| 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) |
| 2026-06-01 00:00 |
15:31:18.26 |
-58:42:10.5 |
HIP 75863 |
14.20 |
| 2026-06-01 12:00 |
15:31:15.64 |
-58:42:03.4 |
HIP 75863 |
13.85 |
| 2026-06-02 00:00 |
15:31:13.03 |
-58:41:56.2 |
HIP 75863 |
13.50 |
| 2026-06-02 12:00 |
15:31:10.43 |
-58:41:48.9 |
HIP 75863 |
13.15 |
| 2026-06-03 00:00 |
15:31:07.84 |
-58:41:41.4 |
HIP 75863 |
12.80 |
| 2026-06-03 12:00 |
15:31:05.25 |
-58:41:33.9 |
HIP 75863 |
12.45 |
| 2026-06-04 00:00 |
15:31:02.67 |
-58:41:26.2 |
HIP 75863 |
12.10 |
| 2026-06-04 12:00 |
15:31:00.10 |
-58:41:18.5 |
HIP 75863 |
11.74 |
| 2026-06-05 00:00 |
15:30:57.54 |
-58:41:10.6 |
HIP 75863 |
11.39 |
| 2026-06-05 12:00 |
15:30:54.98 |
-58:41:02.6 |
HIP 75863 |
11.04 |
| 2026-06-06 00:00 |
15:30:52.43 |
-58:40:54.6 |
HIP 75863 |
10.69 |
| 2026-06-06 12:00 |
15:30:49.89 |
-58:40:46.4 |
HIP 75863 |
10.35 |
| 2026-06-07 00:00 |
15:30:47.36 |
-58:40:38.1 |
HIP 75863 |
10.00 |
| 2026-06-07 12:00 |
15:30:44.84 |
-58:40:29.7 |
HIP 75863 |
9.65 |
| 2026-06-08 00:00 |
15:30:42.32 |
-58:40:21.2 |
HIP 75863 |
9.30 |
| 2026-06-08 12:00 |
15:30:39.82 |
-58:40:12.7 |
HIP 75863 |
8.95 |
| 2026-06-09 00:00 |
15:30:37.33 |
-58:40:04.0 |
HIP 75863 |
8.61 |
| 2026-06-09 12:00 |
15:30:34.84 |
-58:39:55.2 |
HIP 75863 |
8.26 |
| 2026-06-10 00:00 |
15:30:32.36 |
-58:39:46.3 |
HIP 75863 |
7.92 |
| 2026-06-10 12:00 |
15:30:29.90 |
-58:39:37.3 |
HIP 75863 |
7.57 |
| 2026-06-11 00:00 |
15:30:27.44 |
-58:39:28.2 |
HIP 75863 |
7.23 |
| 2026-06-11 12:00 |
15:30:25.00 |
-58:39:19.0 |
HIP 75863 |
6.89 |
| 2026-06-12 00:00 |
15:30:22.56 |
-58:39:09.8 |
HIP 75863 |
6.55 |
| 2026-06-12 12:00 |
15:30:20.14 |
-58:39:00.4 |
HIP 75863 |
6.21 |
| 2026-06-13 00:00 |
15:30:17.72 |
-58:38:50.9 |
HIP 75863 |
5.87 |
| 2026-06-13 12:00 |
15:30:15.32 |
-58:38:41.3 |
HIP 75863 |
5.53 |
| 2026-06-14 00:00 |
15:30:12.93 |
-58:38:31.7 |
HIP 75863 |
5.20 |
| 2026-06-14 12:00 |
15:30:10.55 |
-58:38:21.9 |
HIP 75863 |
4.86 |
| 2026-06-15 00:00 |
15:30:08.18 |
-58:38:12.1 |
HIP 75863 |
4.53 |
| 2026-06-15 12:00 |
15:30:05.82 |
-58:38:02.2 |
HIP 75863 |
4.21 |
| 2026-06-16 00:00 |
15:30:03.48 |
-58:37:52.1 |
HIP 75863 |
3.88 |
| 2026-06-16 12:00 |
15:30:01.15 |
-58:37:42.0 |
HIP 75863 |
3.56 |
| 2026-06-17 00:00 |
15:29:58.83 |
-58:37:31.8 |
HIP 75863 |
3.25 |
| 2026-06-17 12:00 |
15:29:56.52 |
-58:37:21.5 |
HIP 75863 |
2.94 |
| 2026-06-18 00:00 |
15:29:54.22 |
-58:37:11.2 |
HIP 75863 |
2.64 |
| 2026-06-18 12:00 |
15:29:51.94 |
-58:37:00.7 |
HIP 75863 |
2.36 |
| 2026-06-19 00:00 |
15:29:49.67 |
-58:36:50.2 |
HIP 75863 |
2.09 |
| 2026-06-19 12:00 |
15:29:47.42 |
-58:36:39.5 |
HIP 75863 |
1.84 |
| 2026-06-20 00:00 |
15:29:45.18 |
-58:36:28.8 |
HIP 75863 |
1.63 |
| 2026-06-20 12:00 |
15:29:42.95 |
-58:36:18.0 |
HIP 75863 |
1.46 |
| 2026-06-21 00:00 |
15:29:40.74 |
-58:36:07.2 |
HIP 75863 |
1.37 |
| 2026-06-21 12:00 |
15:29:38.53 |
-58:35:56.2 |
HIP 75863 |
1.35 |
| 2026-06-22 00:00 |
15:29:36.35 |
-58:35:45.2 |
HIP 75863 |
1.41 |