| Parameter |
Value |
| Designation |
C/2023 S3 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2024-01-19T14:58:00.491520Z |
| Orbit solution date (soln_date, UTC) |
2024-08-02T01:42:20Z |
| Obs used |
692 |
| NEO |
Yes |
| M1 |
16.300 |
| K1 |
9.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2023-09-25T10:53:32.726400Z |
| Discovery magnitude (MPC) |
19.99 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-12-22.0000000 |
| e |
0.97084030 |
| q (au) |
0.830157 |
| a (au) |
28.469320 |
| i (deg) |
140.498019 |
| Ω (om, deg) |
233.833529 |
| ω (w, deg) |
281.571309 |
| M (ma, deg) |
359.814278 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.227 + 4.398\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.227 |
| n |
4.398 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.998 |
| 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 |
| 2023-09-25 |
2023-11-18 |
-4.1066 |
+1.202 |
| 2023-11-18 |
2024-01-09 |
+21.3814 |
-2.097 |
| 2024-02-11 |
2024-03-09 |
+21.5517 |
-3.253 |
| 2024-03-09 |
2024-06-02 |
+1.1889 |
-1.105 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
12:22:51.34 |
+34:29:33.8 |
HIP 60314 |
17.41 |
| 2026-09-20 12:00 |
12:23:02.56 |
+34:28:45.6 |
HIP 60314 |
18.24 |
| 2026-09-21 00:00 |
12:23:13.78 |
+34:27:58.2 |
HIP 60314 |
19.36 |
| 2026-09-21 12:00 |
12:23:25.01 |
+34:27:11.5 |
HIP 60314 |
20.72 |
| 2026-09-22 00:00 |
12:23:36.25 |
+34:26:25.5 |
HIP 60314 |
22.27 |
| 2026-09-22 12:00 |
12:23:47.50 |
+34:25:40.4 |
HIP 60314 |
23.98 |
| 2026-09-23 00:00 |
12:23:58.74 |
+34:24:56.0 |
HIP 60587 |
24.97 |
| 2026-09-23 12:00 |
12:24:10.00 |
+34:24:12.3 |
HIP 60587 |
24.43 |
| 2026-09-24 00:00 |
12:24:21.26 |
+34:23:29.4 |
HIP 60587 |
24.12 |
| 2026-09-24 12:00 |
12:24:32.52 |
+34:22:47.3 |
HIP 60587 |
24.03 |
| 2026-09-25 00:00 |
12:24:43.78 |
+34:22:06.0 |
HIP 60587 |
24.18 |
| 2026-09-25 12:00 |
12:24:55.05 |
+34:21:25.4 |
HIP 60587 |
24.55 |
| 2026-09-26 00:00 |
12:25:06.32 |
+34:20:45.6 |
HIP 60524 |
25.06 |
| 2026-09-26 12:00 |
12:25:17.59 |
+34:20:06.6 |
HIP 60524 |
25.33 |
| 2026-09-27 00:00 |
12:25:28.86 |
+34:19:28.3 |
HIP 60524 |
25.84 |
| 2026-09-27 12:00 |
12:25:40.13 |
+34:18:50.9 |
HIP 60524 |
26.57 |
| 2026-09-28 00:00 |
12:25:51.41 |
+34:18:14.3 |
HIP 60524 |
27.51 |
| 2026-09-28 12:00 |
12:26:02.68 |
+34:17:38.4 |
HIP 60524 |
28.63 |
| 2026-09-29 00:00 |
12:26:13.94 |
+34:17:03.3 |
HIP 60524 |
29.91 |
| 2026-09-29 12:00 |
12:26:25.21 |
+34:16:29.1 |
HIP 60524 |
31.33 |
| 2026-09-30 00:00 |
12:26:36.47 |
+34:15:55.6 |
HIP 60860 |
31.17 |
| 2026-09-30 12:00 |
12:26:47.73 |
+34:15:23.0 |
HIP 60860 |
29.94 |
| 2026-10-01 00:00 |
12:26:58.99 |
+34:14:51.1 |
HIP 60860 |
28.84 |
| 2026-10-01 12:00 |
12:27:10.24 |
+34:14:20.1 |
HIP 60860 |
27.89 |
| 2026-10-02 00:00 |
12:27:21.49 |
+34:13:49.9 |
HIP 60860 |
27.10 |
| 2026-10-02 12:00 |
12:27:32.73 |
+34:13:20.5 |
HIP 60860 |
26.50 |
| 2026-10-03 00:00 |
12:27:43.96 |
+34:12:51.9 |
HIP 60860 |
26.08 |
| 2026-10-03 12:00 |
12:27:55.19 |
+34:12:24.2 |
HIP 60860 |
25.86 |
| 2026-10-04 00:00 |
12:28:06.41 |
+34:11:57.3 |
HIP 60860 |
25.84 |
| 2026-10-04 12:00 |
12:28:17.62 |
+34:11:31.2 |
HIP 60860 |
26.02 |
| 2026-10-05 00:00 |
12:28:28.83 |
+34:11:06.0 |
HIP 60860 |
26.39 |
| 2026-10-05 12:00 |
12:28:40.02 |
+34:10:41.6 |
HIP 60860 |
26.96 |
| 2026-10-06 00:00 |
12:28:51.20 |
+34:10:18.1 |
HIP 60860 |
27.69 |
| 2026-10-06 12:00 |
12:29:02.38 |
+34:09:55.5 |
HIP 61036 |
28.10 |
| 2026-10-07 00:00 |
12:29:13.54 |
+34:09:33.7 |
HIP 61036 |
26.90 |
| 2026-10-07 12:00 |
12:29:24.68 |
+34:09:12.7 |
HIP 61036 |
25.83 |
| 2026-10-08 00:00 |
12:29:35.82 |
+34:08:52.6 |
HIP 61036 |
24.93 |
| 2026-10-08 12:00 |
12:29:46.94 |
+34:08:33.4 |
HIP 61036 |
24.21 |
| 2026-10-09 00:00 |
12:29:58.05 |
+34:08:15.1 |
HIP 61036 |
23.68 |
| 2026-10-09 12:00 |
12:30:09.14 |
+34:07:57.6 |
HIP 61036 |
23.35 |
| 2026-10-10 00:00 |
12:30:20.21 |
+34:07:41.0 |
HIP 61039 |
23.00 |
| 2026-10-10 12:00 |
12:30:31.27 |
+34:07:25.4 |
HIP 61039 |
22.51 |
| 2026-10-11 00:00 |
12:30:42.31 |
+34:07:10.5 |
HIP 61039 |
22.26 |