| Parameter |
Value |
| Designation |
501P/Rankin |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2020-12-10T08:39:13.299840Z |
| Orbit solution date (soln_date, UTC) |
2025-07-31T16:54:57Z |
| Obs used |
98 |
| NEO |
Yes |
| M1 |
21.900 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2024-06-15T10:13:37.545600Z |
| Discovery magnitude (MPC) |
20.90 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-05-24.0000000 |
| e |
0.69572032 |
| q (au) |
0.680308 |
| a (au) |
2.235797 |
| i (deg) |
10.104448 |
| Ω (om, deg) |
140.492867 |
| ω (w, deg) |
52.799047 |
| M (ma, deg) |
156.147750 |
Magnitude
Scatter + Global Linear
$$
M_a = (20.000 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
20.000 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.852 |
| k |
0.990 |
| 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 |
| 2024-03-22 |
2024-07-29 |
-14.2233 |
+1.816 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
02:02:44.66 |
+04:45:24.4 |
HIP 9611 |
13.47 |
| 2026-05-12 12:00 |
02:03:15.54 |
+04:47:50.1 |
HIP 9611 |
5.64 |
| 2026-05-13 00:00 |
02:03:46.40 |
+04:50:15.3 |
HIP 9611 |
3.52 |
| 2026-05-13 12:00 |
02:04:17.26 |
+04:52:39.8 |
HIP 9611 |
11.08 |
| 2026-05-14 00:00 |
02:04:48.11 |
+04:55:03.7 |
HIP 9611 |
19.05 |
| 2026-05-14 12:00 |
02:05:18.95 |
+04:57:26.9 |
HIP 9791 |
22.74 |
| 2026-05-15 00:00 |
02:05:49.78 |
+04:59:49.6 |
HIP 9791 |
18.56 |
| 2026-05-15 12:00 |
02:06:20.59 |
+05:02:11.7 |
HIP 9791 |
17.35 |
| 2026-05-16 00:00 |
02:06:51.40 |
+05:04:33.1 |
HIP 9791 |
19.67 |
| 2026-05-16 12:00 |
02:07:22.19 |
+05:06:53.9 |
HIP 9791 |
24.53 |
| 2026-05-17 00:00 |
02:07:52.97 |
+05:09:14.0 |
HIP 9791 |
30.74 |
| 2026-05-17 12:00 |
02:08:23.74 |
+05:11:33.5 |
HIP 10056 |
33.01 |
| 2026-05-18 00:00 |
02:08:54.49 |
+05:13:52.4 |
HIP 10056 |
27.95 |
| 2026-05-18 12:00 |
02:09:25.22 |
+05:16:10.5 |
HIP 10056 |
24.51 |
| 2026-05-19 00:00 |
02:09:55.94 |
+05:18:28.1 |
HIP 10184 |
20.05 |
| 2026-05-19 12:00 |
02:10:26.64 |
+05:20:45.0 |
HIP 10184 |
17.27 |
| 2026-05-20 00:00 |
02:10:57.32 |
+05:23:01.2 |
HIP 10184 |
17.93 |
| 2026-05-20 12:00 |
02:11:27.99 |
+05:25:16.7 |
HIP 10184 |
21.70 |
| 2026-05-21 00:00 |
02:11:58.64 |
+05:27:31.6 |
HIP 10333 |
18.37 |
| 2026-05-21 12:00 |
02:12:29.26 |
+05:29:45.8 |
HIP 10333 |
12.45 |
| 2026-05-22 00:00 |
02:12:59.87 |
+05:31:59.3 |
HIP 10333 |
9.92 |
| 2026-05-22 12:00 |
02:13:30.46 |
+05:34:12.1 |
HIP 10333 |
12.94 |
| 2026-05-23 00:00 |
02:14:01.02 |
+05:36:24.2 |
HIP 10333 |
19.02 |
| 2026-05-23 12:00 |
02:14:31.57 |
+05:38:35.7 |
HIP 10419 |
22.35 |
| 2026-05-24 00:00 |
02:15:02.09 |
+05:40:46.4 |
HIP 10419 |
22.95 |
| 2026-05-24 12:00 |
02:15:32.59 |
+05:42:56.4 |
HIP 10419 |
26.05 |
| 2026-05-25 00:00 |
02:16:03.07 |
+05:45:05.8 |
HIP 10678 |
24.27 |
| 2026-05-25 12:00 |
02:16:33.52 |
+05:47:14.4 |
HIP 10678 |
20.23 |
| 2026-05-26 00:00 |
02:17:03.95 |
+05:49:22.4 |
HIP 10678 |
18.80 |
| 2026-05-26 12:00 |
02:17:34.35 |
+05:51:29.6 |
HIP 10678 |
20.51 |
| 2026-05-27 00:00 |
02:18:04.73 |
+05:53:36.1 |
HIP 10678 |
24.71 |
| 2026-05-27 12:00 |
02:18:35.08 |
+05:55:41.9 |
HIP 10678 |
30.38 |
| 2026-05-28 00:00 |
02:19:05.41 |
+05:57:46.9 |
HIP 10957 |
34.54 |
| 2026-05-28 12:00 |
02:19:35.71 |
+05:59:51.3 |
HIP 10957 |
29.37 |
| 2026-05-29 00:00 |
02:20:05.98 |
+06:01:54.9 |
HIP 10957 |
25.58 |
| 2026-05-29 12:00 |
02:20:36.22 |
+06:03:57.7 |
HIP 10957 |
23.82 |
| 2026-05-30 00:00 |
02:21:06.44 |
+06:05:59.9 |
HIP 10957 |
24.52 |
| 2026-05-30 12:00 |
02:21:36.63 |
+06:08:01.3 |
HIP 11132 |
25.72 |
| 2026-05-31 00:00 |
02:22:06.79 |
+06:10:02.0 |
HIP 11132 |
19.71 |
| 2026-05-31 12:00 |
02:22:36.91 |
+06:12:01.9 |
HIP 11132 |
15.35 |
| 2026-06-01 00:00 |
02:23:07.01 |
+06:14:01.0 |
HIP 11132 |
14.24 |
| 2026-06-01 12:00 |
02:23:37.08 |
+06:15:59.4 |
HIP 11132 |
17.01 |
| 2026-06-02 00:00 |
02:24:07.11 |
+06:17:57.1 |
HIP 11151 |
20.76 |