| Parameter |
Value |
| Designation |
C/1968 L1 (Whitaker-Thomas) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1968-06-04T12:06:59.990400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:17Z |
| Obs used |
23 |
| NEO |
- |
| M1 |
11.900 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1968-07-02.0000000 |
| e |
1.00000000 |
| q (au) |
1.234006 |
| a (au) |
- |
| i (deg) |
61.767368 |
| Ω (om, deg) |
254.716109 |
| ω (w, deg) |
353.977969 |
| M (ma, deg) |
- |
Magnitude
Scatter + Global Linear
$$
M_a = (9.895 + 3.317\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.895 |
| n |
3.317 |
| 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) |
| 2026-03-26 00:00 |
03:53:18.21 |
+38:05:25.4 |
HIP 18240 |
27.75 |
| 2026-03-26 12:00 |
03:53:19.22 |
+38:05:22.1 |
HIP 18240 |
27.73 |
| 2026-03-27 00:00 |
03:53:20.24 |
+38:05:18.8 |
HIP 18240 |
27.72 |
| 2026-03-27 12:00 |
03:53:21.28 |
+38:05:15.6 |
HIP 18240 |
27.71 |
| 2026-03-28 00:00 |
03:53:22.32 |
+38:05:12.4 |
HIP 18240 |
27.70 |
| 2026-03-28 12:00 |
03:53:23.38 |
+38:05:09.3 |
HIP 18240 |
27.68 |
| 2026-03-29 00:00 |
03:53:24.45 |
+38:05:06.3 |
HIP 18240 |
27.67 |
| 2026-03-29 12:00 |
03:53:25.53 |
+38:05:03.3 |
HIP 18240 |
27.66 |
| 2026-03-30 00:00 |
03:53:26.63 |
+38:05:00.4 |
HIP 18240 |
27.65 |
| 2026-03-30 12:00 |
03:53:27.73 |
+38:04:57.5 |
HIP 18240 |
27.63 |
| 2026-03-31 00:00 |
03:53:28.85 |
+38:04:54.7 |
HIP 18240 |
27.62 |
| 2026-03-31 12:00 |
03:53:29.98 |
+38:04:52.0 |
HIP 18358 |
27.49 |
| 2026-04-01 00:00 |
03:53:31.12 |
+38:04:49.4 |
HIP 18358 |
27.32 |
| 2026-04-01 12:00 |
03:53:32.27 |
+38:04:46.8 |
HIP 18358 |
27.15 |
| 2026-04-02 00:00 |
03:53:33.43 |
+38:04:44.2 |
HIP 18358 |
26.97 |
| 2026-04-02 12:00 |
03:53:34.60 |
+38:04:41.8 |
HIP 18358 |
26.80 |
| 2026-04-03 00:00 |
03:53:35.78 |
+38:04:39.4 |
HIP 18358 |
26.62 |
| 2026-04-03 12:00 |
03:53:36.98 |
+38:04:37.0 |
HIP 18358 |
26.45 |
| 2026-04-04 00:00 |
03:53:38.18 |
+38:04:34.8 |
HIP 18358 |
26.27 |
| 2026-04-04 12:00 |
03:53:39.40 |
+38:04:32.5 |
HIP 18358 |
26.09 |
| 2026-04-05 00:00 |
03:53:40.63 |
+38:04:30.4 |
HIP 18358 |
25.91 |
| 2026-04-05 12:00 |
03:53:41.87 |
+38:04:28.3 |
HIP 18358 |
25.72 |
| 2026-04-06 00:00 |
03:53:43.11 |
+38:04:26.3 |
HIP 18358 |
25.54 |
| 2026-04-06 12:00 |
03:53:44.37 |
+38:04:24.3 |
HIP 18358 |
25.35 |
| 2026-04-07 00:00 |
03:53:45.64 |
+38:04:22.4 |
HIP 18358 |
25.17 |
| 2026-04-07 12:00 |
03:53:46.92 |
+38:04:20.6 |
HIP 18358 |
24.98 |
| 2026-04-08 00:00 |
03:53:48.21 |
+38:04:18.9 |
HIP 18358 |
24.79 |
| 2026-04-08 12:00 |
03:53:49.51 |
+38:04:17.2 |
HIP 18358 |
24.60 |
| 2026-04-09 00:00 |
03:53:50.82 |
+38:04:15.5 |
HIP 18358 |
24.41 |
| 2026-04-09 12:00 |
03:53:52.13 |
+38:04:14.0 |
HIP 18358 |
24.22 |
| 2026-04-10 00:00 |
03:53:53.46 |
+38:04:12.5 |
HIP 18358 |
24.03 |
| 2026-04-10 12:00 |
03:53:54.80 |
+38:04:11.0 |
HIP 18358 |
23.83 |
| 2026-04-11 00:00 |
03:53:56.15 |
+38:04:09.7 |
HIP 18358 |
23.64 |
| 2026-04-11 12:00 |
03:53:57.51 |
+38:04:08.3 |
HIP 18358 |
23.45 |
| 2026-04-12 00:00 |
03:53:58.87 |
+38:04:07.1 |
HIP 18358 |
23.25 |
| 2026-04-12 12:00 |
03:54:00.25 |
+38:04:05.9 |
HIP 18358 |
23.05 |
| 2026-04-13 00:00 |
03:54:01.63 |
+38:04:04.8 |
HIP 18358 |
22.86 |
| 2026-04-13 12:00 |
03:54:03.03 |
+38:04:03.8 |
HIP 18358 |
22.66 |
| 2026-04-14 00:00 |
03:54:04.43 |
+38:04:02.8 |
HIP 18358 |
22.46 |
| 2026-04-14 12:00 |
03:54:05.84 |
+38:04:01.9 |
HIP 18358 |
22.27 |
| 2026-04-15 00:00 |
03:54:07.26 |
+38:04:01.0 |
HIP 18358 |
22.07 |
| 2026-04-15 12:00 |
03:54:08.69 |
+38:04:00.2 |
HIP 18358 |
21.87 |
| 2026-04-16 00:00 |
03:54:10.13 |
+38:03:59.5 |
HIP 18358 |
21.67 |