| 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 |
1.000 |
| gb |
-0.948 |
| k |
1.000 |
| 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 |
| 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) |
| 2026-06-01 00:00 |
00:16:34.82 |
+67:21:07.7 |
HIP 1557 |
16.30 |
| 2026-06-01 12:00 |
00:16:48.65 |
+67:23:01.9 |
HIP 1557 |
15.30 |
| 2026-06-02 00:00 |
00:17:02.35 |
+67:24:56.2 |
HIP 1557 |
14.62 |
| 2026-06-02 12:00 |
00:17:15.92 |
+67:26:50.7 |
HIP 1557 |
14.31 |
| 2026-06-03 00:00 |
00:17:29.37 |
+67:28:45.3 |
HIP 1557 |
14.38 |
| 2026-06-03 12:00 |
00:17:42.68 |
+67:30:40.1 |
HIP 1557 |
14.82 |
| 2026-06-04 00:00 |
00:17:55.87 |
+67:32:35.0 |
HIP 1557 |
15.61 |
| 2026-06-04 12:00 |
00:18:08.93 |
+67:34:30.0 |
HIP 1557 |
16.68 |
| 2026-06-05 00:00 |
00:18:21.85 |
+67:36:25.2 |
HIP 1674 |
15.20 |
| 2026-06-05 12:00 |
00:18:34.64 |
+67:38:20.5 |
HIP 1674 |
13.65 |
| 2026-06-06 00:00 |
00:18:47.29 |
+67:40:15.9 |
HIP 1674 |
12.33 |
| 2026-06-06 12:00 |
00:18:59.81 |
+67:42:11.4 |
HIP 1674 |
11.34 |
| 2026-06-07 00:00 |
00:19:12.20 |
+67:44:07.1 |
HIP 1674 |
10.75 |
| 2026-06-07 12:00 |
00:19:24.45 |
+67:46:02.8 |
HIP 1674 |
10.64 |
| 2026-06-08 00:00 |
00:19:36.56 |
+67:47:58.6 |
HIP 1674 |
11.01 |
| 2026-06-08 12:00 |
00:19:48.53 |
+67:49:54.5 |
HIP 1725 |
10.76 |
| 2026-06-09 00:00 |
00:20:00.36 |
+67:51:50.5 |
HIP 1725 |
9.93 |
| 2026-06-09 12:00 |
00:20:12.05 |
+67:53:46.6 |
HIP 1725 |
9.58 |
| 2026-06-10 00:00 |
00:20:23.60 |
+67:55:42.8 |
HIP 1725 |
9.76 |
| 2026-06-10 12:00 |
00:20:35.01 |
+67:57:39.0 |
HIP 1725 |
10.42 |
| 2026-06-11 00:00 |
00:20:46.28 |
+67:59:35.3 |
HIP 1725 |
11.49 |
| 2026-06-11 12:00 |
00:20:57.39 |
+68:01:31.6 |
HIP 1725 |
12.86 |
| 2026-06-12 00:00 |
00:21:08.37 |
+68:03:28.0 |
HIP 1725 |
14.44 |
| 2026-06-12 12:00 |
00:21:19.20 |
+68:05:24.4 |
HIP 1725 |
16.17 |
| 2026-06-13 00:00 |
00:21:29.88 |
+68:07:20.9 |
HIP 1725 |
18.01 |
| 2026-06-13 12:00 |
00:21:40.41 |
+68:09:17.4 |
HIP 1932 |
19.65 |
| 2026-06-14 00:00 |
00:21:50.79 |
+68:11:13.9 |
HIP 1932 |
20.27 |
| 2026-06-14 12:00 |
00:22:01.02 |
+68:13:10.5 |
HIP 1932 |
21.11 |
| 2026-06-15 00:00 |
00:22:11.10 |
+68:15:07.0 |
HIP 1932 |
22.13 |
| 2026-06-15 12:00 |
00:22:21.02 |
+68:17:03.6 |
HIP 1932 |
23.32 |
| 2026-06-16 00:00 |
00:22:30.80 |
+68:19:00.1 |
HIP 1510 |
23.26 |
| 2026-06-16 12:00 |
00:22:40.42 |
+68:20:56.7 |
HIP 1510 |
23.21 |
| 2026-06-17 00:00 |
00:22:49.88 |
+68:22:53.2 |
HIP 1510 |
23.33 |
| 2026-06-17 12:00 |
00:22:59.19 |
+68:24:49.7 |
HIP 1510 |
23.63 |
| 2026-06-18 00:00 |
00:23:08.34 |
+68:26:46.2 |
HIP 1510 |
24.10 |
| 2026-06-18 12:00 |
00:23:17.33 |
+68:28:42.6 |
HIP 1510 |
24.72 |
| 2026-06-19 00:00 |
00:23:26.17 |
+68:30:39.0 |
HIP 1510 |
25.49 |
| 2026-06-19 12:00 |
00:23:34.85 |
+68:32:35.4 |
HIP 1629 |
25.27 |
| 2026-06-20 00:00 |
00:23:43.36 |
+68:34:31.7 |
HIP 1629 |
24.47 |
| 2026-06-20 12:00 |
00:23:51.72 |
+68:36:27.9 |
HIP 1629 |
23.81 |
| 2026-06-21 00:00 |
00:23:59.91 |
+68:38:24.1 |
HIP 1629 |
23.31 |
| 2026-06-21 12:00 |
00:24:07.94 |
+68:40:20.1 |
HIP 1629 |
22.97 |
| 2026-06-22 00:00 |
00:24:15.81 |
+68:42:16.1 |
HIP 1629 |
22.80 |