| Parameter |
Value |
| Designation |
C/1991 F2 (Helin-Lawrence) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1992-01-20T00:37:43.368960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:41Z |
| Obs used |
108 |
| NEO |
- |
| M1 |
9.100 |
| K1 |
5.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1991-12-22.0000000 |
| e |
1.00042110 |
| q (au) |
1.517723 |
| a (au) |
-3604.185791 |
| i (deg) |
95.456559 |
| Ω (om, deg) |
11.835020 |
| ω (w, deg) |
271.158650 |
| M (ma, deg) |
-0.000132 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.280 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.280 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.848 |
| δ90 |
1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
20:38:10.15 |
+59:57:33.8 |
HIP 101973 |
20.24 |
| 2026-06-01 12:00 |
20:38:07.93 |
+59:57:58.1 |
HIP 101973 |
20.73 |
| 2026-06-02 00:00 |
20:38:05.68 |
+59:58:22.3 |
HIP 101973 |
21.22 |
| 2026-06-02 12:00 |
20:38:03.40 |
+59:58:46.2 |
HIP 101973 |
21.71 |
| 2026-06-03 00:00 |
20:38:01.09 |
+59:59:10.1 |
HIP 101973 |
22.19 |
| 2026-06-03 12:00 |
20:37:58.76 |
+59:59:33.7 |
HIP 101973 |
22.68 |
| 2026-06-04 00:00 |
20:37:56.39 |
+59:59:57.3 |
HIP 101973 |
23.17 |
| 2026-06-04 12:00 |
20:37:54.00 |
+60:00:20.6 |
HIP 101973 |
23.67 |
| 2026-06-05 00:00 |
20:37:51.58 |
+60:00:43.8 |
HIP 101973 |
24.16 |
| 2026-06-05 12:00 |
20:37:49.14 |
+60:01:06.9 |
HIP 101973 |
24.65 |
| 2026-06-06 00:00 |
20:37:46.66 |
+60:01:29.7 |
HIP 101973 |
25.14 |
| 2026-06-06 12:00 |
20:37:44.16 |
+60:01:52.4 |
HIP 101973 |
25.63 |
| 2026-06-07 00:00 |
20:37:41.64 |
+60:02:15.0 |
HIP 101973 |
26.12 |
| 2026-06-07 12:00 |
20:37:39.08 |
+60:02:37.4 |
HIP 101973 |
26.61 |
| 2026-06-08 00:00 |
20:37:36.50 |
+60:02:59.6 |
HIP 101973 |
27.10 |
| 2026-06-08 12:00 |
20:37:33.90 |
+60:03:21.6 |
HIP 101973 |
27.59 |
| 2026-06-09 00:00 |
20:37:31.26 |
+60:03:43.5 |
HIP 101973 |
28.08 |
| 2026-06-09 12:00 |
20:37:28.61 |
+60:04:05.2 |
HIP 101973 |
28.57 |
| 2026-06-10 00:00 |
20:37:25.92 |
+60:04:26.7 |
HIP 101973 |
29.06 |
| 2026-06-10 12:00 |
20:37:23.21 |
+60:04:48.0 |
HIP 101973 |
29.55 |
| 2026-06-11 00:00 |
20:37:20.47 |
+60:05:09.2 |
HIP 101973 |
30.04 |
| 2026-06-11 12:00 |
20:37:17.71 |
+60:05:30.1 |
HIP 101973 |
30.53 |
| 2026-06-12 00:00 |
20:37:14.92 |
+60:05:50.9 |
HIP 101973 |
31.02 |
| 2026-06-12 12:00 |
20:37:12.11 |
+60:06:11.5 |
HIP 101973 |
31.51 |
| 2026-06-13 00:00 |
20:37:09.27 |
+60:06:31.9 |
HIP 101973 |
32.00 |
| 2026-06-13 12:00 |
20:37:06.41 |
+60:06:52.2 |
HIP 101973 |
32.48 |
| 2026-06-14 00:00 |
20:37:03.52 |
+60:07:12.2 |
HIP 101973 |
32.97 |
| 2026-06-14 12:00 |
20:37:00.61 |
+60:07:32.1 |
HIP 102011 |
33.38 |
| 2026-06-15 00:00 |
20:36:57.68 |
+60:07:51.7 |
HIP 102011 |
33.42 |
| 2026-06-15 12:00 |
20:36:54.72 |
+60:08:11.2 |
HIP 102011 |
33.48 |
| 2026-06-16 00:00 |
20:36:51.74 |
+60:08:30.4 |
HIP 102011 |
33.55 |
| 2026-06-16 12:00 |
20:36:48.73 |
+60:08:49.5 |
HIP 102011 |
33.63 |
| 2026-06-17 00:00 |
20:36:45.70 |
+60:09:08.4 |
HIP 102011 |
33.72 |
| 2026-06-17 12:00 |
20:36:42.65 |
+60:09:27.0 |
HIP 102011 |
33.82 |
| 2026-06-18 00:00 |
20:36:39.58 |
+60:09:45.5 |
HIP 102011 |
33.93 |
| 2026-06-18 12:00 |
20:36:36.48 |
+60:10:03.7 |
HIP 102011 |
34.05 |
| 2026-06-19 00:00 |
20:36:33.36 |
+60:10:21.8 |
HIP 102011 |
34.18 |
| 2026-06-19 12:00 |
20:36:30.22 |
+60:10:39.6 |
HIP 102011 |
34.33 |
| 2026-06-20 00:00 |
20:36:27.06 |
+60:10:57.3 |
HIP 102011 |
34.48 |
| 2026-06-20 12:00 |
20:36:23.87 |
+60:11:14.7 |
HIP 101294 |
34.54 |
| 2026-06-21 00:00 |
20:36:20.66 |
+60:11:31.9 |
HIP 101294 |
34.22 |
| 2026-06-21 12:00 |
20:36:17.44 |
+60:11:48.9 |
HIP 101294 |
33.89 |
| 2026-06-22 00:00 |
20:36:14.19 |
+60:12:05.7 |
HIP 101294 |
33.56 |