C/2019 K4 (Ye)
| Parameter |
Value |
| Designation |
C/2019 K4 (Ye) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-06-16T10:03:46.733760Z |
| Orbit solution date (soln_date, UTC) |
2021-05-02T23:42:41Z |
| Obs used |
609 |
| NEO |
- |
| M1 |
12.900 |
| K1 |
8.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2019-05-30T11:03:04.003200Z |
| Discovery magnitude (MPC) |
17.14 r |
| Discovery observatory (MPC) |
I41 · Palomar Mountain–ZTF |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-08-25.0000000 |
| e |
0.99906130 |
| q (au) |
2.259417 |
| a (au) |
2406.958686 |
| i (deg) |
105.305274 |
| Ω (om, deg) |
180.165129 |
| ω (w, deg) |
139.772154 |
| M (ma, deg) |
0.000581 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.560 + 5.292\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.560 |
| n |
5.292 |
| gf |
0.999 |
| gb |
-0.735 |
| k |
0.992 |
| 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) |
| 2026-02-03 00:00 |
09:01:16.28 |
-81:37:49.6 |
HIP 45183 |
25.53 |
| 2026-02-03 12:00 |
09:00:36.15 |
-81:37:42.5 |
HIP 45183 |
26.94 |
| 2026-02-04 00:00 |
08:59:56.05 |
-81:37:34.4 |
HIP 45183 |
28.37 |
| 2026-02-04 12:00 |
08:59:15.98 |
-81:37:25.1 |
HIP 44288 |
29.76 |
| 2026-02-05 00:00 |
08:58:35.96 |
-81:37:14.7 |
HIP 44288 |
30.16 |
| 2026-02-05 12:00 |
08:57:56.00 |
-81:37:03.2 |
HIP 44288 |
30.64 |
| 2026-02-06 00:00 |
08:57:16.09 |
-81:36:50.6 |
HIP 44288 |
31.19 |
| 2026-02-06 12:00 |
08:56:36.25 |
-81:36:36.9 |
HIP 44288 |
31.81 |
| 2026-02-07 00:00 |
08:55:56.48 |
-81:36:22.0 |
HIP 44288 |
32.50 |
| 2026-02-07 12:00 |
08:55:16.80 |
-81:36:06.1 |
HIP 44288 |
33.25 |
| 2026-02-08 00:00 |
08:54:37.20 |
-81:35:49.0 |
HIP 43092 |
33.67 |
| 2026-02-08 12:00 |
08:53:57.70 |
-81:35:30.9 |
HIP 43092 |
32.64 |
| 2026-02-09 00:00 |
08:53:18.30 |
-81:35:11.6 |
HIP 43092 |
31.64 |
| 2026-02-09 12:00 |
08:52:39.01 |
-81:34:51.2 |
HIP 43092 |
30.66 |
| 2026-02-10 00:00 |
08:51:59.84 |
-81:34:29.8 |
HIP 43092 |
29.71 |
| 2026-02-10 12:00 |
08:51:20.79 |
-81:34:07.2 |
HIP 43092 |
28.79 |
| 2026-02-11 00:00 |
08:50:41.87 |
-81:33:43.6 |
HIP 43092 |
27.91 |
| 2026-02-11 12:00 |
08:50:03.09 |
-81:33:18.8 |
HIP 43092 |
27.06 |
| 2026-02-12 00:00 |
08:49:24.46 |
-81:32:53.0 |
HIP 43092 |
26.26 |
| 2026-02-12 12:00 |
08:48:45.97 |
-81:32:26.1 |
HIP 43092 |
25.51 |
| 2026-02-13 00:00 |
08:48:07.64 |
-81:31:58.1 |
HIP 43092 |
24.81 |
| 2026-02-13 12:00 |
08:47:29.48 |
-81:31:29.0 |
HIP 43092 |
24.17 |
| 2026-02-14 00:00 |
08:46:51.49 |
-81:30:58.9 |
HIP 43092 |
23.59 |
| 2026-02-14 12:00 |
08:46:13.67 |
-81:30:27.7 |
HIP 43092 |
23.08 |
| 2026-02-15 00:00 |
08:45:36.04 |
-81:29:55.4 |
HIP 43092 |
22.64 |
| 2026-02-15 12:00 |
08:44:58.60 |
-81:29:22.0 |
HIP 43092 |
22.28 |
| 2026-02-16 00:00 |
08:44:21.36 |
-81:28:47.6 |
HIP 43092 |
22.00 |
| 2026-02-16 12:00 |
08:43:44.31 |
-81:28:12.2 |
HIP 43092 |
21.80 |
| 2026-02-17 00:00 |
08:43:07.48 |
-81:27:35.7 |
HIP 43092 |
21.69 |
| 2026-02-17 12:00 |
08:42:30.87 |
-81:26:58.1 |
HIP 43092 |
21.66 |
| 2026-02-18 00:00 |
08:41:54.47 |
-81:26:19.5 |
HIP 43092 |
21.73 |
| 2026-02-18 12:00 |
08:41:18.30 |
-81:25:39.9 |
HIP 43092 |
21.88 |
| 2026-02-19 00:00 |
08:40:42.36 |
-81:24:59.3 |
HIP 43092 |
22.13 |
| 2026-02-19 12:00 |
08:40:06.67 |
-81:24:17.6 |
HIP 43092 |
22.45 |
| 2026-02-20 00:00 |
08:39:31.21 |
-81:23:35.0 |
HIP 43092 |
22.86 |
| 2026-02-20 12:00 |
08:38:56.00 |
-81:22:51.3 |
HIP 43092 |
23.34 |
| 2026-02-21 00:00 |
08:38:21.05 |
-81:22:06.7 |
HIP 43092 |
23.90 |
| 2026-02-21 12:00 |
08:37:46.36 |
-81:21:21.0 |
HIP 43092 |
24.52 |
| 2026-02-22 00:00 |
08:37:11.93 |
-81:20:34.4 |
HIP 43092 |
25.21 |
| 2026-02-22 12:00 |
08:36:37.77 |
-81:19:46.7 |
HIP 42221 |
24.68 |
| 2026-02-23 00:00 |
08:36:03.89 |
-81:18:58.2 |
HIP 42221 |
23.88 |
| 2026-02-23 12:00 |
08:35:30.28 |
-81:18:08.6 |
HIP 42221 |
23.15 |
| 2026-02-24 00:00 |
08:34:56.95 |
-81:17:18.1 |
HIP 42221 |
22.48 |