| Parameter |
Value |
| Designation |
C/1999 K1 (SOHO) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1999-05-21T08:52:48Z |
| Orbit solution date (soln_date, UTC) |
- |
| Obs used |
40 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1999-05-21.3700000 |
| e |
1.00000000 |
| q (au) |
0.005100 |
| a (au) |
- |
| i (deg) |
143.780000 |
| Ω (om, deg) |
5.490000 |
| ω (w, deg) |
83.510000 |
| M (ma, deg) |
- |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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) |
| 2026-09-20 00:00 |
06:53:47.84 |
-12:57:27.1 |
HIP 33119 |
13.74 |
| 2026-09-20 12:00 |
06:53:48.41 |
-12:57:47.0 |
HIP 33119 |
13.40 |
| 2026-09-21 00:00 |
06:53:48.96 |
-12:58:06.9 |
HIP 33119 |
13.06 |
| 2026-09-21 12:00 |
06:53:49.49 |
-12:58:26.9 |
HIP 33119 |
12.72 |
| 2026-09-22 00:00 |
06:53:50.00 |
-12:58:46.9 |
HIP 33119 |
12.38 |
| 2026-09-22 12:00 |
06:53:50.49 |
-12:59:06.9 |
HIP 33119 |
12.04 |
| 2026-09-23 00:00 |
06:53:50.96 |
-12:59:26.9 |
HIP 33119 |
11.71 |
| 2026-09-23 12:00 |
06:53:51.41 |
-12:59:46.9 |
HIP 33119 |
11.37 |
| 2026-09-24 00:00 |
06:53:51.84 |
-13:00:07.0 |
HIP 33119 |
11.04 |
| 2026-09-24 12:00 |
06:53:52.26 |
-13:00:27.0 |
HIP 33119 |
10.70 |
| 2026-09-25 00:00 |
06:53:52.65 |
-13:00:47.1 |
HIP 33119 |
10.37 |
| 2026-09-25 12:00 |
06:53:53.02 |
-13:01:07.2 |
HIP 33119 |
10.03 |
| 2026-09-26 00:00 |
06:53:53.38 |
-13:01:27.3 |
HIP 33119 |
9.70 |
| 2026-09-26 12:00 |
06:53:53.72 |
-13:01:47.5 |
HIP 33119 |
9.37 |
| 2026-09-27 00:00 |
06:53:54.03 |
-13:02:07.6 |
HIP 33119 |
9.04 |
| 2026-09-27 12:00 |
06:53:54.33 |
-13:02:27.8 |
HIP 33119 |
8.71 |
| 2026-09-28 00:00 |
06:53:54.61 |
-13:02:47.9 |
HIP 33119 |
8.37 |
| 2026-09-28 12:00 |
06:53:54.86 |
-13:03:08.1 |
HIP 33119 |
8.04 |
| 2026-09-29 00:00 |
06:53:55.10 |
-13:03:28.2 |
HIP 33119 |
7.71 |
| 2026-09-29 12:00 |
06:53:55.32 |
-13:03:48.4 |
HIP 33119 |
7.39 |
| 2026-09-30 00:00 |
06:53:55.52 |
-13:04:08.6 |
HIP 33119 |
7.06 |
| 2026-09-30 12:00 |
06:53:55.70 |
-13:04:28.7 |
HIP 33119 |
6.73 |
| 2026-10-01 00:00 |
06:53:55.86 |
-13:04:48.9 |
HIP 33119 |
6.40 |
| 2026-10-01 12:00 |
06:53:56.00 |
-13:05:09.1 |
HIP 33119 |
6.07 |
| 2026-10-02 00:00 |
06:53:56.12 |
-13:05:29.2 |
HIP 33119 |
5.75 |
| 2026-10-02 12:00 |
06:53:56.22 |
-13:05:49.4 |
HIP 33119 |
5.42 |
| 2026-10-03 00:00 |
06:53:56.30 |
-13:06:09.5 |
HIP 33119 |
5.09 |
| 2026-10-03 12:00 |
06:53:56.36 |
-13:06:29.7 |
HIP 33119 |
4.77 |
| 2026-10-04 00:00 |
06:53:56.40 |
-13:06:49.8 |
HIP 33119 |
4.44 |
| 2026-10-04 12:00 |
06:53:56.42 |
-13:07:09.9 |
HIP 33119 |
4.12 |
| 2026-10-05 00:00 |
06:53:56.42 |
-13:07:30.0 |
HIP 33119 |
3.79 |
| 2026-10-05 12:00 |
06:53:56.40 |
-13:07:50.1 |
HIP 33119 |
3.47 |
| 2026-10-06 00:00 |
06:53:56.36 |
-13:08:10.2 |
HIP 33119 |
3.15 |
| 2026-10-06 12:00 |
06:53:56.30 |
-13:08:30.3 |
HIP 33119 |
2.83 |
| 2026-10-07 00:00 |
06:53:56.22 |
-13:08:50.3 |
HIP 33119 |
2.51 |
| 2026-10-07 12:00 |
06:53:56.12 |
-13:09:10.4 |
HIP 33119 |
2.20 |
| 2026-10-08 00:00 |
06:53:55.99 |
-13:09:30.4 |
HIP 33119 |
1.89 |
| 2026-10-08 12:00 |
06:53:55.85 |
-13:09:50.3 |
HIP 33119 |
1.59 |
| 2026-10-09 00:00 |
06:53:55.69 |
-13:10:10.3 |
HIP 33119 |
1.30 |
| 2026-10-09 12:00 |
06:53:55.51 |
-13:10:30.2 |
HIP 33119 |
1.04 |
| 2026-10-10 00:00 |
06:53:55.31 |
-13:10:50.1 |
HIP 33119 |
0.83 |
| 2026-10-10 12:00 |
06:53:55.09 |
-13:11:10.0 |
HIP 33119 |
0.71 |
| 2026-10-11 00:00 |
06:53:54.84 |
-13:11:29.8 |
HIP 33119 |
0.74 |