| Parameter |
Value |
| Designation |
C/1977 H1 (Helin) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1977-06-30T23:22:37.151040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:27Z |
| Obs used |
35 |
| NEO |
- |
| M1 |
14.600 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1977-04-22.0000000 |
| e |
0.99999249 |
| q (au) |
1.117547 |
| a (au) |
148777.258886 |
| i (deg) |
43.194938 |
| Ω (om, deg) |
20.138583 |
| ω (w, deg) |
249.358219 |
| M (ma, deg) |
359.999999 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.630 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.630 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.502 |
| k |
1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
03:41:49.61 |
+54:26:17.2 |
HIP 17200 |
27.09 |
| 2026-06-01 12:00 |
03:41:52.20 |
+54:26:24.6 |
HIP 17200 |
27.31 |
| 2026-06-02 00:00 |
03:41:54.78 |
+54:26:32.1 |
HIP 17200 |
27.53 |
| 2026-06-02 12:00 |
03:41:57.36 |
+54:26:39.7 |
HIP 17200 |
27.76 |
| 2026-06-03 00:00 |
03:41:59.93 |
+54:26:47.4 |
HIP 17200 |
27.99 |
| 2026-06-03 12:00 |
03:42:02.50 |
+54:26:55.2 |
HIP 17200 |
28.23 |
| 2026-06-04 00:00 |
03:42:05.07 |
+54:27:03.1 |
HIP 17285 |
28.20 |
| 2026-06-04 12:00 |
03:42:07.63 |
+54:27:11.1 |
HIP 17285 |
28.07 |
| 2026-06-05 00:00 |
03:42:10.18 |
+54:27:19.2 |
HIP 17285 |
27.95 |
| 2026-06-05 12:00 |
03:42:12.73 |
+54:27:27.3 |
HIP 17285 |
27.83 |
| 2026-06-06 00:00 |
03:42:15.27 |
+54:27:35.6 |
HIP 17285 |
27.71 |
| 2026-06-06 12:00 |
03:42:17.81 |
+54:27:44.0 |
HIP 17285 |
27.60 |
| 2026-06-07 00:00 |
03:42:20.33 |
+54:27:52.4 |
HIP 17285 |
27.49 |
| 2026-06-07 12:00 |
03:42:22.86 |
+54:28:01.0 |
HIP 17285 |
27.39 |
| 2026-06-08 00:00 |
03:42:25.37 |
+54:28:09.6 |
HIP 17285 |
27.29 |
| 2026-06-08 12:00 |
03:42:27.88 |
+54:28:18.3 |
HIP 17285 |
27.19 |
| 2026-06-09 00:00 |
03:42:30.38 |
+54:28:27.2 |
HIP 17285 |
27.10 |
| 2026-06-09 12:00 |
03:42:32.88 |
+54:28:36.1 |
HIP 17285 |
27.01 |
| 2026-06-10 00:00 |
03:42:35.37 |
+54:28:45.1 |
HIP 17285 |
26.92 |
| 2026-06-10 12:00 |
03:42:37.85 |
+54:28:54.2 |
HIP 17285 |
26.83 |
| 2026-06-11 00:00 |
03:42:40.32 |
+54:29:03.3 |
HIP 17285 |
26.76 |
| 2026-06-11 12:00 |
03:42:42.78 |
+54:29:12.6 |
HIP 17285 |
26.68 |
| 2026-06-12 00:00 |
03:42:45.24 |
+54:29:22.0 |
HIP 17285 |
26.61 |
| 2026-06-12 12:00 |
03:42:47.69 |
+54:29:31.4 |
HIP 17285 |
26.54 |
| 2026-06-13 00:00 |
03:42:50.13 |
+54:29:41.0 |
HIP 17285 |
26.47 |
| 2026-06-13 12:00 |
03:42:52.56 |
+54:29:50.6 |
HIP 17285 |
26.41 |
| 2026-06-14 00:00 |
03:42:54.99 |
+54:30:00.3 |
HIP 17285 |
26.36 |
| 2026-06-14 12:00 |
03:42:57.40 |
+54:30:10.1 |
HIP 17285 |
26.30 |
| 2026-06-15 00:00 |
03:42:59.80 |
+54:30:20.0 |
HIP 17285 |
26.25 |
| 2026-06-15 12:00 |
03:43:02.20 |
+54:30:29.9 |
HIP 17285 |
26.21 |
| 2026-06-16 00:00 |
03:43:04.59 |
+54:30:40.0 |
HIP 17285 |
26.17 |
| 2026-06-16 12:00 |
03:43:06.96 |
+54:30:50.1 |
HIP 17285 |
26.13 |
| 2026-06-17 00:00 |
03:43:09.33 |
+54:31:00.3 |
HIP 17285 |
26.09 |
| 2026-06-17 12:00 |
03:43:11.69 |
+54:31:10.6 |
HIP 17285 |
26.06 |
| 2026-06-18 00:00 |
03:43:14.04 |
+54:31:20.9 |
HIP 17285 |
26.04 |
| 2026-06-18 12:00 |
03:43:16.37 |
+54:31:31.4 |
HIP 17285 |
26.01 |
| 2026-06-19 00:00 |
03:43:18.70 |
+54:31:41.9 |
HIP 17285 |
25.99 |
| 2026-06-19 12:00 |
03:43:21.01 |
+54:31:52.5 |
HIP 17285 |
25.98 |
| 2026-06-20 00:00 |
03:43:23.32 |
+54:32:03.2 |
HIP 17285 |
25.96 |
| 2026-06-20 12:00 |
03:43:25.61 |
+54:32:14.0 |
HIP 17285 |
25.96 |
| 2026-06-21 00:00 |
03:43:27.90 |
+54:32:24.8 |
HIP 17285 |
25.95 |
| 2026-06-21 12:00 |
03:43:30.17 |
+54:32:35.7 |
HIP 17285 |
25.95 |
| 2026-06-22 00:00 |
03:43:32.43 |
+54:32:46.7 |
HIP 17285 |
25.95 |