| Parameter |
Value |
| Designation |
C/2007 Y2 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-04-08T09:35:06.708480Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:15Z |
| Obs used |
81 |
| NEO |
- |
| M1 |
9.200 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-03-10.0000000 |
| e |
0.99652600 |
| q (au) |
4.208958 |
| a (au) |
1211.561103 |
| i (deg) |
98.503197 |
| Ω (om, deg) |
303.462012 |
| ω (w, deg) |
257.686731 |
| M (ma, deg) |
359.999313 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.768 + 3.627\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.768 |
| n |
3.627 |
| gf |
0.997 |
| gb |
-1.000 |
| k |
0.998 |
| 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) |
| 2026-09-20 00:00 |
19:21:47.42 |
+16:04:45.5 |
HIP 95346 |
29.83 |
| 2026-09-20 12:00 |
19:21:46.08 |
+16:04:18.2 |
HIP 95346 |
30.09 |
| 2026-09-21 00:00 |
19:21:44.78 |
+16:03:50.8 |
HIP 95346 |
30.35 |
| 2026-09-21 12:00 |
19:21:43.50 |
+16:03:23.4 |
HIP 95346 |
30.62 |
| 2026-09-22 00:00 |
19:21:42.25 |
+16:02:56.0 |
HIP 95346 |
30.88 |
| 2026-09-22 12:00 |
19:21:41.03 |
+16:02:28.5 |
HIP 95346 |
31.15 |
| 2026-09-23 00:00 |
19:21:39.84 |
+16:02:01.0 |
HIP 95346 |
31.41 |
| 2026-09-23 12:00 |
19:21:38.68 |
+16:01:33.4 |
HIP 95346 |
31.68 |
| 2026-09-24 00:00 |
19:21:37.55 |
+16:01:05.9 |
HIP 95346 |
31.95 |
| 2026-09-24 12:00 |
19:21:36.44 |
+16:00:38.3 |
HIP 95346 |
32.21 |
| 2026-09-25 00:00 |
19:21:35.36 |
+16:00:10.7 |
HIP 95346 |
32.48 |
| 2026-09-25 12:00 |
19:21:34.32 |
+15:59:43.0 |
HIP 95346 |
32.74 |
| 2026-09-26 00:00 |
19:21:33.30 |
+15:59:15.4 |
HIP 95346 |
33.01 |
| 2026-09-26 12:00 |
19:21:32.31 |
+15:58:47.7 |
HIP 95346 |
33.27 |
| 2026-09-27 00:00 |
19:21:31.35 |
+15:58:20.0 |
HIP 95346 |
33.53 |
| 2026-09-27 12:00 |
19:21:30.42 |
+15:57:52.3 |
HIP 95346 |
33.80 |
| 2026-09-28 00:00 |
19:21:29.51 |
+15:57:24.6 |
HIP 95346 |
34.06 |
| 2026-09-28 12:00 |
19:21:28.64 |
+15:56:56.9 |
HIP 95334 |
34.23 |
| 2026-09-29 00:00 |
19:21:27.80 |
+15:56:29.2 |
HIP 95334 |
34.27 |
| 2026-09-29 12:00 |
19:21:26.98 |
+15:56:01.4 |
HIP 95334 |
34.31 |
| 2026-09-30 00:00 |
19:21:26.20 |
+15:55:33.7 |
HIP 95334 |
34.35 |
| 2026-09-30 12:00 |
19:21:25.44 |
+15:55:06.0 |
HIP 95334 |
34.40 |
| 2026-10-01 00:00 |
19:21:24.71 |
+15:54:38.3 |
HIP 95334 |
34.44 |
| 2026-10-01 12:00 |
19:21:24.01 |
+15:54:10.5 |
HIP 95334 |
34.49 |
| 2026-10-02 00:00 |
19:21:23.35 |
+15:53:42.8 |
HIP 95334 |
34.53 |
| 2026-10-02 12:00 |
19:21:22.71 |
+15:53:15.1 |
HIP 95334 |
34.58 |
| 2026-10-03 00:00 |
19:21:22.10 |
+15:52:47.4 |
HIP 95334 |
34.62 |
| 2026-10-03 12:00 |
19:21:21.52 |
+15:52:19.8 |
HIP 95334 |
34.66 |
| 2026-10-04 00:00 |
19:21:20.97 |
+15:51:52.1 |
HIP 95334 |
34.71 |
| 2026-10-04 12:00 |
19:21:20.45 |
+15:51:24.5 |
HIP 95334 |
34.75 |
| 2026-10-05 00:00 |
19:21:19.96 |
+15:50:56.9 |
HIP 95334 |
34.79 |
| 2026-10-05 12:00 |
19:21:19.50 |
+15:50:29.3 |
HIP 95334 |
34.84 |
| 2026-10-06 00:00 |
19:21:19.07 |
+15:50:01.7 |
HIP 95334 |
34.88 |
| 2026-10-06 12:00 |
19:21:18.67 |
+15:49:34.2 |
HIP 95334 |
34.92 |
| 2026-10-07 00:00 |
19:21:18.30 |
+15:49:06.7 |
HIP 95334 |
34.96 |
| 2026-10-07 12:00 |
19:21:17.96 |
+15:48:39.2 |
HIP 95334 |
35.00 |
| 2026-10-08 00:00 |
19:21:17.65 |
+15:48:11.8 |
HIP 95334 |
35.04 |
| 2026-10-08 12:00 |
19:21:17.37 |
+15:47:44.4 |
HIP 95334 |
35.07 |
| 2026-10-09 00:00 |
19:21:17.12 |
+15:47:17.0 |
HIP 95334 |
35.11 |
| 2026-10-09 12:00 |
19:21:16.89 |
+15:46:49.7 |
HIP 95334 |
35.14 |
| 2026-10-10 00:00 |
19:21:16.70 |
+15:46:22.5 |
HIP 95334 |
35.18 |
| 2026-10-10 12:00 |
19:21:16.54 |
+15:45:55.3 |
HIP 95334 |
35.21 |
| 2026-10-11 00:00 |
19:21:16.41 |
+15:45:28.1 |
HIP 95334 |
35.24 |