| Parameter |
Value |
| Designation |
6P/d’Arrest |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-09-17T18:56:35.044800Z |
| Orbit solution date (soln_date, UTC) |
2022-11-23T09:15:27Z |
| Obs used |
1093 |
| NEO |
- |
| M1 |
15.900 |
| K1 |
8.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-03-29.0000000 |
| e |
0.61267012 |
| q (au) |
1.354585 |
| a (au) |
3.497239 |
| i (deg) |
19.512431 |
| Ω (om, deg) |
138.937100 |
| ω (w, deg) |
178.106460 |
| M (ma, deg) |
333.960485 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.690 + 3.915\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.690 |
| n |
3.915 |
| 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 |
| 2021-03-10 |
2021-07-17 |
-7.6930 |
+2.374 |
| 2021-07-17 |
2021-09-17 |
+39.7603 |
-6.394 |
| 2021-09-18 |
2022-04-02 |
-14.7809 |
-1.960 |
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 |
10:17:35.56 |
+19:14:23.2 |
HIP 50375 |
26.98 |
| 2026-05-12 12:00 |
10:17:37.46 |
+19:13:58.6 |
HIP 50375 |
26.69 |
| 2026-05-13 00:00 |
10:17:39.56 |
+19:13:32.9 |
HIP 50375 |
26.41 |
| 2026-05-13 12:00 |
10:17:41.86 |
+19:13:06.0 |
HIP 50375 |
26.14 |
| 2026-05-14 00:00 |
10:17:44.36 |
+19:12:38.0 |
HIP 50375 |
25.89 |
| 2026-05-14 12:00 |
10:17:47.06 |
+19:12:08.9 |
HIP 50375 |
25.65 |
| 2026-05-15 00:00 |
10:17:49.96 |
+19:11:38.6 |
HIP 50375 |
25.44 |
| 2026-05-15 12:00 |
10:17:53.05 |
+19:11:07.3 |
HIP 50375 |
25.25 |
| 2026-05-16 00:00 |
10:17:56.35 |
+19:10:34.8 |
HIP 50375 |
25.11 |
| 2026-05-16 12:00 |
10:17:59.84 |
+19:10:01.3 |
HIP 50375 |
25.00 |
| 2026-05-17 00:00 |
10:18:03.53 |
+19:09:26.7 |
HIP 50375 |
24.94 |
| 2026-05-17 12:00 |
10:18:07.42 |
+19:08:50.9 |
HIP 50375 |
24.94 |
| 2026-05-18 00:00 |
10:18:11.50 |
+19:08:14.1 |
HIP 50375 |
25.00 |
| 2026-05-18 12:00 |
10:18:15.78 |
+19:07:36.3 |
HIP 50375 |
25.12 |
| 2026-05-19 00:00 |
10:18:20.25 |
+19:06:57.4 |
HIP 50375 |
25.32 |
| 2026-05-19 12:00 |
10:18:24.91 |
+19:06:17.4 |
HIP 50375 |
25.60 |
| 2026-05-20 00:00 |
10:18:29.76 |
+19:05:36.4 |
HIP 50375 |
25.96 |
| 2026-05-20 12:00 |
10:18:34.81 |
+19:04:54.3 |
HIP 50375 |
26.41 |
| 2026-05-21 00:00 |
10:18:40.05 |
+19:04:11.2 |
HIP 50375 |
26.95 |
| 2026-05-21 12:00 |
10:18:45.48 |
+19:03:27.1 |
HIP 50375 |
27.58 |
| 2026-05-22 00:00 |
10:18:51.09 |
+19:02:42.0 |
HIP 50375 |
28.30 |
| 2026-05-22 12:00 |
10:18:56.90 |
+19:01:55.9 |
HIP 50564 |
28.63 |
| 2026-05-23 00:00 |
10:19:02.89 |
+19:01:08.7 |
HIP 50564 |
28.85 |
| 2026-05-23 12:00 |
10:19:09.06 |
+19:00:20.6 |
HIP 50564 |
29.15 |
| 2026-05-24 00:00 |
10:19:15.42 |
+18:59:31.5 |
HIP 50564 |
29.56 |
| 2026-05-24 12:00 |
10:19:21.97 |
+18:58:41.4 |
HIP 50564 |
30.06 |
| 2026-05-25 00:00 |
10:19:28.70 |
+18:57:50.4 |
HIP 50564 |
30.67 |
| 2026-05-25 12:00 |
10:19:35.61 |
+18:56:58.4 |
HIP 50564 |
31.38 |
| 2026-05-26 00:00 |
10:19:42.70 |
+18:56:05.4 |
HIP 50564 |
32.20 |
| 2026-05-26 12:00 |
10:19:49.97 |
+18:55:11.5 |
HIP 50564 |
33.12 |
| 2026-05-27 00:00 |
10:19:57.42 |
+18:54:16.6 |
HIP 50564 |
34.15 |
| 2026-05-27 12:00 |
10:20:05.05 |
+18:53:20.8 |
HIP 50564 |
35.28 |
| 2026-05-28 00:00 |
10:20:12.86 |
+18:52:24.1 |
HIP 50564 |
36.51 |
| 2026-05-28 12:00 |
10:20:20.84 |
+18:51:26.4 |
HIP 50564 |
37.84 |
| 2026-05-29 00:00 |
10:20:29.00 |
+18:50:27.9 |
HIP 50564 |
39.27 |
| 2026-05-29 12:00 |
10:20:37.34 |
+18:49:28.4 |
HIP 50848 |
38.25 |
| 2026-05-30 00:00 |
10:20:45.85 |
+18:48:28.0 |
HIP 50848 |
37.02 |
| 2026-05-30 12:00 |
10:20:54.53 |
+18:47:26.8 |
HIP 50848 |
35.86 |
| 2026-05-31 00:00 |
10:21:03.38 |
+18:46:24.6 |
HIP 50848 |
34.79 |
| 2026-05-31 12:00 |
10:21:12.40 |
+18:45:21.6 |
HIP 50848 |
33.83 |
| 2026-06-01 00:00 |
10:21:21.60 |
+18:44:17.6 |
HIP 50848 |
32.99 |
| 2026-06-01 12:00 |
10:21:30.96 |
+18:43:12.8 |
HIP 50848 |
32.30 |
| 2026-06-02 00:00 |
10:21:40.49 |
+18:42:07.2 |
HIP 50848 |
31.77 |