C/1999 H1 (Lee)
| Parameter |
Value |
| Designation |
C/1999 H1 (Lee) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1999-07-11T04:07:54.053760Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:59Z |
| Obs used |
1019 |
| NEO |
- |
| M1 |
9.400 |
| K1 |
11.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1999-08-17.0000000 |
| e |
0.99974475 |
| q (au) |
0.708107 |
| a (au) |
2774.129592 |
| i (deg) |
149.352905 |
| Ω (om, deg) |
162.650897 |
| ω (w, deg) |
40.701567 |
| M (ma, deg) |
0.000248 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.906 + 4.943\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.906 |
| n |
4.943 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.998 |
| 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 |
| 1999-04-16 |
1999-05-14 |
+7.7311 |
-0.623 |
| 1999-05-14 |
1999-07-04 |
-1.8550 |
+0.208 |
| 1999-07-27 |
2000-01-08 |
+0.8828 |
+0.043 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
21:43:35.78 |
-27:33:42.7 |
HIP 107147 |
19.43 |
| 2026-02-03 12:00 |
21:43:38.24 |
-27:33:30.6 |
HIP 107147 |
19.90 |
| 2026-02-04 00:00 |
21:43:40.71 |
-27:33:18.5 |
HIP 107147 |
20.38 |
| 2026-02-04 12:00 |
21:43:43.17 |
-27:33:06.5 |
HIP 107147 |
20.86 |
| 2026-02-05 00:00 |
21:43:45.65 |
-27:32:54.6 |
HIP 107305 |
20.99 |
| 2026-02-05 12:00 |
21:43:48.12 |
-27:32:42.7 |
HIP 107305 |
21.10 |
| 2026-02-06 00:00 |
21:43:50.60 |
-27:32:30.9 |
HIP 107305 |
21.22 |
| 2026-02-06 12:00 |
21:43:53.07 |
-27:32:19.1 |
HIP 107305 |
21.36 |
| 2026-02-07 00:00 |
21:43:55.55 |
-27:32:07.4 |
HIP 107305 |
21.51 |
| 2026-02-07 12:00 |
21:43:58.04 |
-27:31:55.8 |
HIP 107305 |
21.68 |
| 2026-02-08 00:00 |
21:44:00.52 |
-27:31:44.2 |
HIP 107305 |
21.86 |
| 2026-02-08 12:00 |
21:44:03.01 |
-27:31:32.7 |
HIP 107305 |
22.06 |
| 2026-02-09 00:00 |
21:44:05.49 |
-27:31:21.2 |
HIP 107305 |
22.26 |
| 2026-02-09 12:00 |
21:44:07.98 |
-27:31:09.9 |
HIP 107305 |
22.48 |
| 2026-02-10 00:00 |
21:44:10.47 |
-27:30:58.5 |
HIP 107305 |
22.71 |
| 2026-02-10 12:00 |
21:44:12.96 |
-27:30:47.3 |
HIP 107305 |
22.95 |
| 2026-02-11 00:00 |
21:44:15.45 |
-27:30:36.1 |
HIP 107305 |
23.20 |
| 2026-02-11 12:00 |
21:44:17.95 |
-27:30:25.0 |
HIP 107305 |
23.46 |
| 2026-02-12 00:00 |
21:44:20.44 |
-27:30:14.0 |
HIP 107305 |
23.74 |
| 2026-02-12 12:00 |
21:44:22.93 |
-27:30:03.0 |
HIP 107305 |
24.02 |
| 2026-02-13 00:00 |
21:44:25.42 |
-27:29:52.1 |
HIP 107305 |
24.31 |
| 2026-02-13 12:00 |
21:44:27.92 |
-27:29:41.3 |
HIP 107305 |
24.61 |
| 2026-02-14 00:00 |
21:44:30.41 |
-27:29:30.5 |
HIP 107305 |
24.92 |
| 2026-02-14 12:00 |
21:44:32.90 |
-27:29:19.8 |
HIP 107305 |
25.24 |
| 2026-02-15 00:00 |
21:44:35.39 |
-27:29:09.2 |
HIP 107305 |
25.57 |
| 2026-02-15 12:00 |
21:44:37.88 |
-27:28:58.7 |
HIP 107305 |
25.90 |
| 2026-02-16 00:00 |
21:44:40.37 |
-27:28:48.2 |
HIP 107305 |
26.24 |
| 2026-02-16 12:00 |
21:44:42.85 |
-27:28:37.9 |
HIP 107305 |
26.59 |
| 2026-02-17 00:00 |
21:44:45.34 |
-27:28:27.6 |
HIP 107305 |
26.94 |
| 2026-02-17 12:00 |
21:44:47.82 |
-27:28:17.4 |
HIP 107305 |
27.30 |
| 2026-02-18 00:00 |
21:44:50.30 |
-27:28:07.2 |
HIP 107305 |
27.67 |
| 2026-02-18 12:00 |
21:44:52.78 |
-27:27:57.2 |
HIP 107305 |
28.04 |
| 2026-02-19 00:00 |
21:44:55.26 |
-27:27:47.2 |
HIP 107305 |
28.42 |
| 2026-02-19 12:00 |
21:44:57.74 |
-27:27:37.3 |
HIP 107305 |
28.80 |
| 2026-02-20 00:00 |
21:45:00.21 |
-27:27:27.5 |
HIP 107305 |
29.19 |
| 2026-02-20 12:00 |
21:45:02.68 |
-27:27:17.8 |
HIP 107305 |
29.58 |
| 2026-02-21 00:00 |
21:45:05.14 |
-27:27:08.1 |
HIP 107305 |
29.97 |
| 2026-02-21 12:00 |
21:45:07.61 |
-27:26:58.6 |
HIP 107305 |
30.37 |
| 2026-02-22 00:00 |
21:45:10.07 |
-27:26:49.1 |
HIP 107305 |
30.78 |
| 2026-02-22 12:00 |
21:45:12.52 |
-27:26:39.7 |
HIP 107305 |
31.18 |
| 2026-02-23 00:00 |
21:45:14.97 |
-27:26:30.5 |
HIP 107305 |
31.59 |
| 2026-02-23 12:00 |
21:45:17.42 |
-27:26:21.3 |
HIP 107305 |
32.01 |
| 2026-02-24 00:00 |
21:45:19.86 |
-27:26:12.1 |
HIP 107305 |
32.42 |