C/2015 F2 (Polonia)
| Parameter |
Value |
| Designation |
C/2015 F2 (Polonia) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-04-28T19:46:02.029440Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:09Z |
| Obs used |
308 |
| NEO |
- |
| M1 |
14.900 |
| K1 |
21.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-05-14.0000000 |
| e |
0.96844230 |
| q (au) |
1.210552 |
| a (au) |
38.359944 |
| i (deg) |
28.693745 |
| Ω (om, deg) |
262.551624 |
| ω (w, deg) |
352.034051 |
| M (ma, deg) |
0.062959 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.056 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.056 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.502 |
| k |
1.000 |
| 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 |
03:10:23.15 |
+31:59:54.3 |
HIP 14784 |
15.01 |
| 2026-02-03 12:00 |
03:10:22.92 |
+31:59:33.3 |
HIP 14784 |
15.35 |
| 2026-02-04 00:00 |
03:10:22.75 |
+31:59:12.5 |
HIP 14784 |
15.68 |
| 2026-02-04 12:00 |
03:10:22.63 |
+31:58:51.8 |
HIP 14784 |
16.01 |
| 2026-02-05 00:00 |
03:10:22.56 |
+31:58:31.2 |
HIP 14784 |
16.33 |
| 2026-02-05 12:00 |
03:10:22.53 |
+31:58:10.9 |
HIP 14784 |
16.64 |
| 2026-02-06 00:00 |
03:10:22.56 |
+31:57:50.7 |
HIP 14784 |
16.95 |
| 2026-02-06 12:00 |
03:10:22.63 |
+31:57:30.7 |
HIP 14784 |
17.26 |
| 2026-02-07 00:00 |
03:10:22.75 |
+31:57:10.9 |
HIP 14784 |
17.56 |
| 2026-02-07 12:00 |
03:10:22.92 |
+31:56:51.3 |
HIP 14784 |
17.85 |
| 2026-02-08 00:00 |
03:10:23.14 |
+31:56:31.8 |
HIP 14784 |
18.14 |
| 2026-02-08 12:00 |
03:10:23.41 |
+31:56:12.5 |
HIP 14784 |
18.42 |
| 2026-02-09 00:00 |
03:10:23.73 |
+31:55:53.4 |
HIP 14784 |
18.70 |
| 2026-02-09 12:00 |
03:10:24.09 |
+31:55:34.5 |
HIP 14784 |
18.98 |
| 2026-02-10 00:00 |
03:10:24.51 |
+31:55:15.8 |
HIP 14784 |
19.25 |
| 2026-02-10 12:00 |
03:10:24.97 |
+31:54:57.3 |
HIP 14784 |
19.51 |
| 2026-02-11 00:00 |
03:10:25.48 |
+31:54:38.9 |
HIP 14784 |
19.77 |
| 2026-02-11 12:00 |
03:10:26.04 |
+31:54:20.7 |
HIP 14784 |
20.03 |
| 2026-02-12 00:00 |
03:10:26.65 |
+31:54:02.8 |
HIP 14784 |
20.28 |
| 2026-02-12 12:00 |
03:10:27.31 |
+31:53:45.0 |
HIP 14784 |
20.53 |
| 2026-02-13 00:00 |
03:10:28.01 |
+31:53:27.4 |
HIP 14784 |
20.78 |
| 2026-02-13 12:00 |
03:10:28.77 |
+31:53:10.0 |
HIP 14784 |
21.02 |
| 2026-02-14 00:00 |
03:10:29.57 |
+31:52:52.8 |
HIP 14784 |
21.26 |
| 2026-02-14 12:00 |
03:10:30.42 |
+31:52:35.8 |
HIP 14784 |
21.50 |
| 2026-02-15 00:00 |
03:10:31.31 |
+31:52:19.0 |
HIP 14784 |
21.73 |
| 2026-02-15 12:00 |
03:10:32.26 |
+31:52:02.3 |
HIP 14784 |
21.96 |
| 2026-02-16 00:00 |
03:10:33.25 |
+31:51:45.9 |
HIP 14784 |
22.19 |
| 2026-02-16 12:00 |
03:10:34.29 |
+31:51:29.7 |
HIP 14784 |
22.42 |
| 2026-02-17 00:00 |
03:10:35.38 |
+31:51:13.7 |
HIP 14784 |
22.65 |
| 2026-02-17 12:00 |
03:10:36.51 |
+31:50:57.9 |
HIP 14784 |
22.87 |
| 2026-02-18 00:00 |
03:10:37.69 |
+31:50:42.2 |
HIP 14784 |
23.09 |
| 2026-02-18 12:00 |
03:10:38.92 |
+31:50:26.8 |
HIP 14784 |
23.32 |
| 2026-02-19 00:00 |
03:10:40.20 |
+31:50:11.6 |
HIP 14784 |
23.54 |
| 2026-02-19 12:00 |
03:10:41.52 |
+31:49:56.6 |
HIP 14784 |
23.76 |
| 2026-02-20 00:00 |
03:10:42.89 |
+31:49:41.8 |
HIP 14784 |
23.98 |
| 2026-02-20 12:00 |
03:10:44.30 |
+31:49:27.2 |
HIP 14784 |
24.20 |
| 2026-02-21 00:00 |
03:10:45.76 |
+31:49:12.8 |
HIP 14784 |
24.42 |
| 2026-02-21 12:00 |
03:10:47.27 |
+31:48:58.6 |
HIP 14784 |
24.64 |
| 2026-02-22 00:00 |
03:10:48.83 |
+31:48:44.6 |
HIP 14784 |
24.86 |
| 2026-02-22 12:00 |
03:10:50.42 |
+31:48:30.9 |
HIP 14784 |
25.08 |
| 2026-02-23 00:00 |
03:10:52.07 |
+31:48:17.3 |
HIP 14784 |
25.30 |
| 2026-02-23 12:00 |
03:10:53.76 |
+31:48:03.9 |
HIP 14784 |
25.53 |
| 2026-02-24 00:00 |
03:10:55.49 |
+31:47:50.8 |
HIP 14784 |
25.75 |