| Parameter |
Value |
| Designation |
C/2018 O1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-08-31T13:40:52.855680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:46Z |
| Obs used |
331 |
| NEO |
- |
| M1 |
12.100 |
| K1 |
34.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2018-07-22T13:05:00.960000Z |
| Discovery magnitude (MPC) |
18.70 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-08-03.0000000 |
| e |
0.94409847 |
| q (au) |
1.558174 |
| a (au) |
27.873557 |
| i (deg) |
154.041045 |
| Ω (om, deg) |
87.619000 |
| ω (w, deg) |
162.502789 |
| M (ma, deg) |
359.808651 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.182 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.182 |
| n |
6.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
08:19:18.15 |
+00:26:54.1 |
HIP 40627 |
24.89 |
| 2026-03-26 12:00 |
08:19:14.67 |
+00:27:37.9 |
HIP 40627 |
23.97 |
| 2026-03-27 00:00 |
08:19:11.24 |
+00:28:21.6 |
HIP 40627 |
23.09 |
| 2026-03-27 12:00 |
08:19:07.87 |
+00:29:05.2 |
HIP 40627 |
22.25 |
| 2026-03-28 00:00 |
08:19:04.55 |
+00:29:48.7 |
HIP 40627 |
21.44 |
| 2026-03-28 12:00 |
08:19:01.28 |
+00:30:32.2 |
HIP 40627 |
20.67 |
| 2026-03-29 00:00 |
08:18:58.06 |
+00:31:15.5 |
HIP 40627 |
19.95 |
| 2026-03-29 12:00 |
08:18:54.90 |
+00:31:58.8 |
HIP 40627 |
19.27 |
| 2026-03-30 00:00 |
08:18:51.80 |
+00:32:41.9 |
HIP 40627 |
18.65 |
| 2026-03-30 12:00 |
08:18:48.74 |
+00:33:25.0 |
HIP 40627 |
18.07 |
| 2026-03-31 00:00 |
08:18:45.74 |
+00:34:07.9 |
HIP 40627 |
17.56 |
| 2026-03-31 12:00 |
08:18:42.80 |
+00:34:50.8 |
HIP 40627 |
17.10 |
| 2026-04-01 00:00 |
08:18:39.91 |
+00:35:33.5 |
HIP 40627 |
16.70 |
| 2026-04-01 12:00 |
08:18:37.07 |
+00:36:16.1 |
HIP 40627 |
16.37 |
| 2026-04-02 00:00 |
08:18:34.28 |
+00:36:58.6 |
HIP 40627 |
16.10 |
| 2026-04-02 12:00 |
08:18:31.55 |
+00:37:41.0 |
HIP 40627 |
15.90 |
| 2026-04-03 00:00 |
08:18:28.88 |
+00:38:23.2 |
HIP 40627 |
15.77 |
| 2026-04-03 12:00 |
08:18:26.26 |
+00:39:05.4 |
HIP 40627 |
15.71 |
| 2026-04-04 00:00 |
08:18:23.69 |
+00:39:47.4 |
HIP 40627 |
15.72 |
| 2026-04-04 12:00 |
08:18:21.18 |
+00:40:29.3 |
HIP 40627 |
15.79 |
| 2026-04-05 00:00 |
08:18:18.72 |
+00:41:11.0 |
HIP 40627 |
15.92 |
| 2026-04-05 12:00 |
08:18:16.31 |
+00:41:52.7 |
HIP 40627 |
16.11 |
| 2026-04-06 00:00 |
08:18:13.96 |
+00:42:34.2 |
HIP 40627 |
16.36 |
| 2026-04-06 12:00 |
08:18:11.67 |
+00:43:15.5 |
HIP 40627 |
16.65 |
| 2026-04-07 00:00 |
08:18:09.43 |
+00:43:56.7 |
HIP 40627 |
16.99 |
| 2026-04-07 12:00 |
08:18:07.24 |
+00:44:37.8 |
HIP 40627 |
17.38 |
| 2026-04-08 00:00 |
08:18:05.11 |
+00:45:18.7 |
HIP 40627 |
17.80 |
| 2026-04-08 12:00 |
08:18:03.03 |
+00:45:59.5 |
HIP 40627 |
18.25 |
| 2026-04-09 00:00 |
08:18:01.01 |
+00:46:40.1 |
HIP 40627 |
18.74 |
| 2026-04-09 12:00 |
08:17:59.05 |
+00:47:20.6 |
HIP 40627 |
19.25 |
| 2026-04-10 00:00 |
08:17:57.13 |
+00:48:00.9 |
HIP 40627 |
19.78 |
| 2026-04-10 12:00 |
08:17:55.28 |
+00:48:41.1 |
HIP 40627 |
20.34 |
| 2026-04-11 00:00 |
08:17:53.48 |
+00:49:21.1 |
HIP 40624 |
19.92 |
| 2026-04-11 12:00 |
08:17:51.73 |
+00:50:00.9 |
HIP 40624 |
19.18 |
| 2026-04-12 00:00 |
08:17:50.04 |
+00:50:40.6 |
HIP 40624 |
18.45 |
| 2026-04-12 12:00 |
08:17:48.40 |
+00:51:20.1 |
HIP 40624 |
17.72 |
| 2026-04-13 00:00 |
08:17:46.82 |
+00:51:59.4 |
HIP 40624 |
17.01 |
| 2026-04-13 12:00 |
08:17:45.29 |
+00:52:38.6 |
HIP 40624 |
16.30 |
| 2026-04-14 00:00 |
08:17:43.82 |
+00:53:17.6 |
HIP 40624 |
15.61 |
| 2026-04-14 12:00 |
08:17:42.40 |
+00:53:56.4 |
HIP 40624 |
14.92 |
| 2026-04-15 00:00 |
08:17:41.04 |
+00:54:35.0 |
HIP 40624 |
14.25 |
| 2026-04-15 12:00 |
08:17:39.73 |
+00:55:13.5 |
HIP 40624 |
13.58 |
| 2026-04-16 00:00 |
08:17:38.48 |
+00:55:51.7 |
HIP 40624 |
12.92 |