C/2020 R7 (ATLAS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2020 R7 (ATLAS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-09-16T06:03:23.394240Z |
| Orbit solution date (soln_date, UTC) | 2024-08-11T00:12:15Z |
| Obs used | 1812 |
| NEO | - |
| M1 | 11.500 |
| K1 | 4.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2020-09-15T14:23:18.614400Z |
| Discovery magnitude (MPC) | 19.00 o |
| Discovery observatory (MPC) | T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2023-02-02.0000000 |
| e | 1.00021432 |
| q (au) | 2.956013 |
| a (au) | -13792.591193 |
| i (deg) | 114.893954 |
| Ω (om, deg) | 268.282599 |
| ω (w, deg) | 347.841392 |
| M (ma, deg) | 0.000084 |
Magnitude
Scatter + Global Linear
$$ M_a = (9.379 + 2.863\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 9.379 |
| n | 2.863 |
| gf | 0.980 |
| gb | -1.000 |
| k | 0.999 |
| δ90 | 9.998 |
| 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 |
|---|---|---|---|
| 2019-12-03 | 2020-09-23 | +20.8410 | -18.349 |
| 2020-09-23 | 2021-08-10 | +4.7347 | -4.468 |
| 2021-08-10 | 2022-03-31 | -0.0032 | -1.068 |
| 2022-03-31 | 2022-09-15 | -12.9278 | +5.677 |
| 2022-09-19 | 2024-07-31 | +4.7248 | -2.800 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Finding Chart
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 13:09:13.55 | +70:35:14.0 | HIP 64024 | 30.59 |
| 2026-03-26 12:00 | 13:08:36.05 | +70:36:20.0 | HIP 64024 | 30.76 |
| 2026-03-27 00:00 | 13:07:58.47 | +70:37:24.1 | HIP 64024 | 31.25 |
| 2026-03-27 12:00 | 13:07:20.81 | +70:38:26.2 | HIP 64024 | 32.04 |
| 2026-03-28 00:00 | 13:06:43.07 | +70:39:26.4 | HIP 64024 | 33.13 |
| 2026-03-28 12:00 | 13:06:05.26 | +70:40:24.7 | HIP 64024 | 34.47 |
| 2026-03-29 00:00 | 13:05:27.38 | +70:41:21.1 | HIP 63370 | 32.12 |
| 2026-03-29 12:00 | 13:04:49.45 | +70:42:15.5 | HIP 63370 | 29.21 |
| 2026-03-30 00:00 | 13:04:11.46 | +70:43:08.0 | HIP 63370 | 26.37 |
| 2026-03-30 12:00 | 13:03:33.43 | +70:43:58.6 | HIP 63370 | 23.63 |
| 2026-03-31 00:00 | 13:02:55.34 | +70:44:47.3 | HIP 63370 | 21.03 |
| 2026-03-31 12:00 | 13:02:17.22 | +70:45:34.0 | HIP 63370 | 18.62 |
| 2026-04-01 00:00 | 13:01:39.07 | +70:46:18.8 | HIP 63370 | 16.48 |
| 2026-04-01 12:00 | 13:01:00.89 | +70:47:01.6 | HIP 63370 | 14.72 |
| 2026-04-02 00:00 | 13:00:22.68 | +70:47:42.6 | HIP 63370 | 13.50 |
| 2026-04-02 12:00 | 12:59:44.45 | +70:48:21.6 | HIP 63370 | 12.96 |
| 2026-04-03 00:00 | 12:59:06.21 | +70:48:58.7 | HIP 63216 | 10.28 |
| 2026-04-03 12:00 | 12:58:27.97 | +70:49:33.8 | HIP 63216 | 7.73 |
| 2026-04-04 00:00 | 12:57:49.72 | +70:50:07.0 | HIP 63216 | 5.83 |
| 2026-04-04 12:00 | 12:57:11.47 | +70:50:38.3 | HIP 63216 | 5.32 |
| 2026-04-05 00:00 | 12:56:33.23 | +70:51:07.7 | HIP 63216 | 6.53 |
| 2026-04-05 12:00 | 12:55:55.00 | +70:51:35.2 | HIP 63216 | 8.76 |
| 2026-04-06 00:00 | 12:55:16.79 | +70:52:00.7 | HIP 63216 | 11.42 |
| 2026-04-06 12:00 | 12:54:38.60 | +70:52:24.4 | HIP 63216 | 14.28 |
| 2026-04-07 00:00 | 12:54:00.45 | +70:52:46.1 | HIP 63216 | 17.22 |
| 2026-04-07 12:00 | 12:53:22.32 | +70:53:05.9 | HIP 63216 | 20.21 |
| 2026-04-08 00:00 | 12:52:44.23 | +70:53:23.8 | HIP 62627 | 22.79 |
| 2026-04-08 12:00 | 12:52:06.19 | +70:53:39.8 | HIP 62455 | 20.41 |
| 2026-04-09 00:00 | 12:51:28.20 | +70:53:53.9 | HIP 62455 | 17.31 |
| 2026-04-09 12:00 | 12:50:50.25 | +70:54:06.2 | HIP 62455 | 14.22 |
| 2026-04-10 00:00 | 12:50:12.37 | +70:54:16.5 | HIP 62455 | 11.16 |
| 2026-04-10 12:00 | 12:49:34.56 | +70:54:25.0 | HIP 62455 | 8.13 |
| 2026-04-11 00:00 | 12:48:56.81 | +70:54:31.5 | HIP 62455 | 5.21 |
| 2026-04-11 12:00 | 12:48:19.13 | +70:54:36.2 | HIP 62455 | 2.72 |
| 2026-04-12 00:00 | 12:47:41.54 | +70:54:39.1 | HIP 62455 | 2.59 |
| 2026-04-12 12:00 | 12:47:04.03 | +70:54:40.0 | HIP 62455 | 4.99 |
| 2026-04-13 00:00 | 12:46:26.61 | +70:54:39.2 | HIP 62455 | 7.87 |
| 2026-04-13 12:00 | 12:45:49.28 | +70:54:36.4 | HIP 62455 | 10.85 |
| 2026-04-14 00:00 | 12:45:12.06 | +70:54:31.9 | HIP 62455 | 13.85 |
| 2026-04-14 12:00 | 12:44:34.93 | +70:54:25.5 | HIP 62455 | 16.87 |
| 2026-04-15 00:00 | 12:43:57.92 | +70:54:17.2 | HIP 62455 | 19.88 |
| 2026-04-15 12:00 | 12:43:21.02 | +70:54:07.2 | HIP 61822 | 17.16 |
| 2026-04-16 00:00 | 12:42:44.24 | +70:53:55.3 | HIP 61822 | 14.38 |