C/1977 H1 (Helin)
| 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 |
-0.500 |
| 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) |
| 2026-02-03 00:00 |
03:35:28.02 |
+54:46:48.9 |
HIP 16599 |
19.54 |
| 2026-02-03 12:00 |
03:35:27.46 |
+54:46:34.3 |
HIP 16599 |
19.62 |
| 2026-02-04 00:00 |
03:35:26.93 |
+54:46:19.8 |
HIP 16599 |
19.71 |
| 2026-02-04 12:00 |
03:35:26.42 |
+54:46:05.2 |
HIP 16599 |
19.80 |
| 2026-02-05 00:00 |
03:35:25.94 |
+54:45:50.7 |
HIP 16599 |
19.90 |
| 2026-02-05 12:00 |
03:35:25.48 |
+54:45:36.3 |
HIP 16599 |
20.01 |
| 2026-02-06 00:00 |
03:35:25.04 |
+54:45:21.8 |
HIP 16599 |
20.12 |
| 2026-02-06 12:00 |
03:35:24.63 |
+54:45:07.4 |
HIP 16599 |
20.23 |
| 2026-02-07 00:00 |
03:35:24.24 |
+54:44:53.0 |
HIP 16599 |
20.35 |
| 2026-02-07 12:00 |
03:35:23.87 |
+54:44:38.6 |
HIP 16599 |
20.47 |
| 2026-02-08 00:00 |
03:35:23.53 |
+54:44:24.2 |
HIP 16888 |
20.41 |
| 2026-02-08 12:00 |
03:35:23.21 |
+54:44:09.9 |
HIP 16888 |
20.31 |
| 2026-02-09 00:00 |
03:35:22.92 |
+54:43:55.6 |
HIP 16888 |
20.22 |
| 2026-02-09 12:00 |
03:35:22.65 |
+54:43:41.3 |
HIP 16888 |
20.12 |
| 2026-02-10 00:00 |
03:35:22.40 |
+54:43:27.1 |
HIP 16888 |
20.02 |
| 2026-02-10 12:00 |
03:35:22.18 |
+54:43:12.9 |
HIP 16888 |
19.93 |
| 2026-02-11 00:00 |
03:35:21.98 |
+54:42:58.7 |
HIP 16888 |
19.83 |
| 2026-02-11 12:00 |
03:35:21.81 |
+54:42:44.5 |
HIP 16888 |
19.73 |
| 2026-02-12 00:00 |
03:35:21.66 |
+54:42:30.4 |
HIP 16888 |
19.63 |
| 2026-02-12 12:00 |
03:35:21.53 |
+54:42:16.4 |
HIP 16888 |
19.53 |
| 2026-02-13 00:00 |
03:35:21.43 |
+54:42:02.3 |
HIP 16888 |
19.44 |
| 2026-02-13 12:00 |
03:35:21.35 |
+54:41:48.3 |
HIP 16888 |
19.34 |
| 2026-02-14 00:00 |
03:35:21.30 |
+54:41:34.4 |
HIP 16888 |
19.24 |
| 2026-02-14 12:00 |
03:35:21.27 |
+54:41:20.5 |
HIP 16888 |
19.14 |
| 2026-02-15 00:00 |
03:35:21.26 |
+54:41:06.6 |
HIP 16888 |
19.04 |
| 2026-02-15 12:00 |
03:35:21.28 |
+54:40:52.8 |
HIP 16888 |
18.93 |
| 2026-02-16 00:00 |
03:35:21.32 |
+54:40:39.0 |
HIP 16888 |
18.83 |
| 2026-02-16 12:00 |
03:35:21.38 |
+54:40:25.2 |
HIP 16888 |
18.73 |
| 2026-02-17 00:00 |
03:35:21.47 |
+54:40:11.5 |
HIP 16888 |
18.63 |
| 2026-02-17 12:00 |
03:35:21.58 |
+54:39:57.9 |
HIP 16888 |
18.52 |
| 2026-02-18 00:00 |
03:35:21.72 |
+54:39:44.3 |
HIP 16888 |
18.42 |
| 2026-02-18 12:00 |
03:35:21.88 |
+54:39:30.8 |
HIP 16888 |
18.31 |
| 2026-02-19 00:00 |
03:35:22.06 |
+54:39:17.3 |
HIP 16888 |
18.21 |
| 2026-02-19 12:00 |
03:35:22.27 |
+54:39:03.8 |
HIP 16888 |
18.10 |
| 2026-02-20 00:00 |
03:35:22.50 |
+54:38:50.4 |
HIP 16888 |
17.99 |
| 2026-02-20 12:00 |
03:35:22.76 |
+54:38:37.1 |
HIP 16888 |
17.89 |
| 2026-02-21 00:00 |
03:35:23.04 |
+54:38:23.8 |
HIP 16888 |
17.78 |
| 2026-02-21 12:00 |
03:35:23.34 |
+54:38:10.6 |
HIP 16888 |
17.67 |
| 2026-02-22 00:00 |
03:35:23.67 |
+54:37:57.4 |
HIP 16888 |
17.56 |
| 2026-02-22 12:00 |
03:35:24.02 |
+54:37:44.3 |
HIP 16888 |
17.45 |
| 2026-02-23 00:00 |
03:35:24.39 |
+54:37:31.3 |
HIP 16888 |
17.34 |
| 2026-02-23 12:00 |
03:35:24.79 |
+54:37:18.3 |
HIP 16888 |
17.22 |
| 2026-02-24 00:00 |
03:35:25.20 |
+54:37:05.4 |
HIP 16888 |
17.11 |