| Parameter |
Value |
| Designation |
C/2015 C2 (SWAN) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-03-04T13:33:59.673600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:06Z |
| Obs used |
151 |
| NEO |
- |
| M1 |
12.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-04-26.0000000 |
| e |
0.99851030 |
| q (au) |
0.711377 |
| a (au) |
477.531702 |
| i (deg) |
94.501074 |
| Ω (om, deg) |
49.529700 |
| ω (w, deg) |
334.134062 |
| M (ma, deg) |
0.004952 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.217 + 3.643\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.217 |
| n |
3.643 |
| gf |
1.000 |
| gb |
-1.000 |
| 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) |
| 2026-05-12 00:00 |
16:11:32.80 |
+25:26:25.9 |
HIP 79225 |
19.69 |
| 2026-05-12 12:00 |
16:11:28.04 |
+25:26:42.7 |
HIP 79225 |
18.59 |
| 2026-05-13 00:00 |
16:11:23.28 |
+25:26:59.2 |
HIP 79225 |
17.48 |
| 2026-05-13 12:00 |
16:11:18.51 |
+25:27:15.2 |
HIP 79225 |
16.38 |
| 2026-05-14 00:00 |
16:11:13.73 |
+25:27:30.8 |
HIP 79225 |
15.28 |
| 2026-05-14 12:00 |
16:11:08.94 |
+25:27:46.1 |
HIP 79225 |
14.18 |
| 2026-05-15 00:00 |
16:11:04.14 |
+25:28:00.9 |
HIP 79225 |
13.07 |
| 2026-05-15 12:00 |
16:10:59.34 |
+25:28:15.3 |
HIP 79225 |
11.97 |
| 2026-05-16 00:00 |
16:10:54.52 |
+25:28:29.4 |
HIP 79225 |
10.87 |
| 2026-05-16 12:00 |
16:10:49.71 |
+25:28:43.0 |
HIP 79225 |
9.77 |
| 2026-05-17 00:00 |
16:10:44.88 |
+25:28:56.2 |
HIP 79225 |
8.67 |
| 2026-05-17 12:00 |
16:10:40.05 |
+25:29:09.0 |
HIP 79225 |
7.58 |
| 2026-05-18 00:00 |
16:10:35.22 |
+25:29:21.4 |
HIP 79225 |
6.49 |
| 2026-05-18 12:00 |
16:10:30.37 |
+25:29:33.4 |
HIP 79225 |
5.40 |
| 2026-05-19 00:00 |
16:10:25.53 |
+25:29:45.0 |
HIP 79225 |
4.33 |
| 2026-05-19 12:00 |
16:10:20.68 |
+25:29:56.1 |
HIP 79225 |
3.27 |
| 2026-05-20 00:00 |
16:10:15.83 |
+25:30:06.9 |
HIP 79225 |
2.27 |
| 2026-05-20 12:00 |
16:10:10.97 |
+25:30:17.2 |
HIP 79225 |
1.44 |
| 2026-05-21 00:00 |
16:10:06.11 |
+25:30:27.1 |
HIP 79225 |
1.19 |
| 2026-05-21 12:00 |
16:10:01.25 |
+25:30:36.7 |
HIP 79225 |
1.79 |
| 2026-05-22 00:00 |
16:09:56.39 |
+25:30:45.7 |
HIP 79225 |
2.72 |
| 2026-05-22 12:00 |
16:09:51.52 |
+25:30:54.4 |
HIP 79225 |
3.75 |
| 2026-05-23 00:00 |
16:09:46.66 |
+25:31:02.7 |
HIP 79225 |
4.81 |
| 2026-05-23 12:00 |
16:09:41.79 |
+25:31:10.5 |
HIP 79225 |
5.89 |
| 2026-05-24 00:00 |
16:09:36.92 |
+25:31:18.0 |
HIP 79225 |
6.97 |
| 2026-05-24 12:00 |
16:09:32.05 |
+25:31:25.0 |
HIP 79225 |
8.06 |
| 2026-05-25 00:00 |
16:09:27.19 |
+25:31:31.6 |
HIP 79225 |
9.15 |
| 2026-05-25 12:00 |
16:09:22.32 |
+25:31:37.8 |
HIP 79225 |
10.24 |
| 2026-05-26 00:00 |
16:09:17.45 |
+25:31:43.6 |
HIP 79225 |
11.33 |
| 2026-05-26 12:00 |
16:09:12.59 |
+25:31:48.9 |
HIP 79225 |
12.42 |
| 2026-05-27 00:00 |
16:09:07.73 |
+25:31:53.8 |
HIP 79225 |
13.51 |
| 2026-05-27 12:00 |
16:09:02.87 |
+25:31:58.4 |
HIP 79225 |
14.61 |
| 2026-05-28 00:00 |
16:08:58.01 |
+25:32:02.5 |
HIP 79225 |
15.70 |
| 2026-05-28 12:00 |
16:08:53.15 |
+25:32:06.1 |
HIP 79225 |
16.79 |
| 2026-05-29 00:00 |
16:08:48.30 |
+25:32:09.4 |
HIP 79225 |
17.87 |
| 2026-05-29 12:00 |
16:08:43.45 |
+25:32:12.3 |
HIP 79225 |
18.96 |
| 2026-05-30 00:00 |
16:08:38.61 |
+25:32:14.7 |
HIP 79225 |
20.05 |
| 2026-05-30 12:00 |
16:08:33.77 |
+25:32:16.7 |
HIP 79225 |
21.13 |
| 2026-05-31 00:00 |
16:08:28.93 |
+25:32:18.3 |
HIP 79225 |
22.22 |
| 2026-05-31 12:00 |
16:08:24.10 |
+25:32:19.5 |
HIP 79225 |
23.30 |
| 2026-06-01 00:00 |
16:08:19.27 |
+25:32:20.2 |
HIP 79225 |
24.38 |
| 2026-06-01 12:00 |
16:08:14.45 |
+25:32:20.6 |
HIP 79225 |
25.46 |
| 2026-06-02 00:00 |
16:08:09.64 |
+25:32:20.5 |
HIP 79225 |
26.54 |