C/2017 W2 (Leonard)
| Parameter |
Value |
| Designation |
C/2017 W2 (Leonard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-11-01T22:30:18.835200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:38Z |
| Obs used |
169 |
| NEO |
- |
| M1 |
10.900 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-12-26.0000000 |
| e |
0.71125672 |
| q (au) |
3.957327 |
| a (au) |
13.705348 |
| i (deg) |
98.179291 |
| Ω (om, deg) |
312.809062 |
| ω (w, deg) |
169.157714 |
| M (ma, deg) |
1.050179 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.278 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.278 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.700 |
| k |
0.800 |
| 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 |
23:15:20.96 |
-56:31:33.3 |
HIP 114810 |
9.96 |
| 2026-02-03 12:00 |
23:15:29.79 |
-56:30:07.8 |
HIP 114810 |
11.41 |
| 2026-02-04 00:00 |
23:15:38.67 |
-56:28:42.8 |
HIP 114810 |
12.97 |
| 2026-02-04 12:00 |
23:15:47.60 |
-56:27:18.3 |
HIP 114810 |
14.59 |
| 2026-02-05 00:00 |
23:15:56.57 |
-56:25:54.3 |
HIP 114810 |
16.26 |
| 2026-02-05 12:00 |
23:16:05.59 |
-56:24:30.8 |
HIP 114810 |
17.96 |
| 2026-02-06 00:00 |
23:16:14.65 |
-56:23:07.9 |
HIP 114810 |
19.69 |
| 2026-02-06 12:00 |
23:16:23.75 |
-56:21:45.4 |
HIP 114810 |
21.43 |
| 2026-02-07 00:00 |
23:16:32.90 |
-56:20:23.4 |
HIP 114810 |
23.19 |
| 2026-02-07 12:00 |
23:16:42.09 |
-56:19:02.0 |
HIP 114810 |
24.96 |
| 2026-02-08 00:00 |
23:16:51.32 |
-56:17:41.1 |
HIP 114810 |
26.73 |
| 2026-02-08 12:00 |
23:17:00.60 |
-56:16:20.8 |
HIP 114810 |
28.51 |
| 2026-02-09 00:00 |
23:17:09.91 |
-56:15:00.9 |
HIP 114810 |
30.30 |
| 2026-02-09 12:00 |
23:17:19.26 |
-56:13:41.7 |
HIP 115295 |
31.43 |
| 2026-02-10 00:00 |
23:17:28.65 |
-56:12:22.9 |
HIP 115295 |
30.37 |
| 2026-02-10 12:00 |
23:17:38.08 |
-56:11:04.7 |
HIP 115295 |
29.38 |
| 2026-02-11 00:00 |
23:17:47.55 |
-56:09:47.0 |
HIP 115295 |
28.46 |
| 2026-02-11 12:00 |
23:17:57.06 |
-56:08:29.9 |
HIP 115295 |
27.64 |
| 2026-02-12 00:00 |
23:18:06.60 |
-56:07:13.4 |
HIP 115295 |
26.90 |
| 2026-02-12 12:00 |
23:18:16.17 |
-56:05:57.4 |
HIP 115295 |
26.26 |
| 2026-02-13 00:00 |
23:18:25.78 |
-56:04:42.0 |
HIP 115295 |
25.72 |
| 2026-02-13 12:00 |
23:18:35.42 |
-56:03:27.1 |
HIP 115295 |
25.30 |
| 2026-02-14 00:00 |
23:18:45.10 |
-56:02:12.9 |
HIP 115295 |
24.99 |
| 2026-02-14 12:00 |
23:18:54.81 |
-56:00:59.1 |
HIP 115295 |
24.81 |
| 2026-02-15 00:00 |
23:19:04.55 |
-55:59:46.0 |
HIP 115295 |
24.74 |
| 2026-02-15 12:00 |
23:19:14.32 |
-55:58:33.5 |
HIP 115295 |
24.80 |
| 2026-02-16 00:00 |
23:19:24.12 |
-55:57:21.5 |
HIP 115295 |
24.98 |
| 2026-02-16 12:00 |
23:19:33.95 |
-55:56:10.1 |
HIP 115295 |
25.28 |
| 2026-02-17 00:00 |
23:19:43.81 |
-55:54:59.3 |
HIP 115295 |
25.69 |
| 2026-02-17 12:00 |
23:19:53.70 |
-55:53:49.2 |
HIP 115295 |
26.21 |
| 2026-02-18 00:00 |
23:20:03.61 |
-55:52:39.6 |
HIP 115295 |
26.84 |
| 2026-02-18 12:00 |
23:20:13.55 |
-55:51:30.6 |
HIP 115295 |
27.55 |
| 2026-02-19 00:00 |
23:20:23.51 |
-55:50:22.2 |
HIP 115295 |
28.35 |
| 2026-02-19 12:00 |
23:20:33.50 |
-55:49:14.4 |
HIP 115462 |
28.66 |
| 2026-02-20 00:00 |
23:20:43.52 |
-55:48:07.3 |
HIP 115462 |
26.87 |
| 2026-02-20 12:00 |
23:20:53.55 |
-55:47:00.7 |
HIP 115462 |
25.09 |
| 2026-02-21 00:00 |
23:21:03.61 |
-55:45:54.8 |
HIP 115462 |
23.30 |
| 2026-02-21 12:00 |
23:21:13.69 |
-55:44:49.5 |
HIP 115462 |
21.52 |
| 2026-02-22 00:00 |
23:21:23.79 |
-55:43:44.8 |
HIP 115462 |
19.74 |
| 2026-02-22 12:00 |
23:21:33.91 |
-55:42:40.8 |
HIP 115462 |
17.97 |
| 2026-02-23 00:00 |
23:21:44.05 |
-55:41:37.3 |
HIP 115462 |
16.20 |
| 2026-02-23 12:00 |
23:21:54.21 |
-55:40:34.6 |
HIP 115462 |
14.43 |
| 2026-02-24 00:00 |
23:22:04.39 |
-55:39:32.4 |
HIP 115462 |
12.67 |