| 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) |
| 2026-07-29 00:00 |
16:01:03.90 |
+24:50:33.1 |
HIP 78457 |
23.51 |
| 2026-07-29 12:00 |
16:01:01.84 |
+24:49:53.3 |
HIP 78457 |
22.85 |
| 2026-07-30 00:00 |
16:00:59.81 |
+24:49:13.2 |
HIP 78457 |
22.19 |
| 2026-07-30 12:00 |
16:00:57.83 |
+24:48:32.9 |
HIP 78457 |
21.53 |
| 2026-07-31 00:00 |
16:00:55.87 |
+24:47:52.4 |
HIP 78457 |
20.88 |
| 2026-07-31 12:00 |
16:00:53.96 |
+24:47:11.7 |
HIP 78457 |
20.24 |
| 2026-08-01 00:00 |
16:00:52.08 |
+24:46:30.8 |
HIP 78457 |
19.61 |
| 2026-08-01 12:00 |
16:00:50.24 |
+24:45:49.6 |
HIP 78457 |
18.98 |
| 2026-08-02 00:00 |
16:00:48.43 |
+24:45:08.3 |
HIP 78457 |
18.37 |
| 2026-08-02 12:00 |
16:00:46.67 |
+24:44:26.8 |
HIP 78457 |
17.76 |
| 2026-08-03 00:00 |
16:00:44.94 |
+24:43:45.1 |
HIP 78457 |
17.17 |
| 2026-08-03 12:00 |
16:00:43.24 |
+24:43:03.2 |
HIP 78457 |
16.58 |
| 2026-08-04 00:00 |
16:00:41.59 |
+24:42:21.1 |
HIP 78457 |
16.01 |
| 2026-08-04 12:00 |
16:00:39.97 |
+24:41:38.9 |
HIP 78457 |
15.46 |
| 2026-08-05 00:00 |
16:00:38.39 |
+24:40:56.4 |
HIP 78457 |
14.92 |
| 2026-08-05 12:00 |
16:00:36.84 |
+24:40:13.8 |
HIP 78457 |
14.39 |
| 2026-08-06 00:00 |
16:00:35.34 |
+24:39:31.0 |
HIP 78457 |
13.89 |
| 2026-08-06 12:00 |
16:00:33.87 |
+24:38:48.0 |
HIP 78457 |
13.41 |
| 2026-08-07 00:00 |
16:00:32.44 |
+24:38:04.9 |
HIP 78457 |
12.95 |
| 2026-08-07 12:00 |
16:00:31.05 |
+24:37:21.6 |
HIP 78457 |
12.52 |
| 2026-08-08 00:00 |
16:00:29.69 |
+24:36:38.1 |
HIP 78457 |
12.11 |
| 2026-08-08 12:00 |
16:00:28.38 |
+24:35:54.5 |
HIP 78457 |
11.74 |
| 2026-08-09 00:00 |
16:00:27.10 |
+24:35:10.7 |
HIP 78457 |
11.40 |
| 2026-08-09 12:00 |
16:00:25.86 |
+24:34:26.7 |
HIP 78457 |
11.10 |
| 2026-08-10 00:00 |
16:00:24.66 |
+24:33:42.6 |
HIP 78457 |
10.84 |
| 2026-08-10 12:00 |
16:00:23.50 |
+24:32:58.3 |
HIP 78457 |
10.62 |
| 2026-08-11 00:00 |
16:00:22.37 |
+24:32:13.9 |
HIP 78457 |
10.44 |
| 2026-08-11 12:00 |
16:00:21.29 |
+24:31:29.4 |
HIP 78457 |
10.32 |
| 2026-08-12 00:00 |
16:00:20.24 |
+24:30:44.7 |
HIP 78457 |
10.24 |
| 2026-08-12 12:00 |
16:00:19.23 |
+24:30:00.0 |
HIP 78457 |
10.21 |
| 2026-08-13 00:00 |
16:00:18.26 |
+24:29:15.0 |
HIP 78457 |
10.24 |
| 2026-08-13 12:00 |
16:00:17.33 |
+24:28:29.9 |
HIP 78457 |
10.31 |
| 2026-08-14 00:00 |
16:00:16.44 |
+24:27:44.7 |
HIP 78457 |
10.44 |
| 2026-08-14 12:00 |
16:00:15.59 |
+24:26:59.4 |
HIP 78370 |
10.30 |
| 2026-08-15 00:00 |
16:00:14.77 |
+24:26:13.9 |
HIP 78370 |
9.53 |
| 2026-08-15 12:00 |
16:00:14.00 |
+24:25:28.4 |
HIP 78370 |
8.76 |
| 2026-08-16 00:00 |
16:00:13.26 |
+24:24:42.7 |
HIP 78370 |
7.99 |
| 2026-08-16 12:00 |
16:00:12.56 |
+24:23:56.9 |
HIP 78370 |
7.22 |
| 2026-08-17 00:00 |
16:00:11.91 |
+24:23:11.0 |
HIP 78370 |
6.47 |
| 2026-08-17 12:00 |
16:00:11.29 |
+24:22:25.1 |
HIP 78370 |
5.72 |
| 2026-08-18 00:00 |
16:00:10.71 |
+24:21:39.0 |
HIP 78370 |
4.98 |
| 2026-08-18 12:00 |
16:00:10.16 |
+24:20:52.8 |
HIP 78370 |
4.26 |
| 2026-08-19 00:00 |
16:00:09.66 |
+24:20:06.5 |
HIP 78370 |
3.58 |