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
$$ M_a = (10.038 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 10.038 |
| n | 2.000 |
| gf | 0.998 |
| gb | -0.735 |
| 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 | +10.8460 | -6.986 |
| 2024-10-21 | 2025-12-30 | -4.0607 | +2.693 |
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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 23:49:30.30 | -47:14:46.3 | HIP 117478 | 7.58 |
| 2026-05-12 12:00 | 23:49:32.43 | -47:15:47.1 | HIP 117478 | 8.65 |
| 2026-05-13 00:00 | 23:49:34.40 | -47:16:49.3 | HIP 117478 | 9.74 |
| 2026-05-13 12:00 | 23:49:36.21 | -47:17:53.1 | HIP 117478 | 10.85 |
| 2026-05-14 00:00 | 23:49:37.86 | -47:18:58.3 | HIP 117571 | 10.44 |
| 2026-05-14 12:00 | 23:49:39.35 | -47:20:05.1 | HIP 117547 | 9.74 |
| 2026-05-15 00:00 | 23:49:40.67 | -47:21:13.4 | HIP 117547 | 8.77 |
| 2026-05-15 12:00 | 23:49:41.83 | -47:22:23.2 | HIP 117547 | 7.86 |
| 2026-05-16 00:00 | 23:49:42.82 | -47:23:34.5 | HIP 117547 | 7.05 |
| 2026-05-16 12:00 | 23:49:43.63 | -47:24:47.2 | HIP 117547 | 6.38 |
| 2026-05-17 00:00 | 23:49:44.28 | -47:26:01.4 | HIP 117547 | 5.90 |
| 2026-05-17 12:00 | 23:49:44.75 | -47:27:17.1 | HIP 117547 | 5.70 |
| 2026-05-18 00:00 | 23:49:45.05 | -47:28:34.3 | HIP 117547 | 5.81 |
| 2026-05-18 12:00 | 23:49:45.18 | -47:29:52.9 | HIP 117547 | 6.22 |
| 2026-05-19 00:00 | 23:49:45.13 | -47:31:13.0 | HIP 117547 | 6.90 |
| 2026-05-19 12:00 | 23:49:44.90 | -47:32:34.5 | HIP 117547 | 7.80 |
| 2026-05-20 00:00 | 23:49:44.49 | -47:33:57.5 | HIP 117547 | 8.85 |
| 2026-05-20 12:00 | 23:49:43.90 | -47:35:21.9 | HIP 117547 | 10.02 |
| 2026-05-21 00:00 | 23:49:43.12 | -47:36:47.7 | HIP 117444 | 9.53 |
| 2026-05-21 12:00 | 23:49:42.17 | -47:38:14.9 | HIP 117444 | 9.14 |
| 2026-05-22 00:00 | 23:49:41.03 | -47:39:43.5 | HIP 117444 | 8.94 |
| 2026-05-22 12:00 | 23:49:39.70 | -47:41:13.5 | HIP 117444 | 8.97 |
| 2026-05-23 00:00 | 23:49:38.19 | -47:42:44.8 | HIP 117444 | 9.22 |
| 2026-05-23 12:00 | 23:49:36.48 | -47:44:17.6 | HIP 117444 | 9.71 |
| 2026-05-24 00:00 | 23:49:34.59 | -47:45:51.7 | HIP 117444 | 10.40 |
| 2026-05-24 12:00 | 23:49:32.50 | -47:47:27.2 | HIP 117444 | 11.28 |
| 2026-05-25 00:00 | 23:49:30.23 | -47:49:04.0 | HIP 117444 | 12.31 |
| 2026-05-25 12:00 | 23:49:27.76 | -47:50:42.1 | HIP 117444 | 13.47 |
| 2026-05-26 00:00 | 23:49:25.09 | -47:52:21.6 | HIP 117504 | 12.76 |
| 2026-05-26 12:00 | 23:49:22.23 | -47:54:02.4 | HIP 117504 | 11.25 |
| 2026-05-27 00:00 | 23:49:19.17 | -47:55:44.5 | HIP 117504 | 9.82 |
| 2026-05-27 12:00 | 23:49:15.92 | -47:57:27.9 | HIP 117504 | 8.51 |
| 2026-05-28 00:00 | 23:49:12.46 | -47:59:12.6 | HIP 117504 | 7.42 |
| 2026-05-28 12:00 | 23:49:08.80 | -48:00:58.5 | HIP 117504 | 6.68 |
| 2026-05-29 00:00 | 23:49:04.94 | -48:02:45.8 | HIP 117504 | 6.45 |
| 2026-05-29 12:00 | 23:49:00.87 | -48:04:34.3 | HIP 117504 | 6.79 |
| 2026-05-30 00:00 | 23:48:56.60 | -48:06:24.0 | HIP 117504 | 7.66 |
| 2026-05-30 12:00 | 23:48:52.12 | -48:08:15.0 | HIP 117504 | 8.93 |
| 2026-05-31 00:00 | 23:48:47.44 | -48:10:07.2 | HIP 117504 | 10.46 |
| 2026-05-31 12:00 | 23:48:42.55 | -48:12:00.6 | HIP 117504 | 12.18 |
| 2026-06-01 00:00 | 23:48:37.44 | -48:13:55.3 | HIP 117320 | 12.96 |
| 2026-06-01 12:00 | 23:48:32.12 | -48:15:51.1 | HIP 117320 | 11.83 |
| 2026-06-02 00:00 | 23:48:26.59 | -48:17:48.1 | HIP 117320 | 10.96 |