| Parameter |
Value |
| Designation |
C/2021 S1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-02-28T22:41:40.444800Z |
| Orbit solution date (soln_date, UTC) |
2024-06-06T23:12:23Z |
| Obs used |
476 |
| NEO |
- |
| M1 |
6.700 |
| K1 |
10.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-09-27T13:41:00.096000Z |
| Discovery magnitude (MPC) |
17.82 o |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-03-23.0000000 |
| e |
1.00095649 |
| q (au) |
6.119212 |
| a (au) |
-6397.577104 |
| i (deg) |
52.088959 |
| Ω (om, deg) |
299.873636 |
| ω (w, deg) |
148.188635 |
| M (ma, deg) |
0.000042 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.453 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.453 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.717 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
09:27:05.32 |
-30:27:33.6 |
HIP 46279 |
28.04 |
| 2026-03-26 12:00 |
09:26:58.63 |
-30:26:28.7 |
HIP 46279 |
26.47 |
| 2026-03-27 00:00 |
09:26:52.03 |
-30:25:23.4 |
HIP 46279 |
24.93 |
| 2026-03-27 12:00 |
09:26:45.51 |
-30:24:17.7 |
HIP 46279 |
23.42 |
| 2026-03-28 00:00 |
09:26:39.08 |
-30:23:11.6 |
HIP 46279 |
21.96 |
| 2026-03-28 12:00 |
09:26:32.73 |
-30:22:05.0 |
HIP 46279 |
20.54 |
| 2026-03-29 00:00 |
09:26:26.47 |
-30:20:58.1 |
HIP 46279 |
19.17 |
| 2026-03-29 12:00 |
09:26:20.30 |
-30:19:50.8 |
HIP 46279 |
17.87 |
| 2026-03-30 00:00 |
09:26:14.22 |
-30:18:43.2 |
HIP 46279 |
16.65 |
| 2026-03-30 12:00 |
09:26:08.22 |
-30:17:35.2 |
HIP 46279 |
15.51 |
| 2026-03-31 00:00 |
09:26:02.32 |
-30:16:26.8 |
HIP 46279 |
14.48 |
| 2026-03-31 12:00 |
09:25:56.50 |
-30:15:18.2 |
HIP 46279 |
13.58 |
| 2026-04-01 00:00 |
09:25:50.77 |
-30:14:09.2 |
HIP 46279 |
12.84 |
| 2026-04-01 12:00 |
09:25:45.14 |
-30:12:59.8 |
HIP 46279 |
12.26 |
| 2026-04-02 00:00 |
09:25:39.59 |
-30:11:50.2 |
HIP 46279 |
11.89 |
| 2026-04-02 12:00 |
09:25:34.13 |
-30:10:40.3 |
HIP 46279 |
11.72 |
| 2026-04-03 00:00 |
09:25:28.76 |
-30:09:30.1 |
HIP 46279 |
11.77 |
| 2026-04-03 12:00 |
09:25:23.49 |
-30:08:19.6 |
HIP 46279 |
12.03 |
| 2026-04-04 00:00 |
09:25:18.31 |
-30:07:08.8 |
HIP 46279 |
12.48 |
| 2026-04-04 12:00 |
09:25:13.22 |
-30:05:57.8 |
HIP 46279 |
13.10 |
| 2026-04-05 00:00 |
09:25:08.22 |
-30:04:46.6 |
HIP 46279 |
13.86 |
| 2026-04-05 12:00 |
09:25:03.31 |
-30:03:35.1 |
HIP 46279 |
14.73 |
| 2026-04-06 00:00 |
09:24:58.50 |
-30:02:23.4 |
HIP 46279 |
15.70 |
| 2026-04-06 12:00 |
09:24:53.78 |
-30:01:11.5 |
HIP 46279 |
16.75 |
| 2026-04-07 00:00 |
09:24:49.15 |
-29:59:59.4 |
HIP 46279 |
17.85 |
| 2026-04-07 12:00 |
09:24:44.62 |
-29:58:47.1 |
HIP 46279 |
19.00 |
| 2026-04-08 00:00 |
09:24:40.18 |
-29:57:34.6 |
HIP 46279 |
20.18 |
| 2026-04-08 12:00 |
09:24:35.83 |
-29:56:21.9 |
HIP 46279 |
21.39 |
| 2026-04-09 00:00 |
09:24:31.58 |
-29:55:09.0 |
HIP 46279 |
22.63 |
| 2026-04-09 12:00 |
09:24:27.43 |
-29:53:56.0 |
HIP 46279 |
23.87 |
| 2026-04-10 00:00 |
09:24:23.37 |
-29:52:42.9 |
HIP 46279 |
25.13 |
| 2026-04-10 12:00 |
09:24:19.41 |
-29:51:29.6 |
HIP 46279 |
26.40 |
| 2026-04-11 00:00 |
09:24:15.54 |
-29:50:16.2 |
HIP 46279 |
27.67 |
| 2026-04-11 12:00 |
09:24:11.77 |
-29:49:02.7 |
HIP 46279 |
28.94 |
| 2026-04-12 00:00 |
09:24:08.09 |
-29:47:49.1 |
HIP 46279 |
30.22 |
| 2026-04-12 12:00 |
09:24:04.51 |
-29:46:35.4 |
HIP 46279 |
31.49 |
| 2026-04-13 00:00 |
09:24:01.03 |
-29:45:21.6 |
HIP 46279 |
32.77 |
| 2026-04-13 12:00 |
09:23:57.64 |
-29:44:07.8 |
HIP 46127 |
33.74 |
| 2026-04-14 00:00 |
09:23:54.36 |
-29:42:53.9 |
HIP 46127 |
32.65 |
| 2026-04-14 12:00 |
09:23:51.17 |
-29:41:39.9 |
HIP 46127 |
31.58 |
| 2026-04-15 00:00 |
09:23:48.07 |
-29:40:25.9 |
HIP 46127 |
30.54 |
| 2026-04-15 12:00 |
09:23:45.08 |
-29:39:11.9 |
HIP 46127 |
29.52 |
| 2026-04-16 00:00 |
09:23:42.18 |
-29:37:57.8 |
HIP 46127 |
28.53 |