| 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) |
| 2026-03-26 00:00 |
12:37:02.41 |
-20:03:30.4 |
HIP 61588 |
2.69 |
| 2026-03-26 12:00 |
12:36:57.74 |
-20:03:06.8 |
HIP 61588 |
3.85 |
| 2026-03-27 00:00 |
12:36:53.06 |
-20:02:42.9 |
HIP 61588 |
5.01 |
| 2026-03-27 12:00 |
12:36:48.39 |
-20:02:18.8 |
HIP 61588 |
6.18 |
| 2026-03-28 00:00 |
12:36:43.71 |
-20:01:54.5 |
HIP 61588 |
7.35 |
| 2026-03-28 12:00 |
12:36:39.03 |
-20:01:30.0 |
HIP 61588 |
8.52 |
| 2026-03-29 00:00 |
12:36:34.34 |
-20:01:05.3 |
HIP 61588 |
9.69 |
| 2026-03-29 12:00 |
12:36:29.66 |
-20:00:40.4 |
HIP 61588 |
10.87 |
| 2026-03-30 00:00 |
12:36:24.97 |
-20:00:15.3 |
HIP 61588 |
12.05 |
| 2026-03-30 12:00 |
12:36:20.28 |
-19:59:50.0 |
HIP 61588 |
13.23 |
| 2026-03-31 00:00 |
12:36:15.59 |
-19:59:24.5 |
HIP 61588 |
14.41 |
| 2026-03-31 12:00 |
12:36:10.91 |
-19:58:58.9 |
HIP 61588 |
15.59 |
| 2026-04-01 00:00 |
12:36:06.22 |
-19:58:33.0 |
HIP 61588 |
16.77 |
| 2026-04-01 12:00 |
12:36:01.53 |
-19:58:07.0 |
HIP 61588 |
17.96 |
| 2026-04-02 00:00 |
12:35:56.84 |
-19:57:40.7 |
HIP 61588 |
19.14 |
| 2026-04-02 12:00 |
12:35:52.16 |
-19:57:14.3 |
HIP 61588 |
20.33 |
| 2026-04-03 00:00 |
12:35:47.48 |
-19:56:47.7 |
HIP 61588 |
21.51 |
| 2026-04-03 12:00 |
12:35:42.80 |
-19:56:21.0 |
HIP 61588 |
22.70 |
| 2026-04-04 00:00 |
12:35:38.12 |
-19:55:54.0 |
HIP 61588 |
23.89 |
| 2026-04-04 12:00 |
12:35:33.44 |
-19:55:26.9 |
HIP 61588 |
25.07 |
| 2026-04-05 00:00 |
12:35:28.77 |
-19:54:59.6 |
HIP 61588 |
26.26 |
| 2026-04-05 12:00 |
12:35:24.10 |
-19:54:32.2 |
HIP 61588 |
27.45 |
| 2026-04-06 00:00 |
12:35:19.44 |
-19:54:04.6 |
HIP 61270 |
28.31 |
| 2026-04-06 12:00 |
12:35:14.78 |
-19:53:36.8 |
HIP 61270 |
27.14 |
| 2026-04-07 00:00 |
12:35:10.12 |
-19:53:08.9 |
HIP 61270 |
25.97 |
| 2026-04-07 12:00 |
12:35:05.47 |
-19:52:40.8 |
HIP 61270 |
24.81 |
| 2026-04-08 00:00 |
12:35:00.83 |
-19:52:12.5 |
HIP 61270 |
23.64 |
| 2026-04-08 12:00 |
12:34:56.19 |
-19:51:44.1 |
HIP 61270 |
22.48 |
| 2026-04-09 00:00 |
12:34:51.56 |
-19:51:15.6 |
HIP 61270 |
21.33 |
| 2026-04-09 12:00 |
12:34:46.94 |
-19:50:46.9 |
HIP 61270 |
20.17 |
| 2026-04-10 00:00 |
12:34:42.32 |
-19:50:18.0 |
HIP 61270 |
19.03 |
| 2026-04-10 12:00 |
12:34:37.71 |
-19:49:49.0 |
HIP 61270 |
17.89 |
| 2026-04-11 00:00 |
12:34:33.11 |
-19:49:19.9 |
HIP 61270 |
16.76 |
| 2026-04-11 12:00 |
12:34:28.52 |
-19:48:50.6 |
HIP 61270 |
15.64 |
| 2026-04-12 00:00 |
12:34:23.94 |
-19:48:21.2 |
HIP 61270 |
14.53 |
| 2026-04-12 12:00 |
12:34:19.36 |
-19:47:51.7 |
HIP 61270 |
13.43 |
| 2026-04-13 00:00 |
12:34:14.80 |
-19:47:22.0 |
HIP 61270 |
12.36 |
| 2026-04-13 12:00 |
12:34:10.24 |
-19:46:52.3 |
HIP 61270 |
11.31 |
| 2026-04-14 00:00 |
12:34:05.70 |
-19:46:22.3 |
HIP 61270 |
10.28 |
| 2026-04-14 12:00 |
12:34:01.17 |
-19:45:52.3 |
HIP 61270 |
9.30 |
| 2026-04-15 00:00 |
12:33:56.65 |
-19:45:22.2 |
HIP 61270 |
8.38 |
| 2026-04-15 12:00 |
12:33:52.14 |
-19:44:51.9 |
HIP 61270 |
7.52 |
| 2026-04-16 00:00 |
12:33:47.64 |
-19:44:21.5 |
HIP 61270 |
6.77 |