| 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) |
| 2026-05-12 00:00 |
08:39:44.36 |
+66:37:16.4 |
HIP 42160 |
27.87 |
| 2026-05-12 12:00 |
08:39:53.16 |
+66:35:54.5 |
HIP 42160 |
28.03 |
| 2026-05-13 00:00 |
08:40:02.12 |
+66:34:32.7 |
HIP 42160 |
28.29 |
| 2026-05-13 12:00 |
08:40:11.22 |
+66:33:11.0 |
HIP 42160 |
28.65 |
| 2026-05-14 00:00 |
08:40:20.46 |
+66:31:49.3 |
HIP 42160 |
29.12 |
| 2026-05-14 12:00 |
08:40:29.84 |
+66:30:27.7 |
HIP 42593 |
27.77 |
| 2026-05-15 00:00 |
08:40:39.37 |
+66:29:06.2 |
HIP 42593 |
26.36 |
| 2026-05-15 12:00 |
08:40:49.04 |
+66:27:44.8 |
HIP 42593 |
24.97 |
| 2026-05-16 00:00 |
08:40:58.85 |
+66:26:23.4 |
HIP 42593 |
23.63 |
| 2026-05-16 12:00 |
08:41:08.80 |
+66:25:02.2 |
HIP 42593 |
22.33 |
| 2026-05-17 00:00 |
08:41:18.88 |
+66:23:41.0 |
HIP 42593 |
21.09 |
| 2026-05-17 12:00 |
08:41:29.11 |
+66:22:20.0 |
HIP 42593 |
19.92 |
| 2026-05-18 00:00 |
08:41:39.47 |
+66:20:59.0 |
HIP 42593 |
18.84 |
| 2026-05-18 12:00 |
08:41:49.96 |
+66:19:38.2 |
HIP 42593 |
17.86 |
| 2026-05-19 00:00 |
08:42:00.59 |
+66:18:17.4 |
HIP 42593 |
17.01 |
| 2026-05-19 12:00 |
08:42:11.36 |
+66:16:56.8 |
HIP 42593 |
16.31 |
| 2026-05-20 00:00 |
08:42:22.25 |
+66:15:36.3 |
HIP 42593 |
15.77 |
| 2026-05-20 12:00 |
08:42:33.28 |
+66:14:16.0 |
HIP 42593 |
15.42 |
| 2026-05-21 00:00 |
08:42:44.43 |
+66:12:55.8 |
HIP 42593 |
15.28 |
| 2026-05-21 12:00 |
08:42:55.72 |
+66:11:35.7 |
HIP 42593 |
15.35 |
| 2026-05-22 00:00 |
08:43:07.13 |
+66:10:15.8 |
HIP 42593 |
15.64 |
| 2026-05-22 12:00 |
08:43:18.67 |
+66:08:56.0 |
HIP 42593 |
16.13 |
| 2026-05-23 00:00 |
08:43:30.34 |
+66:07:36.4 |
HIP 42593 |
16.80 |
| 2026-05-23 12:00 |
08:43:42.13 |
+66:06:16.9 |
HIP 42593 |
17.65 |
| 2026-05-24 00:00 |
08:43:54.04 |
+66:04:57.6 |
HIP 42593 |
18.64 |
| 2026-05-24 12:00 |
08:44:06.08 |
+66:03:38.4 |
HIP 42593 |
19.76 |
| 2026-05-25 00:00 |
08:44:18.23 |
+66:02:19.4 |
HIP 42593 |
20.99 |
| 2026-05-25 12:00 |
08:44:30.51 |
+66:01:00.6 |
HIP 42593 |
22.31 |
| 2026-05-26 00:00 |
08:44:42.91 |
+65:59:42.0 |
HIP 43185 |
23.02 |
| 2026-05-26 12:00 |
08:44:55.42 |
+65:58:23.5 |
HIP 43185 |
22.79 |
| 2026-05-27 00:00 |
08:45:08.06 |
+65:57:05.2 |
HIP 43185 |
22.68 |
| 2026-05-27 12:00 |
08:45:20.81 |
+65:55:47.1 |
HIP 43185 |
22.71 |
| 2026-05-28 00:00 |
08:45:33.67 |
+65:54:29.2 |
HIP 43185 |
22.88 |
| 2026-05-28 12:00 |
08:45:46.65 |
+65:53:11.5 |
HIP 43185 |
23.18 |
| 2026-05-29 00:00 |
08:45:59.75 |
+65:51:54.0 |
HIP 43185 |
23.62 |
| 2026-05-29 12:00 |
08:46:12.95 |
+65:50:36.7 |
HIP 43094 |
23.42 |
| 2026-05-30 00:00 |
08:46:26.27 |
+65:49:19.6 |
HIP 43094 |
22.04 |
| 2026-05-30 12:00 |
08:46:39.70 |
+65:48:02.7 |
HIP 43094 |
20.73 |
| 2026-05-31 00:00 |
08:46:53.24 |
+65:46:45.9 |
HIP 43094 |
19.52 |
| 2026-05-31 12:00 |
08:47:06.89 |
+65:45:29.5 |
HIP 43094 |
18.44 |
| 2026-06-01 00:00 |
08:47:20.64 |
+65:44:13.2 |
HIP 43094 |
17.50 |
| 2026-06-01 12:00 |
08:47:34.51 |
+65:42:57.1 |
HIP 43094 |
16.74 |
| 2026-06-02 00:00 |
08:47:48.48 |
+65:41:41.3 |
HIP 43094 |
16.17 |