| Parameter |
Value |
| Designation |
C/2020 M5 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-08-19T21:12:41.952960Z |
| Orbit solution date (soln_date, UTC) |
2023-03-28T19:42:35Z |
| Obs used |
1605 |
| NEO |
- |
| M1 |
7.600 |
| K1 |
11.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-06-30T13:19:39.388800Z |
| Discovery magnitude (MPC) |
19.44 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-08-02.0000000 |
| e |
0.99994908 |
| q (au) |
3.004334 |
| a (au) |
59004.546918 |
| i (deg) |
93.222721 |
| Ω (om, deg) |
352.095028 |
| ω (w, deg) |
126.340033 |
| M (ma, deg) |
359.999999 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.967 + 5.727\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.967 |
| n |
5.727 |
| gf |
1.000 |
| gb |
-0.785 |
| k |
0.800 |
| 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 |
| 2019-08-10 |
2021-08-18 |
+1.0283 |
-0.456 |
| 2021-08-23 |
2022-02-06 |
-4.3432 |
+1.747 |
| 2022-02-06 |
2022-04-28 |
-5.1639 |
+2.582 |
| 2022-04-28 |
2023-02-27 |
-0.1853 |
-0.920 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
07:55:34.12 |
-53:28:19.8 |
HIP 38698 |
8.65 |
| 2026-05-12 12:00 |
07:55:37.97 |
-53:26:41.5 |
HIP 38698 |
10.38 |
| 2026-05-13 00:00 |
07:55:41.92 |
-53:25:03.7 |
HIP 38698 |
12.09 |
| 2026-05-13 12:00 |
07:55:45.98 |
-53:23:26.6 |
HIP 38698 |
13.81 |
| 2026-05-14 00:00 |
07:55:50.14 |
-53:21:50.0 |
HIP 38698 |
15.53 |
| 2026-05-14 12:00 |
07:55:54.41 |
-53:20:14.0 |
HIP 38698 |
17.24 |
| 2026-05-15 00:00 |
07:55:58.77 |
-53:18:38.6 |
HIP 38698 |
18.94 |
| 2026-05-15 12:00 |
07:56:03.24 |
-53:17:03.9 |
HIP 38827 |
19.26 |
| 2026-05-16 00:00 |
07:56:07.80 |
-53:15:29.7 |
HIP 38827 |
17.55 |
| 2026-05-16 12:00 |
07:56:12.46 |
-53:13:56.2 |
HIP 38827 |
15.85 |
| 2026-05-17 00:00 |
07:56:17.22 |
-53:12:23.3 |
HIP 38827 |
14.16 |
| 2026-05-17 12:00 |
07:56:22.08 |
-53:10:51.0 |
HIP 38827 |
12.47 |
| 2026-05-18 00:00 |
07:56:27.03 |
-53:09:19.4 |
HIP 38827 |
10.79 |
| 2026-05-18 12:00 |
07:56:32.08 |
-53:07:48.4 |
HIP 38827 |
9.13 |
| 2026-05-19 00:00 |
07:56:37.23 |
-53:06:18.1 |
HIP 38827 |
7.50 |
| 2026-05-19 12:00 |
07:56:42.46 |
-53:04:48.5 |
HIP 38827 |
5.90 |
| 2026-05-20 00:00 |
07:56:47.80 |
-53:03:19.5 |
HIP 38827 |
4.38 |
| 2026-05-20 12:00 |
07:56:53.22 |
-53:01:51.2 |
HIP 38827 |
3.07 |
| 2026-05-21 00:00 |
07:56:58.73 |
-53:00:23.6 |
HIP 38827 |
2.31 |
| 2026-05-21 12:00 |
07:57:04.34 |
-52:58:56.6 |
HIP 38827 |
2.65 |
| 2026-05-22 00:00 |
07:57:10.03 |
-52:57:30.4 |
HIP 38827 |
3.79 |
| 2026-05-22 12:00 |
07:57:15.81 |
-52:56:04.8 |
HIP 38827 |
5.23 |
| 2026-05-23 00:00 |
07:57:21.68 |
-52:54:40.0 |
HIP 38827 |
6.78 |
| 2026-05-23 12:00 |
07:57:27.64 |
-52:53:15.8 |
HIP 38827 |
8.38 |
| 2026-05-24 00:00 |
07:57:33.68 |
-52:51:52.4 |
HIP 38827 |
10.00 |
| 2026-05-24 12:00 |
07:57:39.81 |
-52:50:29.7 |
HIP 38827 |
11.64 |
| 2026-05-25 00:00 |
07:57:46.02 |
-52:49:07.7 |
HIP 38827 |
13.28 |
| 2026-05-25 12:00 |
07:57:52.32 |
-52:47:46.4 |
HIP 38827 |
14.92 |
| 2026-05-26 00:00 |
07:57:58.70 |
-52:46:25.8 |
HIP 38827 |
16.57 |
| 2026-05-26 12:00 |
07:58:05.16 |
-52:45:06.0 |
HIP 39051 |
17.15 |
| 2026-05-27 00:00 |
07:58:11.70 |
-52:43:46.9 |
HIP 39051 |
15.51 |
| 2026-05-27 12:00 |
07:58:18.33 |
-52:42:28.6 |
HIP 39051 |
13.88 |
| 2026-05-28 00:00 |
07:58:25.03 |
-52:41:11.0 |
HIP 39051 |
12.25 |
| 2026-05-28 12:00 |
07:58:31.81 |
-52:39:54.1 |
HIP 39051 |
10.62 |
| 2026-05-29 00:00 |
07:58:38.67 |
-52:38:38.0 |
HIP 39051 |
8.99 |
| 2026-05-29 12:00 |
07:58:45.61 |
-52:37:22.7 |
HIP 39051 |
7.37 |
| 2026-05-30 00:00 |
07:58:52.63 |
-52:36:08.1 |
HIP 39051 |
5.76 |
| 2026-05-30 12:00 |
07:58:59.72 |
-52:34:54.2 |
HIP 39051 |
4.16 |
| 2026-05-31 00:00 |
07:59:06.88 |
-52:33:41.2 |
HIP 39051 |
2.61 |
| 2026-05-31 12:00 |
07:59:14.12 |
-52:32:28.9 |
HIP 39051 |
1.26 |
| 2026-06-01 00:00 |
07:59:21.44 |
-52:31:17.4 |
HIP 39051 |
1.29 |
| 2026-06-01 12:00 |
07:59:28.83 |
-52:30:06.7 |
HIP 39051 |
2.65 |
| 2026-06-02 00:00 |
07:59:36.29 |
-52:28:56.7 |
HIP 39051 |
4.20 |