| Parameter |
Value |
| Designation |
C/2023 F2 (SOHO) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-03-21T03:59:23.654400Z |
| Orbit solution date (soln_date, UTC) |
2025-02-28T10:03:47Z |
| Obs used |
82 |
| NEO |
- |
| M1 |
20.800 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2023-03-21T00:06:17.568000Z |
| Discovery magnitude (MPC) |
4.90 V |
| Discovery observatory (MPC) |
249 · SOHO |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-03-21.0000000 |
| e |
1.01189649 |
| q (au) |
0.034240 |
| a (au) |
-2.878182 |
| i (deg) |
72.567452 |
| Ω (om, deg) |
71.422437 |
| ω (w, deg) |
57.765098 |
| M (ma, deg) |
-0.033557 |
Magnitude
Scatter + Global Linear
$$
M_a = (20.000 + 3.781\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
20.000 |
| n |
3.781 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
0.800 |
| δ90 |
1.000 |
| 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) |
| 2026-05-12 00:00 |
18:22:58.99 |
-70:03:42.7 |
HIP 89737 |
35.27 |
| 2026-05-12 12:00 |
18:22:43.18 |
-70:04:40.9 |
HIP 89737 |
35.23 |
| 2026-05-13 00:00 |
18:22:27.22 |
-70:05:38.4 |
HIP 89737 |
35.25 |
| 2026-05-13 12:00 |
18:22:11.12 |
-70:06:35.4 |
HIP 89737 |
35.34 |
| 2026-05-14 00:00 |
18:21:54.87 |
-70:07:31.8 |
HIP 89737 |
35.50 |
| 2026-05-14 12:00 |
18:21:38.47 |
-70:08:27.5 |
HIP 89737 |
35.72 |
| 2026-05-15 00:00 |
18:21:21.93 |
-70:09:22.7 |
HIP 89737 |
36.01 |
| 2026-05-15 12:00 |
18:21:05.25 |
-70:10:17.2 |
HIP 89721 |
35.86 |
| 2026-05-16 00:00 |
18:20:48.43 |
-70:11:11.2 |
HIP 89721 |
34.55 |
| 2026-05-16 12:00 |
18:20:31.47 |
-70:12:04.5 |
HIP 89721 |
33.27 |
| 2026-05-17 00:00 |
18:20:14.37 |
-70:12:57.1 |
HIP 89721 |
32.04 |
| 2026-05-17 12:00 |
18:19:57.13 |
-70:13:49.2 |
HIP 89721 |
30.86 |
| 2026-05-18 00:00 |
18:19:39.76 |
-70:14:40.5 |
HIP 89533 |
29.70 |
| 2026-05-18 12:00 |
18:19:22.26 |
-70:15:31.3 |
HIP 89533 |
28.16 |
| 2026-05-19 00:00 |
18:19:04.63 |
-70:16:21.3 |
HIP 89533 |
26.64 |
| 2026-05-19 12:00 |
18:18:46.86 |
-70:17:10.7 |
HIP 89533 |
25.15 |
| 2026-05-20 00:00 |
18:18:28.97 |
-70:17:59.5 |
HIP 89533 |
23.69 |
| 2026-05-20 12:00 |
18:18:10.96 |
-70:18:47.5 |
HIP 89533 |
22.28 |
| 2026-05-21 00:00 |
18:17:52.82 |
-70:19:34.9 |
HIP 89533 |
20.91 |
| 2026-05-21 12:00 |
18:17:34.56 |
-70:20:21.6 |
HIP 89533 |
19.61 |
| 2026-05-22 00:00 |
18:17:16.18 |
-70:21:07.6 |
HIP 89533 |
18.38 |
| 2026-05-22 12:00 |
18:16:57.69 |
-70:21:52.9 |
HIP 89533 |
17.25 |
| 2026-05-23 00:00 |
18:16:39.07 |
-70:22:37.5 |
HIP 89533 |
16.23 |
| 2026-05-23 12:00 |
18:16:20.35 |
-70:23:21.4 |
HIP 89533 |
15.35 |
| 2026-05-24 00:00 |
18:16:01.51 |
-70:24:04.5 |
HIP 89533 |
14.63 |
| 2026-05-24 12:00 |
18:15:42.56 |
-70:24:47.0 |
HIP 89533 |
14.10 |
| 2026-05-25 00:00 |
18:15:23.50 |
-70:25:28.7 |
HIP 89533 |
13.78 |
| 2026-05-25 12:00 |
18:15:04.34 |
-70:26:09.7 |
HIP 89533 |
13.69 |
| 2026-05-26 00:00 |
18:14:45.07 |
-70:26:50.0 |
HIP 89533 |
13.83 |
| 2026-05-26 12:00 |
18:14:25.70 |
-70:27:29.6 |
HIP 89533 |
14.20 |
| 2026-05-27 00:00 |
18:14:06.23 |
-70:28:08.4 |
HIP 89162 |
14.75 |
| 2026-05-27 12:00 |
18:13:46.67 |
-70:28:46.4 |
HIP 89162 |
13.92 |
| 2026-05-28 00:00 |
18:13:27.00 |
-70:29:23.8 |
HIP 89162 |
13.26 |
| 2026-05-28 12:00 |
18:13:07.24 |
-70:30:00.3 |
HIP 89162 |
12.79 |
| 2026-05-29 00:00 |
18:12:47.39 |
-70:30:36.2 |
HIP 89162 |
12.55 |
| 2026-05-29 12:00 |
18:12:27.45 |
-70:31:11.2 |
HIP 89162 |
12.54 |
| 2026-05-30 00:00 |
18:12:07.42 |
-70:31:45.5 |
HIP 89162 |
12.76 |
| 2026-05-30 12:00 |
18:11:47.30 |
-70:32:19.0 |
HIP 89162 |
13.20 |
| 2026-05-31 00:00 |
18:11:27.10 |
-70:32:51.8 |
HIP 89162 |
13.85 |
| 2026-05-31 12:00 |
18:11:06.82 |
-70:33:23.8 |
HIP 89162 |
14.68 |
| 2026-06-01 00:00 |
18:10:46.45 |
-70:33:55.0 |
HIP 89162 |
15.65 |
| 2026-06-01 12:00 |
18:10:26.01 |
-70:34:25.4 |
HIP 89162 |
16.75 |
| 2026-06-02 00:00 |
18:10:05.49 |
-70:34:55.1 |
HIP 89162 |
17.95 |