| Parameter |
Value |
| Designation |
C/2018 S2 (TESS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-11-05T04:38:14.709120Z |
| Orbit solution date (soln_date, UTC) |
2022-08-25T20:42:05Z |
| Obs used |
803 |
| NEO |
- |
| M1 |
6.700 |
| K1 |
11.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2018-09-23T18:44:41.078400Z |
| Discovery magnitude (MPC) |
18.50 G |
| Discovery observatory (MPC) |
C57 · TESS |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-04-11.0000000 |
| e |
0.61491477 |
| q (au) |
5.470619 |
| a (au) |
14.206254 |
| i (deg) |
64.220443 |
| Ω (om, deg) |
85.125919 |
| ω (w, deg) |
290.683496 |
| M (ma, deg) |
356.167772 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.540 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.540 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.935 |
| k |
0.800 |
| 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 |
08:38:39.56 |
+68:35:56.2 |
HIP 42476 |
8.84 |
| 2026-03-26 12:00 |
08:38:31.49 |
+68:34:56.5 |
HIP 42476 |
8.53 |
| 2026-03-27 00:00 |
08:38:23.60 |
+68:33:56.2 |
HIP 42476 |
8.37 |
| 2026-03-27 12:00 |
08:38:15.92 |
+68:32:55.4 |
HIP 42476 |
8.38 |
| 2026-03-28 00:00 |
08:38:08.42 |
+68:31:53.9 |
HIP 42476 |
8.54 |
| 2026-03-28 12:00 |
08:38:01.13 |
+68:30:51.9 |
HIP 42476 |
8.86 |
| 2026-03-29 00:00 |
08:37:54.03 |
+68:29:49.4 |
HIP 42476 |
9.31 |
| 2026-03-29 12:00 |
08:37:47.12 |
+68:28:46.3 |
HIP 42476 |
9.87 |
| 2026-03-30 00:00 |
08:37:40.41 |
+68:27:42.7 |
HIP 42476 |
10.53 |
| 2026-03-30 12:00 |
08:37:33.89 |
+68:26:38.6 |
HIP 42476 |
11.28 |
| 2026-03-31 00:00 |
08:37:27.57 |
+68:25:34.0 |
HIP 42476 |
12.08 |
| 2026-03-31 12:00 |
08:37:21.45 |
+68:24:28.8 |
HIP 42476 |
12.94 |
| 2026-04-01 00:00 |
08:37:15.52 |
+68:23:23.2 |
HIP 42476 |
13.84 |
| 2026-04-01 12:00 |
08:37:09.79 |
+68:22:17.0 |
HIP 42476 |
14.78 |
| 2026-04-02 00:00 |
08:37:04.25 |
+68:21:10.4 |
HIP 42476 |
15.74 |
| 2026-04-02 12:00 |
08:36:58.91 |
+68:20:03.3 |
HIP 42476 |
16.73 |
| 2026-04-03 00:00 |
08:36:53.76 |
+68:18:55.7 |
HIP 42476 |
17.74 |
| 2026-04-03 12:00 |
08:36:48.81 |
+68:17:47.7 |
HIP 42476 |
18.76 |
| 2026-04-04 00:00 |
08:36:44.05 |
+68:16:39.2 |
HIP 42476 |
19.79 |
| 2026-04-04 12:00 |
08:36:39.49 |
+68:15:30.3 |
HIP 42476 |
20.84 |
| 2026-04-05 00:00 |
08:36:35.13 |
+68:14:21.0 |
HIP 42476 |
21.90 |
| 2026-04-05 12:00 |
08:36:30.96 |
+68:13:11.2 |
HIP 42476 |
22.96 |
| 2026-04-06 00:00 |
08:36:26.99 |
+68:12:01.0 |
HIP 42476 |
24.04 |
| 2026-04-06 12:00 |
08:36:23.21 |
+68:10:50.3 |
HIP 42476 |
25.12 |
| 2026-04-07 00:00 |
08:36:19.62 |
+68:09:39.3 |
HIP 42476 |
26.20 |
| 2026-04-07 12:00 |
08:36:16.23 |
+68:08:27.9 |
HIP 42476 |
27.29 |
| 2026-04-08 00:00 |
08:36:13.03 |
+68:07:16.1 |
HIP 42476 |
28.39 |
| 2026-04-08 12:00 |
08:36:10.03 |
+68:06:03.9 |
HIP 42476 |
29.49 |
| 2026-04-09 00:00 |
08:36:07.22 |
+68:04:51.3 |
HIP 42476 |
30.59 |
| 2026-04-09 12:00 |
08:36:04.61 |
+68:03:38.4 |
HIP 42476 |
31.70 |
| 2026-04-10 00:00 |
08:36:02.19 |
+68:02:25.1 |
HIP 42476 |
32.82 |
| 2026-04-10 12:00 |
08:35:59.96 |
+68:01:11.5 |
HIP 42476 |
33.93 |
| 2026-04-11 00:00 |
08:35:57.92 |
+67:59:57.5 |
HIP 42476 |
35.05 |
| 2026-04-11 12:00 |
08:35:56.08 |
+67:58:43.1 |
HIP 42476 |
36.17 |
| 2026-04-12 00:00 |
08:35:54.43 |
+67:57:28.5 |
HIP 42476 |
37.30 |
| 2026-04-12 12:00 |
08:35:52.97 |
+67:56:13.5 |
HIP 42476 |
38.43 |
| 2026-04-13 00:00 |
08:35:51.71 |
+67:54:58.2 |
HIP 42220 |
37.42 |
| 2026-04-13 12:00 |
08:35:50.63 |
+67:53:42.6 |
HIP 42220 |
36.18 |
| 2026-04-14 00:00 |
08:35:49.75 |
+67:52:26.7 |
HIP 42220 |
34.93 |
| 2026-04-14 12:00 |
08:35:49.06 |
+67:51:10.5 |
HIP 42220 |
33.67 |
| 2026-04-15 00:00 |
08:35:48.55 |
+67:49:54.0 |
HIP 42220 |
32.41 |
| 2026-04-15 12:00 |
08:35:48.24 |
+67:48:37.3 |
HIP 42220 |
31.15 |
| 2026-04-16 00:00 |
08:35:48.12 |
+67:47:20.2 |
HIP 42220 |
29.87 |