| Parameter |
Value |
| Designation |
C/1981 G1 (Elias) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1981-08-18T09:31:39.573120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:29Z |
| Obs used |
20 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1982-01-23.0000000 |
| e |
1.00140214 |
| q (au) |
4.742646 |
| a (au) |
-3382.426552 |
| i (deg) |
115.300346 |
| Ω (om, deg) |
176.713357 |
| ω (w, deg) |
310.265581 |
| M (ma, deg) |
0.000790 |
Magnitude
Scatter + Global Linear
$$
M_a = (0.884 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
0.884 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.592 |
| 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 |
00:39:39.90 |
+78:46:15.2 |
HIP 3380 |
27.23 |
| 2026-05-12 12:00 |
00:39:46.17 |
+78:46:32.3 |
HIP 3380 |
26.85 |
| 2026-05-13 00:00 |
00:39:52.39 |
+78:46:49.5 |
HIP 3380 |
26.48 |
| 2026-05-13 12:00 |
00:39:58.57 |
+78:47:06.9 |
HIP 3380 |
26.11 |
| 2026-05-14 00:00 |
00:40:04.71 |
+78:47:24.4 |
HIP 3380 |
25.74 |
| 2026-05-14 12:00 |
00:40:10.81 |
+78:47:42.1 |
HIP 3380 |
25.37 |
| 2026-05-15 00:00 |
00:40:16.86 |
+78:47:59.9 |
HIP 3380 |
25.00 |
| 2026-05-15 12:00 |
00:40:22.87 |
+78:48:17.8 |
HIP 3380 |
24.62 |
| 2026-05-16 00:00 |
00:40:28.84 |
+78:48:35.9 |
HIP 3380 |
24.25 |
| 2026-05-16 12:00 |
00:40:34.77 |
+78:48:54.0 |
HIP 3380 |
23.88 |
| 2026-05-17 00:00 |
00:40:40.64 |
+78:49:12.4 |
HIP 3380 |
23.51 |
| 2026-05-17 12:00 |
00:40:46.48 |
+78:49:30.8 |
HIP 3380 |
23.13 |
| 2026-05-18 00:00 |
00:40:52.27 |
+78:49:49.4 |
HIP 3380 |
22.76 |
| 2026-05-18 12:00 |
00:40:58.01 |
+78:50:08.1 |
HIP 3380 |
22.39 |
| 2026-05-19 00:00 |
00:41:03.71 |
+78:50:26.9 |
HIP 3380 |
22.02 |
| 2026-05-19 12:00 |
00:41:09.35 |
+78:50:45.8 |
HIP 3380 |
21.65 |
| 2026-05-20 00:00 |
00:41:14.96 |
+78:51:04.9 |
HIP 3380 |
21.27 |
| 2026-05-20 12:00 |
00:41:20.51 |
+78:51:24.1 |
HIP 3380 |
20.90 |
| 2026-05-21 00:00 |
00:41:26.02 |
+78:51:43.4 |
HIP 3380 |
20.53 |
| 2026-05-21 12:00 |
00:41:31.48 |
+78:52:02.8 |
HIP 3380 |
20.16 |
| 2026-05-22 00:00 |
00:41:36.89 |
+78:52:22.4 |
HIP 3380 |
19.79 |
| 2026-05-22 12:00 |
00:41:42.25 |
+78:52:42.0 |
HIP 3380 |
19.42 |
| 2026-05-23 00:00 |
00:41:47.56 |
+78:53:01.8 |
HIP 3380 |
19.05 |
| 2026-05-23 12:00 |
00:41:52.82 |
+78:53:21.7 |
HIP 3380 |
18.68 |
| 2026-05-24 00:00 |
00:41:58.03 |
+78:53:41.7 |
HIP 3380 |
18.31 |
| 2026-05-24 12:00 |
00:42:03.19 |
+78:54:01.8 |
HIP 3380 |
17.95 |
| 2026-05-25 00:00 |
00:42:08.30 |
+78:54:22.0 |
HIP 3380 |
17.58 |
| 2026-05-25 12:00 |
00:42:13.36 |
+78:54:42.3 |
HIP 3380 |
17.21 |
| 2026-05-26 00:00 |
00:42:18.37 |
+78:55:02.7 |
HIP 3380 |
16.85 |
| 2026-05-26 12:00 |
00:42:23.33 |
+78:55:23.2 |
HIP 3380 |
16.48 |
| 2026-05-27 00:00 |
00:42:28.23 |
+78:55:43.8 |
HIP 3380 |
16.12 |
| 2026-05-27 12:00 |
00:42:33.08 |
+78:56:04.5 |
HIP 3380 |
15.75 |
| 2026-05-28 00:00 |
00:42:37.88 |
+78:56:25.3 |
HIP 3380 |
15.39 |
| 2026-05-28 12:00 |
00:42:42.63 |
+78:56:46.3 |
HIP 3380 |
15.03 |
| 2026-05-29 00:00 |
00:42:47.32 |
+78:57:07.3 |
HIP 3380 |
14.67 |
| 2026-05-29 12:00 |
00:42:51.96 |
+78:57:28.4 |
HIP 3380 |
14.32 |
| 2026-05-30 00:00 |
00:42:56.54 |
+78:57:49.6 |
HIP 3380 |
13.96 |
| 2026-05-30 12:00 |
00:43:01.07 |
+78:58:10.9 |
HIP 3380 |
13.61 |
| 2026-05-31 00:00 |
00:43:05.54 |
+78:58:32.3 |
HIP 3380 |
13.25 |
| 2026-05-31 12:00 |
00:43:09.96 |
+78:58:53.7 |
HIP 3380 |
12.90 |
| 2026-06-01 00:00 |
00:43:14.33 |
+78:59:15.3 |
HIP 3380 |
12.56 |
| 2026-06-01 12:00 |
00:43:18.64 |
+78:59:36.9 |
HIP 3380 |
12.21 |
| 2026-06-02 00:00 |
00:43:22.89 |
+78:59:58.7 |
HIP 3380 |
11.87 |