C/1981 G1 (Elias)
| 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) |
| 2026-02-03 00:00 |
00:15:36.46 |
+78:50:11.1 |
HIP 1724 |
27.96 |
| 2026-02-03 12:00 |
00:15:41.88 |
+78:49:50.9 |
HIP 1724 |
27.53 |
| 2026-02-04 00:00 |
00:15:47.34 |
+78:49:30.8 |
HIP 1724 |
27.11 |
| 2026-02-04 12:00 |
00:15:52.86 |
+78:49:10.9 |
HIP 1724 |
26.68 |
| 2026-02-05 00:00 |
00:15:58.43 |
+78:48:51.2 |
HIP 1724 |
26.26 |
| 2026-02-05 12:00 |
00:16:04.04 |
+78:48:31.6 |
HIP 1724 |
25.83 |
| 2026-02-06 00:00 |
00:16:09.71 |
+78:48:12.2 |
HIP 1724 |
25.41 |
| 2026-02-06 12:00 |
00:16:15.42 |
+78:47:53.0 |
HIP 1724 |
24.98 |
| 2026-02-07 00:00 |
00:16:21.19 |
+78:47:33.9 |
HIP 1724 |
24.56 |
| 2026-02-07 12:00 |
00:16:27.00 |
+78:47:15.0 |
HIP 1724 |
24.14 |
| 2026-02-08 00:00 |
00:16:32.86 |
+78:46:56.3 |
HIP 1724 |
23.72 |
| 2026-02-08 12:00 |
00:16:38.77 |
+78:46:37.7 |
HIP 1724 |
23.29 |
| 2026-02-09 00:00 |
00:16:44.72 |
+78:46:19.4 |
HIP 1724 |
22.87 |
| 2026-02-09 12:00 |
00:16:50.72 |
+78:46:01.2 |
HIP 1724 |
22.45 |
| 2026-02-10 00:00 |
00:16:56.76 |
+78:45:43.1 |
HIP 1724 |
22.03 |
| 2026-02-10 12:00 |
00:17:02.86 |
+78:45:25.3 |
HIP 1724 |
21.61 |
| 2026-02-11 00:00 |
00:17:08.99 |
+78:45:07.6 |
HIP 1724 |
21.20 |
| 2026-02-11 12:00 |
00:17:15.17 |
+78:44:50.1 |
HIP 1724 |
20.78 |
| 2026-02-12 00:00 |
00:17:21.40 |
+78:44:32.8 |
HIP 1724 |
20.36 |
| 2026-02-12 12:00 |
00:17:27.67 |
+78:44:15.6 |
HIP 1724 |
19.95 |
| 2026-02-13 00:00 |
00:17:33.98 |
+78:43:58.7 |
HIP 1724 |
19.53 |
| 2026-02-13 12:00 |
00:17:40.33 |
+78:43:41.9 |
HIP 1724 |
19.12 |
| 2026-02-14 00:00 |
00:17:46.73 |
+78:43:25.3 |
HIP 1724 |
18.71 |
| 2026-02-14 12:00 |
00:17:53.17 |
+78:43:08.9 |
HIP 1724 |
18.30 |
| 2026-02-15 00:00 |
00:17:59.65 |
+78:42:52.7 |
HIP 1724 |
17.89 |
| 2026-02-15 12:00 |
00:18:06.17 |
+78:42:36.6 |
HIP 1724 |
17.48 |
| 2026-02-16 00:00 |
00:18:12.73 |
+78:42:20.8 |
HIP 1724 |
17.08 |
| 2026-02-16 12:00 |
00:18:19.33 |
+78:42:05.1 |
HIP 1724 |
16.67 |
| 2026-02-17 00:00 |
00:18:25.96 |
+78:41:49.7 |
HIP 1724 |
16.27 |
| 2026-02-17 12:00 |
00:18:32.64 |
+78:41:34.4 |
HIP 1724 |
15.87 |
| 2026-02-18 00:00 |
00:18:39.36 |
+78:41:19.3 |
HIP 1724 |
15.47 |
| 2026-02-18 12:00 |
00:18:46.11 |
+78:41:04.4 |
HIP 1724 |
15.08 |
| 2026-02-19 00:00 |
00:18:52.90 |
+78:40:49.7 |
HIP 1724 |
14.68 |
| 2026-02-19 12:00 |
00:18:59.73 |
+78:40:35.2 |
HIP 1724 |
14.29 |
| 2026-02-20 00:00 |
00:19:06.59 |
+78:40:20.9 |
HIP 1724 |
13.91 |
| 2026-02-20 12:00 |
00:19:13.49 |
+78:40:06.8 |
HIP 1724 |
13.52 |
| 2026-02-21 00:00 |
00:19:20.42 |
+78:39:52.9 |
HIP 1724 |
13.14 |
| 2026-02-21 12:00 |
00:19:27.39 |
+78:39:39.1 |
HIP 1724 |
12.77 |
| 2026-02-22 00:00 |
00:19:34.39 |
+78:39:25.6 |
HIP 1724 |
12.40 |
| 2026-02-22 12:00 |
00:19:41.43 |
+78:39:12.3 |
HIP 1724 |
12.03 |
| 2026-02-23 00:00 |
00:19:48.50 |
+78:38:59.2 |
HIP 1724 |
11.67 |
| 2026-02-23 12:00 |
00:19:55.60 |
+78:38:46.2 |
HIP 1724 |
11.31 |
| 2026-02-24 00:00 |
00:20:02.73 |
+78:38:33.5 |
HIP 1724 |
10.96 |