| Parameter |
Value |
| Designation |
C/2004 U1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-12-08T18:11:10.507200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:44Z |
| Obs used |
545 |
| NEO |
- |
| M1 |
9.000 |
| K1 |
7.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2005-01-05.0000000 |
| e |
0.99920444 |
| q (au) |
2.659383 |
| a (au) |
3342.783641 |
| i (deg) |
130.623493 |
| Ω (om, deg) |
112.546364 |
| ω (w, deg) |
20.127932 |
| M (ma, deg) |
0.000139 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.689 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.689 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.832 |
| 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 |
20:02:31.19 |
-13:10:30.0 |
HIP 98680 |
28.06 |
| 2026-05-12 12:00 |
20:02:30.01 |
-13:10:30.4 |
HIP 98680 |
28.08 |
| 2026-05-13 00:00 |
20:02:28.80 |
-13:10:30.8 |
HIP 98680 |
28.10 |
| 2026-05-13 12:00 |
20:02:27.56 |
-13:10:31.4 |
HIP 98680 |
28.13 |
| 2026-05-14 00:00 |
20:02:26.30 |
-13:10:32.0 |
HIP 98680 |
28.16 |
| 2026-05-14 12:00 |
20:02:25.02 |
-13:10:32.7 |
HIP 98680 |
28.19 |
| 2026-05-15 00:00 |
20:02:23.72 |
-13:10:33.5 |
HIP 98680 |
28.24 |
| 2026-05-15 12:00 |
20:02:22.39 |
-13:10:34.4 |
HIP 98633 |
28.26 |
| 2026-05-16 00:00 |
20:02:21.04 |
-13:10:35.4 |
HIP 98633 |
28.18 |
| 2026-05-16 12:00 |
20:02:19.67 |
-13:10:36.5 |
HIP 98633 |
28.10 |
| 2026-05-17 00:00 |
20:02:18.27 |
-13:10:37.6 |
HIP 98633 |
28.02 |
| 2026-05-17 12:00 |
20:02:16.86 |
-13:10:38.9 |
HIP 98633 |
27.94 |
| 2026-05-18 00:00 |
20:02:15.42 |
-13:10:40.2 |
HIP 98633 |
27.87 |
| 2026-05-18 12:00 |
20:02:13.95 |
-13:10:41.6 |
HIP 98633 |
27.79 |
| 2026-05-19 00:00 |
20:02:12.47 |
-13:10:43.1 |
HIP 98633 |
27.72 |
| 2026-05-19 12:00 |
20:02:10.96 |
-13:10:44.7 |
HIP 98633 |
27.65 |
| 2026-05-20 00:00 |
20:02:09.43 |
-13:10:46.4 |
HIP 98633 |
27.59 |
| 2026-05-20 12:00 |
20:02:07.88 |
-13:10:48.2 |
HIP 98633 |
27.52 |
| 2026-05-21 00:00 |
20:02:06.31 |
-13:10:50.0 |
HIP 98633 |
27.46 |
| 2026-05-21 12:00 |
20:02:04.71 |
-13:10:52.0 |
HIP 98633 |
27.41 |
| 2026-05-22 00:00 |
20:02:03.09 |
-13:10:54.0 |
HIP 98633 |
27.36 |
| 2026-05-22 12:00 |
20:02:01.46 |
-13:10:56.2 |
HIP 98633 |
27.31 |
| 2026-05-23 00:00 |
20:01:59.80 |
-13:10:58.4 |
HIP 98633 |
27.26 |
| 2026-05-23 12:00 |
20:01:58.12 |
-13:11:00.7 |
HIP 98463 |
27.18 |
| 2026-05-24 00:00 |
20:01:56.41 |
-13:11:03.1 |
HIP 98463 |
26.83 |
| 2026-05-24 12:00 |
20:01:54.69 |
-13:11:05.5 |
HIP 98463 |
26.46 |
| 2026-05-25 00:00 |
20:01:52.95 |
-13:11:08.1 |
HIP 98463 |
26.10 |
| 2026-05-25 12:00 |
20:01:51.18 |
-13:11:10.8 |
HIP 98463 |
25.73 |
| 2026-05-26 00:00 |
20:01:49.40 |
-13:11:13.5 |
HIP 98463 |
25.37 |
| 2026-05-26 12:00 |
20:01:47.60 |
-13:11:16.3 |
HIP 98463 |
25.00 |
| 2026-05-27 00:00 |
20:01:45.77 |
-13:11:19.2 |
HIP 98463 |
24.63 |
| 2026-05-27 12:00 |
20:01:43.92 |
-13:11:22.2 |
HIP 98463 |
24.26 |
| 2026-05-28 00:00 |
20:01:42.06 |
-13:11:25.3 |
HIP 98463 |
23.89 |
| 2026-05-28 12:00 |
20:01:40.17 |
-13:11:28.5 |
HIP 98463 |
23.51 |
| 2026-05-29 00:00 |
20:01:38.27 |
-13:11:31.7 |
HIP 98463 |
23.14 |
| 2026-05-29 12:00 |
20:01:36.34 |
-13:11:35.1 |
HIP 98463 |
22.77 |
| 2026-05-30 00:00 |
20:01:34.40 |
-13:11:38.5 |
HIP 98463 |
22.40 |
| 2026-05-30 12:00 |
20:01:32.44 |
-13:11:42.0 |
HIP 98463 |
22.03 |
| 2026-05-31 00:00 |
20:01:30.45 |
-13:11:45.7 |
HIP 98463 |
21.66 |
| 2026-05-31 12:00 |
20:01:28.45 |
-13:11:49.3 |
HIP 98463 |
21.29 |
| 2026-06-01 00:00 |
20:01:26.43 |
-13:11:53.1 |
HIP 98463 |
20.92 |
| 2026-06-01 12:00 |
20:01:24.39 |
-13:11:57.0 |
HIP 98463 |
20.56 |
| 2026-06-02 00:00 |
20:01:22.33 |
-13:12:00.9 |
HIP 98463 |
20.20 |