| 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 |
1.000 |
| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
08:21:26.73 |
+24:25:24.3 |
HIP 40934 |
19.60 |
| 2026-06-03 00:00 |
08:21:56.29 |
+24:23:10.5 |
HIP 41076 |
21.89 |
| 2026-06-03 12:00 |
08:22:25.97 |
+24:20:56.2 |
HIP 41076 |
16.77 |
| 2026-06-04 00:00 |
08:22:55.77 |
+24:18:41.3 |
HIP 41076 |
13.60 |
| 2026-06-04 12:00 |
08:23:25.68 |
+24:16:25.8 |
HIP 41076 |
13.82 |
| 2026-06-05 00:00 |
08:23:55.71 |
+24:14:09.8 |
HIP 41076 |
17.36 |
| 2026-06-05 12:00 |
08:24:25.85 |
+24:11:53.2 |
HIP 41276 |
14.55 |
| 2026-06-06 00:00 |
08:24:56.11 |
+24:09:36.1 |
HIP 41276 |
11.99 |
| 2026-06-06 12:00 |
08:25:26.48 |
+24:07:18.4 |
HIP 41244 |
12.76 |
| 2026-06-07 00:00 |
08:25:56.96 |
+24:05:00.2 |
HIP 41244 |
16.35 |
| 2026-06-07 12:00 |
08:26:27.55 |
+24:02:41.4 |
HIP 41244 |
21.91 |
| 2026-06-08 00:00 |
08:26:58.26 |
+24:00:22.1 |
HIP 41574 |
23.99 |
| 2026-06-08 12:00 |
08:27:29.07 |
+23:58:02.1 |
HIP 41574 |
18.79 |
| 2026-06-09 00:00 |
08:28:00.00 |
+23:55:41.6 |
HIP 41574 |
15.49 |
| 2026-06-09 12:00 |
08:28:31.02 |
+23:53:20.6 |
HIP 41574 |
15.42 |
| 2026-06-10 00:00 |
08:29:02.16 |
+23:50:59.0 |
HIP 41574 |
18.64 |
| 2026-06-10 12:00 |
08:29:33.40 |
+23:48:36.8 |
HIP 41574 |
23.89 |
| 2026-06-11 00:00 |
08:30:04.75 |
+23:46:14.0 |
HIP 41743 |
19.39 |
| 2026-06-11 12:00 |
08:30:36.20 |
+23:43:50.7 |
HIP 41743 |
14.83 |
| 2026-06-12 00:00 |
08:31:07.75 |
+23:41:26.8 |
HIP 41743 |
13.39 |
| 2026-06-12 12:00 |
08:31:39.41 |
+23:39:02.3 |
HIP 41883 |
11.76 |
| 2026-06-13 00:00 |
08:32:11.17 |
+23:36:37.3 |
HIP 41883 |
8.70 |
| 2026-06-13 12:00 |
08:32:43.03 |
+23:34:11.6 |
HIP 41883 |
11.44 |
| 2026-06-14 00:00 |
08:33:14.99 |
+23:31:45.4 |
HIP 41883 |
17.47 |
| 2026-06-14 12:00 |
08:33:47.05 |
+23:29:18.7 |
HIP 41883 |
24.49 |
| 2026-06-15 00:00 |
08:34:19.20 |
+23:26:51.3 |
HIP 42053 |
31.74 |
| 2026-06-15 12:00 |
08:34:51.45 |
+23:24:23.4 |
HIP 42253 |
30.12 |
| 2026-06-16 00:00 |
08:35:23.80 |
+23:21:54.9 |
HIP 42253 |
22.30 |
| 2026-06-16 12:00 |
08:35:56.24 |
+23:19:25.8 |
HIP 42253 |
14.45 |
| 2026-06-17 00:00 |
08:36:28.78 |
+23:16:56.2 |
HIP 42253 |
6.57 |
| 2026-06-17 12:00 |
08:37:01.40 |
+23:14:26.0 |
HIP 42253 |
1.33 |
| 2026-06-18 00:00 |
08:37:34.12 |
+23:11:55.2 |
HIP 42253 |
9.26 |
| 2026-06-18 12:00 |
08:38:06.93 |
+23:09:23.8 |
HIP 42253 |
17.21 |
| 2026-06-19 00:00 |
08:38:39.82 |
+23:06:51.9 |
HIP 42443 |
20.11 |
| 2026-06-19 12:00 |
08:39:12.81 |
+23:04:19.3 |
HIP 42443 |
15.92 |
| 2026-06-20 00:00 |
08:39:45.88 |
+23:01:46.3 |
HIP 42443 |
15.19 |
| 2026-06-20 12:00 |
08:40:19.04 |
+22:59:12.6 |
HIP 42443 |
18.38 |
| 2026-06-21 00:00 |
08:40:52.28 |
+22:56:38.4 |
HIP 42443 |
23.98 |
| 2026-06-21 12:00 |
08:41:25.61 |
+22:54:03.6 |
HIP 42443 |
30.73 |
| 2026-06-22 00:00 |
08:41:59.02 |
+22:51:28.2 |
HIP 42840 |
26.05 |