C/2020 O2 (Amaral)
| 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) |
| 2026-02-03 00:00 |
22:50:00.47 |
+63:48:05.8 |
HIP 112691 |
6.97 |
| 2026-02-03 12:00 |
22:50:24.38 |
+63:47:28.3 |
HIP 112691 |
8.69 |
| 2026-02-04 00:00 |
22:50:48.33 |
+63:46:51.7 |
HIP 112691 |
10.83 |
| 2026-02-04 12:00 |
22:51:12.31 |
+63:46:16.1 |
HIP 112691 |
13.20 |
| 2026-02-05 00:00 |
22:51:36.33 |
+63:45:41.4 |
HIP 112691 |
15.69 |
| 2026-02-05 12:00 |
22:52:00.39 |
+63:45:07.6 |
HIP 112691 |
18.25 |
| 2026-02-06 00:00 |
22:52:24.47 |
+63:44:34.8 |
HIP 112983 |
19.98 |
| 2026-02-06 12:00 |
22:52:48.60 |
+63:44:02.9 |
HIP 112983 |
19.24 |
| 2026-02-07 00:00 |
22:53:12.75 |
+63:43:32.0 |
HIP 113051 |
18.73 |
| 2026-02-07 12:00 |
22:53:36.94 |
+63:43:02.0 |
HIP 113051 |
17.96 |
| 2026-02-08 00:00 |
22:54:01.16 |
+63:42:32.9 |
HIP 113051 |
17.61 |
| 2026-02-08 12:00 |
22:54:25.41 |
+63:42:04.8 |
HIP 113236 |
16.78 |
| 2026-02-09 00:00 |
22:54:49.69 |
+63:41:37.6 |
HIP 113236 |
14.98 |
| 2026-02-09 12:00 |
22:55:14.00 |
+63:41:11.4 |
HIP 113236 |
13.50 |
| 2026-02-10 00:00 |
22:55:38.34 |
+63:40:46.1 |
HIP 113236 |
12.48 |
| 2026-02-10 12:00 |
22:56:02.71 |
+63:40:21.7 |
HIP 113236 |
12.03 |
| 2026-02-11 00:00 |
22:56:27.10 |
+63:39:58.3 |
HIP 113236 |
12.20 |
| 2026-02-11 12:00 |
22:56:51.52 |
+63:39:35.8 |
HIP 113443 |
11.62 |
| 2026-02-12 00:00 |
22:57:15.97 |
+63:39:14.3 |
HIP 113443 |
9.13 |
| 2026-02-12 12:00 |
22:57:40.44 |
+63:38:53.7 |
HIP 113443 |
6.83 |
| 2026-02-13 00:00 |
22:58:04.94 |
+63:38:34.0 |
HIP 113443 |
4.96 |
| 2026-02-13 12:00 |
22:58:29.46 |
+63:38:15.3 |
HIP 113443 |
4.17 |
| 2026-02-14 00:00 |
22:58:54.00 |
+63:37:57.6 |
HIP 113443 |
5.01 |
| 2026-02-14 12:00 |
22:59:18.56 |
+63:37:40.7 |
HIP 113443 |
6.90 |
| 2026-02-15 00:00 |
22:59:43.15 |
+63:37:24.8 |
HIP 113443 |
9.22 |
| 2026-02-15 12:00 |
23:00:07.75 |
+63:37:09.9 |
HIP 113443 |
11.72 |
| 2026-02-16 00:00 |
23:00:32.38 |
+63:36:55.8 |
HIP 113443 |
14.30 |
| 2026-02-16 12:00 |
23:00:57.02 |
+63:36:42.8 |
HIP 113825 |
14.75 |
| 2026-02-17 00:00 |
23:01:21.68 |
+63:36:30.6 |
HIP 113825 |
12.31 |
| 2026-02-17 12:00 |
23:01:46.36 |
+63:36:19.4 |
HIP 113825 |
10.02 |
| 2026-02-18 00:00 |
23:02:11.06 |
+63:36:09.1 |
HIP 113825 |
8.01 |
| 2026-02-18 12:00 |
23:02:35.77 |
+63:35:59.7 |
HIP 113849 |
5.76 |
| 2026-02-19 00:00 |
23:03:00.50 |
+63:35:51.3 |
HIP 113849 |
3.57 |
| 2026-02-19 12:00 |
23:03:25.24 |
+63:35:43.8 |
HIP 113849 |
2.76 |
| 2026-02-20 00:00 |
23:03:49.99 |
+63:35:37.3 |
HIP 113849 |
4.21 |
| 2026-02-20 12:00 |
23:04:14.76 |
+63:35:31.6 |
HIP 113849 |
6.57 |
| 2026-02-21 00:00 |
23:04:39.53 |
+63:35:26.9 |
HIP 113849 |
9.16 |
| 2026-02-21 12:00 |
23:05:04.32 |
+63:35:23.1 |
HIP 113849 |
11.83 |
| 2026-02-22 00:00 |
23:05:29.12 |
+63:35:20.2 |
HIP 113849 |
14.54 |
| 2026-02-22 12:00 |
23:05:53.93 |
+63:35:18.3 |
HIP 114212 |
12.93 |
| 2026-02-23 00:00 |
23:06:18.74 |
+63:35:17.2 |
HIP 114212 |
10.26 |
| 2026-02-23 12:00 |
23:06:43.57 |
+63:35:17.1 |
HIP 114212 |
7.63 |
| 2026-02-24 00:00 |
23:07:08.40 |
+63:35:17.9 |
HIP 114212 |
5.14 |