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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 23:37:20.22 | -47:36:46.0 | HIP 116489 | 13.76 |
| 2026-03-26 12:00 | 23:37:31.78 | -47:35:18.6 | HIP 116489 | 14.52 |
| 2026-03-27 00:00 | 23:37:43.30 | -47:33:52.7 | HIP 116489 | 15.63 |
| 2026-03-27 12:00 | 23:37:54.76 | -47:32:28.4 | HIP 116489 | 17.02 |
| 2026-03-28 00:00 | 23:38:06.18 | -47:31:05.6 | HIP 116489 | 18.61 |
| 2026-03-28 12:00 | 23:38:17.54 | -47:29:44.3 | HIP 116767 | 17.34 |
| 2026-03-29 00:00 | 23:38:28.85 | -47:28:24.6 | HIP 116767 | 16.08 |
| 2026-03-29 12:00 | 23:38:40.11 | -47:27:06.5 | HIP 116767 | 15.05 |
| 2026-03-30 00:00 | 23:38:51.32 | -47:25:49.9 | HIP 116774 | 13.18 |
| 2026-03-30 12:00 | 23:39:02.47 | -47:24:34.9 | HIP 116774 | 10.92 |
| 2026-03-31 00:00 | 23:39:13.56 | -47:23:21.4 | HIP 116774 | 8.70 |
| 2026-03-31 12:00 | 23:39:24.60 | -47:22:09.5 | HIP 116774 | 6.50 |
| 2026-04-01 00:00 | 23:39:35.58 | -47:20:59.1 | HIP 116774 | 4.34 |
| 2026-04-01 12:00 | 23:39:46.50 | -47:19:50.3 | HIP 116774 | 2.28 |
| 2026-04-02 00:00 | 23:39:57.36 | -47:18:43.1 | HIP 116774 | 0.97 |
| 2026-04-02 12:00 | 23:40:08.16 | -47:17:37.4 | HIP 116774 | 2.42 |
| 2026-04-03 00:00 | 23:40:18.89 | -47:16:33.2 | HIP 116774 | 4.43 |
| 2026-04-03 12:00 | 23:40:29.57 | -47:15:30.7 | HIP 116774 | 6.48 |
| 2026-04-04 00:00 | 23:40:40.18 | -47:14:29.7 | HIP 116774 | 8.53 |
| 2026-04-04 12:00 | 23:40:50.72 | -47:13:30.3 | HIP 116774 | 10.56 |
| 2026-04-05 00:00 | 23:41:01.20 | -47:12:32.4 | HIP 116774 | 12.57 |
| 2026-04-05 12:00 | 23:41:11.61 | -47:11:36.1 | HIP 116774 | 14.56 |
| 2026-04-06 00:00 | 23:41:21.95 | -47:10:41.4 | HIP 116774 | 16.53 |
| 2026-04-06 12:00 | 23:41:32.23 | -47:09:48.3 | HIP 116774 | 18.48 |
| 2026-04-07 00:00 | 23:41:42.43 | -47:08:56.7 | HIP 116774 | 20.41 |
| 2026-04-07 12:00 | 23:41:52.56 | -47:08:06.7 | HIP 116774 | 22.31 |
| 2026-04-08 00:00 | 23:42:02.62 | -47:07:18.3 | HIP 116774 | 24.19 |
| 2026-04-08 12:00 | 23:42:12.61 | -47:06:31.5 | HIP 116774 | 26.05 |
| 2026-04-09 00:00 | 23:42:22.52 | -47:05:46.3 | HIP 116774 | 27.89 |
| 2026-04-09 12:00 | 23:42:32.35 | -47:05:02.6 | HIP 117144 | 28.72 |
| 2026-04-10 00:00 | 23:42:42.11 | -47:04:20.5 | HIP 117144 | 27.76 |
| 2026-04-10 12:00 | 23:42:51.79 | -47:03:40.1 | HIP 117144 | 26.87 |
| 2026-04-11 00:00 | 23:43:01.38 | -47:03:01.2 | HIP 117144 | 26.06 |
| 2026-04-11 12:00 | 23:43:10.90 | -47:02:23.9 | HIP 117144 | 25.34 |
| 2026-04-12 00:00 | 23:43:20.34 | -47:01:48.2 | HIP 117144 | 24.71 |
| 2026-04-12 12:00 | 23:43:29.69 | -47:01:14.1 | HIP 117144 | 24.17 |
| 2026-04-13 00:00 | 23:43:38.96 | -47:00:41.6 | HIP 117144 | 23.73 |
| 2026-04-13 12:00 | 23:43:48.15 | -47:00:10.8 | HIP 117144 | 23.37 |
| 2026-04-14 00:00 | 23:43:57.24 | -46:59:41.5 | HIP 117144 | 23.11 |
| 2026-04-14 12:00 | 23:44:06.25 | -46:59:13.8 | HIP 117144 | 22.94 |
| 2026-04-15 00:00 | 23:44:15.17 | -46:58:47.7 | HIP 117144 | 22.87 |
| 2026-04-15 12:00 | 23:44:24.00 | -46:58:23.2 | HIP 117144 | 22.87 |
| 2026-04-16 00:00 | 23:44:32.74 | -46:58:00.4 | HIP 117144 | 22.96 |