| Parameter |
Value |
| Designation |
50P/Arend |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2007-11-02T19:43:29.481600Z |
| Orbit solution date (soln_date, UTC) |
2025-10-01T16:07:23Z |
| Obs used |
1874 |
| NEO |
- |
| M1 |
13.900 |
| K1 |
9.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-07-01.0000000 |
| e |
0.53063813 |
| q (au) |
1.918329 |
| a (au) |
4.087100 |
| i (deg) |
19.155639 |
| Ω (om, deg) |
355.310553 |
| ω (w, deg) |
49.039728 |
| M (ma, deg) |
159.384273 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.457 + 4.038\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.457 |
| n |
4.038 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2023-08-17 |
2024-05-13 |
+13.6006 |
-5.552 |
| 2024-05-13 |
2025-05-02 |
-14.3888 |
+6.578 |
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 |
12:29:02.64 |
-08:35:25.3 |
HIP 60816 |
17.38 |
| 2026-09-20 12:00 |
12:29:24.16 |
-08:38:08.6 |
HIP 60816 |
22.03 |
| 2026-09-21 00:00 |
12:29:45.69 |
-08:40:52.1 |
HIP 60816 |
27.20 |
| 2026-09-21 12:00 |
12:30:07.23 |
-08:43:35.8 |
HIP 61165 |
29.05 |
| 2026-09-22 00:00 |
12:30:28.78 |
-08:46:19.6 |
HIP 61165 |
24.84 |
| 2026-09-22 12:00 |
12:30:50.34 |
-08:49:03.5 |
HIP 61165 |
21.48 |
| 2026-09-23 00:00 |
12:31:11.91 |
-08:51:47.6 |
HIP 61108 |
19.39 |
| 2026-09-23 12:00 |
12:31:33.49 |
-08:54:31.9 |
HIP 61108 |
16.49 |
| 2026-09-24 00:00 |
12:31:55.07 |
-08:57:16.2 |
HIP 61108 |
15.47 |
| 2026-09-24 12:00 |
12:32:16.67 |
-09:00:00.8 |
HIP 61108 |
16.70 |
| 2026-09-25 00:00 |
12:32:38.27 |
-09:02:45.4 |
HIP 61108 |
19.75 |
| 2026-09-25 12:00 |
12:32:59.87 |
-09:05:30.2 |
HIP 61108 |
23.95 |
| 2026-09-26 00:00 |
12:33:21.49 |
-09:08:15.1 |
HIP 61318 |
19.88 |
| 2026-09-26 12:00 |
12:33:43.11 |
-09:11:00.1 |
HIP 61318 |
16.15 |
| 2026-09-27 00:00 |
12:34:04.73 |
-09:13:45.3 |
HIP 61318 |
14.08 |
| 2026-09-27 12:00 |
12:34:26.36 |
-09:16:30.6 |
HIP 61318 |
14.42 |
| 2026-09-28 00:00 |
12:34:47.99 |
-09:19:16.0 |
HIP 61318 |
17.02 |
| 2026-09-28 12:00 |
12:35:09.63 |
-09:22:01.5 |
HIP 61360 |
17.89 |
| 2026-09-29 00:00 |
12:35:31.27 |
-09:24:47.1 |
HIP 61360 |
19.92 |
| 2026-09-29 12:00 |
12:35:52.91 |
-09:27:32.8 |
HIP 61360 |
23.37 |
| 2026-09-30 00:00 |
12:36:14.56 |
-09:30:18.6 |
HIP 61606 |
21.02 |
| 2026-09-30 12:00 |
12:36:36.20 |
-09:33:04.6 |
HIP 61606 |
15.01 |
| 2026-10-01 00:00 |
12:36:57.85 |
-09:35:50.6 |
HIP 61606 |
9.01 |
| 2026-10-01 12:00 |
12:37:19.50 |
-09:38:36.7 |
HIP 61606 |
3.02 |
| 2026-10-02 00:00 |
12:37:41.15 |
-09:41:22.9 |
HIP 61606 |
3.07 |
| 2026-10-02 12:00 |
12:38:02.79 |
-09:44:09.2 |
HIP 61606 |
9.05 |
| 2026-10-03 00:00 |
12:38:24.44 |
-09:46:55.6 |
HIP 61606 |
15.06 |
| 2026-10-03 12:00 |
12:38:46.08 |
-09:49:42.1 |
HIP 61606 |
21.07 |
| 2026-10-04 00:00 |
12:39:07.73 |
-09:52:28.7 |
HIP 61606 |
27.08 |
| 2026-10-04 12:00 |
12:39:29.37 |
-09:55:15.3 |
HIP 61904 |
25.38 |
| 2026-10-05 00:00 |
12:39:51.00 |
-09:58:02.0 |
HIP 61904 |
21.20 |
| 2026-10-05 12:00 |
12:40:12.64 |
-10:00:48.8 |
HIP 61904 |
18.10 |
| 2026-10-06 00:00 |
12:40:34.27 |
-10:03:35.7 |
HIP 61904 |
16.66 |
| 2026-10-06 12:00 |
12:40:55.89 |
-10:06:22.6 |
HIP 61904 |
17.33 |
| 2026-10-07 00:00 |
12:41:17.50 |
-10:09:09.6 |
HIP 61892 |
17.92 |
| 2026-10-07 12:00 |
12:41:39.11 |
-10:11:56.6 |
HIP 61892 |
17.54 |
| 2026-10-08 00:00 |
12:42:00.72 |
-10:14:43.7 |
HIP 61892 |
19.13 |
| 2026-10-08 12:00 |
12:42:22.31 |
-10:17:30.8 |
HIP 61892 |
22.28 |
| 2026-10-09 00:00 |
12:42:43.90 |
-10:20:18.0 |
HIP 61892 |
26.43 |
| 2026-10-09 12:00 |
12:43:05.48 |
-10:23:05.2 |
HIP 62173 |
27.24 |
| 2026-10-10 00:00 |
12:43:27.04 |
-10:25:52.4 |
HIP 62173 |
25.78 |
| 2026-10-10 12:00 |
12:43:48.60 |
-10:28:39.7 |
HIP 62173 |
25.67 |
| 2026-10-11 00:00 |
12:44:10.14 |
-10:31:27.0 |
HIP 62173 |
26.93 |