| 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) |
| 2026-07-29 00:00 |
19:26:21.57 |
+16:41:25.2 |
HIP 95627 |
12.98 |
| 2026-07-29 12:00 |
19:26:18.10 |
+16:41:14.5 |
HIP 95627 |
13.47 |
| 2026-07-30 00:00 |
19:26:14.65 |
+16:41:03.6 |
HIP 95627 |
13.98 |
| 2026-07-30 12:00 |
19:26:11.20 |
+16:40:52.4 |
HIP 95627 |
14.52 |
| 2026-07-31 00:00 |
19:26:07.76 |
+16:40:41.0 |
HIP 95627 |
15.09 |
| 2026-07-31 12:00 |
19:26:04.33 |
+16:40:29.4 |
HIP 95627 |
15.68 |
| 2026-08-01 00:00 |
19:26:00.91 |
+16:40:17.5 |
HIP 95627 |
16.28 |
| 2026-08-01 12:00 |
19:25:57.50 |
+16:40:05.4 |
HIP 95627 |
16.90 |
| 2026-08-02 00:00 |
19:25:54.10 |
+16:39:53.0 |
HIP 95627 |
17.54 |
| 2026-08-02 12:00 |
19:25:50.71 |
+16:39:40.4 |
HIP 95627 |
18.19 |
| 2026-08-03 00:00 |
19:25:47.33 |
+16:39:27.5 |
HIP 95627 |
18.85 |
| 2026-08-03 12:00 |
19:25:43.96 |
+16:39:14.4 |
HIP 95627 |
19.52 |
| 2026-08-04 00:00 |
19:25:40.61 |
+16:39:01.1 |
HIP 95627 |
20.20 |
| 2026-08-04 12:00 |
19:25:37.26 |
+16:38:47.6 |
HIP 95627 |
20.88 |
| 2026-08-05 00:00 |
19:25:33.93 |
+16:38:33.8 |
HIP 95627 |
21.57 |
| 2026-08-05 12:00 |
19:25:30.61 |
+16:38:19.8 |
HIP 95435 |
21.95 |
| 2026-08-06 00:00 |
19:25:27.30 |
+16:38:05.5 |
HIP 95435 |
21.78 |
| 2026-08-06 12:00 |
19:25:24.01 |
+16:37:51.0 |
HIP 95435 |
21.65 |
| 2026-08-07 00:00 |
19:25:20.72 |
+16:37:36.3 |
HIP 95435 |
21.55 |
| 2026-08-07 12:00 |
19:25:17.45 |
+16:37:21.4 |
HIP 95435 |
21.48 |
| 2026-08-08 00:00 |
19:25:14.20 |
+16:37:06.3 |
HIP 95435 |
21.46 |
| 2026-08-08 12:00 |
19:25:10.95 |
+16:36:50.9 |
HIP 95435 |
21.47 |
| 2026-08-09 00:00 |
19:25:07.73 |
+16:36:35.3 |
HIP 95435 |
21.51 |
| 2026-08-09 12:00 |
19:25:04.51 |
+16:36:19.5 |
HIP 95435 |
21.59 |
| 2026-08-10 00:00 |
19:25:01.31 |
+16:36:03.4 |
HIP 95435 |
21.70 |
| 2026-08-10 12:00 |
19:24:58.12 |
+16:35:47.2 |
HIP 95435 |
21.85 |
| 2026-08-11 00:00 |
19:24:54.95 |
+16:35:30.7 |
HIP 95435 |
22.03 |
| 2026-08-11 12:00 |
19:24:51.80 |
+16:35:14.0 |
HIP 95398 |
22.20 |
| 2026-08-12 00:00 |
19:24:48.65 |
+16:34:57.1 |
HIP 95398 |
22.24 |
| 2026-08-12 12:00 |
19:24:45.53 |
+16:34:40.0 |
HIP 95398 |
22.32 |
| 2026-08-13 00:00 |
19:24:42.42 |
+16:34:22.7 |
HIP 95398 |
22.42 |
| 2026-08-13 12:00 |
19:24:39.33 |
+16:34:05.2 |
HIP 95398 |
22.56 |
| 2026-08-14 00:00 |
19:24:36.25 |
+16:33:47.5 |
HIP 95398 |
22.73 |
| 2026-08-14 12:00 |
19:24:33.19 |
+16:33:29.5 |
HIP 95398 |
22.93 |
| 2026-08-15 00:00 |
19:24:30.15 |
+16:33:11.4 |
HIP 95398 |
23.16 |
| 2026-08-15 12:00 |
19:24:27.12 |
+16:32:53.1 |
HIP 95398 |
23.41 |
| 2026-08-16 00:00 |
19:24:24.11 |
+16:32:34.5 |
HIP 95398 |
23.69 |
| 2026-08-16 12:00 |
19:24:21.12 |
+16:32:15.8 |
HIP 95398 |
24.00 |
| 2026-08-17 00:00 |
19:24:18.15 |
+16:31:56.9 |
HIP 95398 |
24.34 |
| 2026-08-17 12:00 |
19:24:15.19 |
+16:31:37.8 |
HIP 95398 |
24.69 |
| 2026-08-18 00:00 |
19:24:12.25 |
+16:31:18.5 |
HIP 95398 |
25.07 |
| 2026-08-18 12:00 |
19:24:09.33 |
+16:30:59.0 |
HIP 95398 |
25.47 |
| 2026-08-19 00:00 |
19:24:06.43 |
+16:30:39.3 |
HIP 95398 |
25.88 |