| 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 |
-0.998 |
| 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) |
| 2026-05-12 00:00 |
11:35:52.42 |
-01:30:43.6 |
HIP 56691 |
23.70 |
| 2026-05-12 12:00 |
11:35:46.52 |
-01:30:31.7 |
HIP 56691 |
25.15 |
| 2026-05-13 00:00 |
11:35:40.83 |
-01:30:20.9 |
HIP 56691 |
26.56 |
| 2026-05-13 12:00 |
11:35:35.34 |
-01:30:11.1 |
HIP 56691 |
27.93 |
| 2026-05-14 00:00 |
11:35:30.04 |
-01:30:02.4 |
HIP 56691 |
29.25 |
| 2026-05-14 12:00 |
11:35:24.94 |
-01:29:54.8 |
HIP 56691 |
30.52 |
| 2026-05-15 00:00 |
11:35:20.04 |
-01:29:48.2 |
HIP 56691 |
31.74 |
| 2026-05-15 12:00 |
11:35:15.34 |
-01:29:42.7 |
HIP 56691 |
32.91 |
| 2026-05-16 00:00 |
11:35:10.84 |
-01:29:38.2 |
HIP 56691 |
34.03 |
| 2026-05-16 12:00 |
11:35:06.54 |
-01:29:34.8 |
HIP 56691 |
35.11 |
| 2026-05-17 00:00 |
11:35:02.43 |
-01:29:32.5 |
HIP 56691 |
36.13 |
| 2026-05-17 12:00 |
11:34:58.53 |
-01:29:31.2 |
HIP 56691 |
37.11 |
| 2026-05-18 00:00 |
11:34:54.82 |
-01:29:31.1 |
HIP 56691 |
38.04 |
| 2026-05-18 12:00 |
11:34:51.30 |
-01:29:32.0 |
HIP 56691 |
38.91 |
| 2026-05-19 00:00 |
11:34:47.99 |
-01:29:33.9 |
HIP 56691 |
39.74 |
| 2026-05-19 12:00 |
11:34:44.87 |
-01:29:37.0 |
HIP 56691 |
40.52 |
| 2026-05-20 00:00 |
11:34:41.95 |
-01:29:41.1 |
HIP 56691 |
41.25 |
| 2026-05-20 12:00 |
11:34:39.22 |
-01:29:46.3 |
HIP 56691 |
41.94 |
| 2026-05-21 00:00 |
11:34:36.69 |
-01:29:52.5 |
HIP 56691 |
42.57 |
| 2026-05-21 12:00 |
11:34:34.36 |
-01:29:59.8 |
HIP 56263 |
42.17 |
| 2026-05-22 00:00 |
11:34:32.21 |
-01:30:08.3 |
HIP 56263 |
41.63 |
| 2026-05-22 12:00 |
11:34:30.27 |
-01:30:17.7 |
HIP 56263 |
41.12 |
| 2026-05-23 00:00 |
11:34:28.51 |
-01:30:28.3 |
HIP 56263 |
40.64 |
| 2026-05-23 12:00 |
11:34:26.95 |
-01:30:39.9 |
HIP 56263 |
40.21 |
| 2026-05-24 00:00 |
11:34:25.58 |
-01:30:52.5 |
HIP 56263 |
39.81 |
| 2026-05-24 12:00 |
11:34:24.40 |
-01:31:06.3 |
HIP 56263 |
39.45 |
| 2026-05-25 00:00 |
11:34:23.41 |
-01:31:21.0 |
HIP 56263 |
39.12 |
| 2026-05-25 12:00 |
11:34:22.61 |
-01:31:36.9 |
HIP 56263 |
38.84 |
| 2026-05-26 00:00 |
11:34:22.00 |
-01:31:53.8 |
HIP 56263 |
38.58 |
| 2026-05-26 12:00 |
11:34:21.58 |
-01:32:11.7 |
HIP 56263 |
38.37 |
| 2026-05-27 00:00 |
11:34:21.34 |
-01:32:30.8 |
HIP 56263 |
38.20 |
| 2026-05-27 12:00 |
11:34:21.29 |
-01:32:50.8 |
HIP 56263 |
38.06 |
| 2026-05-28 00:00 |
11:34:21.43 |
-01:33:11.9 |
HIP 56263 |
37.96 |
| 2026-05-28 12:00 |
11:34:21.76 |
-01:33:34.1 |
HIP 56263 |
37.91 |
| 2026-05-29 00:00 |
11:34:22.26 |
-01:33:57.3 |
HIP 56263 |
37.89 |
| 2026-05-29 12:00 |
11:34:22.96 |
-01:34:21.5 |
HIP 56263 |
37.92 |
| 2026-05-30 00:00 |
11:34:23.83 |
-01:34:46.8 |
HIP 56263 |
37.99 |
| 2026-05-30 12:00 |
11:34:24.89 |
-01:35:13.1 |
HIP 56263 |
38.10 |
| 2026-05-31 00:00 |
11:34:26.13 |
-01:35:40.4 |
HIP 56263 |
38.26 |
| 2026-05-31 12:00 |
11:34:27.55 |
-01:36:08.7 |
HIP 56493 |
38.19 |
| 2026-06-01 00:00 |
11:34:29.15 |
-01:36:38.1 |
HIP 56493 |
37.65 |
| 2026-06-01 12:00 |
11:34:30.93 |
-01:37:08.6 |
HIP 56493 |
37.08 |
| 2026-06-02 00:00 |
11:34:32.89 |
-01:37:40.0 |
HIP 56493 |
36.49 |