| Parameter |
Value |
| Designation |
C/2021 G2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2024-09-09T04:13:56.562240Z |
| Orbit solution date (soln_date, UTC) |
2026-05-28T12:12:15Z |
| Obs used |
4255 |
| NEO |
- |
| M1 |
7.600 |
| K1 |
5.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2024-11-08.0000000 |
| e |
1.00036185 |
| q (au) |
4.982434 |
| a (au) |
-13769.181458 |
| i (deg) |
48.472530 |
| Ω (om, deg) |
221.095251 |
| ω (w, deg) |
343.273606 |
| M (ma, deg) |
0.000036 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.504 + 2.779\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.504 |
| n |
2.779 |
| gf |
0.875 |
| gb |
-0.914 |
| k |
1.000 |
| δ90 |
5.344 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
17:17:36.10 |
+14:56:40.8 |
HIP 84568 |
14.98 |
| 2026-06-01 12:00 |
17:17:24.25 |
+14:58:33.4 |
HIP 84568 |
12.48 |
| 2026-06-02 00:00 |
17:17:12.37 |
+15:00:24.4 |
HIP 84568 |
10.55 |
| 2026-06-02 12:00 |
17:17:00.47 |
+15:02:13.9 |
HIP 84568 |
9.51 |
| 2026-06-03 00:00 |
17:16:48.55 |
+15:04:01.8 |
HIP 84568 |
9.66 |
| 2026-06-03 12:00 |
17:16:36.61 |
+15:05:48.1 |
HIP 84568 |
10.92 |
| 2026-06-04 00:00 |
17:16:24.66 |
+15:07:32.8 |
HIP 84550 |
12.66 |
| 2026-06-04 12:00 |
17:16:12.69 |
+15:09:15.9 |
HIP 84550 |
13.94 |
| 2026-06-05 00:00 |
17:16:00.70 |
+15:10:57.4 |
HIP 84550 |
15.86 |
| 2026-06-05 12:00 |
17:15:48.71 |
+15:12:37.3 |
HIP 84550 |
18.20 |
| 2026-06-06 00:00 |
17:15:36.70 |
+15:14:15.6 |
HIP 84412 |
19.76 |
| 2026-06-06 12:00 |
17:15:24.68 |
+15:15:52.4 |
HIP 84412 |
21.19 |
| 2026-06-07 00:00 |
17:15:12.66 |
+15:17:27.4 |
HIP 84375 |
22.97 |
| 2026-06-07 12:00 |
17:15:00.64 |
+15:19:00.9 |
HIP 84375 |
21.16 |
| 2026-06-08 00:00 |
17:14:48.61 |
+15:20:32.8 |
HIP 84375 |
19.76 |
| 2026-06-08 12:00 |
17:14:36.58 |
+15:22:03.0 |
HIP 84375 |
18.85 |
| 2026-06-09 00:00 |
17:14:24.55 |
+15:23:31.6 |
HIP 84375 |
18.51 |
| 2026-06-09 12:00 |
17:14:12.52 |
+15:24:58.6 |
HIP 84375 |
18.76 |
| 2026-06-10 00:00 |
17:14:00.50 |
+15:26:24.0 |
HIP 84375 |
19.57 |
| 2026-06-10 12:00 |
17:13:48.48 |
+15:27:47.7 |
HIP 84189 |
18.37 |
| 2026-06-11 00:00 |
17:13:36.47 |
+15:29:09.8 |
HIP 84189 |
16.00 |
| 2026-06-11 12:00 |
17:13:24.47 |
+15:30:30.2 |
HIP 84189 |
13.95 |
| 2026-06-12 00:00 |
17:13:12.48 |
+15:31:49.0 |
HIP 84189 |
12.38 |
| 2026-06-12 12:00 |
17:13:00.51 |
+15:33:06.2 |
HIP 84189 |
11.47 |
| 2026-06-13 00:00 |
17:12:48.55 |
+15:34:21.7 |
HIP 84189 |
11.37 |
| 2026-06-13 12:00 |
17:12:36.61 |
+15:35:35.5 |
HIP 84189 |
12.09 |
| 2026-06-14 00:00 |
17:12:24.68 |
+15:36:47.7 |
HIP 84189 |
13.48 |
| 2026-06-14 12:00 |
17:12:12.78 |
+15:37:58.3 |
HIP 84189 |
15.36 |
| 2026-06-15 00:00 |
17:12:00.90 |
+15:39:07.2 |
HIP 84189 |
17.56 |
| 2026-06-15 12:00 |
17:11:49.05 |
+15:40:14.5 |
HIP 84189 |
19.97 |
| 2026-06-16 00:00 |
17:11:37.22 |
+15:41:20.2 |
HIP 84189 |
22.51 |
| 2026-06-16 12:00 |
17:11:25.42 |
+15:42:24.2 |
HIP 84189 |
25.15 |
| 2026-06-17 00:00 |
17:11:13.66 |
+15:43:26.5 |
HIP 84189 |
27.83 |
| 2026-06-17 12:00 |
17:11:01.92 |
+15:44:27.2 |
HIP 84189 |
30.56 |
| 2026-06-18 00:00 |
17:10:50.22 |
+15:45:26.3 |
HIP 84189 |
33.31 |
| 2026-06-18 12:00 |
17:10:38.55 |
+15:46:23.8 |
HIP 84189 |
36.07 |
| 2026-06-19 00:00 |
17:10:26.93 |
+15:47:19.6 |
HIP 83855 |
36.46 |
| 2026-06-19 12:00 |
17:10:15.34 |
+15:48:13.8 |
HIP 83855 |
33.60 |
| 2026-06-20 00:00 |
17:10:03.79 |
+15:49:06.3 |
HIP 83855 |
30.78 |
| 2026-06-20 12:00 |
17:09:52.29 |
+15:49:57.3 |
HIP 83855 |
28.00 |
| 2026-06-21 00:00 |
17:09:40.83 |
+15:50:46.6 |
HIP 83855 |
25.28 |
| 2026-06-21 12:00 |
17:09:29.42 |
+15:51:34.4 |
HIP 83855 |
22.61 |
| 2026-06-22 00:00 |
17:09:18.05 |
+15:52:20.5 |
HIP 83855 |
20.02 |