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 · University of Arizona 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 | 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
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) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 23:10:33.90 | -52:51:18.4 | HIP 114585 | 22.99 |
| 2026-07-29 12:00 | 23:09:59.38 | -52:53:14.2 | HIP 114362 | 27.91 |
| 2026-07-30 00:00 | 23:09:24.66 | -52:55:08.6 | HIP 114138 | 23.80 |
| 2026-07-30 12:00 | 23:08:49.74 | -52:57:01.3 | HIP 114138 | 19.84 |
| 2026-07-31 00:00 | 23:08:14.62 | -52:58:52.4 | HIP 114138 | 16.80 |
| 2026-07-31 12:00 | 23:07:39.30 | -53:00:41.8 | HIP 114138 | 15.27 |
| 2026-08-01 00:00 | 23:07:03.80 | -53:02:29.6 | HIP 114138 | 15.69 |
| 2026-08-01 12:00 | 23:06:28.10 | -53:04:15.8 | HIP 114138 | 17.96 |
| 2026-08-02 00:00 | 23:05:52.21 | -53:06:00.1 | HIP 114138 | 21.50 |
| 2026-08-02 12:00 | 23:05:16.15 | -53:07:42.8 | HIP 113799 | 24.85 |
| 2026-08-03 00:00 | 23:04:39.90 | -53:09:23.7 | HIP 113799 | 20.83 |
| 2026-08-03 12:00 | 23:04:03.48 | -53:11:02.8 | HIP 113799 | 17.72 |
| 2026-08-04 00:00 | 23:03:26.88 | -53:12:40.1 | HIP 113799 | 16.08 |
| 2026-08-04 12:00 | 23:02:50.12 | -53:14:15.6 | HIP 113799 | 16.36 |
| 2026-08-05 00:00 | 23:02:13.19 | -53:15:49.2 | HIP 113596 | 16.15 |
| 2026-08-05 12:00 | 23:01:36.10 | -53:17:20.9 | HIP 113596 | 11.09 |
| 2026-08-06 00:00 | 23:00:58.84 | -53:18:50.7 | HIP 113596 | 7.14 |
| 2026-08-06 12:00 | 23:00:21.44 | -53:20:18.6 | HIP 113596 | 6.71 |
| 2026-08-07 00:00 | 22:59:43.88 | -53:21:44.5 | HIP 113596 | 10.28 |
| 2026-08-07 12:00 | 22:59:06.18 | -53:23:08.5 | HIP 113596 | 15.27 |
| 2026-08-08 00:00 | 22:58:28.33 | -53:24:30.5 | HIP 113596 | 20.69 |
| 2026-08-08 12:00 | 22:57:50.34 | -53:25:50.4 | HIP 113596 | 26.28 |
| 2026-08-09 00:00 | 22:57:12.22 | -53:27:08.4 | HIP 113596 | 31.95 |
| 2026-08-09 12:00 | 22:56:33.97 | -53:28:24.2 | HIP 113596 | 37.67 |
| 2026-08-10 00:00 | 22:55:55.59 | -53:29:38.0 | HIP 112913 | 38.23 |
| 2026-08-10 12:00 | 22:55:17.09 | -53:30:49.7 | HIP 112913 | 33.57 |
| 2026-08-11 00:00 | 22:54:38.47 | -53:31:59.2 | HIP 112913 | 29.31 |
| 2026-08-11 12:00 | 22:53:59.74 | -53:33:06.6 | HIP 112913 | 25.67 |
| 2026-08-12 00:00 | 22:53:20.90 | -53:34:11.9 | HIP 112913 | 22.94 |
| 2026-08-12 12:00 | 22:52:41.95 | -53:35:15.0 | HIP 112913 | 21.47 |
| 2026-08-13 00:00 | 22:52:02.91 | -53:36:15.9 | HIP 112913 | 21.55 |
| 2026-08-13 12:00 | 22:51:23.77 | -53:37:14.5 | HIP 112913 | 23.14 |
| 2026-08-14 00:00 | 22:50:44.54 | -53:38:11.0 | HIP 112715 | 22.18 |
| 2026-08-14 12:00 | 22:50:05.23 | -53:39:05.2 | HIP 112715 | 21.01 |
| 2026-08-15 00:00 | 22:49:25.83 | -53:39:57.1 | HIP 112715 | 21.43 |
| 2026-08-15 12:00 | 22:48:46.37 | -53:40:46.8 | HIP 112715 | 23.37 |
| 2026-08-16 00:00 | 22:48:06.83 | -53:41:34.1 | HIP 112374 | 24.94 |
| 2026-08-16 12:00 | 22:47:27.22 | -53:42:19.2 | HIP 112374 | 20.37 |
| 2026-08-17 00:00 | 22:46:47.56 | -53:43:02.0 | HIP 112374 | 16.63 |
| 2026-08-17 12:00 | 22:46:07.83 | -53:43:42.4 | HIP 112374 | 14.40 |
| 2026-08-18 00:00 | 22:45:28.06 | -53:44:20.5 | HIP 112374 | 14.41 |
| 2026-08-18 12:00 | 22:44:48.24 | -53:44:56.3 | HIP 112374 | 16.64 |
| 2026-08-19 00:00 | 22:44:08.39 | -53:45:29.7 | HIP 112374 | 20.39 |