| Parameter |
Value |
| Designation |
C/1984 W2 (Hartley) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1985-09-28T09:29:19.821120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:31Z |
| Obs used |
53 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1986-02-18.0000000 |
| e |
0.99947295 |
| q (au) |
4.000285 |
| a (au) |
7589.981412 |
| i (deg) |
89.326939 |
| Ω (om, deg) |
250.204076 |
| ω (w, deg) |
255.271872 |
| M (ma, deg) |
0.000213 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.937 + 4.665\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.937 |
| n |
4.665 |
| 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 |
17:03:14.54 |
+24:11:38.2 |
HIP 83375 |
12.88 |
| 2026-06-01 12:00 |
17:03:12.52 |
+24:11:43.8 |
HIP 83375 |
12.53 |
| 2026-06-02 00:00 |
17:03:10.49 |
+24:11:49.2 |
HIP 83375 |
12.19 |
| 2026-06-02 12:00 |
17:03:08.47 |
+24:11:54.5 |
HIP 83375 |
11.85 |
| 2026-06-03 00:00 |
17:03:06.45 |
+24:11:59.5 |
HIP 83375 |
11.52 |
| 2026-06-03 12:00 |
17:03:04.42 |
+24:12:04.4 |
HIP 83375 |
11.20 |
| 2026-06-04 00:00 |
17:03:02.39 |
+24:12:09.2 |
HIP 83375 |
10.89 |
| 2026-06-04 12:00 |
17:03:00.36 |
+24:12:13.7 |
HIP 83375 |
10.59 |
| 2026-06-05 00:00 |
17:02:58.33 |
+24:12:18.1 |
HIP 83375 |
10.29 |
| 2026-06-05 12:00 |
17:02:56.30 |
+24:12:22.3 |
HIP 83375 |
10.01 |
| 2026-06-06 00:00 |
17:02:54.27 |
+24:12:26.3 |
HIP 83375 |
9.74 |
| 2026-06-06 12:00 |
17:02:52.24 |
+24:12:30.2 |
HIP 83375 |
9.48 |
| 2026-06-07 00:00 |
17:02:50.20 |
+24:12:33.9 |
HIP 83375 |
9.24 |
| 2026-06-07 12:00 |
17:02:48.17 |
+24:12:37.4 |
HIP 83375 |
9.01 |
| 2026-06-08 00:00 |
17:02:46.14 |
+24:12:40.7 |
HIP 83375 |
8.80 |
| 2026-06-08 12:00 |
17:02:44.11 |
+24:12:43.9 |
HIP 83375 |
8.61 |
| 2026-06-09 00:00 |
17:02:42.07 |
+24:12:46.9 |
HIP 83375 |
8.44 |
| 2026-06-09 12:00 |
17:02:40.04 |
+24:12:49.7 |
HIP 83375 |
8.28 |
| 2026-06-10 00:00 |
17:02:38.01 |
+24:12:52.3 |
HIP 83375 |
8.15 |
| 2026-06-10 12:00 |
17:02:35.98 |
+24:12:54.7 |
HIP 83375 |
8.04 |
| 2026-06-11 00:00 |
17:02:33.95 |
+24:12:57.0 |
HIP 83375 |
7.95 |
| 2026-06-11 12:00 |
17:02:31.92 |
+24:12:59.1 |
HIP 83375 |
7.89 |
| 2026-06-12 00:00 |
17:02:29.89 |
+24:13:01.0 |
HIP 83375 |
7.84 |
| 2026-06-12 12:00 |
17:02:27.86 |
+24:13:02.7 |
HIP 83375 |
7.83 |
| 2026-06-13 00:00 |
17:02:25.83 |
+24:13:04.3 |
HIP 83375 |
7.84 |
| 2026-06-13 12:00 |
17:02:23.81 |
+24:13:05.7 |
HIP 83375 |
7.87 |
| 2026-06-14 00:00 |
17:02:21.79 |
+24:13:06.9 |
HIP 83375 |
7.93 |
| 2026-06-14 12:00 |
17:02:19.77 |
+24:13:07.9 |
HIP 83375 |
8.01 |
| 2026-06-15 00:00 |
17:02:17.75 |
+24:13:08.7 |
HIP 83375 |
8.11 |
| 2026-06-15 12:00 |
17:02:15.73 |
+24:13:09.4 |
HIP 83375 |
8.23 |
| 2026-06-16 00:00 |
17:02:13.72 |
+24:13:09.9 |
HIP 83375 |
8.38 |
| 2026-06-16 12:00 |
17:02:11.71 |
+24:13:10.2 |
HIP 83375 |
8.54 |
| 2026-06-17 00:00 |
17:02:09.70 |
+24:13:10.4 |
HIP 83375 |
8.72 |
| 2026-06-17 12:00 |
17:02:07.69 |
+24:13:10.3 |
HIP 83375 |
8.92 |
| 2026-06-18 00:00 |
17:02:05.69 |
+24:13:10.1 |
HIP 83375 |
9.13 |
| 2026-06-18 12:00 |
17:02:03.69 |
+24:13:09.7 |
HIP 83375 |
9.36 |
| 2026-06-19 00:00 |
17:02:01.69 |
+24:13:09.1 |
HIP 83375 |
9.61 |
| 2026-06-19 12:00 |
17:01:59.70 |
+24:13:08.4 |
HIP 83375 |
9.86 |
| 2026-06-20 00:00 |
17:01:57.71 |
+24:13:07.5 |
HIP 83375 |
10.13 |
| 2026-06-20 12:00 |
17:01:55.73 |
+24:13:06.4 |
HIP 83375 |
10.40 |
| 2026-06-21 00:00 |
17:01:53.75 |
+24:13:05.1 |
HIP 83375 |
10.69 |
| 2026-06-21 12:00 |
17:01:51.77 |
+24:13:03.7 |
HIP 83375 |
10.98 |
| 2026-06-22 00:00 |
17:01:49.80 |
+24:13:02.0 |
HIP 83375 |
11.28 |