C/1968 Y1 (Thomas)
| Parameter |
Value |
| Designation |
C/1968 Y1 (Thomas) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1969-01-12T06:16:18.609600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:19Z |
| Obs used |
43 |
| NEO |
- |
| M1 |
5.800 |
| K1 |
10.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1969-02-14.0000000 |
| e |
0.99530224 |
| q (au) |
3.316098 |
| a (au) |
705.888695 |
| i (deg) |
45.229346 |
| Ω (om, deg) |
16.110035 |
| ω (w, deg) |
82.582846 |
| M (ma, deg) |
0.001721 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.454 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.454 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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) |
| 2026-02-03 00:00 |
15:37:35.92 |
-58:17:06.3 |
HIP 76623 |
11.03 |
| 2026-02-03 12:00 |
15:37:36.62 |
-58:17:21.6 |
HIP 76623 |
11.05 |
| 2026-02-04 00:00 |
15:37:37.29 |
-58:17:36.9 |
HIP 76623 |
11.08 |
| 2026-02-04 12:00 |
15:37:37.94 |
-58:17:52.2 |
HIP 76623 |
11.12 |
| 2026-02-05 00:00 |
15:37:38.57 |
-58:18:07.4 |
HIP 76623 |
11.17 |
| 2026-02-05 12:00 |
15:37:39.17 |
-58:18:22.7 |
HIP 76623 |
11.22 |
| 2026-02-06 00:00 |
15:37:39.75 |
-58:18:37.9 |
HIP 76623 |
11.29 |
| 2026-02-06 12:00 |
15:37:40.30 |
-58:18:53.1 |
HIP 76623 |
11.36 |
| 2026-02-07 00:00 |
15:37:40.84 |
-58:19:08.3 |
HIP 76623 |
11.45 |
| 2026-02-07 12:00 |
15:37:41.34 |
-58:19:23.5 |
HIP 76623 |
11.54 |
| 2026-02-08 00:00 |
15:37:41.83 |
-58:19:38.7 |
HIP 76623 |
11.63 |
| 2026-02-08 12:00 |
15:37:42.29 |
-58:19:53.9 |
HIP 76623 |
11.74 |
| 2026-02-09 00:00 |
15:37:42.72 |
-58:20:09.1 |
HIP 76623 |
11.85 |
| 2026-02-09 12:00 |
15:37:43.14 |
-58:20:24.2 |
HIP 76623 |
11.97 |
| 2026-02-10 00:00 |
15:37:43.52 |
-58:20:39.3 |
HIP 76623 |
12.10 |
| 2026-02-10 12:00 |
15:37:43.89 |
-58:20:54.4 |
HIP 76623 |
12.23 |
| 2026-02-11 00:00 |
15:37:44.23 |
-58:21:09.5 |
HIP 76623 |
12.37 |
| 2026-02-11 12:00 |
15:37:44.54 |
-58:21:24.5 |
HIP 76623 |
12.51 |
| 2026-02-12 00:00 |
15:37:44.83 |
-58:21:39.6 |
HIP 76623 |
12.66 |
| 2026-02-12 12:00 |
15:37:45.10 |
-58:21:54.6 |
HIP 76623 |
12.81 |
| 2026-02-13 00:00 |
15:37:45.34 |
-58:22:09.5 |
HIP 76623 |
12.97 |
| 2026-02-13 12:00 |
15:37:45.56 |
-58:22:24.5 |
HIP 76623 |
13.13 |
| 2026-02-14 00:00 |
15:37:45.75 |
-58:22:39.4 |
HIP 76623 |
13.30 |
| 2026-02-14 12:00 |
15:37:45.92 |
-58:22:54.3 |
HIP 76623 |
13.48 |
| 2026-02-15 00:00 |
15:37:46.07 |
-58:23:09.2 |
HIP 76623 |
13.65 |
| 2026-02-15 12:00 |
15:37:46.19 |
-58:23:24.0 |
HIP 76623 |
13.83 |
| 2026-02-16 00:00 |
15:37:46.28 |
-58:23:38.8 |
HIP 76623 |
14.02 |
| 2026-02-16 12:00 |
15:37:46.35 |
-58:23:53.6 |
HIP 76623 |
14.20 |
| 2026-02-17 00:00 |
15:37:46.40 |
-58:24:08.3 |
HIP 76623 |
14.39 |
| 2026-02-17 12:00 |
15:37:46.42 |
-58:24:23.0 |
HIP 76623 |
14.59 |
| 2026-02-18 00:00 |
15:37:46.42 |
-58:24:37.6 |
HIP 76623 |
14.78 |
| 2026-02-18 12:00 |
15:37:46.39 |
-58:24:52.3 |
HIP 76623 |
14.98 |
| 2026-02-19 00:00 |
15:37:46.34 |
-58:25:06.8 |
HIP 76623 |
15.19 |
| 2026-02-19 12:00 |
15:37:46.27 |
-58:25:21.4 |
HIP 76623 |
15.39 |
| 2026-02-20 00:00 |
15:37:46.17 |
-58:25:35.9 |
HIP 76623 |
15.60 |
| 2026-02-20 12:00 |
15:37:46.04 |
-58:25:50.3 |
HIP 76623 |
15.81 |
| 2026-02-21 00:00 |
15:37:45.89 |
-58:26:04.7 |
HIP 76623 |
16.02 |
| 2026-02-21 12:00 |
15:37:45.72 |
-58:26:19.1 |
HIP 76623 |
16.23 |
| 2026-02-22 00:00 |
15:37:45.52 |
-58:26:33.4 |
HIP 76623 |
16.45 |
| 2026-02-22 12:00 |
15:37:45.29 |
-58:26:47.7 |
HIP 76623 |
16.66 |
| 2026-02-23 00:00 |
15:37:45.05 |
-58:27:01.9 |
HIP 76623 |
16.88 |
| 2026-02-23 12:00 |
15:37:44.78 |
-58:27:16.1 |
HIP 76623 |
17.10 |
| 2026-02-24 00:00 |
15:37:44.48 |
-58:27:30.2 |
HIP 76623 |
17.32 |