| Parameter |
Value |
| Designation |
C/2017 D3 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-04-26T17:48:37.664640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:30Z |
| Obs used |
523 |
| NEO |
- |
| M1 |
11.100 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-10-06.0000000 |
| e |
1.00243639 |
| q (au) |
4.971286 |
| a (au) |
-2040.429612 |
| i (deg) |
125.570039 |
| Ω (om, deg) |
186.618173 |
| ω (w, deg) |
340.767499 |
| M (ma, deg) |
0.001735 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.067 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.067 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.999 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
03:26:32.62 |
+73:16:45.7 |
HIP 15983 |
5.30 |
| 2026-03-26 12:00 |
03:26:43.08 |
+73:15:51.7 |
HIP 15983 |
5.14 |
| 2026-03-27 00:00 |
03:26:53.65 |
+73:14:58.3 |
HIP 15983 |
5.25 |
| 2026-03-27 12:00 |
03:27:04.31 |
+73:14:05.4 |
HIP 15983 |
5.62 |
| 2026-03-28 00:00 |
03:27:15.07 |
+73:13:12.9 |
HIP 15983 |
6.21 |
| 2026-03-28 12:00 |
03:27:25.93 |
+73:12:21.0 |
HIP 15983 |
6.95 |
| 2026-03-29 00:00 |
03:27:36.88 |
+73:11:29.5 |
HIP 15983 |
7.80 |
| 2026-03-29 12:00 |
03:27:47.92 |
+73:10:38.5 |
HIP 15983 |
8.73 |
| 2026-03-30 00:00 |
03:27:59.05 |
+73:09:48.0 |
HIP 15983 |
9.72 |
| 2026-03-30 12:00 |
03:28:10.28 |
+73:08:58.1 |
HIP 15983 |
10.75 |
| 2026-03-31 00:00 |
03:28:21.60 |
+73:08:08.6 |
HIP 15983 |
11.81 |
| 2026-03-31 12:00 |
03:28:33.00 |
+73:07:19.6 |
HIP 15983 |
12.89 |
| 2026-04-01 00:00 |
03:28:44.49 |
+73:06:31.1 |
HIP 15983 |
13.98 |
| 2026-04-01 12:00 |
03:28:56.08 |
+73:05:43.1 |
HIP 15983 |
15.09 |
| 2026-04-02 00:00 |
03:29:07.74 |
+73:04:55.6 |
HIP 15983 |
16.21 |
| 2026-04-02 12:00 |
03:29:19.49 |
+73:04:08.6 |
HIP 15983 |
17.33 |
| 2026-04-03 00:00 |
03:29:31.33 |
+73:03:22.1 |
HIP 15983 |
18.47 |
| 2026-04-03 12:00 |
03:29:43.25 |
+73:02:36.1 |
HIP 15983 |
19.60 |
| 2026-04-04 00:00 |
03:29:55.25 |
+73:01:50.6 |
HIP 15983 |
20.74 |
| 2026-04-04 12:00 |
03:30:07.33 |
+73:01:05.6 |
HIP 15983 |
21.89 |
| 2026-04-05 00:00 |
03:30:19.50 |
+73:00:21.1 |
HIP 15983 |
23.03 |
| 2026-04-05 12:00 |
03:30:31.74 |
+72:59:37.1 |
HIP 15983 |
24.18 |
| 2026-04-06 00:00 |
03:30:44.06 |
+72:58:53.6 |
HIP 15983 |
25.33 |
| 2026-04-06 12:00 |
03:30:56.46 |
+72:58:10.6 |
HIP 15983 |
26.48 |
| 2026-04-07 00:00 |
03:31:08.93 |
+72:57:28.2 |
HIP 15983 |
27.64 |
| 2026-04-07 12:00 |
03:31:21.48 |
+72:56:46.2 |
HIP 16887 |
27.36 |
| 2026-04-08 00:00 |
03:31:34.11 |
+72:56:04.7 |
HIP 16887 |
26.72 |
| 2026-04-08 12:00 |
03:31:46.81 |
+72:55:23.8 |
HIP 16887 |
26.10 |
| 2026-04-09 00:00 |
03:31:59.58 |
+72:54:43.4 |
HIP 16887 |
25.51 |
| 2026-04-09 12:00 |
03:32:12.42 |
+72:54:03.4 |
HIP 16887 |
24.94 |
| 2026-04-10 00:00 |
03:32:25.34 |
+72:53:24.0 |
HIP 16887 |
24.41 |
| 2026-04-10 12:00 |
03:32:38.32 |
+72:52:45.1 |
HIP 16887 |
23.91 |
| 2026-04-11 00:00 |
03:32:51.38 |
+72:52:06.7 |
HIP 16887 |
23.45 |
| 2026-04-11 12:00 |
03:33:04.50 |
+72:51:28.9 |
HIP 16887 |
23.02 |
| 2026-04-12 00:00 |
03:33:17.69 |
+72:50:51.5 |
HIP 16887 |
22.64 |
| 2026-04-12 12:00 |
03:33:30.95 |
+72:50:14.7 |
HIP 16887 |
22.30 |
| 2026-04-13 00:00 |
03:33:44.27 |
+72:49:38.3 |
HIP 16887 |
22.00 |
| 2026-04-13 12:00 |
03:33:57.66 |
+72:49:02.5 |
HIP 16887 |
21.75 |
| 2026-04-14 00:00 |
03:34:11.11 |
+72:48:27.2 |
HIP 16887 |
21.54 |
| 2026-04-14 12:00 |
03:34:24.62 |
+72:47:52.5 |
HIP 16887 |
21.39 |
| 2026-04-15 00:00 |
03:34:38.19 |
+72:47:18.2 |
HIP 16887 |
21.29 |
| 2026-04-15 12:00 |
03:34:51.83 |
+72:46:44.5 |
HIP 16887 |
21.23 |
| 2026-04-16 00:00 |
03:35:05.52 |
+72:46:11.2 |
HIP 16887 |
21.23 |