| Parameter |
Value |
| Designation |
C/1999 H3 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1999-08-18T05:16:31.920960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:59Z |
| Obs used |
847 |
| NEO |
- |
| M1 |
10.300 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2000-02-08.0000000 |
| e |
1.00296415 |
| q (au) |
3.500834 |
| a (au) |
-1181.056590 |
| i (deg) |
115.837319 |
| Ω (om, deg) |
332.729392 |
| ω (w, deg) |
101.910427 |
| M (ma, deg) |
0.004220 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.669 + 4.197\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.669 |
| n |
4.197 |
| gf |
0.894 |
| gb |
-0.935 |
| k |
1.000 |
| δ90 |
1.000 |
| 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 |
06:27:26.82 |
-33:58:51.1 |
HIP 30658 |
14.46 |
| 2026-05-12 12:00 |
06:27:28.75 |
-33:58:30.5 |
HIP 30658 |
14.56 |
| 2026-05-13 00:00 |
06:27:30.70 |
-33:58:10.1 |
HIP 30658 |
14.67 |
| 2026-05-13 12:00 |
06:27:32.67 |
-33:57:49.8 |
HIP 30658 |
14.81 |
| 2026-05-14 00:00 |
06:27:34.65 |
-33:57:29.8 |
HIP 30658 |
14.98 |
| 2026-05-14 12:00 |
06:27:36.65 |
-33:57:10.0 |
HIP 30658 |
15.16 |
| 2026-05-15 00:00 |
06:27:38.67 |
-33:56:50.3 |
HIP 30658 |
15.36 |
| 2026-05-15 12:00 |
06:27:40.70 |
-33:56:30.9 |
HIP 30658 |
15.59 |
| 2026-05-16 00:00 |
06:27:42.75 |
-33:56:11.7 |
HIP 30658 |
15.83 |
| 2026-05-16 12:00 |
06:27:44.82 |
-33:55:52.6 |
HIP 30658 |
16.09 |
| 2026-05-17 00:00 |
06:27:46.90 |
-33:55:33.8 |
HIP 30658 |
16.37 |
| 2026-05-17 12:00 |
06:27:49.00 |
-33:55:15.2 |
HIP 30658 |
16.67 |
| 2026-05-18 00:00 |
06:27:51.12 |
-33:54:56.8 |
HIP 30658 |
16.98 |
| 2026-05-18 12:00 |
06:27:53.25 |
-33:54:38.7 |
HIP 30658 |
17.31 |
| 2026-05-19 00:00 |
06:27:55.39 |
-33:54:20.7 |
HIP 30658 |
17.65 |
| 2026-05-19 12:00 |
06:27:57.55 |
-33:54:02.9 |
HIP 30658 |
18.01 |
| 2026-05-20 00:00 |
06:27:59.73 |
-33:53:45.4 |
HIP 30658 |
18.37 |
| 2026-05-20 12:00 |
06:28:01.92 |
-33:53:28.1 |
HIP 30658 |
18.75 |
| 2026-05-21 00:00 |
06:28:04.12 |
-33:53:11.0 |
HIP 30658 |
19.15 |
| 2026-05-21 12:00 |
06:28:06.34 |
-33:52:54.1 |
HIP 30658 |
19.55 |
| 2026-05-22 00:00 |
06:28:08.57 |
-33:52:37.4 |
HIP 30658 |
19.96 |
| 2026-05-22 12:00 |
06:28:10.82 |
-33:52:21.0 |
HIP 30658 |
20.38 |
| 2026-05-23 00:00 |
06:28:13.08 |
-33:52:04.7 |
HIP 30929 |
20.59 |
| 2026-05-23 12:00 |
06:28:15.35 |
-33:51:48.7 |
HIP 30929 |
20.42 |
| 2026-05-24 00:00 |
06:28:17.64 |
-33:51:33.0 |
HIP 30929 |
20.25 |
| 2026-05-24 12:00 |
06:28:19.94 |
-33:51:17.4 |
HIP 30929 |
20.10 |
| 2026-05-25 00:00 |
06:28:22.26 |
-33:51:02.1 |
HIP 30929 |
19.95 |
| 2026-05-25 12:00 |
06:28:24.58 |
-33:50:47.0 |
HIP 30929 |
19.82 |
| 2026-05-26 00:00 |
06:28:26.92 |
-33:50:32.1 |
HIP 30929 |
19.69 |
| 2026-05-26 12:00 |
06:28:29.27 |
-33:50:17.4 |
HIP 30929 |
19.57 |
| 2026-05-27 00:00 |
06:28:31.64 |
-33:50:03.0 |
HIP 30929 |
19.46 |
| 2026-05-27 12:00 |
06:28:34.01 |
-33:49:48.8 |
HIP 30929 |
19.37 |
| 2026-05-28 00:00 |
06:28:36.40 |
-33:49:34.9 |
HIP 30929 |
19.28 |
| 2026-05-28 12:00 |
06:28:38.80 |
-33:49:21.1 |
HIP 30929 |
19.20 |
| 2026-05-29 00:00 |
06:28:41.22 |
-33:49:07.6 |
HIP 30929 |
19.14 |
| 2026-05-29 12:00 |
06:28:43.64 |
-33:48:54.4 |
HIP 30929 |
19.08 |
| 2026-05-30 00:00 |
06:28:46.07 |
-33:48:41.3 |
HIP 30929 |
19.04 |
| 2026-05-30 12:00 |
06:28:48.52 |
-33:48:28.5 |
HIP 30929 |
19.01 |
| 2026-05-31 00:00 |
06:28:50.98 |
-33:48:15.9 |
HIP 30929 |
18.99 |
| 2026-05-31 12:00 |
06:28:53.45 |
-33:48:03.6 |
HIP 30929 |
18.98 |
| 2026-06-01 00:00 |
06:28:55.92 |
-33:47:51.5 |
HIP 30929 |
18.98 |
| 2026-06-01 12:00 |
06:28:58.41 |
-33:47:39.6 |
HIP 30929 |
18.99 |
| 2026-06-02 00:00 |
06:29:00.91 |
-33:47:28.0 |
HIP 30929 |
19.02 |