| 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) |
| 2026-06-01 00:00 |
17:33:01.24 |
-10:32:49.1 |
HIP 85946 |
32.35 |
| 2026-06-01 12:00 |
17:32:57.64 |
-10:32:45.3 |
HIP 85946 |
32.79 |
| 2026-06-02 00:00 |
17:32:54.03 |
-10:32:41.5 |
HIP 85946 |
33.25 |
| 2026-06-02 12:00 |
17:32:50.42 |
-10:32:37.8 |
HIP 85946 |
33.72 |
| 2026-06-03 00:00 |
17:32:46.80 |
-10:32:34.2 |
HIP 85741 |
33.74 |
| 2026-06-03 12:00 |
17:32:43.17 |
-10:32:30.7 |
HIP 85741 |
33.22 |
| 2026-06-04 00:00 |
17:32:39.54 |
-10:32:27.2 |
HIP 85741 |
32.71 |
| 2026-06-04 12:00 |
17:32:35.91 |
-10:32:23.9 |
HIP 85741 |
32.21 |
| 2026-06-05 00:00 |
17:32:32.27 |
-10:32:20.6 |
HIP 85741 |
31.73 |
| 2026-06-05 12:00 |
17:32:28.62 |
-10:32:17.5 |
HIP 85741 |
31.27 |
| 2026-06-06 00:00 |
17:32:24.97 |
-10:32:14.4 |
HIP 85741 |
30.82 |
| 2026-06-06 12:00 |
17:32:21.32 |
-10:32:11.4 |
HIP 85741 |
30.39 |
| 2026-06-07 00:00 |
17:32:17.66 |
-10:32:08.5 |
HIP 85741 |
29.99 |
| 2026-06-07 12:00 |
17:32:14.00 |
-10:32:05.7 |
HIP 85741 |
29.60 |
| 2026-06-08 00:00 |
17:32:10.33 |
-10:32:02.9 |
HIP 85741 |
29.23 |
| 2026-06-08 12:00 |
17:32:06.66 |
-10:32:00.3 |
HIP 85741 |
28.88 |
| 2026-06-09 00:00 |
17:32:02.99 |
-10:31:57.8 |
HIP 85741 |
28.56 |
| 2026-06-09 12:00 |
17:31:59.31 |
-10:31:55.3 |
HIP 85741 |
28.26 |
| 2026-06-10 00:00 |
17:31:55.63 |
-10:31:52.9 |
HIP 85741 |
27.98 |
| 2026-06-10 12:00 |
17:31:51.95 |
-10:31:50.7 |
HIP 85741 |
27.73 |
| 2026-06-11 00:00 |
17:31:48.27 |
-10:31:48.5 |
HIP 85741 |
27.51 |
| 2026-06-11 12:00 |
17:31:44.59 |
-10:31:46.4 |
HIP 85741 |
27.31 |
| 2026-06-12 00:00 |
17:31:40.90 |
-10:31:44.4 |
HIP 85741 |
27.14 |
| 2026-06-12 12:00 |
17:31:37.21 |
-10:31:42.5 |
HIP 85741 |
26.99 |
| 2026-06-13 00:00 |
17:31:33.53 |
-10:31:40.6 |
HIP 85741 |
26.88 |
| 2026-06-13 12:00 |
17:31:29.84 |
-10:31:38.9 |
HIP 85741 |
26.79 |
| 2026-06-14 00:00 |
17:31:26.15 |
-10:31:37.3 |
HIP 85741 |
26.74 |
| 2026-06-14 12:00 |
17:31:22.46 |
-10:31:35.7 |
HIP 85741 |
26.71 |
| 2026-06-15 00:00 |
17:31:18.77 |
-10:31:34.3 |
HIP 85741 |
26.71 |
| 2026-06-15 12:00 |
17:31:15.08 |
-10:31:32.9 |
HIP 85741 |
26.74 |
| 2026-06-16 00:00 |
17:31:11.40 |
-10:31:31.7 |
HIP 85741 |
26.80 |
| 2026-06-16 12:00 |
17:31:07.71 |
-10:31:30.5 |
HIP 85741 |
26.88 |
| 2026-06-17 00:00 |
17:31:04.02 |
-10:31:29.4 |
HIP 85741 |
27.00 |
| 2026-06-17 12:00 |
17:31:00.34 |
-10:31:28.5 |
HIP 85675 |
26.81 |
| 2026-06-18 00:00 |
17:30:56.66 |
-10:31:27.6 |
HIP 85675 |
26.56 |
| 2026-06-18 12:00 |
17:30:52.98 |
-10:31:26.8 |
HIP 85675 |
26.33 |
| 2026-06-19 00:00 |
17:30:49.30 |
-10:31:26.1 |
HIP 85675 |
26.13 |
| 2026-06-19 12:00 |
17:30:45.63 |
-10:31:25.5 |
HIP 85675 |
25.97 |
| 2026-06-20 00:00 |
17:30:41.96 |
-10:31:25.0 |
HIP 85675 |
25.83 |
| 2026-06-20 12:00 |
17:30:38.29 |
-10:31:24.5 |
HIP 85675 |
25.73 |
| 2026-06-21 00:00 |
17:30:34.63 |
-10:31:24.2 |
HIP 85675 |
25.67 |
| 2026-06-21 12:00 |
17:30:30.97 |
-10:31:24.0 |
HIP 85675 |
25.63 |
| 2026-06-22 00:00 |
17:30:27.31 |
-10:31:23.9 |
HIP 85675 |
25.63 |