| Parameter |
Value |
| Designation |
C/2023 A1 (Leonard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-03-18T17:25:38.349120Z |
| Orbit solution date (soln_date, UTC) |
2024-04-13T16:42:45Z |
| Obs used |
453 |
| NEO |
- |
| M1 |
6.300 |
| K1 |
37.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2023-01-09T12:59:03.782400Z |
| Discovery magnitude (MPC) |
18.94 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-03-06.0000000 |
| e |
0.99200431 |
| q (au) |
1.834725 |
| a (au) |
229.464077 |
| i (deg) |
94.743121 |
| Ω (om, deg) |
318.307926 |
| ω (w, deg) |
159.249397 |
| M (ma, deg) |
359.996391 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.463 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.463 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.998 |
| 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 |
| 2022-12-15 |
2023-03-18 |
+26.2283 |
-7.251 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
02:40:02.69 |
-63:02:22.1 |
HIP 12404 |
20.69 |
| 2026-06-01 12:00 |
02:40:18.38 |
-63:03:31.1 |
HIP 12404 |
22.08 |
| 2026-06-02 00:00 |
02:40:34.00 |
-63:04:41.3 |
HIP 12726 |
22.70 |
| 2026-06-02 12:00 |
02:40:49.54 |
-63:05:52.5 |
HIP 12726 |
21.67 |
| 2026-06-03 00:00 |
02:41:05.01 |
-63:07:04.9 |
HIP 12726 |
20.83 |
| 2026-06-03 12:00 |
02:41:20.41 |
-63:08:18.4 |
HIP 12726 |
20.19 |
| 2026-06-04 00:00 |
02:41:35.73 |
-63:09:33.0 |
HIP 12726 |
19.79 |
| 2026-06-04 12:00 |
02:41:50.97 |
-63:10:48.8 |
HIP 12726 |
19.64 |
| 2026-06-05 00:00 |
02:42:06.14 |
-63:12:05.6 |
HIP 12726 |
19.74 |
| 2026-06-05 12:00 |
02:42:21.23 |
-63:13:23.6 |
HIP 12726 |
20.09 |
| 2026-06-06 00:00 |
02:42:36.23 |
-63:14:42.7 |
HIP 12726 |
20.68 |
| 2026-06-06 12:00 |
02:42:51.16 |
-63:16:02.8 |
HIP 12726 |
21.49 |
| 2026-06-07 00:00 |
02:43:06.01 |
-63:17:24.1 |
HIP 12726 |
22.50 |
| 2026-06-07 12:00 |
02:43:20.77 |
-63:18:46.5 |
HIP 12910 |
22.98 |
| 2026-06-08 00:00 |
02:43:35.45 |
-63:20:10.0 |
HIP 12910 |
22.67 |
| 2026-06-08 12:00 |
02:43:50.04 |
-63:21:34.5 |
HIP 12910 |
22.59 |
| 2026-06-09 00:00 |
02:44:04.54 |
-63:23:00.2 |
HIP 12871 |
21.37 |
| 2026-06-09 12:00 |
02:44:18.96 |
-63:24:26.9 |
HIP 12871 |
19.39 |
| 2026-06-10 00:00 |
02:44:33.29 |
-63:25:54.7 |
HIP 12871 |
17.43 |
| 2026-06-10 12:00 |
02:44:47.53 |
-63:27:23.6 |
HIP 12871 |
15.53 |
| 2026-06-11 00:00 |
02:45:01.68 |
-63:28:53.6 |
HIP 12871 |
13.68 |
| 2026-06-11 12:00 |
02:45:15.73 |
-63:30:24.6 |
HIP 12871 |
11.93 |
| 2026-06-12 00:00 |
02:45:29.70 |
-63:31:56.7 |
HIP 12871 |
10.33 |
| 2026-06-12 12:00 |
02:45:43.56 |
-63:33:29.9 |
HIP 12871 |
8.95 |
| 2026-06-13 00:00 |
02:45:57.33 |
-63:35:04.1 |
HIP 12871 |
7.93 |
| 2026-06-13 12:00 |
02:46:11.01 |
-63:36:39.4 |
HIP 12871 |
7.41 |
| 2026-06-14 00:00 |
02:46:24.58 |
-63:38:15.7 |
HIP 12871 |
7.50 |
| 2026-06-14 12:00 |
02:46:38.05 |
-63:39:53.1 |
HIP 12871 |
8.18 |
| 2026-06-15 00:00 |
02:46:51.43 |
-63:41:31.5 |
HIP 12871 |
9.33 |
| 2026-06-15 12:00 |
02:47:04.70 |
-63:43:10.9 |
HIP 12871 |
10.81 |
| 2026-06-16 00:00 |
02:47:17.86 |
-63:44:51.3 |
HIP 12871 |
12.49 |
| 2026-06-16 12:00 |
02:47:30.92 |
-63:46:32.8 |
HIP 12871 |
14.31 |
| 2026-06-17 00:00 |
02:47:43.87 |
-63:48:15.3 |
HIP 12871 |
16.23 |
| 2026-06-17 12:00 |
02:47:56.72 |
-63:49:58.8 |
HIP 13216 |
18.18 |
| 2026-06-18 00:00 |
02:48:09.46 |
-63:51:43.2 |
HIP 13216 |
16.00 |
| 2026-06-18 12:00 |
02:48:22.08 |
-63:53:28.7 |
HIP 13216 |
13.85 |
| 2026-06-19 00:00 |
02:48:34.60 |
-63:55:15.2 |
HIP 13216 |
11.74 |
| 2026-06-19 12:00 |
02:48:47.00 |
-63:57:02.6 |
HIP 13216 |
9.70 |
| 2026-06-20 00:00 |
02:48:59.28 |
-63:58:51.0 |
HIP 13216 |
7.78 |
| 2026-06-20 12:00 |
02:49:11.45 |
-64:00:40.4 |
HIP 13216 |
6.11 |
| 2026-06-21 00:00 |
02:49:23.51 |
-64:02:30.7 |
HIP 13216 |
4.96 |
| 2026-06-21 12:00 |
02:49:35.45 |
-64:04:22.0 |
HIP 13216 |
4.72 |
| 2026-06-22 00:00 |
02:49:47.27 |
-64:06:14.2 |
HIP 13216 |
5.52 |