| Parameter |
Value |
| Designation |
C/2017 A3 (Elenin) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-01-30T14:31:52.288320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:28Z |
| Obs used |
186 |
| NEO |
- |
| M1 |
9.700 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-02-10.0000000 |
| e |
0.91107616 |
| q (au) |
3.854543 |
| a (au) |
43.346563 |
| i (deg) |
98.508477 |
| Ω (om, deg) |
97.903943 |
| ω (w, deg) |
304.107532 |
| M (ma, deg) |
0.035899 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.803 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.803 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.998 |
| 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) |
| 2026-09-20 00:00 |
19:18:56.06 |
+78:18:52.9 |
HIP 95087 |
10.75 |
| 2026-09-20 12:00 |
19:18:45.96 |
+78:17:22.7 |
HIP 95087 |
9.79 |
| 2026-09-21 00:00 |
19:18:36.14 |
+78:15:52.1 |
HIP 95087 |
9.00 |
| 2026-09-21 12:00 |
19:18:26.57 |
+78:14:21.3 |
HIP 95087 |
8.42 |
| 2026-09-22 00:00 |
19:18:17.28 |
+78:12:50.2 |
HIP 95087 |
8.11 |
| 2026-09-22 12:00 |
19:18:08.24 |
+78:11:18.8 |
HIP 95087 |
8.09 |
| 2026-09-23 00:00 |
19:17:59.47 |
+78:09:47.1 |
HIP 95087 |
8.37 |
| 2026-09-23 12:00 |
19:17:50.97 |
+78:08:15.2 |
HIP 95087 |
8.92 |
| 2026-09-24 00:00 |
19:17:42.72 |
+78:06:43.1 |
HIP 95087 |
9.69 |
| 2026-09-24 12:00 |
19:17:34.73 |
+78:05:10.7 |
HIP 95087 |
10.63 |
| 2026-09-25 00:00 |
19:17:27.01 |
+78:03:38.1 |
HIP 95087 |
11.71 |
| 2026-09-25 12:00 |
19:17:19.54 |
+78:02:05.2 |
HIP 95087 |
12.89 |
| 2026-09-26 00:00 |
19:17:12.32 |
+78:00:32.1 |
HIP 95087 |
14.15 |
| 2026-09-26 12:00 |
19:17:05.37 |
+77:58:58.8 |
HIP 95087 |
15.46 |
| 2026-09-27 00:00 |
19:16:58.66 |
+77:57:25.3 |
HIP 95087 |
16.81 |
| 2026-09-27 12:00 |
19:16:52.22 |
+77:55:51.6 |
HIP 95087 |
18.20 |
| 2026-09-28 00:00 |
19:16:46.02 |
+77:54:17.7 |
HIP 95087 |
19.62 |
| 2026-09-28 12:00 |
19:16:40.08 |
+77:52:43.6 |
HIP 95297 |
20.78 |
| 2026-09-29 00:00 |
19:16:34.39 |
+77:51:09.3 |
HIP 95297 |
21.28 |
| 2026-09-29 12:00 |
19:16:28.95 |
+77:49:34.9 |
HIP 95297 |
21.88 |
| 2026-09-30 00:00 |
19:16:23.75 |
+77:48:00.3 |
HIP 95297 |
22.57 |
| 2026-09-30 12:00 |
19:16:18.81 |
+77:46:25.5 |
HIP 95297 |
23.34 |
| 2026-10-01 00:00 |
19:16:14.11 |
+77:44:50.6 |
HIP 95297 |
24.18 |
| 2026-10-01 12:00 |
19:16:09.66 |
+77:43:15.5 |
HIP 95297 |
25.08 |
| 2026-10-02 00:00 |
19:16:05.45 |
+77:41:40.2 |
HIP 95297 |
26.04 |
| 2026-10-02 12:00 |
19:16:01.49 |
+77:40:04.9 |
HIP 95297 |
27.06 |
| 2026-10-03 00:00 |
19:15:57.77 |
+77:38:29.4 |
HIP 95297 |
28.12 |
| 2026-10-03 12:00 |
19:15:54.29 |
+77:36:53.8 |
HIP 95297 |
29.22 |
| 2026-10-04 00:00 |
19:15:51.06 |
+77:35:18.1 |
HIP 95297 |
30.35 |
| 2026-10-04 12:00 |
19:15:48.06 |
+77:33:42.2 |
HIP 95297 |
31.53 |
| 2026-10-05 00:00 |
19:15:45.30 |
+77:32:06.3 |
HIP 95178 |
31.41 |
| 2026-10-05 12:00 |
19:15:42.78 |
+77:30:30.2 |
HIP 95178 |
30.29 |
| 2026-10-06 00:00 |
19:15:40.50 |
+77:28:54.1 |
HIP 95178 |
29.20 |
| 2026-10-06 12:00 |
19:15:38.45 |
+77:27:17.9 |
HIP 95178 |
28.15 |
| 2026-10-07 00:00 |
19:15:36.64 |
+77:25:41.6 |
HIP 95178 |
27.14 |
| 2026-10-07 12:00 |
19:15:35.06 |
+77:24:05.3 |
HIP 95178 |
26.18 |
| 2026-10-08 00:00 |
19:15:33.71 |
+77:22:28.9 |
HIP 95178 |
25.28 |
| 2026-10-08 12:00 |
19:15:32.59 |
+77:20:52.4 |
HIP 95178 |
24.44 |
| 2026-10-09 00:00 |
19:15:31.71 |
+77:19:15.9 |
HIP 95178 |
23.67 |
| 2026-10-09 12:00 |
19:15:31.05 |
+77:17:39.4 |
HIP 95178 |
22.98 |
| 2026-10-10 00:00 |
19:15:30.62 |
+77:16:02.8 |
HIP 95178 |
22.36 |
| 2026-10-10 12:00 |
19:15:30.41 |
+77:14:26.2 |
HIP 95178 |
21.84 |
| 2026-10-11 00:00 |
19:15:30.43 |
+77:12:49.6 |
HIP 95178 |
21.41 |