| Parameter |
Value |
| Designation |
C/2007 U1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-08-07T01:09:20.272320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:13Z |
| Obs used |
871 |
| NEO |
- |
| M1 |
10.300 |
| K1 |
7.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-09-04.0000000 |
| e |
1.00142595 |
| q (au) |
3.329202 |
| a (au) |
-2334.730148 |
| i (deg) |
157.786616 |
| Ω (om, deg) |
50.043135 |
| ω (w, deg) |
0.927038 |
| M (ma, deg) |
0.000244 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.191 + 3.897\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.191 |
| n |
3.897 |
| gf |
0.822 |
| gb |
-0.613 |
| k |
0.994 |
| δ90 |
4.869 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2007-10-19 |
2008-02-05 |
+14.6991 |
-8.562 |
| 2008-02-05 |
2008-07-29 |
+6.0207 |
-3.221 |
| 2008-08-07 |
2009-11-18 |
-1.6673 |
+0.718 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
17:24:02.42 |
-10:52:43.0 |
HIP 85041 |
21.51 |
| 2026-09-20 12:00 |
17:24:02.56 |
-10:52:54.7 |
HIP 85041 |
21.65 |
| 2026-09-21 00:00 |
17:24:02.73 |
-10:53:06.4 |
HIP 85041 |
21.80 |
| 2026-09-21 12:00 |
17:24:02.93 |
-10:53:18.1 |
HIP 85041 |
21.96 |
| 2026-09-22 00:00 |
17:24:03.16 |
-10:53:29.9 |
HIP 85041 |
22.12 |
| 2026-09-22 12:00 |
17:24:03.42 |
-10:53:41.6 |
HIP 85041 |
22.28 |
| 2026-09-23 00:00 |
17:24:03.70 |
-10:53:53.4 |
HIP 85041 |
22.46 |
| 2026-09-23 12:00 |
17:24:04.01 |
-10:54:05.1 |
HIP 85041 |
22.64 |
| 2026-09-24 00:00 |
17:24:04.35 |
-10:54:16.9 |
HIP 85041 |
22.82 |
| 2026-09-24 12:00 |
17:24:04.72 |
-10:54:28.7 |
HIP 85041 |
23.02 |
| 2026-09-25 00:00 |
17:24:05.12 |
-10:54:40.5 |
HIP 85041 |
23.21 |
| 2026-09-25 12:00 |
17:24:05.54 |
-10:54:52.2 |
HIP 85041 |
23.42 |
| 2026-09-26 00:00 |
17:24:05.99 |
-10:55:04.0 |
HIP 85041 |
23.63 |
| 2026-09-26 12:00 |
17:24:06.47 |
-10:55:15.8 |
HIP 85041 |
23.84 |
| 2026-09-27 00:00 |
17:24:06.98 |
-10:55:27.6 |
HIP 85041 |
24.06 |
| 2026-09-27 12:00 |
17:24:07.51 |
-10:55:39.4 |
HIP 85041 |
24.29 |
| 2026-09-28 00:00 |
17:24:08.07 |
-10:55:51.1 |
HIP 85041 |
24.52 |
| 2026-09-28 12:00 |
17:24:08.66 |
-10:56:02.9 |
HIP 85041 |
24.75 |
| 2026-09-29 00:00 |
17:24:09.28 |
-10:56:14.7 |
HIP 85041 |
24.99 |
| 2026-09-29 12:00 |
17:24:09.92 |
-10:56:26.5 |
HIP 85041 |
25.24 |
| 2026-09-30 00:00 |
17:24:10.60 |
-10:56:38.2 |
HIP 85041 |
25.49 |
| 2026-09-30 12:00 |
17:24:11.29 |
-10:56:50.0 |
HIP 85041 |
25.75 |
| 2026-10-01 00:00 |
17:24:12.02 |
-10:57:01.8 |
HIP 85041 |
26.01 |
| 2026-10-01 12:00 |
17:24:12.77 |
-10:57:13.5 |
HIP 85041 |
26.28 |
| 2026-10-02 00:00 |
17:24:13.55 |
-10:57:25.3 |
HIP 85041 |
26.55 |
| 2026-10-02 12:00 |
17:24:14.36 |
-10:57:37.0 |
HIP 85041 |
26.83 |
| 2026-10-03 00:00 |
17:24:15.19 |
-10:57:48.8 |
HIP 85041 |
27.11 |
| 2026-10-03 12:00 |
17:24:16.05 |
-10:58:00.5 |
HIP 85041 |
27.40 |
| 2026-10-04 00:00 |
17:24:16.94 |
-10:58:12.2 |
HIP 85041 |
27.69 |
| 2026-10-04 12:00 |
17:24:17.85 |
-10:58:23.9 |
HIP 85041 |
27.99 |
| 2026-10-05 00:00 |
17:24:18.80 |
-10:58:35.6 |
HIP 85041 |
28.29 |
| 2026-10-05 12:00 |
17:24:19.76 |
-10:58:47.3 |
HIP 85041 |
28.60 |
| 2026-10-06 00:00 |
17:24:20.76 |
-10:58:59.0 |
HIP 85331 |
28.62 |
| 2026-10-06 12:00 |
17:24:21.78 |
-10:59:10.6 |
HIP 85331 |
28.36 |
| 2026-10-07 00:00 |
17:24:22.82 |
-10:59:22.3 |
HIP 85331 |
28.10 |
| 2026-10-07 12:00 |
17:24:23.90 |
-10:59:33.9 |
HIP 85331 |
27.84 |
| 2026-10-08 00:00 |
17:24:24.99 |
-10:59:45.5 |
HIP 85331 |
27.57 |
| 2026-10-08 12:00 |
17:24:26.12 |
-10:59:57.1 |
HIP 85331 |
27.30 |
| 2026-10-09 00:00 |
17:24:27.27 |
-11:00:08.7 |
HIP 85331 |
27.02 |
| 2026-10-09 12:00 |
17:24:28.45 |
-11:00:20.3 |
HIP 85331 |
26.73 |
| 2026-10-10 00:00 |
17:24:29.65 |
-11:00:31.8 |
HIP 85331 |
26.45 |
| 2026-10-10 12:00 |
17:24:30.88 |
-11:00:43.3 |
HIP 85331 |
26.15 |
| 2026-10-11 00:00 |
17:24:32.13 |
-11:00:54.8 |
HIP 85331 |
25.85 |