| Parameter |
Value |
| Designation |
C/2021 G2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2024-09-09T03:25:52.919040Z |
| Orbit solution date (soln_date, UTC) |
2026-07-28T14:12:17Z |
| Obs used |
4846 |
| NEO |
- |
| M1 |
7.400 |
| K1 |
6.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-01-20.0000000 |
| e |
1.00050148 |
| q (au) |
4.982391 |
| a (au) |
-9935.305098 |
| i (deg) |
48.471056 |
| Ω (om, deg) |
221.095390 |
| ω (w, deg) |
343.268856 |
| M (ma, deg) |
0.000132 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.192 + 2.462\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.192 |
| n |
2.462 |
| gf |
0.897 |
| gb |
-0.887 |
| k |
1.000 |
| δ90 |
4.156 |
| 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) |
| 2026-07-29 00:00 |
16:59:04.31 |
+15:43:08.8 |
HIP 83083 |
17.13 |
| 2026-07-29 12:00 |
16:59:00.11 |
+15:42:16.6 |
HIP 83083 |
15.96 |
| 2026-07-30 00:00 |
16:58:56.04 |
+15:41:23.6 |
HIP 83083 |
14.81 |
| 2026-07-30 12:00 |
16:58:52.09 |
+15:40:29.6 |
HIP 83083 |
13.68 |
| 2026-07-31 00:00 |
16:58:48.27 |
+15:39:34.8 |
HIP 83083 |
12.59 |
| 2026-07-31 12:00 |
16:58:44.58 |
+15:38:39.1 |
HIP 83083 |
11.52 |
| 2026-08-01 00:00 |
16:58:41.02 |
+15:37:42.6 |
HIP 83083 |
10.49 |
| 2026-08-01 12:00 |
16:58:37.59 |
+15:36:45.2 |
HIP 83083 |
9.51 |
| 2026-08-02 00:00 |
16:58:34.28 |
+15:35:47.0 |
HIP 83083 |
8.59 |
| 2026-08-02 12:00 |
16:58:31.11 |
+15:34:47.9 |
HIP 83083 |
7.73 |
| 2026-08-03 00:00 |
16:58:28.07 |
+15:33:48.0 |
HIP 83083 |
6.98 |
| 2026-08-03 12:00 |
16:58:25.15 |
+15:32:47.4 |
HIP 83083 |
6.35 |
| 2026-08-04 00:00 |
16:58:22.37 |
+15:31:45.9 |
HIP 83083 |
5.88 |
| 2026-08-04 12:00 |
16:58:19.72 |
+15:30:43.7 |
HIP 83083 |
5.61 |
| 2026-08-05 00:00 |
16:58:17.20 |
+15:29:40.7 |
HIP 83083 |
5.56 |
| 2026-08-05 12:00 |
16:58:14.81 |
+15:28:36.9 |
HIP 83083 |
5.74 |
| 2026-08-06 00:00 |
16:58:12.56 |
+15:27:32.4 |
HIP 83083 |
6.12 |
| 2026-08-06 12:00 |
16:58:10.44 |
+15:26:27.1 |
HIP 83083 |
6.67 |
| 2026-08-07 00:00 |
16:58:08.44 |
+15:25:21.2 |
HIP 83083 |
7.35 |
| 2026-08-07 12:00 |
16:58:06.59 |
+15:24:14.5 |
HIP 83083 |
8.13 |
| 2026-08-08 00:00 |
16:58:04.86 |
+15:23:07.1 |
HIP 83083 |
8.97 |
| 2026-08-08 12:00 |
16:58:03.27 |
+15:21:59.0 |
HIP 83083 |
9.87 |
| 2026-08-09 00:00 |
16:58:01.81 |
+15:20:50.3 |
HIP 83083 |
10.81 |
| 2026-08-09 12:00 |
16:58:00.49 |
+15:19:40.9 |
HIP 83034 |
10.55 |
| 2026-08-10 00:00 |
16:57:59.30 |
+15:18:30.8 |
HIP 83034 |
9.42 |
| 2026-08-10 12:00 |
16:57:58.25 |
+15:17:20.1 |
HIP 83034 |
8.30 |
| 2026-08-11 00:00 |
16:57:57.33 |
+15:16:08.8 |
HIP 83034 |
7.19 |
| 2026-08-11 12:00 |
16:57:56.54 |
+15:14:56.9 |
HIP 83034 |
6.10 |
| 2026-08-12 00:00 |
16:57:55.89 |
+15:13:44.3 |
HIP 83034 |
5.04 |
| 2026-08-12 12:00 |
16:57:55.38 |
+15:12:31.2 |
HIP 83034 |
4.04 |
| 2026-08-13 00:00 |
16:57:55.00 |
+15:11:17.5 |
HIP 83034 |
3.17 |
| 2026-08-13 12:00 |
16:57:54.75 |
+15:10:03.3 |
HIP 83034 |
2.58 |
| 2026-08-14 00:00 |
16:57:54.64 |
+15:08:48.5 |
HIP 83034 |
2.48 |
| 2026-08-14 12:00 |
16:57:54.67 |
+15:07:33.1 |
HIP 83034 |
2.94 |
| 2026-08-15 00:00 |
16:57:54.83 |
+15:06:17.3 |
HIP 83034 |
3.77 |
| 2026-08-15 12:00 |
16:57:55.13 |
+15:05:00.9 |
HIP 83034 |
4.78 |
| 2026-08-16 00:00 |
16:57:55.56 |
+15:03:44.0 |
HIP 83034 |
5.89 |
| 2026-08-16 12:00 |
16:57:56.13 |
+15:02:26.7 |
HIP 83034 |
7.06 |
| 2026-08-17 00:00 |
16:57:56.83 |
+15:01:08.8 |
HIP 83034 |
8.26 |
| 2026-08-17 12:00 |
16:57:57.67 |
+14:59:50.6 |
HIP 83034 |
9.50 |
| 2026-08-18 00:00 |
16:57:58.64 |
+14:58:31.8 |
HIP 83034 |
10.76 |
| 2026-08-18 12:00 |
16:57:59.75 |
+14:57:12.7 |
HIP 83034 |
12.04 |
| 2026-08-19 00:00 |
16:58:00.99 |
+14:55:53.1 |
HIP 83034 |
13.33 |