| 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) |
| 2026-03-26 00:00 |
00:27:50.39 |
+78:32:08.0 |
HIP 1724 |
18.65 |
| 2026-03-26 12:00 |
00:27:58.54 |
+78:32:08.0 |
HIP 1724 |
19.05 |
| 2026-03-27 00:00 |
00:28:06.69 |
+78:32:08.3 |
HIP 1724 |
19.45 |
| 2026-03-27 12:00 |
00:28:14.84 |
+78:32:08.7 |
HIP 1724 |
19.85 |
| 2026-03-28 00:00 |
00:28:22.99 |
+78:32:09.3 |
HIP 1724 |
20.25 |
| 2026-03-28 12:00 |
00:28:31.14 |
+78:32:10.2 |
HIP 1724 |
20.65 |
| 2026-03-29 00:00 |
00:28:39.29 |
+78:32:11.2 |
HIP 1724 |
21.06 |
| 2026-03-29 12:00 |
00:28:47.43 |
+78:32:12.5 |
HIP 1724 |
21.46 |
| 2026-03-30 00:00 |
00:28:55.58 |
+78:32:13.9 |
HIP 1724 |
21.86 |
| 2026-03-30 12:00 |
00:29:03.72 |
+78:32:15.6 |
HIP 1724 |
22.27 |
| 2026-03-31 00:00 |
00:29:11.87 |
+78:32:17.5 |
HIP 1724 |
22.67 |
| 2026-03-31 12:00 |
00:29:20.00 |
+78:32:19.6 |
HIP 1724 |
23.08 |
| 2026-04-01 00:00 |
00:29:28.14 |
+78:32:21.8 |
HIP 1724 |
23.48 |
| 2026-04-01 12:00 |
00:29:36.27 |
+78:32:24.3 |
HIP 1724 |
23.89 |
| 2026-04-02 00:00 |
00:29:44.40 |
+78:32:27.0 |
HIP 1724 |
24.29 |
| 2026-04-02 12:00 |
00:29:52.52 |
+78:32:29.9 |
HIP 1724 |
24.70 |
| 2026-04-03 00:00 |
00:30:00.64 |
+78:32:33.0 |
HIP 1724 |
25.11 |
| 2026-04-03 12:00 |
00:30:08.75 |
+78:32:36.3 |
HIP 1724 |
25.51 |
| 2026-04-04 00:00 |
00:30:16.85 |
+78:32:39.9 |
HIP 1724 |
25.92 |
| 2026-04-04 12:00 |
00:30:24.95 |
+78:32:43.6 |
HIP 1724 |
26.33 |
| 2026-04-05 00:00 |
00:30:33.04 |
+78:32:47.5 |
HIP 1724 |
26.73 |
| 2026-04-05 12:00 |
00:30:41.13 |
+78:32:51.6 |
HIP 2575 |
26.88 |
| 2026-04-06 00:00 |
00:30:49.20 |
+78:32:55.9 |
HIP 2575 |
26.86 |
| 2026-04-06 12:00 |
00:30:57.27 |
+78:33:00.4 |
HIP 2575 |
26.85 |
| 2026-04-07 00:00 |
00:31:05.33 |
+78:33:05.2 |
HIP 2575 |
26.85 |
| 2026-04-07 12:00 |
00:31:13.38 |
+78:33:10.1 |
HIP 2575 |
26.86 |
| 2026-04-08 00:00 |
00:31:21.42 |
+78:33:15.2 |
HIP 2575 |
26.88 |
| 2026-04-08 12:00 |
00:31:29.46 |
+78:33:20.5 |
HIP 2575 |
26.90 |
| 2026-04-09 00:00 |
00:31:37.48 |
+78:33:26.1 |
HIP 2575 |
26.94 |
| 2026-04-09 12:00 |
00:31:45.49 |
+78:33:31.8 |
HIP 2575 |
26.99 |
| 2026-04-10 00:00 |
00:31:53.48 |
+78:33:37.7 |
HIP 2575 |
27.05 |
| 2026-04-10 12:00 |
00:32:01.47 |
+78:33:43.8 |
HIP 2575 |
27.11 |
| 2026-04-11 00:00 |
00:32:09.44 |
+78:33:50.1 |
HIP 2575 |
27.19 |
| 2026-04-11 12:00 |
00:32:17.40 |
+78:33:56.6 |
HIP 2575 |
27.28 |
| 2026-04-12 00:00 |
00:32:25.35 |
+78:34:03.4 |
HIP 2575 |
27.37 |
| 2026-04-12 12:00 |
00:32:33.28 |
+78:34:10.3 |
HIP 2575 |
27.48 |
| 2026-04-13 00:00 |
00:32:41.20 |
+78:34:17.4 |
HIP 2575 |
27.59 |
| 2026-04-13 12:00 |
00:32:49.11 |
+78:34:24.6 |
HIP 2575 |
27.71 |
| 2026-04-14 00:00 |
00:32:57.00 |
+78:34:32.1 |
HIP 2575 |
27.84 |
| 2026-04-14 12:00 |
00:33:04.87 |
+78:34:39.8 |
HIP 2575 |
27.98 |
| 2026-04-15 00:00 |
00:33:12.73 |
+78:34:47.7 |
HIP 2575 |
28.13 |
| 2026-04-15 12:00 |
00:33:20.57 |
+78:34:55.8 |
HIP 2575 |
28.29 |
| 2026-04-16 00:00 |
00:33:28.39 |
+78:35:04.0 |
HIP 2575 |
28.46 |