:36:37.56 |
+56:52:38.6 |
HIP 42046 |
20.01 |
| 2026-04-13 12:00 |
08:36:31.13 |
+56:51:29.3 |
HIP 42046 |
19.35 |
| 2026-04-14 00:00 |
08:36:24.84 |
+56:50:19.6 |
HIP 42046 |
18.79 |
| 2026-04-14 12:00 |
08:36:18.69 |
+56:49:09.7 |
HIP 42046 |
18.35 |
| 2026-04-15 00:00 |
08:36:12.68 |
+56:47:59.4 |
HIP 42046 |
18.03 |
| 2026-04-15 12:00 |
08:36:06.82 |
+56:46:48.9 |
HIP 42046 |
17.84 |
| 2026-04-16 00:00 |
08:36:01.10 |
+56:45:38.2 |
HIP 42046 |
17.78 |