| Parameter |
Value |
| Designation |
496P/Hill |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2025-03-11T10:59:53.473920Z |
| Orbit solution date (soln_date, UTC) |
2025-09-30T13:39:54Z |
| Obs used |
1688 |
| NEO |
- |
| M1 |
11.200 |
| K1 |
20.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2024-09-26T14:11:19.680000Z |
| Discovery magnitude (MPC) |
20.22 G |
| Discovery observatory (MPC) |
F52 · Pan-STARRS 2, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-09-12.0000000 |
| e |
0.73348756 |
| q (au) |
1.620113 |
| a (au) |
6.078939 |
| i (deg) |
14.831238 |
| Ω (om, deg) |
63.817654 |
| ω (w, deg) |
42.159614 |
| M (ma, deg) |
276.059995 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.592 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.592 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2024-09-11 |
2024-11-06 |
+18.6955 |
-6.087 |
| 2024-11-06 |
2024-12-27 |
-5.6666 |
+2.049 |
| 2024-12-27 |
2025-03-11 |
+13.4429 |
-2.871 |
| 2025-03-14 |
2025-06-28 |
-8.8446 |
+1.243 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
15:21:21.06 |
-10:53:27.5 |
HIP 75136 |
9.44 |
| 2026-03-26 12:00 |
15:21:07.82 |
-10:52:49.4 |
HIP 75136 |
9.06 |
| 2026-03-27 00:00 |
15:20:54.34 |
-10:52:10.8 |
HIP 75136 |
9.88 |
| 2026-03-27 12:00 |
15:20:40.61 |
-10:51:31.8 |
HIP 75075 |
10.67 |
| 2026-03-28 00:00 |
15:20:26.66 |
-10:50:52.2 |
HIP 75075 |
11.14 |
| 2026-03-28 12:00 |
15:20:12.47 |
-10:50:12.1 |
HIP 75075 |
12.62 |
| 2026-03-29 00:00 |
15:19:58.05 |
-10:49:31.5 |
HIP 75075 |
14.85 |
| 2026-03-29 12:00 |
15:19:43.40 |
-10:48:50.5 |
HIP 75075 |
17.59 |
| 2026-03-30 00:00 |
15:19:28.53 |
-10:48:09.0 |
HIP 75075 |
20.67 |
| 2026-03-30 12:00 |
15:19:13.43 |
-10:47:27.0 |
HIP 75075 |
23.97 |
| 2026-03-31 00:00 |
15:18:58.11 |
-10:46:44.6 |
HIP 74825 |
26.94 |
| 2026-03-31 12:00 |
15:18:42.57 |
-10:46:01.8 |
HIP 74825 |
23.57 |
| 2026-04-01 00:00 |
15:18:26.81 |
-10:45:18.5 |
HIP 74825 |
20.35 |
| 2026-04-01 12:00 |
15:18:10.84 |
-10:44:34.9 |
HIP 74825 |
17.38 |
| 2026-04-02 00:00 |
15:17:54.66 |
-10:43:50.8 |
HIP 74825 |
14.88 |
| 2026-04-02 12:00 |
15:17:38.26 |
-10:43:06.3 |
HIP 74825 |
13.16 |
| 2026-04-03 00:00 |
15:17:21.66 |
-10:42:21.4 |
HIP 74825 |
12.59 |
| 2026-04-03 12:00 |
15:17:04.86 |
-10:41:36.2 |
HIP 74764 |
11.93 |
| 2026-04-04 00:00 |
15:16:47.85 |
-10:40:50.6 |
HIP 74764 |
10.47 |
| 2026-04-04 12:00 |
15:16:30.65 |
-10:40:04.7 |
HIP 74764 |
10.64 |
| 2026-04-05 00:00 |
15:16:13.25 |
-10:39:18.4 |
HIP 74764 |
12.44 |
| 2026-04-05 12:00 |
15:15:55.66 |
-10:38:31.7 |
HIP 74652 |
10.94 |
| 2026-04-06 00:00 |
15:15:37.87 |
-10:37:44.8 |
HIP 74652 |
6.70 |
| 2026-04-06 12:00 |
15:15:19.90 |
-10:36:57.5 |
HIP 74652 |
3.07 |
| 2026-04-07 00:00 |
15:15:01.74 |
-10:36:10.0 |
HIP 74652 |
3.81 |
| 2026-04-07 12:00 |
15:14:43.41 |
-10:35:22.2 |
HIP 74652 |
7.83 |
| 2026-04-08 00:00 |
15:14:24.89 |
-10:34:34.1 |
HIP 74652 |
12.29 |
| 2026-04-08 12:00 |
15:14:06.20 |
-10:33:45.7 |
HIP 74652 |
16.88 |
| 2026-04-09 00:00 |
15:13:47.33 |
-10:32:57.1 |
HIP 74652 |
21.55 |
| 2026-04-09 12:00 |
15:13:28.30 |
-10:32:08.2 |
HIP 74652 |
26.27 |
| 2026-04-10 00:00 |
15:13:09.10 |
-10:31:19.2 |
HIP 74488 |
29.13 |
| 2026-04-10 12:00 |
15:12:49.73 |
-10:30:29.9 |
HIP 74488 |
30.55 |
| 2026-04-11 00:00 |
15:12:30.21 |
-10:29:40.4 |
HIP 74488 |
32.64 |
| 2026-04-11 12:00 |
15:12:10.53 |
-10:28:50.7 |
HIP 74488 |
35.30 |
| 2026-04-12 00:00 |
15:11:50.70 |
-10:28:00.9 |
HIP 74313 |
36.07 |
| 2026-04-12 12:00 |
15:11:30.72 |
-10:27:10.9 |
HIP 74313 |
36.25 |
| 2026-04-13 00:00 |
15:11:10.59 |
-10:26:20.7 |
HIP 74246 |
35.29 |
| 2026-04-13 12:00 |
15:10:50.33 |
-10:25:30.5 |
HIP 74246 |
33.09 |
| 2026-04-14 00:00 |
15:10:29.92 |
-10:24:40.1 |
HIP 74246 |
31.56 |
| 2026-04-14 12:00 |
15:10:09.38 |
-10:23:49.6 |
HIP 74246 |
30.81 |
| 2026-04-15 00:00 |
15:09:48.70 |
-10:22:59.0 |
HIP 74246 |
30.90 |
| 2026-04-15 12:00 |
15:09:27.90 |
-10:22:08.3 |
HIP 74246 |
31.85 |
| 2026-04-16 00:00 |
15:09:06.98 |
-10:21:17.6 |
HIP 74246 |
33.60 |