| Parameter |
Value |
| Designation |
C/1999 K2 (Ferris) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1999-04-10T12:51:40.688640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:00Z |
| Obs used |
101 |
| NEO |
- |
| M1 |
7.000 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1999-06-24.0000000 |
| e |
0.96579603 |
| q (au) |
5.290256 |
| a (au) |
154.667896 |
| i (deg) |
82.190925 |
| Ω (om, deg) |
300.318118 |
| ω (w, deg) |
4.570397 |
| M (ma, deg) |
0.038155 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.566 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.566 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.664 |
| k |
0.800 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
08:26:19.87 |
+52:04:09.7 |
HIP 41380 |
9.77 |
| 2026-07-29 12:00 |
08:26:23.90 |
+52:04:00.0 |
HIP 41380 |
9.52 |
| 2026-07-30 00:00 |
08:26:27.93 |
+52:03:50.4 |
HIP 41380 |
9.30 |
| 2026-07-30 12:00 |
08:26:31.96 |
+52:03:41.0 |
HIP 41380 |
9.13 |
| 2026-07-31 00:00 |
08:26:35.99 |
+52:03:31.8 |
HIP 41380 |
9.01 |
| 2026-07-31 12:00 |
08:26:40.01 |
+52:03:22.7 |
HIP 41380 |
8.93 |
| 2026-08-01 00:00 |
08:26:44.03 |
+52:03:13.8 |
HIP 41380 |
8.90 |
| 2026-08-01 12:00 |
08:26:48.05 |
+52:03:05.1 |
HIP 41380 |
8.92 |
| 2026-08-02 00:00 |
08:26:52.06 |
+52:02:56.6 |
HIP 41380 |
8.98 |
| 2026-08-02 12:00 |
08:26:56.08 |
+52:02:48.2 |
HIP 41380 |
9.09 |
| 2026-08-03 00:00 |
08:27:00.08 |
+52:02:40.0 |
HIP 41380 |
9.25 |
| 2026-08-03 12:00 |
08:27:04.09 |
+52:02:32.0 |
HIP 41380 |
9.44 |
| 2026-08-04 00:00 |
08:27:08.09 |
+52:02:24.2 |
HIP 41380 |
9.68 |
| 2026-08-04 12:00 |
08:27:12.09 |
+52:02:16.5 |
HIP 41380 |
9.95 |
| 2026-08-05 00:00 |
08:27:16.08 |
+52:02:09.0 |
HIP 41380 |
10.26 |
| 2026-08-05 12:00 |
08:27:20.07 |
+52:02:01.7 |
HIP 41380 |
10.60 |
| 2026-08-06 00:00 |
08:27:24.05 |
+52:01:54.6 |
HIP 41380 |
10.96 |
| 2026-08-06 12:00 |
08:27:28.02 |
+52:01:47.6 |
HIP 41380 |
11.35 |
| 2026-08-07 00:00 |
08:27:32.00 |
+52:01:40.9 |
HIP 41380 |
11.75 |
| 2026-08-07 12:00 |
08:27:35.96 |
+52:01:34.3 |
HIP 41380 |
12.18 |
| 2026-08-08 00:00 |
08:27:39.92 |
+52:01:27.8 |
HIP 41380 |
12.63 |
| 2026-08-08 12:00 |
08:27:43.87 |
+52:01:21.6 |
HIP 41380 |
13.09 |
| 2026-08-09 00:00 |
08:27:47.82 |
+52:01:15.5 |
HIP 41380 |
13.56 |
| 2026-08-09 12:00 |
08:27:51.76 |
+52:01:09.7 |
HIP 41380 |
14.04 |
| 2026-08-10 00:00 |
08:27:55.69 |
+52:01:04.0 |
HIP 41380 |
14.54 |
| 2026-08-10 12:00 |
08:27:59.62 |
+52:00:58.4 |
HIP 41380 |
15.04 |
| 2026-08-11 00:00 |
08:28:03.54 |
+52:00:53.1 |
HIP 41651 |
14.47 |
| 2026-08-11 12:00 |
08:28:07.45 |
+52:00:47.9 |
HIP 41651 |
13.89 |
| 2026-08-12 00:00 |
08:28:11.35 |
+52:00:43.0 |
HIP 41651 |
13.31 |
| 2026-08-12 12:00 |
08:28:15.24 |
+52:00:38.2 |
HIP 41651 |
12.74 |
| 2026-08-13 00:00 |
08:28:19.12 |
+52:00:33.5 |
HIP 41651 |
12.17 |
| 2026-08-13 12:00 |
08:28:23.00 |
+52:00:29.1 |
HIP 41651 |
11.61 |
| 2026-08-14 00:00 |
08:28:26.87 |
+52:00:24.9 |
HIP 41651 |
11.05 |
| 2026-08-14 12:00 |
08:28:30.72 |
+52:00:20.8 |
HIP 41651 |
10.50 |
| 2026-08-15 00:00 |
08:28:34.57 |
+52:00:16.9 |
HIP 41651 |
9.95 |
| 2026-08-15 12:00 |
08:28:38.40 |
+52:00:13.2 |
HIP 41651 |
9.40 |
| 2026-08-16 00:00 |
08:28:42.23 |
+52:00:09.7 |
HIP 41651 |
8.87 |
| 2026-08-16 12:00 |
08:28:46.04 |
+52:00:06.4 |
HIP 41651 |
8.34 |
| 2026-08-17 00:00 |
08:28:49.85 |
+52:00:03.2 |
HIP 41651 |
7.82 |
| 2026-08-17 12:00 |
08:28:53.64 |
+52:00:00.3 |
HIP 41651 |
7.31 |
| 2026-08-18 00:00 |
08:28:57.42 |
+51:59:57.5 |
HIP 41651 |
6.81 |
| 2026-08-18 12:00 |
08:29:01.19 |
+51:59:54.9 |
HIP 41651 |
6.33 |
| 2026-08-19 00:00 |
08:29:04.95 |
+51:59:52.5 |
HIP 41651 |
5.86 |