| 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) |
| 2026-03-26 00:00 |
10:29:38.71 |
+18:15:14.6 |
HIP 51318 |
14.16 |
| 2026-03-26 12:00 |
10:29:22.58 |
+18:16:57.8 |
HIP 51318 |
13.27 |
| 2026-03-27 00:00 |
10:29:06.58 |
+18:18:39.6 |
HIP 51318 |
13.66 |
| 2026-03-27 12:00 |
10:28:50.73 |
+18:20:20.1 |
HIP 51318 |
15.20 |
| 2026-03-28 00:00 |
10:28:35.02 |
+18:21:59.1 |
HIP 51241 |
16.05 |
| 2026-03-28 12:00 |
10:28:19.45 |
+18:23:36.8 |
HIP 51241 |
12.88 |
| 2026-03-29 00:00 |
10:28:04.03 |
+18:25:13.1 |
HIP 51241 |
10.37 |
| 2026-03-29 12:00 |
10:27:48.75 |
+18:26:47.9 |
HIP 51241 |
9.02 |
| 2026-03-30 00:00 |
10:27:33.63 |
+18:28:21.4 |
HIP 51241 |
9.28 |
| 2026-03-30 12:00 |
10:27:18.66 |
+18:29:53.4 |
HIP 51241 |
11.00 |
| 2026-03-31 00:00 |
10:27:03.84 |
+18:31:24.0 |
HIP 51241 |
13.61 |
| 2026-03-31 12:00 |
10:26:49.18 |
+18:32:53.2 |
HIP 51241 |
16.65 |
| 2026-04-01 00:00 |
10:26:34.68 |
+18:34:21.0 |
HIP 51241 |
19.92 |
| 2026-04-01 12:00 |
10:26:20.33 |
+18:35:47.3 |
HIP 51241 |
23.28 |
| 2026-04-02 00:00 |
10:26:06.15 |
+18:37:12.3 |
HIP 51241 |
26.69 |
| 2026-04-02 12:00 |
10:25:52.13 |
+18:38:35.7 |
HIP 50936 |
24.54 |
| 2026-04-03 00:00 |
10:25:38.27 |
+18:39:57.8 |
HIP 50936 |
21.82 |
| 2026-04-03 12:00 |
10:25:24.58 |
+18:41:18.4 |
HIP 50936 |
19.40 |
| 2026-04-04 00:00 |
10:25:11.06 |
+18:42:37.6 |
HIP 50936 |
17.37 |
| 2026-04-04 12:00 |
10:24:57.71 |
+18:43:55.3 |
HIP 50936 |
15.86 |
| 2026-04-05 00:00 |
10:24:44.53 |
+18:45:11.6 |
HIP 50936 |
14.99 |
| 2026-04-05 12:00 |
10:24:31.53 |
+18:46:26.5 |
HIP 50936 |
14.84 |
| 2026-04-06 00:00 |
10:24:18.69 |
+18:47:39.9 |
HIP 50936 |
15.41 |
| 2026-04-06 12:00 |
10:24:06.04 |
+18:48:51.8 |
HIP 50936 |
16.58 |
| 2026-04-07 00:00 |
10:23:53.56 |
+18:50:02.3 |
HIP 50936 |
18.23 |
| 2026-04-07 12:00 |
10:23:41.26 |
+18:51:11.4 |
HIP 50848 |
19.40 |
| 2026-04-08 00:00 |
10:23:29.15 |
+18:52:19.0 |
HIP 50848 |
17.07 |
| 2026-04-08 12:00 |
10:23:17.21 |
+18:53:25.1 |
HIP 50848 |
15.05 |
| 2026-04-09 00:00 |
10:23:05.46 |
+18:54:29.8 |
HIP 50848 |
13.44 |
| 2026-04-09 12:00 |
10:22:53.89 |
+18:55:33.0 |
HIP 50848 |
12.37 |
| 2026-04-10 00:00 |
10:22:42.51 |
+18:56:34.8 |
HIP 50848 |
11.95 |
| 2026-04-10 12:00 |
10:22:31.32 |
+18:57:35.2 |
HIP 50848 |
12.21 |
| 2026-04-11 00:00 |
10:22:20.31 |
+18:58:34.0 |
HIP 50848 |
13.07 |
| 2026-04-11 12:00 |
10:22:09.50 |
+18:59:31.5 |
HIP 50848 |
14.41 |
| 2026-04-12 00:00 |
10:21:58.88 |
+19:00:27.4 |
HIP 50848 |
16.07 |
| 2026-04-12 12:00 |
10:21:48.45 |
+19:01:22.0 |
HIP 50848 |
17.94 |
| 2026-04-13 00:00 |
10:21:38.21 |
+19:02:15.0 |
HIP 50848 |
19.95 |
| 2026-04-13 12:00 |
10:21:28.17 |
+19:03:06.7 |
HIP 50848 |
22.03 |
| 2026-04-14 00:00 |
10:21:18.33 |
+19:03:56.8 |
HIP 50848 |
24.16 |
| 2026-04-14 12:00 |
10:21:08.68 |
+19:04:45.6 |
HIP 50848 |
26.30 |
| 2026-04-15 00:00 |
10:20:59.23 |
+19:05:32.8 |
HIP 50663 |
26.93 |
| 2026-04-15 12:00 |
10:20:49.98 |
+19:06:18.7 |
HIP 50663 |
26.03 |
| 2026-04-16 00:00 |
10:20:40.93 |
+19:07:03.1 |
HIP 50564 |
25.09 |