| Parameter |
Value |
| Designation |
C/1991 L3 (Levy) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1991-07-08T04:44:18.885120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:41Z |
| Obs used |
136 |
| NEO |
Yes |
| M1 |
8.900 |
| K1 |
14.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1991-12-29.0000000 |
| e |
0.92885840 |
| q (au) |
0.982684 |
| a (au) |
13.813077 |
| i (deg) |
19.190108 |
| Ω (om, deg) |
329.431597 |
| ω (w, deg) |
41.478818 |
| M (ma, deg) |
3.336757 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.810 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.810 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.533 |
| k |
0.800 |
| 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 |
| 1991-07-08 |
1991-10-09 |
+1.2945 |
-0.124 |
| 1991-10-09 |
1993-01-21 |
-0.0631 |
+0.767 |
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 |
12:28:30.85 |
-18:56:18.1 |
HIP 60844 |
7.40 |
| 2026-06-01 12:00 |
12:28:28.85 |
-18:55:49.8 |
HIP 60844 |
7.62 |
| 2026-06-02 00:00 |
12:28:26.88 |
-18:55:21.7 |
HIP 60844 |
7.90 |
| 2026-06-02 12:00 |
12:28:24.96 |
-18:54:53.7 |
HIP 60844 |
8.22 |
| 2026-06-03 00:00 |
12:28:23.07 |
-18:54:25.9 |
HIP 60844 |
8.57 |
| 2026-06-03 12:00 |
12:28:21.21 |
-18:53:58.2 |
HIP 60844 |
8.96 |
| 2026-06-04 00:00 |
12:28:19.40 |
-18:53:30.7 |
HIP 60844 |
9.37 |
| 2026-06-04 12:00 |
12:28:17.62 |
-18:53:03.3 |
HIP 60844 |
9.81 |
| 2026-06-05 00:00 |
12:28:15.88 |
-18:52:36.1 |
HIP 60844 |
10.26 |
| 2026-06-05 12:00 |
12:28:14.17 |
-18:52:09.0 |
HIP 60844 |
10.72 |
| 2026-06-06 00:00 |
12:28:12.51 |
-18:51:42.1 |
HIP 60844 |
11.19 |
| 2026-06-06 12:00 |
12:28:10.88 |
-18:51:15.4 |
HIP 60844 |
11.67 |
| 2026-06-07 00:00 |
12:28:09.29 |
-18:50:48.9 |
HIP 60844 |
12.16 |
| 2026-06-07 12:00 |
12:28:07.74 |
-18:50:22.5 |
HIP 60844 |
12.65 |
| 2026-06-08 00:00 |
12:28:06.23 |
-18:49:56.3 |
HIP 60844 |
13.14 |
| 2026-06-08 12:00 |
12:28:04.75 |
-18:49:30.2 |
HIP 60818 |
13.05 |
| 2026-06-09 00:00 |
12:28:03.31 |
-18:49:04.3 |
HIP 60818 |
12.58 |
| 2026-06-09 12:00 |
12:28:01.92 |
-18:48:38.6 |
HIP 60818 |
12.12 |
| 2026-06-10 00:00 |
12:28:00.56 |
-18:48:13.1 |
HIP 60818 |
11.67 |
| 2026-06-10 12:00 |
12:27:59.24 |
-18:47:47.8 |
HIP 60818 |
11.23 |
| 2026-06-11 00:00 |
12:27:57.96 |
-18:47:22.6 |
HIP 60818 |
10.80 |
| 2026-06-11 12:00 |
12:27:56.71 |
-18:46:57.7 |
HIP 60818 |
10.38 |
| 2026-06-12 00:00 |
12:27:55.51 |
-18:46:32.9 |
HIP 60818 |
9.97 |
| 2026-06-12 12:00 |
12:27:54.35 |
-18:46:08.3 |
HIP 60818 |
9.57 |
| 2026-06-13 00:00 |
12:27:53.22 |
-18:45:43.9 |
HIP 60818 |
9.19 |
| 2026-06-13 12:00 |
12:27:52.14 |
-18:45:19.7 |
HIP 60818 |
8.82 |
| 2026-06-14 00:00 |
12:27:51.09 |
-18:44:55.7 |
HIP 60818 |
8.46 |
| 2026-06-14 12:00 |
12:27:50.08 |
-18:44:31.9 |
HIP 60818 |
8.11 |
| 2026-06-15 00:00 |
12:27:49.11 |
-18:44:08.3 |
HIP 60818 |
7.77 |
| 2026-06-15 12:00 |
12:27:48.19 |
-18:43:44.9 |
HIP 60818 |
7.45 |
| 2026-06-16 00:00 |
12:27:47.30 |
-18:43:21.7 |
HIP 60818 |
7.15 |
| 2026-06-16 12:00 |
12:27:46.45 |
-18:42:58.7 |
HIP 60818 |
6.85 |
| 2026-06-17 00:00 |
12:27:45.64 |
-18:42:35.9 |
HIP 60818 |
6.58 |
| 2026-06-17 12:00 |
12:27:44.87 |
-18:42:13.3 |
HIP 60818 |
6.31 |
| 2026-06-18 00:00 |
12:27:44.14 |
-18:41:50.9 |
HIP 60818 |
6.07 |
| 2026-06-18 12:00 |
12:27:43.45 |
-18:41:28.8 |
HIP 60818 |
5.84 |
| 2026-06-19 00:00 |
12:27:42.80 |
-18:41:06.8 |
HIP 60818 |
5.62 |
| 2026-06-19 12:00 |
12:27:42.19 |
-18:40:45.1 |
HIP 60818 |
5.43 |
| 2026-06-20 00:00 |
12:27:41.62 |
-18:40:23.6 |
HIP 60818 |
5.25 |
| 2026-06-20 12:00 |
12:27:41.09 |
-18:40:02.3 |
HIP 60818 |
5.09 |
| 2026-06-21 00:00 |
12:27:40.60 |
-18:39:41.2 |
HIP 60818 |
4.95 |
| 2026-06-21 12:00 |
12:27:40.15 |
-18:39:20.3 |
HIP 60818 |
4.83 |
| 2026-06-22 00:00 |
12:27:39.74 |
-18:38:59.7 |
HIP 60818 |
4.72 |