| Parameter |
Value |
| Designation |
278P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2013-08-02T10:27:33.508800Z |
| Orbit solution date (soln_date, UTC) |
2021-09-20T00:13:08Z |
| Obs used |
519 |
| NEO |
- |
| M1 |
12.600 |
| K1 |
13.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-06-08.0000000 |
| e |
0.43343798 |
| q (au) |
2.096064 |
| a (au) |
3.699620 |
| i (deg) |
6.683671 |
| Ω (om, deg) |
15.492573 |
| ω (w, deg) |
237.922750 |
| M (ma, deg) |
93.431156 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.947 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.947 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-0.946 |
| 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 |
08:02:23.57 |
+25:52:56.5 |
HIP 39401 |
26.20 |
| 2026-05-12 12:00 |
08:02:46.93 |
+25:51:05.2 |
HIP 39401 |
25.96 |
| 2026-05-13 00:00 |
08:03:10.46 |
+25:49:13.4 |
HIP 39401 |
26.89 |
| 2026-05-13 12:00 |
08:03:34.16 |
+25:47:21.2 |
HIP 39401 |
28.92 |
| 2026-05-14 00:00 |
08:03:58.03 |
+25:45:28.4 |
HIP 39603 |
30.45 |
| 2026-05-14 12:00 |
08:04:22.07 |
+25:43:35.1 |
HIP 39648 |
27.53 |
| 2026-05-15 00:00 |
08:04:46.28 |
+25:41:41.3 |
HIP 39648 |
21.89 |
| 2026-05-15 12:00 |
08:05:10.65 |
+25:39:47.0 |
HIP 39648 |
16.32 |
| 2026-05-16 00:00 |
08:05:35.19 |
+25:37:52.1 |
HIP 39648 |
10.97 |
| 2026-05-16 12:00 |
08:05:59.89 |
+25:35:56.8 |
HIP 39648 |
6.53 |
| 2026-05-17 00:00 |
08:06:24.75 |
+25:34:00.9 |
HIP 39648 |
5.89 |
| 2026-05-17 12:00 |
08:06:49.77 |
+25:32:04.5 |
HIP 39648 |
9.88 |
| 2026-05-18 00:00 |
08:07:14.95 |
+25:30:07.6 |
HIP 39835 |
15.02 |
| 2026-05-18 12:00 |
08:07:40.28 |
+25:28:10.2 |
HIP 39835 |
10.29 |
| 2026-05-19 00:00 |
08:08:05.78 |
+25:26:12.3 |
HIP 39835 |
7.68 |
| 2026-05-19 12:00 |
08:08:31.42 |
+25:24:13.8 |
HIP 39835 |
9.30 |
| 2026-05-20 00:00 |
08:08:57.22 |
+25:22:14.9 |
HIP 39835 |
13.77 |
| 2026-05-20 12:00 |
08:09:23.17 |
+25:20:15.4 |
HIP 39969 |
13.98 |
| 2026-05-21 00:00 |
08:09:49.27 |
+25:18:15.4 |
HIP 40023 |
14.94 |
| 2026-05-21 12:00 |
08:10:15.52 |
+25:16:14.8 |
HIP 40023 |
14.49 |
| 2026-05-22 00:00 |
08:10:41.92 |
+25:14:13.8 |
HIP 40023 |
16.60 |
| 2026-05-22 12:00 |
08:11:08.46 |
+25:12:12.2 |
HIP 40157 |
12.71 |
| 2026-05-23 00:00 |
08:11:35.15 |
+25:10:10.1 |
HIP 40157 |
6.64 |
| 2026-05-23 12:00 |
08:12:01.98 |
+25:08:07.5 |
HIP 40157 |
2.75 |
| 2026-05-24 00:00 |
08:12:28.95 |
+25:06:04.4 |
HIP 40157 |
7.32 |
| 2026-05-24 12:00 |
08:12:56.06 |
+25:04:00.7 |
HIP 40157 |
13.54 |
| 2026-05-25 00:00 |
08:13:23.31 |
+25:01:56.6 |
HIP 40234 |
17.46 |
| 2026-05-25 12:00 |
08:13:50.70 |
+24:59:51.9 |
HIP 40388 |
19.81 |
| 2026-05-26 00:00 |
08:14:18.23 |
+24:57:46.6 |
HIP 40388 |
14.84 |
| 2026-05-26 12:00 |
08:14:45.89 |
+24:55:40.9 |
HIP 40388 |
11.60 |
| 2026-05-27 00:00 |
08:15:13.68 |
+24:53:34.6 |
HIP 40388 |
11.70 |
| 2026-05-27 12:00 |
08:15:41.61 |
+24:51:27.8 |
HIP 40388 |
15.10 |
| 2026-05-28 00:00 |
08:16:09.67 |
+24:49:20.4 |
HIP 40595 |
17.55 |
| 2026-05-28 12:00 |
08:16:37.86 |
+24:47:12.6 |
HIP 40595 |
11.01 |
| 2026-05-29 00:00 |
08:17:06.18 |
+24:45:04.2 |
HIP 40595 |
5.02 |
| 2026-05-29 12:00 |
08:17:34.63 |
+24:42:55.2 |
HIP 40595 |
4.61 |
| 2026-05-30 00:00 |
08:18:03.21 |
+24:40:45.7 |
HIP 40595 |
10.52 |
| 2026-05-30 12:00 |
08:18:31.91 |
+24:38:35.7 |
HIP 40595 |
17.17 |
| 2026-05-31 00:00 |
08:19:00.74 |
+24:36:25.2 |
HIP 40625 |
23.63 |
| 2026-05-31 12:00 |
08:19:29.70 |
+24:34:14.1 |
HIP 40756 |
24.20 |
| 2026-06-01 00:00 |
08:19:58.77 |
+24:32:02.5 |
HIP 40934 |
21.08 |
| 2026-06-01 12:00 |
08:20:27.97 |
+24:29:50.3 |
HIP 40934 |
18.06 |
| 2026-06-02 00:00 |
08:20:57.29 |
+24:27:37.6 |
HIP 40934 |
17.48 |