| Parameter |
Value |
| Designation |
P/2017 Y3 (Leonard) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2018-02-11T06:14:12.742080Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:39Z |
| Obs used |
93 |
| NEO |
Yes |
| M1 |
16.500 |
| K1 |
11.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-02-20.0000000 |
| e |
0.87071088 |
| q (au) |
1.275381 |
| a (au) |
9.864564 |
| i (deg) |
27.585652 |
| Ω (om, deg) |
153.873913 |
| ω (w, deg) |
67.528786 |
| M (ma, deg) |
0.278039 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.771 + 4.270\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.771 |
| n |
4.270 |
| gf |
1.000 |
| gb |
-1.000 |
| 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 |
02:13:25.28 |
-09:07:50.5 |
HIP 10396 |
8.03 |
| 2026-06-01 12:00 |
02:13:31.59 |
-09:07:45.9 |
HIP 10396 |
6.67 |
| 2026-06-02 00:00 |
02:13:37.88 |
-09:07:41.8 |
HIP 10396 |
5.43 |
| 2026-06-02 12:00 |
02:13:44.14 |
-09:07:38.1 |
HIP 10396 |
4.42 |
| 2026-06-03 00:00 |
02:13:50.36 |
-09:07:34.9 |
HIP 10396 |
3.78 |
| 2026-06-03 12:00 |
02:13:56.56 |
-09:07:32.0 |
HIP 10396 |
3.73 |
| 2026-06-04 00:00 |
02:14:02.72 |
-09:07:29.7 |
HIP 10396 |
4.26 |
| 2026-06-04 12:00 |
02:14:08.85 |
-09:07:27.7 |
HIP 10396 |
5.20 |
| 2026-06-05 00:00 |
02:14:14.95 |
-09:07:26.2 |
HIP 10396 |
6.37 |
| 2026-06-05 12:00 |
02:14:21.02 |
-09:07:25.1 |
HIP 10396 |
7.65 |
| 2026-06-06 00:00 |
02:14:27.06 |
-09:07:24.5 |
HIP 10396 |
8.99 |
| 2026-06-06 12:00 |
02:14:33.06 |
-09:07:24.3 |
HIP 10396 |
10.37 |
| 2026-06-07 00:00 |
02:14:39.04 |
-09:07:24.6 |
HIP 10396 |
11.77 |
| 2026-06-07 12:00 |
02:14:44.97 |
-09:07:25.2 |
HIP 10396 |
13.18 |
| 2026-06-08 00:00 |
02:14:50.88 |
-09:07:26.4 |
HIP 10532 |
14.20 |
| 2026-06-08 12:00 |
02:14:56.75 |
-09:07:27.9 |
HIP 10532 |
12.95 |
| 2026-06-09 00:00 |
02:15:02.58 |
-09:07:29.9 |
HIP 10532 |
11.76 |
| 2026-06-09 12:00 |
02:15:08.38 |
-09:07:32.4 |
HIP 10532 |
10.64 |
| 2026-06-10 00:00 |
02:15:14.15 |
-09:07:35.3 |
HIP 10532 |
9.62 |
| 2026-06-10 12:00 |
02:15:19.87 |
-09:07:38.6 |
HIP 10532 |
8.72 |
| 2026-06-11 00:00 |
02:15:25.57 |
-09:07:42.4 |
HIP 10532 |
7.98 |
| 2026-06-11 12:00 |
02:15:31.22 |
-09:07:46.6 |
HIP 10532 |
7.45 |
| 2026-06-12 00:00 |
02:15:36.84 |
-09:07:51.3 |
HIP 10532 |
7.17 |
| 2026-06-12 12:00 |
02:15:42.43 |
-09:07:56.4 |
HIP 10532 |
7.15 |
| 2026-06-13 00:00 |
02:15:47.97 |
-09:08:02.0 |
HIP 10532 |
7.41 |
| 2026-06-13 12:00 |
02:15:53.48 |
-09:08:08.0 |
HIP 10532 |
7.90 |
| 2026-06-14 00:00 |
02:15:58.95 |
-09:08:14.4 |
HIP 10532 |
8.58 |
| 2026-06-14 12:00 |
02:16:04.38 |
-09:08:21.3 |
HIP 10532 |
9.41 |
| 2026-06-15 00:00 |
02:16:09.77 |
-09:08:28.7 |
HIP 10532 |
10.35 |
| 2026-06-15 12:00 |
02:16:15.13 |
-09:08:36.5 |
HIP 10532 |
11.37 |
| 2026-06-16 00:00 |
02:16:20.44 |
-09:08:44.7 |
HIP 10532 |
12.44 |
| 2026-06-16 12:00 |
02:16:25.71 |
-09:08:53.4 |
HIP 10532 |
13.55 |
| 2026-06-17 00:00 |
02:16:30.95 |
-09:09:02.5 |
HIP 10532 |
14.69 |
| 2026-06-17 12:00 |
02:16:36.14 |
-09:09:12.1 |
HIP 10532 |
15.85 |
| 2026-06-18 00:00 |
02:16:41.29 |
-09:09:22.1 |
HIP 10532 |
17.03 |
| 2026-06-18 12:00 |
02:16:46.40 |
-09:09:32.6 |
HIP 10573 |
18.14 |
| 2026-06-19 00:00 |
02:16:51.47 |
-09:09:43.5 |
HIP 10573 |
18.99 |
| 2026-06-19 12:00 |
02:16:56.49 |
-09:09:54.9 |
HIP 10573 |
19.89 |
| 2026-06-20 00:00 |
02:17:01.48 |
-09:10:06.7 |
HIP 10573 |
20.82 |
| 2026-06-20 12:00 |
02:17:06.42 |
-09:10:18.9 |
HIP 10573 |
21.78 |
| 2026-06-21 00:00 |
02:17:11.32 |
-09:10:31.6 |
HIP 10573 |
22.77 |
| 2026-06-21 12:00 |
02:17:16.17 |
-09:10:44.7 |
HIP 10573 |
23.78 |
| 2026-06-22 00:00 |
02:17:20.99 |
-09:10:58.3 |
HIP 10573 |
24.80 |