| Parameter |
Value |
| Designation |
111P/Helin-Roman-Crockett |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2013-01-30T15:06:06.327360Z |
| Orbit solution date (soln_date, UTC) |
2013-01-28T09:17:54Z |
| Obs used |
137 |
| NEO |
- |
| M1 |
8.400 |
| K1 |
17.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-01-28.0000000 |
| e |
0.10962077 |
| q (au) |
3.704303 |
| a (au) |
4.160366 |
| i (deg) |
4.228807 |
| Ω (om, deg) |
89.793998 |
| ω (w, deg) |
3.377942 |
| M (ma, deg) |
359.694623 |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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) |
| 2026-09-20 00:00 |
19:52:39.86 |
-23:53:54.6 |
HIP 97805 |
3.79 |
| 2026-09-20 12:00 |
19:52:38.86 |
-23:53:50.8 |
HIP 97805 |
3.71 |
| 2026-09-21 00:00 |
19:52:38.10 |
-23:53:46.3 |
HIP 97805 |
3.68 |
| 2026-09-21 12:00 |
19:52:37.58 |
-23:53:41.1 |
HIP 97805 |
3.70 |
| 2026-09-22 00:00 |
19:52:37.30 |
-23:53:35.2 |
HIP 97805 |
3.76 |
| 2026-09-22 12:00 |
19:52:37.26 |
-23:53:28.6 |
HIP 97805 |
3.85 |
| 2026-09-23 00:00 |
19:52:37.46 |
-23:53:21.3 |
HIP 97805 |
3.98 |
| 2026-09-23 12:00 |
19:52:37.91 |
-23:53:13.3 |
HIP 97805 |
4.15 |
| 2026-09-24 00:00 |
19:52:38.59 |
-23:53:04.6 |
HIP 97805 |
4.35 |
| 2026-09-24 12:00 |
19:52:39.52 |
-23:52:55.2 |
HIP 97805 |
4.58 |
| 2026-09-25 00:00 |
19:52:40.68 |
-23:52:45.2 |
HIP 97805 |
4.86 |
| 2026-09-25 12:00 |
19:52:42.08 |
-23:52:34.4 |
HIP 97805 |
5.18 |
| 2026-09-26 00:00 |
19:52:43.72 |
-23:52:23.0 |
HIP 97805 |
5.55 |
| 2026-09-26 12:00 |
19:52:45.60 |
-23:52:10.9 |
HIP 97805 |
5.96 |
| 2026-09-27 00:00 |
19:52:47.72 |
-23:51:58.2 |
HIP 97805 |
6.43 |
| 2026-09-27 12:00 |
19:52:50.08 |
-23:51:44.7 |
HIP 97805 |
6.95 |
| 2026-09-28 00:00 |
19:52:52.67 |
-23:51:30.6 |
HIP 97805 |
7.52 |
| 2026-09-28 12:00 |
19:52:55.50 |
-23:51:15.8 |
HIP 97805 |
8.15 |
| 2026-09-29 00:00 |
19:52:58.56 |
-23:51:00.4 |
HIP 97805 |
8.84 |
| 2026-09-29 12:00 |
19:53:01.87 |
-23:50:44.3 |
HIP 97805 |
9.59 |
| 2026-09-30 00:00 |
19:53:05.40 |
-23:50:27.5 |
HIP 97805 |
10.39 |
| 2026-09-30 12:00 |
19:53:09.17 |
-23:50:10.1 |
HIP 97805 |
11.25 |
| 2026-10-01 00:00 |
19:53:13.18 |
-23:49:52.0 |
HIP 97805 |
12.16 |
| 2026-10-01 12:00 |
19:53:17.42 |
-23:49:33.2 |
HIP 97805 |
13.14 |
| 2026-10-02 00:00 |
19:53:21.90 |
-23:49:13.8 |
HIP 97805 |
14.17 |
| 2026-10-02 12:00 |
19:53:26.60 |
-23:48:53.7 |
HIP 97944 |
13.91 |
| 2026-10-03 00:00 |
19:53:31.54 |
-23:48:33.0 |
HIP 97944 |
13.18 |
| 2026-10-03 12:00 |
19:53:36.72 |
-23:48:11.7 |
HIP 97944 |
12.48 |
| 2026-10-04 00:00 |
19:53:42.12 |
-23:47:49.6 |
HIP 97944 |
11.84 |
| 2026-10-04 12:00 |
19:53:47.76 |
-23:47:27.0 |
HIP 97944 |
11.29 |
| 2026-10-05 00:00 |
19:53:53.63 |
-23:47:03.7 |
HIP 97944 |
10.86 |
| 2026-10-05 12:00 |
19:53:59.73 |
-23:46:39.7 |
HIP 97944 |
10.59 |
| 2026-10-06 00:00 |
19:54:06.05 |
-23:46:15.1 |
HIP 97944 |
10.50 |
| 2026-10-06 12:00 |
19:54:12.61 |
-23:45:49.8 |
HIP 97944 |
10.64 |
| 2026-10-07 00:00 |
19:54:19.40 |
-23:45:23.9 |
HIP 97944 |
11.01 |
| 2026-10-07 12:00 |
19:54:26.42 |
-23:44:57.4 |
HIP 97944 |
11.62 |
| 2026-10-08 00:00 |
19:54:33.66 |
-23:44:30.2 |
HIP 97944 |
12.44 |
| 2026-10-08 12:00 |
19:54:41.13 |
-23:44:02.4 |
HIP 98024 |
12.43 |
| 2026-10-09 00:00 |
19:54:48.83 |
-23:43:33.9 |
HIP 98024 |
12.00 |
| 2026-10-09 12:00 |
19:54:56.75 |
-23:43:04.8 |
HIP 98024 |
11.82 |
| 2026-10-10 00:00 |
19:55:04.90 |
-23:42:35.1 |
HIP 98024 |
11.95 |
| 2026-10-10 12:00 |
19:55:13.27 |
-23:42:04.7 |
HIP 98024 |
12.39 |
| 2026-10-11 00:00 |
19:55:21.86 |
-23:41:33.7 |
HIP 98024 |
13.14 |