| Parameter |
Value |
| Designation |
C/1978 G2 (McNaught-Tritton) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1978-08-23T23:05:11.348160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:27Z |
| Obs used |
5 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1978-08-28.0000000 |
| e |
1.00462671 |
| q (au) |
6.284334 |
| a (au) |
-1358.272229 |
| i (deg) |
153.180957 |
| Ω (om, deg) |
72.213979 |
| ω (w, deg) |
229.460098 |
| M (ma, deg) |
0.000080 |
Magnitude
Scatter + Global Linear
$$
M_a = (1.134 + 5.745\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
1.134 |
| n |
5.745 |
| gf |
0.991 |
| gb |
-0.731 |
| 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 |
03:43:28.19 |
+26:07:38.4 |
HIP 17407 |
15.75 |
| 2026-05-12 12:00 |
03:43:29.91 |
+26:07:43.9 |
HIP 17407 |
15.56 |
| 2026-05-13 00:00 |
03:43:31.63 |
+26:07:49.4 |
HIP 17407 |
15.39 |
| 2026-05-13 12:00 |
03:43:33.35 |
+26:07:55.0 |
HIP 17407 |
15.22 |
| 2026-05-14 00:00 |
03:43:35.07 |
+26:08:00.5 |
HIP 17407 |
15.06 |
| 2026-05-14 12:00 |
03:43:36.79 |
+26:08:06.1 |
HIP 17407 |
14.91 |
| 2026-05-15 00:00 |
03:43:38.52 |
+26:08:11.7 |
HIP 17407 |
14.77 |
| 2026-05-15 12:00 |
03:43:40.25 |
+26:08:17.4 |
HIP 17407 |
14.64 |
| 2026-05-16 00:00 |
03:43:41.97 |
+26:08:23.1 |
HIP 17407 |
14.51 |
| 2026-05-16 12:00 |
03:43:43.70 |
+26:08:28.8 |
HIP 17407 |
14.40 |
| 2026-05-17 00:00 |
03:43:45.43 |
+26:08:34.5 |
HIP 17407 |
14.30 |
| 2026-05-17 12:00 |
03:43:47.16 |
+26:08:40.2 |
HIP 17407 |
14.20 |
| 2026-05-18 00:00 |
03:43:48.89 |
+26:08:46.0 |
HIP 17407 |
14.12 |
| 2026-05-18 12:00 |
03:43:50.62 |
+26:08:51.8 |
HIP 17407 |
14.04 |
| 2026-05-19 00:00 |
03:43:52.35 |
+26:08:57.6 |
HIP 17407 |
13.98 |
| 2026-05-19 12:00 |
03:43:54.08 |
+26:09:03.5 |
HIP 17407 |
13.93 |
| 2026-05-20 00:00 |
03:43:55.81 |
+26:09:09.3 |
HIP 17407 |
13.89 |
| 2026-05-20 12:00 |
03:43:57.54 |
+26:09:15.2 |
HIP 17407 |
13.86 |
| 2026-05-21 00:00 |
03:43:59.27 |
+26:09:21.1 |
HIP 17407 |
13.84 |
| 2026-05-21 12:00 |
03:44:01.00 |
+26:09:27.0 |
HIP 17407 |
13.83 |
| 2026-05-22 00:00 |
03:44:02.73 |
+26:09:33.0 |
HIP 17407 |
13.84 |
| 2026-05-22 12:00 |
03:44:04.46 |
+26:09:39.0 |
HIP 17407 |
13.85 |
| 2026-05-23 00:00 |
03:44:06.18 |
+26:09:44.9 |
HIP 17407 |
13.88 |
| 2026-05-23 12:00 |
03:44:07.91 |
+26:09:50.9 |
HIP 17407 |
13.91 |
| 2026-05-24 00:00 |
03:44:09.64 |
+26:09:57.0 |
HIP 17407 |
13.96 |
| 2026-05-24 12:00 |
03:44:11.36 |
+26:10:03.0 |
HIP 17407 |
14.02 |
| 2026-05-25 00:00 |
03:44:13.08 |
+26:10:09.1 |
HIP 17407 |
14.09 |
| 2026-05-25 12:00 |
03:44:14.80 |
+26:10:15.2 |
HIP 17525 |
14.03 |
| 2026-05-26 00:00 |
03:44:16.52 |
+26:10:21.3 |
HIP 17525 |
13.64 |
| 2026-05-26 12:00 |
03:44:18.24 |
+26:10:27.4 |
HIP 17525 |
13.26 |
| 2026-05-27 00:00 |
03:44:19.96 |
+26:10:33.5 |
HIP 17525 |
12.88 |
| 2026-05-27 12:00 |
03:44:21.67 |
+26:10:39.6 |
HIP 17525 |
12.51 |
| 2026-05-28 00:00 |
03:44:23.38 |
+26:10:45.8 |
HIP 17525 |
12.13 |
| 2026-05-28 12:00 |
03:44:25.09 |
+26:10:52.0 |
HIP 17525 |
11.76 |
| 2026-05-29 00:00 |
03:44:26.80 |
+26:10:58.2 |
HIP 17525 |
11.38 |
| 2026-05-29 12:00 |
03:44:28.51 |
+26:11:04.4 |
HIP 17525 |
11.01 |
| 2026-05-30 00:00 |
03:44:30.21 |
+26:11:10.6 |
HIP 17525 |
10.64 |
| 2026-05-30 12:00 |
03:44:31.91 |
+26:11:16.8 |
HIP 17525 |
10.28 |
| 2026-05-31 00:00 |
03:44:33.61 |
+26:11:23.1 |
HIP 17525 |
9.91 |
| 2026-05-31 12:00 |
03:44:35.30 |
+26:11:29.4 |
HIP 17525 |
9.55 |
| 2026-06-01 00:00 |
03:44:36.99 |
+26:11:35.6 |
HIP 17525 |
9.19 |
| 2026-06-01 12:00 |
03:44:38.68 |
+26:11:41.9 |
HIP 17525 |
8.84 |
| 2026-06-02 00:00 |
03:44:40.36 |
+26:11:48.2 |
HIP 17525 |
8.49 |