C/2023 U1 (Fuls)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2023 U1 (Fuls) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2024-10-12T19:51:42.851520Z |
| Orbit solution date (soln_date, UTC) | 2026-01-07T15:42:42Z |
| Obs used | 641 |
| NEO | - |
| M1 | 9.900 |
| K1 | 6.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2023-10-16T11:27:03.686400Z |
| Discovery magnitude (MPC) | 19.34 G |
| Discovery observatory (MPC) | G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2025-02-02.0000000 |
| e | 0.99787289 |
| q (au) | 4.972919 |
| a (au) | 2337.878590 |
| i (deg) | 108.145664 |
| Ω (om, deg) | 305.805991 |
| ω (w, deg) | 255.633994 |
| M (ma, deg) | 0.000978 |
Magnitude
Scatter + Global Linear
$$ M_a = (5.153 + 4.788\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 5.153 |
| n | 4.788 |
| gf | 0.999 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) | End (UTC) | a | b |
|---|---|---|---|
| 2023-01-14 | 2024-10-05 | +3.8773 | -2.102 |
| 2024-10-21 | 2025-10-01 | -18.1229 | +12.630 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Finding Chart
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 23:17:07.58 | -52:14:03.1 | HIP 114946 | 22.38 |
| 2026-02-03 12:00 | 23:17:17.54 | -52:10:10.5 | HIP 114946 | 18.72 |
| 2026-02-04 00:00 | 23:17:27.59 | -52:06:19.1 | HIP 114946 | 15.35 |
| 2026-02-04 12:00 | 23:17:37.72 | -52:02:29.1 | HIP 114946 | 12.48 |
| 2026-02-05 00:00 | 23:17:47.94 | -51:58:40.3 | HIP 114946 | 10.52 |
| 2026-02-05 12:00 | 23:17:58.24 | -51:54:52.7 | HIP 114946 | 10.01 |
| 2026-02-06 00:00 | 23:18:08.63 | -51:51:06.5 | HIP 114946 | 11.13 |
| 2026-02-06 12:00 | 23:18:19.09 | -51:47:21.6 | HIP 114946 | 13.47 |
| 2026-02-07 00:00 | 23:18:29.63 | -51:43:37.9 | HIP 114946 | 16.50 |
| 2026-02-07 12:00 | 23:18:40.25 | -51:39:55.5 | HIP 115221 | 15.07 |
| 2026-02-08 00:00 | 23:18:50.94 | -51:36:14.4 | HIP 115221 | 13.28 |
| 2026-02-08 12:00 | 23:19:01.70 | -51:32:34.6 | HIP 115221 | 12.56 |
| 2026-02-09 00:00 | 23:19:12.54 | -51:28:56.2 | HIP 115221 | 13.08 |
| 2026-02-09 12:00 | 23:19:23.45 | -51:25:19.0 | HIP 115221 | 14.68 |
| 2026-02-10 00:00 | 23:19:34.43 | -51:21:43.1 | HIP 115221 | 17.06 |
| 2026-02-10 12:00 | 23:19:45.47 | -51:18:08.6 | HIP 115221 | 19.93 |
| 2026-02-11 00:00 | 23:19:56.58 | -51:14:35.3 | HIP 115221 | 23.11 |
| 2026-02-11 12:00 | 23:20:07.75 | -51:11:03.4 | HIP 115221 | 26.47 |
| 2026-02-12 00:00 | 23:20:18.98 | -51:07:32.8 | HIP 115221 | 29.95 |
| 2026-02-12 12:00 | 23:20:30.28 | -51:04:03.6 | HIP 115221 | 33.51 |
| 2026-02-13 00:00 | 23:20:41.63 | -51:00:35.6 | HIP 115246 | 35.12 |
| 2026-02-13 12:00 | 23:20:53.05 | -50:57:09.1 | HIP 115246 | 31.79 |
| 2026-02-14 00:00 | 23:21:04.51 | -50:53:43.8 | HIP 115246 | 28.62 |
| 2026-02-14 12:00 | 23:21:16.04 | -50:50:19.9 | HIP 115246 | 25.68 |
| 2026-02-15 00:00 | 23:21:27.61 | -50:46:57.4 | HIP 115246 | 23.03 |
| 2026-02-15 12:00 | 23:21:39.24 | -50:43:36.2 | HIP 115246 | 20.78 |
| 2026-02-16 00:00 | 23:21:50.92 | -50:40:16.3 | HIP 115246 | 19.07 |
| 2026-02-16 12:00 | 23:22:02.64 | -50:36:57.9 | HIP 115246 | 18.03 |
| 2026-02-17 00:00 | 23:22:14.41 | -50:33:40.7 | HIP 115246 | 17.79 |
| 2026-02-17 12:00 | 23:22:26.23 | -50:30:25.0 | HIP 115246 | 18.36 |
| 2026-02-18 00:00 | 23:22:38.09 | -50:27:10.6 | HIP 115427 | 15.94 |
| 2026-02-18 12:00 | 23:22:49.99 | -50:23:57.6 | HIP 115427 | 12.57 |
| 2026-02-19 00:00 | 23:23:01.94 | -50:20:46.0 | HIP 115427 | 9.49 |
| 2026-02-19 12:00 | 23:23:13.92 | -50:17:35.8 | HIP 115427 | 7.09 |
| 2026-02-20 00:00 | 23:23:25.94 | -50:14:27.0 | HIP 115427 | 6.18 |
| 2026-02-20 12:00 | 23:23:37.99 | -50:11:19.5 | HIP 115427 | 7.30 |
| 2026-02-21 00:00 | 23:23:50.08 | -50:08:13.5 | HIP 115427 | 9.77 |
| 2026-02-21 12:00 | 23:24:02.20 | -50:05:08.8 | HIP 115427 | 12.82 |
| 2026-02-22 00:00 | 23:24:14.36 | -50:02:05.6 | HIP 115427 | 16.11 |
| 2026-02-22 12:00 | 23:24:26.54 | -49:59:03.7 | HIP 115427 | 19.51 |
| 2026-02-23 00:00 | 23:24:38.75 | -49:56:03.3 | HIP 115427 | 22.96 |
| 2026-02-23 12:00 | 23:24:50.99 | -49:53:04.2 | HIP 115427 | 26.44 |
| 2026-02-24 00:00 | 23:25:03.25 | -49:50:06.6 | HIP 115759 | 27.97 |