| Parameter |
Value |
| Designation |
C/2001 G1 (LONEOS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2001-10-09T05:10:18.793920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:08Z |
| Obs used |
134 |
| NEO |
- |
| M1 |
9.800 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2002-01-12.0000000 |
| e |
1.00280088 |
| q (au) |
8.235531 |
| a (au) |
-2940.336115 |
| i (deg) |
45.364449 |
| Ω (om, deg) |
203.891133 |
| ω (w, deg) |
343.281547 |
| M (ma, deg) |
0.000586 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.467 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.467 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.506 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2002-04-04 |
2004-05-28 |
-40.2814 |
+37.563 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
20:44:09.47 |
+25:03:53.3 |
HIP 102388 |
15.75 |
| 2026-03-26 12:00 |
20:44:11.49 |
+25:04:22.3 |
HIP 102388 |
15.09 |
| 2026-03-27 00:00 |
20:44:13.50 |
+25:04:51.5 |
HIP 102388 |
14.42 |
| 2026-03-27 12:00 |
20:44:15.48 |
+25:05:20.7 |
HIP 102388 |
13.76 |
| 2026-03-28 00:00 |
20:44:17.44 |
+25:05:49.9 |
HIP 102388 |
13.11 |
| 2026-03-28 12:00 |
20:44:19.38 |
+25:06:19.3 |
HIP 102388 |
12.45 |
| 2026-03-29 00:00 |
20:44:21.29 |
+25:06:48.7 |
HIP 102388 |
11.80 |
| 2026-03-29 12:00 |
20:44:23.19 |
+25:07:18.2 |
HIP 102388 |
11.15 |
| 2026-03-30 00:00 |
20:44:25.06 |
+25:07:47.8 |
HIP 102388 |
10.50 |
| 2026-03-30 12:00 |
20:44:26.91 |
+25:08:17.4 |
HIP 102388 |
9.86 |
| 2026-03-31 00:00 |
20:44:28.74 |
+25:08:47.1 |
HIP 102388 |
9.21 |
| 2026-03-31 12:00 |
20:44:30.54 |
+25:09:16.8 |
HIP 102388 |
8.57 |
| 2026-04-01 00:00 |
20:44:32.32 |
+25:09:46.6 |
HIP 102388 |
7.93 |
| 2026-04-01 12:00 |
20:44:34.08 |
+25:10:16.5 |
HIP 102388 |
7.30 |
| 2026-04-02 00:00 |
20:44:35.82 |
+25:10:46.4 |
HIP 102388 |
6.66 |
| 2026-04-02 12:00 |
20:44:37.53 |
+25:11:16.4 |
HIP 102388 |
6.03 |
| 2026-04-03 00:00 |
20:44:39.23 |
+25:11:46.5 |
HIP 102388 |
5.40 |
| 2026-04-03 12:00 |
20:44:40.89 |
+25:12:16.5 |
HIP 102388 |
4.78 |
| 2026-04-04 00:00 |
20:44:42.54 |
+25:12:46.7 |
HIP 102388 |
4.15 |
| 2026-04-04 12:00 |
20:44:44.16 |
+25:13:16.9 |
HIP 102388 |
3.53 |
| 2026-04-05 00:00 |
20:44:45.76 |
+25:13:47.1 |
HIP 102388 |
2.91 |
| 2026-04-05 12:00 |
20:44:47.33 |
+25:14:17.4 |
HIP 102388 |
2.30 |
| 2026-04-06 00:00 |
20:44:48.88 |
+25:14:47.7 |
HIP 102388 |
1.68 |
| 2026-04-06 12:00 |
20:44:50.41 |
+25:15:18.0 |
HIP 102388 |
1.07 |
| 2026-04-07 00:00 |
20:44:51.92 |
+25:15:48.4 |
HIP 102388 |
0.48 |
| 2026-04-07 12:00 |
20:44:53.40 |
+25:16:18.8 |
HIP 102388 |
0.20 |
| 2026-04-08 00:00 |
20:44:54.85 |
+25:16:49.3 |
HIP 102388 |
0.77 |
| 2026-04-08 12:00 |
20:44:56.28 |
+25:17:19.8 |
HIP 102388 |
1.36 |
| 2026-04-09 00:00 |
20:44:57.69 |
+25:17:50.3 |
HIP 102388 |
1.96 |
| 2026-04-09 12:00 |
20:44:59.08 |
+25:18:20.8 |
HIP 102388 |
2.56 |
| 2026-04-10 00:00 |
20:45:00.44 |
+25:18:51.4 |
HIP 102388 |
3.15 |
| 2026-04-10 12:00 |
20:45:01.77 |
+25:19:21.9 |
HIP 102388 |
3.74 |
| 2026-04-11 00:00 |
20:45:03.08 |
+25:19:52.6 |
HIP 102388 |
4.33 |
| 2026-04-11 12:00 |
20:45:04.37 |
+25:20:23.2 |
HIP 102388 |
4.92 |
| 2026-04-12 00:00 |
20:45:05.63 |
+25:20:53.8 |
HIP 102388 |
5.50 |
| 2026-04-12 12:00 |
20:45:06.87 |
+25:21:24.5 |
HIP 102388 |
6.08 |
| 2026-04-13 00:00 |
20:45:08.08 |
+25:21:55.1 |
HIP 102388 |
6.66 |
| 2026-04-13 12:00 |
20:45:09.27 |
+25:22:25.8 |
HIP 102388 |
7.24 |
| 2026-04-14 00:00 |
20:45:10.43 |
+25:22:56.5 |
HIP 102388 |
7.81 |
| 2026-04-14 12:00 |
20:45:11.57 |
+25:23:27.2 |
HIP 102388 |
8.38 |
| 2026-04-15 00:00 |
20:45:12.68 |
+25:23:57.8 |
HIP 102388 |
8.95 |
| 2026-04-15 12:00 |
20:45:13.77 |
+25:24:28.5 |
HIP 102388 |
9.51 |
| 2026-04-16 00:00 |
20:45:14.83 |
+25:24:59.2 |
HIP 102388 |
10.08 |