C/2023 X1 (Leonard)
| Parameter |
Value |
| Designation |
C/2023 X1 (Leonard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-10-18T02:08:14.887680Z |
| Orbit solution date (soln_date, UTC) |
2024-04-13T16:42:53Z |
| Obs used |
255 |
| NEO |
- |
| M1 |
17.400 |
| K1 |
7.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2023-12-04T10:33:40.492800Z |
| Discovery magnitude (MPC) |
17.38 G |
| Discovery observatory (MPC) |
703 · Catalina Sky Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-12-12.0000000 |
| e |
0.99415118 |
| q (au) |
0.950488 |
| a (au) |
162.509349 |
| i (deg) |
110.586652 |
| Ω (om, deg) |
137.010668 |
| ω (w, deg) |
321.470854 |
| M (ma, deg) |
0.026124 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.820 + 3.580\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.820 |
| n |
3.580 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.951 |
| 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 |
| 2023-11-02 |
2025-08-30 |
-5.8104 |
+0.399 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
21:34:55.85 |
+54:22:33.0 |
HIP 106462 |
10.82 |
| 2026-02-03 12:00 |
21:35:16.85 |
+54:22:09.7 |
HIP 106462 |
13.65 |
| 2026-02-04 00:00 |
21:35:37.83 |
+54:21:47.8 |
HIP 106462 |
16.57 |
| 2026-02-04 12:00 |
21:35:58.80 |
+54:21:27.3 |
HIP 106713 |
18.85 |
| 2026-02-05 00:00 |
21:36:19.75 |
+54:21:08.3 |
HIP 106713 |
17.99 |
| 2026-02-05 12:00 |
21:36:40.69 |
+54:20:50.6 |
HIP 106713 |
17.60 |
| 2026-02-06 00:00 |
21:37:01.60 |
+54:20:34.3 |
HIP 106713 |
17.71 |
| 2026-02-06 12:00 |
21:37:22.50 |
+54:20:19.4 |
HIP 106771 |
17.95 |
| 2026-02-07 00:00 |
21:37:43.38 |
+54:20:05.9 |
HIP 106771 |
17.58 |
| 2026-02-07 12:00 |
21:38:04.24 |
+54:19:53.8 |
HIP 106771 |
17.76 |
| 2026-02-08 00:00 |
21:38:25.08 |
+54:19:43.1 |
HIP 106771 |
18.47 |
| 2026-02-08 12:00 |
21:38:45.89 |
+54:19:33.8 |
HIP 107036 |
16.51 |
| 2026-02-09 00:00 |
21:39:06.69 |
+54:19:25.8 |
HIP 107036 |
13.47 |
| 2026-02-09 12:00 |
21:39:27.46 |
+54:19:19.2 |
HIP 107036 |
10.45 |
| 2026-02-10 00:00 |
21:39:48.21 |
+54:19:14.0 |
HIP 107036 |
7.42 |
| 2026-02-10 12:00 |
21:40:08.93 |
+54:19:10.1 |
HIP 107036 |
4.41 |
| 2026-02-11 00:00 |
21:40:29.62 |
+54:19:07.6 |
HIP 107036 |
1.43 |
| 2026-02-11 12:00 |
21:40:50.29 |
+54:19:06.5 |
HIP 107036 |
1.67 |
| 2026-02-12 00:00 |
21:41:10.94 |
+54:19:06.7 |
HIP 107036 |
4.66 |
| 2026-02-12 12:00 |
21:41:31.55 |
+54:19:08.3 |
HIP 107036 |
7.66 |
| 2026-02-13 00:00 |
21:41:52.13 |
+54:19:11.2 |
HIP 107036 |
10.65 |
| 2026-02-13 12:00 |
21:42:12.69 |
+54:19:15.5 |
HIP 107036 |
13.65 |
| 2026-02-14 00:00 |
21:42:33.21 |
+54:19:21.1 |
HIP 107215 |
14.74 |
| 2026-02-14 12:00 |
21:42:53.71 |
+54:19:28.1 |
HIP 107215 |
14.25 |
| 2026-02-15 00:00 |
21:43:14.17 |
+54:19:36.3 |
HIP 107215 |
14.35 |
| 2026-02-15 12:00 |
21:43:34.60 |
+54:19:45.9 |
HIP 107215 |
15.03 |
| 2026-02-16 00:00 |
21:43:54.99 |
+54:19:56.9 |
HIP 107293 |
15.26 |
| 2026-02-16 12:00 |
21:44:15.35 |
+54:20:09.1 |
HIP 107396 |
13.21 |
| 2026-02-17 00:00 |
21:44:35.67 |
+54:20:22.7 |
HIP 107396 |
11.42 |
| 2026-02-17 12:00 |
21:44:55.95 |
+54:20:37.5 |
HIP 107396 |
10.17 |
| 2026-02-18 00:00 |
21:45:16.20 |
+54:20:53.7 |
HIP 107396 |
9.68 |
| 2026-02-18 12:00 |
21:45:36.41 |
+54:21:11.2 |
HIP 107396 |
10.05 |
| 2026-02-19 00:00 |
21:45:56.58 |
+54:21:29.9 |
HIP 107396 |
11.19 |
| 2026-02-19 12:00 |
21:46:16.71 |
+54:21:50.0 |
HIP 107396 |
12.89 |
| 2026-02-20 00:00 |
21:46:36.80 |
+54:22:11.3 |
HIP 107650 |
14.48 |
| 2026-02-20 12:00 |
21:46:56.85 |
+54:22:33.9 |
HIP 107650 |
11.55 |
| 2026-02-21 00:00 |
21:47:16.85 |
+54:22:57.8 |
HIP 107650 |
8.62 |
| 2026-02-21 12:00 |
21:47:36.81 |
+54:23:22.9 |
HIP 107650 |
5.71 |
| 2026-02-22 00:00 |
21:47:56.72 |
+54:23:49.3 |
HIP 107650 |
2.87 |
| 2026-02-22 12:00 |
21:48:16.59 |
+54:24:17.0 |
HIP 107650 |
1.05 |
| 2026-02-23 00:00 |
21:48:36.42 |
+54:24:45.9 |
HIP 107650 |
3.34 |
| 2026-02-23 12:00 |
21:48:56.20 |
+54:25:16.0 |
HIP 107733 |
4.90 |
| 2026-02-24 00:00 |
21:49:15.92 |
+54:25:47.4 |
HIP 107733 |
3.21 |