| Parameter |
Value |
| Designation |
C/2022 U2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-01-14T05:16:42.461760Z |
| Orbit solution date (soln_date, UTC) |
2023-11-04T19:42:53Z |
| Obs used |
996 |
| NEO |
- |
| M1 |
13.600 |
| K1 |
19.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2022-10-25T05:05:57.926400Z |
| Discovery magnitude (MPC) |
19.13 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-01-07.0000000 |
| e |
0.98612019 |
| q (au) |
1.328023 |
| a (au) |
95.680211 |
| i (deg) |
48.249781 |
| Ω (om, deg) |
304.475901 |
| ω (w, deg) |
147.908535 |
| M (ma, deg) |
359.992397 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.410 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.410 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.998 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2022-10-25 |
2022-11-25 |
+10.6742 |
-2.041 |
| 2022-11-25 |
2023-01-13 |
+45.3999 |
-7.789 |
| 2023-01-14 |
2023-05-19 |
+3.5650 |
-2.032 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
14:20:27.80 |
-66:35:21.2 |
HIP 70196 |
10.92 |
| 2026-06-01 12:00 |
14:20:10.23 |
-66:33:44.7 |
HIP 70196 |
13.29 |
| 2026-06-02 00:00 |
14:19:52.82 |
-66:32:07.4 |
HIP 70196 |
15.66 |
| 2026-06-02 12:00 |
14:19:35.59 |
-66:30:29.3 |
HIP 70019 |
17.61 |
| 2026-06-03 00:00 |
14:19:18.54 |
-66:28:50.3 |
HIP 69796 |
16.61 |
| 2026-06-03 12:00 |
14:19:01.66 |
-66:27:10.6 |
HIP 69796 |
14.27 |
| 2026-06-04 00:00 |
14:18:44.96 |
-66:25:30.2 |
HIP 69796 |
11.95 |
| 2026-06-04 12:00 |
14:18:28.43 |
-66:23:48.9 |
HIP 69796 |
9.66 |
| 2026-06-05 00:00 |
14:18:12.09 |
-66:22:06.9 |
HIP 69796 |
7.41 |
| 2026-06-05 12:00 |
14:17:55.93 |
-66:20:24.2 |
HIP 69796 |
5.29 |
| 2026-06-06 00:00 |
14:17:39.95 |
-66:18:40.8 |
HIP 69796 |
3.48 |
| 2026-06-06 12:00 |
14:17:24.16 |
-66:16:56.6 |
HIP 69796 |
2.74 |
| 2026-06-07 00:00 |
14:17:08.55 |
-66:15:11.8 |
HIP 69796 |
3.75 |
| 2026-06-07 12:00 |
14:16:53.12 |
-66:13:26.3 |
HIP 69725 |
3.72 |
| 2026-06-08 00:00 |
14:16:37.89 |
-66:11:40.1 |
HIP 69725 |
1.71 |
| 2026-06-08 12:00 |
14:16:22.84 |
-66:09:53.2 |
HIP 69725 |
1.72 |
| 2026-06-09 00:00 |
14:16:07.98 |
-66:08:05.7 |
HIP 69725 |
3.74 |
| 2026-06-09 12:00 |
14:15:53.31 |
-66:06:17.6 |
HIP 69725 |
6.00 |
| 2026-06-10 00:00 |
14:15:38.84 |
-66:04:28.8 |
HIP 69584 |
8.03 |
| 2026-06-10 12:00 |
14:15:24.55 |
-66:02:39.5 |
HIP 69584 |
8.28 |
| 2026-06-11 00:00 |
14:15:10.46 |
-66:00:49.5 |
HIP 69584 |
9.16 |
| 2026-06-11 12:00 |
14:14:56.56 |
-65:58:59.0 |
HIP 69584 |
10.50 |
| 2026-06-12 00:00 |
14:14:42.86 |
-65:57:07.9 |
HIP 69584 |
12.14 |
| 2026-06-12 12:00 |
14:14:29.35 |
-65:55:16.2 |
HIP 69591 |
13.23 |
| 2026-06-13 00:00 |
14:14:16.04 |
-65:53:24.0 |
HIP 69591 |
11.57 |
| 2026-06-13 12:00 |
14:14:02.93 |
-65:51:31.3 |
HIP 69591 |
10.16 |
| 2026-06-14 00:00 |
14:13:50.02 |
-65:49:38.1 |
HIP 69591 |
9.11 |
| 2026-06-14 12:00 |
14:13:37.30 |
-65:47:44.3 |
HIP 69591 |
8.54 |
| 2026-06-15 00:00 |
14:13:24.79 |
-65:45:50.1 |
HIP 69591 |
8.56 |
| 2026-06-15 12:00 |
14:13:12.48 |
-65:43:55.4 |
HIP 69591 |
9.15 |
| 2026-06-16 00:00 |
14:13:00.36 |
-65:42:00.3 |
HIP 69591 |
10.22 |
| 2026-06-16 12:00 |
14:12:48.45 |
-65:40:04.7 |
HIP 69591 |
11.62 |
| 2026-06-17 00:00 |
14:12:36.74 |
-65:38:08.6 |
HIP 69445 |
11.60 |
| 2026-06-17 12:00 |
14:12:25.24 |
-65:36:12.2 |
HIP 69445 |
10.13 |
| 2026-06-18 00:00 |
14:12:13.93 |
-65:34:15.4 |
HIP 69445 |
8.99 |
| 2026-06-18 12:00 |
14:12:02.83 |
-65:32:18.1 |
HIP 69445 |
8.31 |
| 2026-06-19 00:00 |
14:11:51.94 |
-65:30:20.5 |
HIP 69445 |
8.20 |
| 2026-06-19 12:00 |
14:11:41.25 |
-65:28:22.6 |
HIP 69445 |
8.67 |
| 2026-06-20 00:00 |
14:11:30.76 |
-65:26:24.3 |
HIP 69445 |
9.65 |
| 2026-06-20 12:00 |
14:11:20.47 |
-65:24:25.6 |
HIP 69445 |
10.99 |
| 2026-06-21 00:00 |
14:11:10.39 |
-65:22:26.7 |
HIP 69445 |
12.58 |
| 2026-06-21 12:00 |
14:11:00.52 |
-65:20:27.4 |
HIP 69445 |
14.32 |
| 2026-06-22 00:00 |
14:10:50.84 |
-65:18:27.9 |
HIP 69445 |
16.18 |