| 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) |
| 2026-09-20 00:00 |
14:55:51.22 |
-14:27:32.0 |
HIP 73064 |
33.50 |
| 2026-09-20 12:00 |
14:56:11.55 |
-14:29:34.7 |
HIP 73187 |
31.20 |
| 2026-09-21 00:00 |
14:56:31.95 |
-14:31:37.4 |
HIP 73187 |
26.75 |
| 2026-09-21 12:00 |
14:56:52.43 |
-14:33:40.1 |
HIP 73187 |
22.67 |
| 2026-09-22 00:00 |
14:57:12.97 |
-14:35:42.8 |
HIP 73187 |
19.23 |
| 2026-09-22 12:00 |
14:57:33.59 |
-14:37:45.5 |
HIP 73187 |
16.84 |
| 2026-09-23 00:00 |
14:57:54.28 |
-14:39:48.2 |
HIP 73187 |
15.98 |
| 2026-09-23 12:00 |
14:58:15.04 |
-14:41:50.8 |
HIP 73187 |
16.91 |
| 2026-09-24 00:00 |
14:58:35.87 |
-14:43:53.5 |
HIP 73187 |
19.39 |
| 2026-09-24 12:00 |
14:58:56.76 |
-14:45:56.1 |
HIP 73416 |
18.65 |
| 2026-09-25 00:00 |
14:59:17.72 |
-14:47:58.7 |
HIP 73416 |
14.11 |
| 2026-09-25 12:00 |
14:59:38.75 |
-14:50:01.3 |
HIP 73416 |
10.48 |
| 2026-09-26 00:00 |
14:59:59.85 |
-14:52:03.9 |
HIP 73416 |
8.97 |
| 2026-09-26 12:00 |
15:00:21.01 |
-14:54:06.4 |
HIP 73416 |
10.56 |
| 2026-09-27 00:00 |
15:00:42.23 |
-14:56:08.8 |
HIP 73416 |
14.26 |
| 2026-09-27 12:00 |
15:01:03.52 |
-14:58:11.3 |
HIP 73416 |
18.88 |
| 2026-09-28 00:00 |
15:01:24.88 |
-15:00:13.7 |
HIP 73613 |
19.97 |
| 2026-09-28 12:00 |
15:01:46.29 |
-15:02:16.0 |
HIP 73613 |
14.62 |
| 2026-09-29 00:00 |
15:02:07.77 |
-15:04:18.3 |
HIP 73613 |
9.50 |
| 2026-09-29 12:00 |
15:02:29.31 |
-15:06:20.5 |
HIP 73613 |
5.38 |
| 2026-09-30 00:00 |
15:02:50.91 |
-15:08:22.7 |
HIP 73613 |
5.47 |
| 2026-09-30 12:00 |
15:03:12.57 |
-15:10:24.8 |
HIP 73613 |
9.68 |
| 2026-10-01 00:00 |
15:03:34.29 |
-15:12:26.9 |
HIP 73613 |
14.86 |
| 2026-10-01 12:00 |
15:03:56.07 |
-15:14:28.9 |
HIP 73720 |
13.56 |
| 2026-10-02 00:00 |
15:04:17.90 |
-15:16:30.8 |
HIP 73720 |
11.38 |
| 2026-10-02 12:00 |
15:04:39.80 |
-15:18:32.6 |
HIP 73720 |
11.78 |
| 2026-10-03 00:00 |
15:05:01.75 |
-15:20:34.4 |
HIP 73720 |
14.58 |
| 2026-10-03 12:00 |
15:05:23.76 |
-15:22:36.1 |
HIP 73724 |
18.26 |
| 2026-10-04 00:00 |
15:05:45.82 |
-15:24:37.7 |
HIP 73724 |
22.68 |
| 2026-10-04 12:00 |
15:06:07.94 |
-15:26:39.2 |
HIP 74007 |
18.88 |
| 2026-10-05 00:00 |
15:06:30.12 |
-15:28:40.7 |
HIP 74007 |
13.96 |
| 2026-10-05 12:00 |
15:06:52.35 |
-15:30:42.0 |
HIP 74007 |
9.91 |
| 2026-10-06 00:00 |
15:07:14.63 |
-15:32:43.2 |
HIP 74007 |
8.19 |
| 2026-10-06 12:00 |
15:07:36.97 |
-15:34:44.4 |
HIP 74007 |
10.09 |
| 2026-10-07 00:00 |
15:07:59.35 |
-15:36:45.4 |
HIP 74007 |
14.24 |
| 2026-10-07 12:00 |
15:08:21.79 |
-15:38:46.4 |
HIP 74007 |
19.24 |
| 2026-10-08 00:00 |
15:08:44.28 |
-15:40:47.2 |
HIP 74209 |
16.60 |
| 2026-10-08 12:00 |
15:09:06.82 |
-15:42:47.9 |
HIP 74209 |
11.10 |
| 2026-10-09 00:00 |
15:09:29.41 |
-15:44:48.5 |
HIP 74209 |
6.15 |
| 2026-10-09 12:00 |
15:09:52.05 |
-15:46:48.9 |
HIP 74209 |
4.43 |
| 2026-10-10 00:00 |
15:10:14.73 |
-15:48:49.3 |
HIP 74209 |
8.30 |
| 2026-10-10 12:00 |
15:10:37.46 |
-15:50:49.5 |
HIP 74209 |
13.64 |
| 2026-10-11 00:00 |
15:11:00.24 |
-15:52:49.6 |
HIP 74209 |
19.27 |