| Parameter |
Value |
| Designation |
C/2021 Q3 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-01-26T01:52:57.941760Z |
| Orbit solution date (soln_date, UTC) |
2023-03-20T19:42:36Z |
| Obs used |
180 |
| NEO |
- |
| M1 |
6.900 |
| K1 |
11.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-08-26T07:07:01.228800Z |
| Discovery magnitude (MPC) |
19.02 o |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-01-10.0000000 |
| e |
0.93033551 |
| q (au) |
5.204636 |
| a (au) |
74.710023 |
| i (deg) |
77.777282 |
| Ω (om, deg) |
307.900611 |
| ω (w, deg) |
114.090847 |
| M (ma, deg) |
359.975460 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.505 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.505 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
08:16:27.28 |
-11:37:18.2 |
HIP 40437 |
24.96 |
| 2026-05-12 12:00 |
08:16:30.54 |
-11:36:56.2 |
HIP 40437 |
25.18 |
| 2026-05-13 00:00 |
08:16:33.87 |
-11:36:34.7 |
HIP 40437 |
25.44 |
| 2026-05-13 12:00 |
08:16:37.28 |
-11:36:13.8 |
HIP 40437 |
25.75 |
| 2026-05-14 00:00 |
08:16:40.77 |
-11:35:53.3 |
HIP 40437 |
26.10 |
| 2026-05-14 12:00 |
08:16:44.32 |
-11:35:33.3 |
HIP 40437 |
26.50 |
| 2026-05-15 00:00 |
08:16:47.96 |
-11:35:13.8 |
HIP 40437 |
26.95 |
| 2026-05-15 12:00 |
08:16:51.66 |
-11:34:54.8 |
HIP 40437 |
27.44 |
| 2026-05-16 00:00 |
08:16:55.44 |
-11:34:36.4 |
HIP 40437 |
27.98 |
| 2026-05-16 12:00 |
08:16:59.29 |
-11:34:18.4 |
HIP 40437 |
28.55 |
| 2026-05-17 00:00 |
08:17:03.21 |
-11:34:01.0 |
HIP 40437 |
29.17 |
| 2026-05-17 12:00 |
08:17:07.21 |
-11:33:44.1 |
HIP 40437 |
29.83 |
| 2026-05-18 00:00 |
08:17:11.27 |
-11:33:27.7 |
HIP 40437 |
30.53 |
| 2026-05-18 12:00 |
08:17:15.41 |
-11:33:11.8 |
HIP 40437 |
31.27 |
| 2026-05-19 00:00 |
08:17:19.61 |
-11:32:56.5 |
HIP 40437 |
32.04 |
| 2026-05-19 12:00 |
08:17:23.89 |
-11:32:41.6 |
HIP 40437 |
32.85 |
| 2026-05-20 00:00 |
08:17:28.23 |
-11:32:27.4 |
HIP 40437 |
33.69 |
| 2026-05-20 12:00 |
08:17:32.64 |
-11:32:13.6 |
HIP 40437 |
34.57 |
| 2026-05-21 00:00 |
08:17:37.12 |
-11:32:00.4 |
HIP 40786 |
34.59 |
| 2026-05-21 12:00 |
08:17:41.67 |
-11:31:47.8 |
HIP 40786 |
33.84 |
| 2026-05-22 00:00 |
08:17:46.28 |
-11:31:35.6 |
HIP 40786 |
33.10 |
| 2026-05-22 12:00 |
08:17:50.96 |
-11:31:24.0 |
HIP 40786 |
32.36 |
| 2026-05-23 00:00 |
08:17:55.71 |
-11:31:13.0 |
HIP 40786 |
31.63 |
| 2026-05-23 12:00 |
08:18:00.52 |
-11:31:02.5 |
HIP 40786 |
30.91 |
| 2026-05-24 00:00 |
08:18:05.39 |
-11:30:52.6 |
HIP 40786 |
30.20 |
| 2026-05-24 12:00 |
08:18:10.33 |
-11:30:43.2 |
HIP 40786 |
29.51 |
| 2026-05-25 00:00 |
08:18:15.33 |
-11:30:34.4 |
HIP 40786 |
28.84 |
| 2026-05-25 12:00 |
08:18:20.40 |
-11:30:26.1 |
HIP 40786 |
28.18 |
| 2026-05-26 00:00 |
08:18:25.53 |
-11:30:18.4 |
HIP 40850 |
27.13 |
| 2026-05-26 12:00 |
08:18:30.72 |
-11:30:11.2 |
HIP 40850 |
25.91 |
| 2026-05-27 00:00 |
08:18:35.97 |
-11:30:04.6 |
HIP 40850 |
24.70 |
| 2026-05-27 12:00 |
08:18:41.28 |
-11:29:58.5 |
HIP 40850 |
23.48 |
| 2026-05-28 00:00 |
08:18:46.66 |
-11:29:53.0 |
HIP 40850 |
22.26 |
| 2026-05-28 12:00 |
08:18:52.09 |
-11:29:48.1 |
HIP 40850 |
21.05 |
| 2026-05-29 00:00 |
08:18:57.59 |
-11:29:43.7 |
HIP 40850 |
19.85 |
| 2026-05-29 12:00 |
08:19:03.14 |
-11:29:39.9 |
HIP 40850 |
18.65 |
| 2026-05-30 00:00 |
08:19:08.75 |
-11:29:36.7 |
HIP 40850 |
17.48 |
| 2026-05-30 12:00 |
08:19:14.42 |
-11:29:34.0 |
HIP 40850 |
16.33 |
| 2026-05-31 00:00 |
08:19:20.15 |
-11:29:31.9 |
HIP 40850 |
15.22 |
| 2026-05-31 12:00 |
08:19:25.93 |
-11:29:30.4 |
HIP 40850 |
14.16 |
| 2026-06-01 00:00 |
08:19:31.77 |
-11:29:29.4 |
HIP 40850 |
13.16 |
| 2026-06-01 12:00 |
08:19:37.67 |
-11:29:29.0 |
HIP 40850 |
12.25 |
| 2026-06-02 00:00 |
08:19:43.62 |
-11:29:29.2 |
HIP 40850 |
11.45 |