| 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 |
-0.971 |
| 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) |
| 2026-05-12 00:00 |
21:03:05.10 |
+78:23:25.9 |
HIP 104105 |
17.47 |
| 2026-05-12 12:00 |
21:02:59.09 |
+78:24:41.9 |
HIP 104105 |
18.74 |
| 2026-05-13 00:00 |
21:02:52.83 |
+78:25:57.7 |
HIP 104105 |
20.02 |
| 2026-05-13 12:00 |
21:02:46.32 |
+78:27:13.4 |
HIP 104105 |
21.31 |
| 2026-05-14 00:00 |
21:02:39.55 |
+78:28:28.9 |
HIP 104414 |
22.31 |
| 2026-05-14 12:00 |
21:02:32.53 |
+78:29:44.4 |
HIP 104414 |
21.99 |
| 2026-05-15 00:00 |
21:02:25.25 |
+78:30:59.7 |
HIP 104414 |
21.76 |
| 2026-05-15 12:00 |
21:02:17.71 |
+78:32:14.9 |
HIP 104414 |
21.61 |
| 2026-05-16 00:00 |
21:02:09.91 |
+78:33:29.9 |
HIP 104414 |
21.56 |
| 2026-05-16 12:00 |
21:02:01.85 |
+78:34:44.7 |
HIP 104414 |
21.60 |
| 2026-05-17 00:00 |
21:01:53.53 |
+78:35:59.4 |
HIP 104414 |
21.73 |
| 2026-05-17 12:00 |
21:01:44.96 |
+78:37:13.9 |
HIP 104414 |
21.94 |
| 2026-05-18 00:00 |
21:01:36.12 |
+78:38:28.2 |
HIP 104414 |
22.25 |
| 2026-05-18 12:00 |
21:01:27.01 |
+78:39:42.4 |
HIP 104414 |
22.64 |
| 2026-05-19 00:00 |
21:01:17.65 |
+78:40:56.3 |
HIP 104414 |
23.10 |
| 2026-05-19 12:00 |
21:01:08.02 |
+78:42:10.0 |
HIP 104414 |
23.65 |
| 2026-05-20 00:00 |
21:00:58.12 |
+78:43:23.6 |
HIP 104414 |
24.26 |
| 2026-05-20 12:00 |
21:00:47.97 |
+78:44:36.9 |
HIP 104414 |
24.94 |
| 2026-05-21 00:00 |
21:00:37.54 |
+78:45:49.9 |
HIP 104414 |
25.68 |
| 2026-05-21 12:00 |
21:00:26.85 |
+78:47:02.8 |
HIP 104414 |
26.47 |
| 2026-05-22 00:00 |
21:00:15.90 |
+78:48:15.4 |
HIP 104414 |
27.31 |
| 2026-05-22 12:00 |
21:00:04.68 |
+78:49:27.7 |
HIP 104414 |
28.20 |
| 2026-05-23 00:00 |
20:59:53.19 |
+78:50:39.8 |
HIP 103754 |
27.44 |
| 2026-05-23 12:00 |
20:59:41.44 |
+78:51:51.6 |
HIP 103602 |
26.32 |
| 2026-05-24 00:00 |
20:59:29.42 |
+78:53:03.2 |
HIP 103602 |
25.12 |
| 2026-05-24 12:00 |
20:59:17.13 |
+78:54:14.5 |
HIP 103602 |
23.93 |
| 2026-05-25 00:00 |
20:59:04.58 |
+78:55:25.4 |
HIP 103602 |
22.77 |
| 2026-05-25 12:00 |
20:58:51.76 |
+78:56:36.1 |
HIP 103602 |
21.63 |
| 2026-05-26 00:00 |
20:58:38.67 |
+78:57:46.5 |
HIP 103602 |
20.53 |
| 2026-05-26 12:00 |
20:58:25.31 |
+78:58:56.6 |
HIP 103602 |
19.45 |
| 2026-05-27 00:00 |
20:58:11.68 |
+79:00:06.4 |
HIP 103602 |
18.41 |
| 2026-05-27 12:00 |
20:57:57.78 |
+79:01:15.9 |
HIP 103602 |
17.43 |
| 2026-05-28 00:00 |
20:57:43.62 |
+79:02:25.0 |
HIP 103602 |
16.50 |
| 2026-05-28 12:00 |
20:57:29.18 |
+79:03:33.8 |
HIP 103602 |
15.63 |
| 2026-05-29 00:00 |
20:57:14.48 |
+79:04:42.3 |
HIP 103602 |
14.85 |
| 2026-05-29 12:00 |
20:56:59.51 |
+79:05:50.4 |
HIP 103602 |
14.15 |
| 2026-05-30 00:00 |
20:56:44.27 |
+79:06:58.1 |
HIP 103602 |
13.57 |
| 2026-05-30 12:00 |
20:56:28.76 |
+79:08:05.5 |
HIP 103602 |
13.10 |
| 2026-05-31 00:00 |
20:56:12.98 |
+79:09:12.5 |
HIP 103602 |
12.78 |
| 2026-05-31 12:00 |
20:55:56.93 |
+79:10:19.2 |
HIP 103602 |
12.59 |
| 2026-06-01 00:00 |
20:55:40.61 |
+79:11:25.4 |
HIP 103602 |
12.57 |
| 2026-06-01 12:00 |
20:55:24.02 |
+79:12:31.3 |
HIP 103602 |
12.69 |
| 2026-06-02 00:00 |
20:55:07.17 |
+79:13:36.8 |
HIP 103602 |
12.97 |