| 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) |
| 2026-03-26 00:00 |
03:41:11.90 |
+26:01:53.9 |
HIP 17245 |
25.33 |
| 2026-03-26 12:00 |
03:41:12.93 |
+26:01:55.3 |
HIP 17245 |
25.30 |
| 2026-03-27 00:00 |
03:41:13.96 |
+26:01:56.9 |
HIP 17245 |
25.28 |
| 2026-03-27 12:00 |
03:41:15.01 |
+26:01:58.4 |
HIP 17245 |
25.26 |
| 2026-03-28 00:00 |
03:41:16.06 |
+26:02:00.1 |
HIP 17245 |
25.24 |
| 2026-03-28 12:00 |
03:41:17.14 |
+26:02:01.8 |
HIP 17245 |
25.23 |
| 2026-03-29 00:00 |
03:41:18.22 |
+26:02:03.5 |
HIP 17245 |
25.22 |
| 2026-03-29 12:00 |
03:41:19.31 |
+26:02:05.3 |
HIP 17245 |
25.21 |
| 2026-03-30 00:00 |
03:41:20.42 |
+26:02:07.2 |
HIP 17245 |
25.20 |
| 2026-03-30 12:00 |
03:41:21.54 |
+26:02:09.1 |
HIP 17245 |
25.20 |
| 2026-03-31 00:00 |
03:41:22.67 |
+26:02:11.0 |
HIP 17245 |
25.20 |
| 2026-03-31 12:00 |
03:41:23.81 |
+26:02:13.0 |
HIP 17245 |
25.20 |
| 2026-04-01 00:00 |
03:41:24.96 |
+26:02:15.1 |
HIP 17245 |
25.21 |
| 2026-04-01 12:00 |
03:41:26.12 |
+26:02:17.2 |
HIP 17245 |
25.22 |
| 2026-04-02 00:00 |
03:41:27.30 |
+26:02:19.3 |
HIP 17245 |
25.24 |
| 2026-04-02 12:00 |
03:41:28.48 |
+26:02:21.6 |
HIP 17245 |
25.25 |
| 2026-04-03 00:00 |
03:41:29.68 |
+26:02:23.8 |
HIP 17245 |
25.27 |
| 2026-04-03 12:00 |
03:41:30.89 |
+26:02:26.1 |
HIP 17245 |
25.30 |
| 2026-04-04 00:00 |
03:41:32.11 |
+26:02:28.5 |
HIP 17245 |
25.33 |
| 2026-04-04 12:00 |
03:41:33.34 |
+26:02:30.9 |
HIP 17245 |
25.36 |
| 2026-04-05 00:00 |
03:41:34.58 |
+26:02:33.4 |
HIP 17245 |
25.39 |
| 2026-04-05 12:00 |
03:41:35.83 |
+26:02:35.9 |
HIP 17245 |
25.43 |
| 2026-04-06 00:00 |
03:41:37.09 |
+26:02:38.5 |
HIP 17245 |
25.48 |
| 2026-04-06 12:00 |
03:41:38.36 |
+26:02:41.1 |
HIP 17245 |
25.52 |
| 2026-04-07 00:00 |
03:41:39.65 |
+26:02:43.7 |
HIP 17245 |
25.58 |
| 2026-04-07 12:00 |
03:41:40.94 |
+26:02:46.5 |
HIP 17245 |
25.63 |
| 2026-04-08 00:00 |
03:41:42.24 |
+26:02:49.2 |
HIP 17245 |
25.69 |
| 2026-04-08 12:00 |
03:41:43.55 |
+26:02:52.0 |
HIP 17245 |
25.76 |
| 2026-04-09 00:00 |
03:41:44.87 |
+26:02:54.9 |
HIP 17245 |
25.82 |
| 2026-04-09 12:00 |
03:41:46.21 |
+26:02:57.8 |
HIP 17245 |
25.90 |
| 2026-04-10 00:00 |
03:41:47.55 |
+26:03:00.8 |
HIP 17245 |
25.97 |
| 2026-04-10 12:00 |
03:41:48.90 |
+26:03:03.8 |
HIP 17245 |
26.06 |
| 2026-04-11 00:00 |
03:41:50.26 |
+26:03:06.9 |
HIP 17245 |
26.14 |
| 2026-04-11 12:00 |
03:41:51.63 |
+26:03:10.0 |
HIP 17245 |
26.23 |
| 2026-04-12 00:00 |
03:41:53.01 |
+26:03:13.1 |
HIP 17245 |
26.33 |
| 2026-04-12 12:00 |
03:41:54.40 |
+26:03:16.3 |
HIP 17245 |
26.43 |
| 2026-04-13 00:00 |
03:41:55.80 |
+26:03:19.6 |
HIP 17245 |
26.53 |
| 2026-04-13 12:00 |
03:41:57.20 |
+26:03:22.9 |
HIP 17245 |
26.64 |
| 2026-04-14 00:00 |
03:41:58.62 |
+26:03:26.2 |
HIP 17245 |
26.75 |
| 2026-04-14 12:00 |
03:42:00.04 |
+26:03:29.6 |
HIP 17245 |
26.87 |
| 2026-04-15 00:00 |
03:42:01.47 |
+26:03:33.0 |
HIP 17245 |
26.99 |
| 2026-04-15 12:00 |
03:42:02.91 |
+26:03:36.5 |
HIP 17245 |
27.12 |
| 2026-04-16 00:00 |
03:42:04.36 |
+26:03:40.0 |
HIP 17245 |
27.25 |