| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
08:19:49.63 |
-11:29:30.0 |
HIP 40850 |
10.79 |
| 2026-06-03 00:00 |
08:19:55.69 |
-11:29:31.3 |
HIP 40850 |
10.31 |
| 2026-06-03 12:00 |
08:20:01.81 |
-11:29:33.2 |
HIP 40850 |
10.03 |
| 2026-06-04 00:00 |
08:20:07.98 |
-11:29:35.7 |
HIP 40850 |
9.98 |
| 2026-06-04 12:00 |
08:20:14.20 |
-11:29:38.8 |
HIP 40850 |
10.18 |
| 2026-06-05 00:00 |
08:20:20.48 |
-11:29:42.4 |
HIP 40850 |
10.60 |
| 2026-06-05 12:00 |
08:20:26.81 |
-11:29:46.7 |
HIP 40850 |
11.24 |
| 2026-06-06 00:00 |
08:20:33.19 |
-11:29:51.5 |
HIP 40850 |
12.06 |
| 2026-06-06 12:00 |
08:20:39.63 |
-11:29:56.9 |
HIP 40850 |
13.03 |
| 2026-06-07 00:00 |
08:20:46.11 |
-11:30:02.9 |
HIP 40850 |
14.13 |
| 2026-06-07 12:00 |
08:20:52.65 |
-11:30:09.4 |
HIP 40850 |
15.33 |
| 2026-06-08 00:00 |
08:20:59.23 |
-11:30:16.6 |
HIP 40850 |
16.61 |
| 2026-06-08 12:00 |
08:21:05.87 |
-11:30:24.4 |
HIP 40850 |
17.97 |
| 2026-06-09 00:00 |
08:21:12.56 |
-11:30:32.7 |
HIP 40850 |
19.38 |
| 2026-06-09 12:00 |
08:21:19.29 |
-11:30:41.7 |
HIP 40850 |
20.84 |
| 2026-06-10 00:00 |
08:21:26.07 |
-11:30:51.2 |
HIP 40850 |
22.35 |
| 2026-06-10 12:00 |
08:21:32.90 |
-11:31:01.3 |
HIP 40850 |
23.89 |
| 2026-06-11 00:00 |
08:21:39.78 |
-11:31:12.1 |
HIP 40850 |
25.46 |
| 2026-06-11 12:00 |
08:21:46.70 |
-11:31:23.4 |
HIP 40850 |
27.06 |
| 2026-06-12 00:00 |
08:21:53.67 |
-11:31:35.3 |
HIP 40850 |
28.69 |
| 2026-06-12 12:00 |
08:22:00.69 |
-11:31:47.8 |
HIP 40965 |
29.67 |
| 2026-06-13 00:00 |
08:22:07.75 |
-11:32:01.0 |
HIP 40965 |
30.27 |
| 2026-06-13 12:00 |
08:22:14.86 |
-11:32:14.7 |
HIP 41178 |
28.93 |
| 2026-06-14 00:00 |
08:22:22.01 |
-11:32:29.1 |
HIP 41178 |
27.27 |
| 2026-06-14 12:00 |
08:22:29.20 |
-11:32:44.0 |
HIP 41178 |
25.61 |
| 2026-06-15 00:00 |
08:22:36.44 |
-11:32:59.5 |
HIP 41178 |
23.97 |
| 2026-06-15 12:00 |
08:22:43.72 |
-11:33:15.7 |
HIP 41178 |
22.34 |
| 2026-06-16 00:00 |
08:22:51.04 |
-11:33:32.5 |
HIP 41178 |
20.74 |
| 2026-06-16 12:00 |
08:22:58.40 |
-11:33:49.8 |
HIP 41178 |
19.17 |
| 2026-06-17 00:00 |
08:23:05.81 |
-11:34:07.8 |
HIP 41178 |
17.65 |
| 2026-06-17 12:00 |
08:23:13.25 |
-11:34:26.4 |
HIP 41178 |
16.18 |
| 2026-06-18 00:00 |
08:23:20.74 |
-11:34:45.6 |
HIP 41178 |
14.80 |
| 2026-06-18 12:00 |
08:23:28.26 |
-11:35:05.4 |
HIP 41178 |
13.54 |
| 2026-06-19 00:00 |
08:23:35.82 |
-11:35:25.8 |
HIP 41178 |
12.43 |
| 2026-06-19 12:00 |
08:23:43.42 |
-11:35:46.9 |
HIP 41178 |
11.53 |
| 2026-06-20 00:00 |
08:23:51.06 |
-11:36:08.5 |
HIP 41178 |
10.89 |
| 2026-06-20 12:00 |
08:23:58.74 |
-11:36:30.7 |
HIP 41178 |
10.56 |
| 2026-06-21 00:00 |
08:24:06.45 |
-11:36:53.6 |
HIP 41221 |
9.76 |
| 2026-06-21 12:00 |
08:24:14.19 |
-11:37:17.0 |
HIP 41221 |
8.51 |
| 2026-06-22 00:00 |
08:24:21.98 |
-11:37:41.1 |
HIP 41221 |
7.56 |