| Parameter |
Value |
| Designation |
P/2008 Y3 (McNaught) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2009-01-11T23:10:23.174400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:26Z |
| Obs used |
164 |
| NEO |
- |
| M1 |
4.500 |
| K1 |
16.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-02-17.0000000 |
| e |
0.44766720 |
| q (au) |
4.434244 |
| a (au) |
8.028211 |
| i (deg) |
38.813188 |
| Ω (om, deg) |
262.934144 |
| ω (w, deg) |
238.279400 |
| M (ma, deg) |
1.561327 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.713 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.713 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.998 |
| 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 |
23:57:19.20 |
+37:40:26.4 |
HIP 118297 |
28.75 |
| 2026-05-12 12:00 |
23:57:31.97 |
+37:42:38.1 |
HIP 118297 |
25.77 |
| 2026-05-13 00:00 |
23:57:44.67 |
+37:44:50.1 |
HIP 118297 |
22.91 |
| 2026-05-13 12:00 |
23:57:57.30 |
+37:47:02.3 |
HIP 118297 |
20.22 |
| 2026-05-14 00:00 |
23:58:09.86 |
+37:49:14.8 |
HIP 118297 |
17.76 |
| 2026-05-14 12:00 |
23:58:22.36 |
+37:51:27.5 |
HIP 118297 |
15.63 |
| 2026-05-15 00:00 |
23:58:34.78 |
+37:53:40.4 |
HIP 118297 |
13.99 |
| 2026-05-15 12:00 |
23:58:47.14 |
+37:55:53.5 |
HIP 118297 |
13.02 |
| 2026-05-16 00:00 |
23:58:59.42 |
+37:58:06.9 |
HIP 118297 |
12.86 |
| 2026-05-16 12:00 |
23:59:11.63 |
+38:00:20.4 |
HIP 118297 |
13.53 |
| 2026-05-17 00:00 |
23:59:23.77 |
+38:02:34.2 |
HIP 118297 |
14.92 |
| 2026-05-17 12:00 |
23:59:35.84 |
+38:04:48.2 |
HIP 19 |
15.28 |
| 2026-05-18 00:00 |
23:59:47.83 |
+38:07:02.3 |
HIP 19 |
12.23 |
| 2026-05-18 12:00 |
23:59:59.76 |
+38:09:16.6 |
HIP 19 |
9.33 |
| 2026-05-19 00:00 |
00:00:11.60 |
+38:11:31.1 |
HIP 19 |
6.73 |
| 2026-05-19 12:00 |
00:00:23.37 |
+38:13:45.8 |
HIP 19 |
4.94 |
| 2026-05-20 00:00 |
00:00:35.07 |
+38:16:00.7 |
HIP 19 |
4.91 |
| 2026-05-20 12:00 |
00:00:46.68 |
+38:18:15.7 |
HIP 19 |
6.65 |
| 2026-05-21 00:00 |
00:00:58.22 |
+38:20:30.8 |
HIP 19 |
9.19 |
| 2026-05-21 12:00 |
00:01:09.69 |
+38:22:46.1 |
HIP 19 |
12.04 |
| 2026-05-22 00:00 |
00:01:21.07 |
+38:25:01.6 |
HIP 19 |
15.00 |
| 2026-05-22 12:00 |
00:01:32.38 |
+38:27:17.2 |
HIP 19 |
18.03 |
| 2026-05-23 00:00 |
00:01:43.61 |
+38:29:32.9 |
HIP 19 |
21.08 |
| 2026-05-23 12:00 |
00:01:54.76 |
+38:31:48.7 |
HIP 264 |
23.91 |
| 2026-05-24 00:00 |
00:02:05.82 |
+38:34:04.7 |
HIP 264 |
24.23 |
| 2026-05-24 12:00 |
00:02:16.81 |
+38:36:20.7 |
HIP 264 |
24.96 |
| 2026-05-25 00:00 |
00:02:27.72 |
+38:38:36.9 |
HIP 264 |
26.05 |
| 2026-05-25 12:00 |
00:02:38.54 |
+38:40:53.2 |
HIP 387 |
26.39 |
| 2026-05-26 00:00 |
00:02:49.29 |
+38:43:09.6 |
HIP 387 |
23.87 |
| 2026-05-26 12:00 |
00:02:59.95 |
+38:45:26.1 |
HIP 387 |
21.51 |
| 2026-05-27 00:00 |
00:03:10.52 |
+38:47:42.7 |
HIP 387 |
19.38 |
| 2026-05-27 12:00 |
00:03:21.01 |
+38:49:59.3 |
HIP 387 |
17.55 |
| 2026-05-28 00:00 |
00:03:31.42 |
+38:52:16.0 |
HIP 387 |
16.12 |
| 2026-05-28 12:00 |
00:03:41.75 |
+38:54:32.9 |
HIP 325 |
13.84 |
| 2026-05-29 00:00 |
00:03:51.99 |
+38:56:49.7 |
HIP 325 |
10.98 |
| 2026-05-29 12:00 |
00:04:02.14 |
+38:59:06.7 |
HIP 325 |
8.26 |
| 2026-05-30 00:00 |
00:04:12.20 |
+39:01:23.7 |
HIP 325 |
5.82 |
| 2026-05-30 12:00 |
00:04:22.18 |
+39:03:40.7 |
HIP 325 |
4.20 |
| 2026-05-31 00:00 |
00:04:32.07 |
+39:05:57.8 |
HIP 325 |
4.37 |
| 2026-05-31 12:00 |
00:04:41.88 |
+39:08:14.9 |
HIP 325 |
6.18 |
| 2026-06-01 00:00 |
00:04:51.59 |
+39:10:32.1 |
HIP 325 |
8.64 |
| 2026-06-01 12:00 |
00:05:01.22 |
+39:12:49.3 |
HIP 325 |
11.33 |
| 2026-06-02 00:00 |
00:05:10.76 |
+39:15:06.5 |
HIP 325 |
14.10 |