| Parameter |
Value |
| Designation |
C/2023 S2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-10-15T09:03:22.020480Z |
| Orbit solution date (soln_date, UTC) |
2024-06-06T23:12:32Z |
| Obs used |
392 |
| NEO |
- |
| M1 |
14.500 |
| K1 |
25.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2023-09-28T23:40:21.590400Z |
| Discovery magnitude (MPC) |
15.15 o |
| Discovery observatory (MPC) |
W68 · ATLAS Chile, Rio Hurtado |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-10-11.0000000 |
| e |
0.99288676 |
| q (au) |
1.067716 |
| a (au) |
150.102592 |
| i (deg) |
20.485436 |
| Ω (om, deg) |
230.562176 |
| ω (w, deg) |
78.109160 |
| M (ma, deg) |
359.997654 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.113 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.113 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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) |
| 2026-03-26 00:00 |
05:25:24.41 |
+11:00:18.7 |
HIP 25323 |
9.48 |
| 2026-03-26 12:00 |
05:25:29.69 |
+11:00:53.5 |
HIP 25323 |
9.95 |
| 2026-03-27 00:00 |
05:25:35.07 |
+11:01:28.1 |
HIP 25323 |
10.61 |
| 2026-03-27 12:00 |
05:25:40.54 |
+11:02:02.7 |
HIP 25323 |
11.44 |
| 2026-03-28 00:00 |
05:25:46.11 |
+11:02:37.2 |
HIP 25323 |
12.40 |
| 2026-03-28 12:00 |
05:25:51.76 |
+11:03:11.6 |
HIP 25323 |
13.48 |
| 2026-03-29 00:00 |
05:25:57.51 |
+11:03:45.9 |
HIP 25323 |
14.66 |
| 2026-03-29 12:00 |
05:26:03.35 |
+11:04:20.1 |
HIP 25323 |
15.92 |
| 2026-03-30 00:00 |
05:26:09.28 |
+11:04:54.2 |
HIP 25323 |
17.24 |
| 2026-03-30 12:00 |
05:26:15.30 |
+11:05:28.2 |
HIP 25323 |
18.63 |
| 2026-03-31 00:00 |
05:26:21.41 |
+11:06:02.2 |
HIP 25323 |
20.07 |
| 2026-03-31 12:00 |
05:26:27.61 |
+11:06:36.0 |
HIP 25323 |
21.55 |
| 2026-04-01 00:00 |
05:26:33.90 |
+11:07:09.7 |
HIP 25323 |
23.07 |
| 2026-04-01 12:00 |
05:26:40.28 |
+11:07:43.2 |
HIP 25540 |
22.89 |
| 2026-04-02 00:00 |
05:26:46.74 |
+11:08:16.7 |
HIP 25540 |
21.49 |
| 2026-04-02 12:00 |
05:26:53.29 |
+11:08:50.1 |
HIP 25540 |
20.12 |
| 2026-04-03 00:00 |
05:26:59.92 |
+11:09:23.3 |
HIP 25540 |
18.79 |
| 2026-04-03 12:00 |
05:27:06.64 |
+11:09:56.4 |
HIP 25540 |
17.53 |
| 2026-04-04 00:00 |
05:27:13.45 |
+11:10:29.4 |
HIP 25540 |
16.34 |
| 2026-04-04 12:00 |
05:27:20.34 |
+11:11:02.3 |
HIP 25540 |
15.26 |
| 2026-04-05 00:00 |
05:27:27.31 |
+11:11:35.0 |
HIP 25540 |
14.32 |
| 2026-04-05 12:00 |
05:27:34.36 |
+11:12:07.6 |
HIP 25540 |
13.56 |
| 2026-04-06 00:00 |
05:27:41.50 |
+11:12:40.1 |
HIP 25540 |
13.00 |
| 2026-04-06 12:00 |
05:27:48.72 |
+11:13:12.4 |
HIP 25540 |
12.70 |
| 2026-04-07 00:00 |
05:27:56.03 |
+11:13:44.6 |
HIP 25540 |
12.67 |
| 2026-04-07 12:00 |
05:28:03.41 |
+11:14:16.7 |
HIP 25540 |
12.93 |
| 2026-04-08 00:00 |
05:28:10.87 |
+11:14:48.6 |
HIP 25540 |
13.46 |
| 2026-04-08 12:00 |
05:28:18.42 |
+11:15:20.4 |
HIP 25540 |
14.24 |
| 2026-04-09 00:00 |
05:28:26.04 |
+11:15:52.0 |
HIP 25540 |
15.25 |
| 2026-04-09 12:00 |
05:28:33.74 |
+11:16:23.5 |
HIP 25540 |
16.44 |
| 2026-04-10 00:00 |
05:28:41.52 |
+11:16:54.8 |
HIP 25540 |
17.78 |
| 2026-04-10 12:00 |
05:28:49.38 |
+11:17:26.0 |
HIP 25540 |
19.25 |
| 2026-04-11 00:00 |
05:28:57.31 |
+11:17:57.0 |
HIP 25540 |
20.83 |
| 2026-04-11 12:00 |
05:29:05.32 |
+11:18:27.8 |
HIP 25540 |
22.50 |
| 2026-04-12 00:00 |
05:29:13.40 |
+11:18:58.5 |
HIP 25540 |
24.24 |
| 2026-04-12 12:00 |
05:29:21.57 |
+11:19:29.0 |
HIP 25540 |
26.04 |
| 2026-04-13 00:00 |
05:29:29.80 |
+11:19:59.4 |
HIP 25540 |
27.90 |
| 2026-04-13 12:00 |
05:29:38.11 |
+11:20:29.6 |
HIP 25540 |
29.80 |
| 2026-04-14 00:00 |
05:29:46.49 |
+11:20:59.6 |
HIP 25540 |
31.75 |
| 2026-04-14 12:00 |
05:29:54.95 |
+11:21:29.4 |
HIP 25917 |
30.29 |
| 2026-04-15 00:00 |
05:30:03.48 |
+11:21:59.1 |
HIP 25917 |
28.47 |
| 2026-04-15 12:00 |
05:30:12.08 |
+11:22:28.6 |
HIP 25917 |
26.68 |
| 2026-04-16 00:00 |
05:30:20.75 |
+11:22:57.9 |
HIP 25917 |
24.94 |