| Parameter |
Value |
| Designation |
C/2020 O2 (Amaral) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-08-28T14:45:24.552000Z |
| Orbit solution date (soln_date, UTC) |
2024-05-14T12:42:17Z |
| Obs used |
1595 |
| NEO |
- |
| M1 |
5.900 |
| K1 |
10.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-07-23T23:20:29.184000Z |
| Discovery magnitude (MPC) |
18.10 R |
| Discovery observatory (MPC) |
X74 · Observatório Campo dos Amarais |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-02-27.0000000 |
| e |
1.00232543 |
| q (au) |
4.862254 |
| a (au) |
-2090.901073 |
| i (deg) |
71.750811 |
| Ω (om, deg) |
256.757254 |
| ω (w, deg) |
10.309432 |
| M (ma, deg) |
0.001880 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.977 + 4.155\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.977 |
| n |
4.155 |
| gf |
0.986 |
| gb |
-0.948 |
| k |
1.000 |
| δ90 |
9.957 |
| 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 |
| 2020-07-23 |
2021-08-28 |
+6.9479 |
-4.707 |
| 2021-08-29 |
2023-09-21 |
-0.9103 |
+0.615 |
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 |
23:31:47.57 |
+64:02:14.7 |
HIP 116197 |
7.75 |
| 2026-03-26 12:00 |
23:32:11.65 |
+64:03:06.1 |
HIP 116197 |
5.52 |
| 2026-03-27 00:00 |
23:32:35.69 |
+64:03:58.3 |
HIP 116197 |
4.02 |
| 2026-03-27 12:00 |
23:32:59.70 |
+64:04:51.3 |
HIP 116197 |
4.12 |
| 2026-03-28 00:00 |
23:33:23.67 |
+64:05:44.9 |
HIP 116197 |
5.74 |
| 2026-03-28 12:00 |
23:33:47.61 |
+64:06:39.3 |
HIP 116197 |
8.01 |
| 2026-03-29 00:00 |
23:34:11.52 |
+64:07:34.4 |
HIP 116197 |
10.51 |
| 2026-03-29 12:00 |
23:34:35.39 |
+64:08:30.2 |
HIP 116197 |
13.11 |
| 2026-03-30 00:00 |
23:34:59.22 |
+64:09:26.8 |
HIP 116197 |
15.77 |
| 2026-03-30 12:00 |
23:35:23.02 |
+64:10:24.0 |
HIP 116197 |
18.45 |
| 2026-03-31 00:00 |
23:35:46.78 |
+64:11:21.9 |
HIP 116648 |
18.79 |
| 2026-03-31 12:00 |
23:36:10.51 |
+64:12:20.6 |
HIP 116648 |
16.05 |
| 2026-04-01 00:00 |
23:36:34.19 |
+64:13:19.9 |
HIP 116648 |
13.33 |
| 2026-04-01 12:00 |
23:36:57.84 |
+64:14:19.9 |
HIP 116648 |
10.61 |
| 2026-04-02 00:00 |
23:37:21.45 |
+64:15:20.7 |
HIP 116648 |
7.93 |
| 2026-04-02 12:00 |
23:37:45.02 |
+64:16:22.1 |
HIP 116648 |
5.31 |
| 2026-04-03 00:00 |
23:38:08.55 |
+64:17:24.1 |
HIP 116648 |
2.93 |
| 2026-04-03 12:00 |
23:38:32.03 |
+64:18:26.9 |
HIP 116648 |
2.04 |
| 2026-04-04 00:00 |
23:38:55.48 |
+64:19:30.4 |
HIP 116648 |
3.85 |
| 2026-04-04 12:00 |
23:39:18.88 |
+64:20:34.5 |
HIP 116648 |
6.37 |
| 2026-04-05 00:00 |
23:39:42.25 |
+64:21:39.3 |
HIP 116648 |
9.02 |
| 2026-04-05 12:00 |
23:40:05.57 |
+64:22:44.7 |
HIP 116648 |
11.71 |
| 2026-04-06 00:00 |
23:40:28.84 |
+64:23:50.8 |
HIP 116948 |
14.00 |
| 2026-04-06 12:00 |
23:40:52.07 |
+64:24:57.6 |
HIP 116948 |
11.28 |
| 2026-04-07 00:00 |
23:41:15.26 |
+64:26:05.1 |
HIP 116948 |
8.57 |
| 2026-04-07 12:00 |
23:41:38.40 |
+64:27:13.2 |
HIP 116948 |
5.89 |
| 2026-04-08 00:00 |
23:42:01.50 |
+64:28:21.9 |
HIP 116948 |
3.31 |
| 2026-04-08 12:00 |
23:42:24.55 |
+64:29:31.3 |
HIP 116948 |
1.46 |
| 2026-04-09 00:00 |
23:42:47.55 |
+64:30:41.3 |
HIP 116948 |
2.87 |
| 2026-04-09 12:00 |
23:43:10.50 |
+64:31:52.0 |
HIP 116948 |
5.41 |
| 2026-04-10 00:00 |
23:43:33.41 |
+64:33:03.3 |
HIP 116948 |
8.08 |
| 2026-04-10 12:00 |
23:43:56.26 |
+64:34:15.3 |
HIP 117069 |
10.22 |
| 2026-04-11 00:00 |
23:44:19.07 |
+64:35:27.8 |
HIP 117069 |
9.26 |
| 2026-04-11 12:00 |
23:44:41.82 |
+64:36:41.1 |
HIP 117069 |
9.05 |
| 2026-04-12 00:00 |
23:45:04.53 |
+64:37:54.9 |
HIP 117069 |
9.61 |
| 2026-04-12 12:00 |
23:45:27.18 |
+64:39:09.3 |
HIP 117069 |
10.84 |
| 2026-04-13 00:00 |
23:45:49.78 |
+64:40:24.4 |
HIP 117069 |
12.54 |
| 2026-04-13 12:00 |
23:46:12.33 |
+64:41:40.1 |
HIP 117069 |
14.53 |
| 2026-04-14 00:00 |
23:46:34.82 |
+64:42:56.4 |
HIP 117430 |
16.37 |
| 2026-04-14 12:00 |
23:46:57.26 |
+64:44:13.3 |
HIP 117430 |
13.69 |
| 2026-04-15 00:00 |
23:47:19.64 |
+64:45:30.8 |
HIP 117430 |
11.02 |
| 2026-04-15 12:00 |
23:47:41.97 |
+64:46:48.9 |
HIP 117430 |
8.38 |
| 2026-04-16 00:00 |
23:48:04.24 |
+64:48:07.6 |
HIP 117430 |
5.80 |