| 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) |
| 2026-05-12 00:00 |
20:37:47.70 |
-20:28:20.4 |
HIP 101666 |
20.19 |
| 2026-05-12 12:00 |
20:37:54.01 |
-20:28:22.9 |
HIP 101666 |
21.58 |
| 2026-05-13 00:00 |
20:38:00.11 |
-20:28:26.2 |
HIP 101666 |
22.92 |
| 2026-05-13 12:00 |
20:38:06.00 |
-20:28:30.3 |
HIP 101666 |
24.22 |
| 2026-05-14 00:00 |
20:38:11.66 |
-20:28:35.2 |
HIP 101666 |
25.48 |
| 2026-05-14 12:00 |
20:38:17.12 |
-20:28:41.0 |
HIP 101666 |
26.69 |
| 2026-05-15 00:00 |
20:38:22.35 |
-20:28:47.7 |
HIP 101666 |
27.86 |
| 2026-05-15 12:00 |
20:38:27.37 |
-20:28:55.2 |
HIP 101952 |
28.54 |
| 2026-05-16 00:00 |
20:38:32.17 |
-20:29:03.5 |
HIP 101952 |
28.04 |
| 2026-05-16 12:00 |
20:38:36.75 |
-20:29:12.8 |
HIP 101952 |
27.61 |
| 2026-05-17 00:00 |
20:38:41.11 |
-20:29:22.8 |
HIP 101952 |
27.26 |
| 2026-05-17 12:00 |
20:38:45.26 |
-20:29:33.8 |
HIP 101952 |
26.98 |
| 2026-05-18 00:00 |
20:38:49.18 |
-20:29:45.6 |
HIP 101952 |
26.76 |
| 2026-05-18 12:00 |
20:38:52.88 |
-20:29:58.2 |
HIP 101952 |
26.61 |
| 2026-05-19 00:00 |
20:38:56.36 |
-20:30:11.7 |
HIP 101952 |
26.52 |
| 2026-05-19 12:00 |
20:38:59.62 |
-20:30:26.1 |
HIP 101952 |
26.49 |
| 2026-05-20 00:00 |
20:39:02.66 |
-20:30:41.4 |
HIP 101952 |
26.51 |
| 2026-05-20 12:00 |
20:39:05.48 |
-20:30:57.5 |
HIP 101952 |
26.58 |
| 2026-05-21 00:00 |
20:39:08.07 |
-20:31:14.5 |
HIP 101952 |
26.69 |
| 2026-05-21 12:00 |
20:39:10.44 |
-20:31:32.3 |
HIP 101952 |
26.85 |
| 2026-05-22 00:00 |
20:39:12.59 |
-20:31:51.0 |
HIP 101952 |
27.05 |
| 2026-05-22 12:00 |
20:39:14.52 |
-20:32:10.6 |
HIP 101952 |
27.28 |
| 2026-05-23 00:00 |
20:39:16.22 |
-20:32:31.0 |
HIP 101952 |
27.54 |
| 2026-05-23 12:00 |
20:39:17.70 |
-20:32:52.3 |
HIP 101994 |
27.68 |
| 2026-05-24 00:00 |
20:39:18.96 |
-20:33:14.5 |
HIP 101994 |
27.21 |
| 2026-05-24 12:00 |
20:39:20.00 |
-20:33:37.5 |
HIP 101994 |
26.76 |
| 2026-05-25 00:00 |
20:39:20.81 |
-20:34:01.4 |
HIP 101994 |
26.32 |
| 2026-05-25 12:00 |
20:39:21.39 |
-20:34:26.1 |
HIP 101994 |
25.89 |
| 2026-05-26 00:00 |
20:39:21.76 |
-20:34:51.7 |
HIP 101994 |
25.47 |
| 2026-05-26 12:00 |
20:39:21.90 |
-20:35:18.2 |
HIP 101994 |
25.06 |
| 2026-05-27 00:00 |
20:39:21.81 |
-20:35:45.5 |
HIP 101994 |
24.67 |
| 2026-05-27 12:00 |
20:39:21.50 |
-20:36:13.7 |
HIP 101994 |
24.29 |
| 2026-05-28 00:00 |
20:39:20.97 |
-20:36:42.7 |
HIP 101994 |
23.92 |
| 2026-05-28 12:00 |
20:39:20.21 |
-20:37:12.6 |
HIP 101994 |
23.58 |
| 2026-05-29 00:00 |
20:39:19.23 |
-20:37:43.3 |
HIP 101994 |
23.25 |
| 2026-05-29 12:00 |
20:39:18.02 |
-20:38:14.9 |
HIP 101994 |
22.95 |
| 2026-05-30 00:00 |
20:39:16.59 |
-20:38:47.3 |
HIP 101994 |
22.68 |
| 2026-05-30 12:00 |
20:39:14.93 |
-20:39:20.6 |
HIP 101994 |
22.44 |
| 2026-05-31 00:00 |
20:39:13.05 |
-20:39:54.7 |
HIP 101994 |
22.25 |
| 2026-05-31 12:00 |
20:39:10.94 |
-20:40:29.7 |
HIP 101858 |
21.90 |
| 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 |