| 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) |
| 2026-06-01 00:00 |
08:19:20.13 |
+01:37:38.9 |
HIP 40783 |
2.06 |
| 2026-06-01 12:00 |
08:19:23.29 |
+01:37:53.6 |
HIP 40783 |
1.84 |
| 2026-06-02 00:00 |
08:19:26.50 |
+01:38:07.9 |
HIP 40783 |
1.96 |
| 2026-06-02 12:00 |
08:19:29.74 |
+01:38:22.0 |
HIP 40783 |
2.39 |
| 2026-06-03 00:00 |
08:19:33.01 |
+01:38:35.7 |
HIP 40783 |
3.01 |
| 2026-06-03 12:00 |
08:19:36.32 |
+01:38:49.2 |
HIP 40783 |
3.72 |
| 2026-06-04 00:00 |
08:19:39.67 |
+01:39:02.4 |
HIP 40783 |
4.48 |
| 2026-06-04 12:00 |
08:19:43.05 |
+01:39:15.3 |
HIP 40783 |
5.28 |
| 2026-06-05 00:00 |
08:19:46.46 |
+01:39:27.9 |
HIP 40783 |
6.11 |
| 2026-06-05 12:00 |
08:19:49.91 |
+01:39:40.2 |
HIP 40783 |
6.95 |
| 2026-06-06 00:00 |
08:19:53.40 |
+01:39:52.2 |
HIP 40783 |
7.81 |
| 2026-06-06 12:00 |
08:19:56.92 |
+01:40:03.9 |
HIP 40783 |
8.68 |
| 2026-06-07 00:00 |
08:20:00.47 |
+01:40:15.4 |
HIP 40783 |
9.56 |
| 2026-06-07 12:00 |
08:20:04.05 |
+01:40:26.5 |
HIP 40783 |
10.45 |
| 2026-06-08 00:00 |
08:20:07.67 |
+01:40:37.4 |
HIP 40783 |
11.35 |
| 2026-06-08 12:00 |
08:20:11.32 |
+01:40:47.9 |
HIP 40783 |
12.26 |
| 2026-06-09 00:00 |
08:20:15.00 |
+01:40:58.2 |
HIP 40783 |
13.18 |
| 2026-06-09 12:00 |
08:20:18.71 |
+01:41:08.2 |
HIP 40783 |
14.10 |
| 2026-06-10 00:00 |
08:20:22.46 |
+01:41:17.9 |
HIP 40783 |
15.04 |
| 2026-06-10 12:00 |
08:20:26.24 |
+01:41:27.3 |
HIP 40783 |
15.98 |
| 2026-06-11 00:00 |
08:20:30.05 |
+01:41:36.4 |
HIP 40783 |
16.93 |
| 2026-06-11 12:00 |
08:20:33.89 |
+01:41:45.2 |
HIP 40783 |
17.89 |
| 2026-06-12 00:00 |
08:20:37.76 |
+01:41:53.7 |
HIP 40903 |
18.79 |
| 2026-06-12 12:00 |
08:20:41.66 |
+01:42:01.9 |
HIP 40903 |
18.82 |
| 2026-06-13 00:00 |
08:20:45.59 |
+01:42:09.8 |
HIP 40903 |
18.89 |
| 2026-06-13 12:00 |
08:20:49.55 |
+01:42:17.5 |
HIP 40903 |
19.01 |
| 2026-06-14 00:00 |
08:20:53.54 |
+01:42:24.8 |
HIP 40903 |
19.18 |
| 2026-06-14 12:00 |
08:20:57.56 |
+01:42:31.9 |
HIP 40903 |
19.39 |
| 2026-06-15 00:00 |
08:21:01.60 |
+01:42:38.6 |
HIP 40903 |
19.65 |
| 2026-06-15 12:00 |
08:21:05.68 |
+01:42:45.1 |
HIP 40903 |
19.96 |
| 2026-06-16 00:00 |
08:21:09.78 |
+01:42:51.3 |
HIP 40903 |
20.31 |
| 2026-06-16 12:00 |
08:21:13.91 |
+01:42:57.2 |
HIP 40903 |
20.70 |
| 2026-06-17 00:00 |
08:21:18.07 |
+01:43:02.7 |
HIP 40903 |
21.14 |
| 2026-06-17 12:00 |
08:21:22.25 |
+01:43:08.0 |
HIP 40903 |
21.61 |
| 2026-06-18 00:00 |
08:21:26.46 |
+01:43:13.1 |
HIP 40903 |
22.12 |
| 2026-06-18 12:00 |
08:21:30.70 |
+01:43:17.8 |
HIP 40903 |
22.67 |
| 2026-06-19 00:00 |
08:21:34.96 |
+01:43:22.2 |
HIP 40903 |
23.25 |
| 2026-06-19 12:00 |
08:21:39.25 |
+01:43:26.4 |
HIP 40903 |
23.87 |
| 2026-06-20 00:00 |
08:21:43.56 |
+01:43:30.2 |
HIP 40903 |
24.52 |
| 2026-06-20 12:00 |
08:21:47.90 |
+01:43:33.8 |
HIP 40903 |
25.19 |
| 2026-06-21 00:00 |
08:21:52.26 |
+01:43:37.1 |
HIP 40903 |
25.90 |
| 2026-06-21 12:00 |
08:21:56.65 |
+01:43:40.1 |
HIP 41012 |
25.69 |
| 2026-06-22 00:00 |
08:22:01.05 |
+01:43:42.8 |
HIP 41012 |
25.51 |