| 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) |
| 2026-06-01 00:00 |
20:39:08.61 |
-20:41:05.5 |
HIP 101858 |
21.11 |
| 2026-06-01 12:00 |
20:39:06.05 |
-20:41:42.1 |
HIP 101858 |
20.29 |
| 2026-06-02 00:00 |
20:39:03.27 |
-20:42:19.6 |
HIP 101858 |
19.44 |
| 2026-06-02 12:00 |
20:39:00.26 |
-20:42:57.9 |
HIP 101858 |
18.55 |
| 2026-06-03 00:00 |
20:38:57.03 |
-20:43:37.1 |
HIP 101858 |
17.64 |
| 2026-06-03 12:00 |
20:38:53.57 |
-20:44:17.0 |
HIP 101858 |
16.70 |
| 2026-06-04 00:00 |
20:38:49.89 |
-20:44:57.8 |
HIP 101858 |
15.75 |
| 2026-06-04 12:00 |
20:38:45.98 |
-20:45:39.4 |
HIP 101858 |
14.78 |
| 2026-06-05 00:00 |
20:38:41.85 |
-20:46:21.8 |
HIP 101858 |
13.82 |
| 2026-06-05 12:00 |
20:38:37.50 |
-20:47:05.1 |
HIP 101858 |
12.87 |
| 2026-06-06 00:00 |
20:38:32.92 |
-20:47:49.1 |
HIP 101858 |
11.95 |
| 2026-06-06 12:00 |
20:38:28.11 |
-20:48:34.0 |
HIP 101858 |
11.09 |
| 2026-06-07 00:00 |
20:38:23.08 |
-20:49:19.6 |
HIP 101858 |
10.33 |
| 2026-06-07 12:00 |
20:38:17.83 |
-20:50:06.1 |
HIP 101858 |
9.70 |
| 2026-06-08 00:00 |
20:38:12.36 |
-20:50:53.3 |
HIP 101858 |
9.27 |
| 2026-06-08 12:00 |
20:38:06.66 |
-20:51:41.3 |
HIP 101858 |
9.08 |
| 2026-06-09 00:00 |
20:38:00.74 |
-20:52:30.1 |
HIP 101858 |
9.17 |
| 2026-06-09 12:00 |
20:37:54.60 |
-20:53:19.7 |
HIP 101858 |
9.57 |
| 2026-06-10 00:00 |
20:37:48.24 |
-20:54:10.1 |
HIP 101858 |
10.26 |
| 2026-06-10 12:00 |
20:37:41.65 |
-20:55:01.2 |
HIP 101858 |
11.22 |
| 2026-06-11 00:00 |
20:37:34.84 |
-20:55:53.1 |
HIP 101858 |
12.39 |
| 2026-06-11 12:00 |
20:37:27.82 |
-20:56:45.8 |
HIP 101858 |
13.75 |
| 2026-06-12 00:00 |
20:37:20.57 |
-20:57:39.2 |
HIP 101858 |
15.27 |
| 2026-06-12 12:00 |
20:37:13.11 |
-20:58:33.3 |
HIP 101858 |
16.91 |
| 2026-06-13 00:00 |
20:37:05.43 |
-20:59:28.2 |
HIP 101858 |
18.67 |
| 2026-06-13 12:00 |
20:36:57.53 |
-21:00:23.8 |
HIP 101858 |
20.53 |
| 2026-06-14 00:00 |
20:36:49.42 |
-21:01:20.1 |
HIP 101774 |
21.68 |
| 2026-06-14 12:00 |
20:36:41.09 |
-21:02:17.1 |
HIP 101774 |
21.94 |
| 2026-06-15 00:00 |
20:36:32.54 |
-21:03:14.9 |
HIP 101774 |
22.42 |
| 2026-06-15 12:00 |
20:36:23.78 |
-21:04:13.3 |
HIP 101774 |
23.13 |
| 2026-06-16 00:00 |
20:36:14.82 |
-21:05:12.4 |
HIP 101774 |
24.07 |
| 2026-06-16 12:00 |
20:36:05.64 |
-21:06:12.2 |
HIP 101774 |
25.22 |
| 2026-06-17 00:00 |
20:35:56.25 |
-21:07:12.6 |
HIP 101774 |
26.56 |
| 2026-06-17 12:00 |
20:35:46.65 |
-21:08:13.7 |
HIP 101774 |
28.09 |
| 2026-06-18 00:00 |
20:35:36.85 |
-21:09:15.5 |
HIP 101445 |
29.10 |
| 2026-06-18 12:00 |
20:35:26.85 |
-21:10:17.8 |
HIP 101445 |
26.61 |
| 2026-06-19 00:00 |
20:35:16.64 |
-21:11:20.9 |
HIP 101445 |
24.08 |
| 2026-06-19 12:00 |
20:35:06.22 |
-21:12:24.5 |
HIP 101445 |
21.52 |
| 2026-06-20 00:00 |
20:34:55.61 |
-21:13:28.7 |
HIP 101445 |
18.93 |
| 2026-06-20 12:00 |
20:34:44.80 |
-21:14:33.5 |
HIP 101445 |
16.34 |
| 2026-06-21 00:00 |
20:34:33.79 |
-21:15:38.9 |
HIP 101445 |
13.76 |
| 2026-06-21 12:00 |
20:34:22.59 |
-21:16:44.8 |
HIP 101445 |
11.24 |
| 2026-06-22 00:00 |
20:34:11.19 |
-21:17:51.3 |
HIP 101445 |
8.86 |