| Parameter |
Value |
| Designation |
C/2005 W2 (Christensen) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2006-03-27T09:29:05.815680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:54Z |
| Obs used |
219 |
| NEO |
- |
| M1 |
13.800 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2005-12-19.0000000 |
| e |
0.82445359 |
| q (au) |
3.331620 |
| a (au) |
18.978569 |
| i (deg) |
11.264027 |
| Ω (om, deg) |
336.615180 |
| ω (w, deg) |
111.670116 |
| M (ma, deg) |
358.827041 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.408 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.408 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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 |
16:30:32.88 |
-33:36:07.2 |
HIP 80875 |
16.37 |
| 2026-05-12 12:00 |
16:30:28.47 |
-33:36:03.1 |
HIP 80875 |
16.52 |
| 2026-05-13 00:00 |
16:30:24.05 |
-33:35:58.9 |
HIP 80875 |
16.72 |
| 2026-05-13 12:00 |
16:30:19.62 |
-33:35:54.5 |
HIP 80875 |
16.97 |
| 2026-05-14 00:00 |
16:30:15.17 |
-33:35:50.0 |
HIP 80875 |
17.27 |
| 2026-05-14 12:00 |
16:30:10.71 |
-33:35:45.4 |
HIP 80875 |
17.61 |
| 2026-05-15 00:00 |
16:30:06.24 |
-33:35:40.6 |
HIP 80875 |
17.99 |
| 2026-05-15 12:00 |
16:30:01.76 |
-33:35:35.7 |
HIP 80770 |
17.84 |
| 2026-05-16 00:00 |
16:29:57.26 |
-33:35:30.6 |
HIP 80770 |
17.41 |
| 2026-05-16 12:00 |
16:29:52.76 |
-33:35:25.4 |
HIP 80770 |
17.01 |
| 2026-05-17 00:00 |
16:29:48.24 |
-33:35:20.0 |
HIP 80770 |
16.66 |
| 2026-05-17 12:00 |
16:29:43.71 |
-33:35:14.5 |
HIP 80770 |
16.35 |
| 2026-05-18 00:00 |
16:29:39.17 |
-33:35:08.9 |
HIP 80770 |
16.09 |
| 2026-05-18 12:00 |
16:29:34.62 |
-33:35:03.1 |
HIP 80770 |
15.88 |
| 2026-05-19 00:00 |
16:29:30.07 |
-33:34:57.2 |
HIP 80770 |
15.72 |
| 2026-05-19 12:00 |
16:29:25.50 |
-33:34:51.2 |
HIP 80770 |
15.62 |
| 2026-05-20 00:00 |
16:29:20.93 |
-33:34:45.0 |
HIP 80770 |
15.57 |
| 2026-05-20 12:00 |
16:29:16.35 |
-33:34:38.7 |
HIP 80770 |
15.59 |
| 2026-05-21 00:00 |
16:29:11.76 |
-33:34:32.2 |
HIP 80770 |
15.65 |
| 2026-05-21 12:00 |
16:29:07.16 |
-33:34:25.6 |
HIP 80770 |
15.78 |
| 2026-05-22 00:00 |
16:29:02.56 |
-33:34:18.9 |
HIP 80770 |
15.96 |
| 2026-05-22 12:00 |
16:28:57.95 |
-33:34:12.0 |
HIP 80770 |
16.19 |
| 2026-05-23 00:00 |
16:28:53.33 |
-33:34:05.0 |
HIP 80770 |
16.48 |
| 2026-05-23 12:00 |
16:28:48.71 |
-33:33:57.9 |
HIP 80770 |
16.82 |
| 2026-05-24 00:00 |
16:28:44.09 |
-33:33:50.7 |
HIP 80770 |
17.20 |
| 2026-05-24 12:00 |
16:28:39.46 |
-33:33:43.3 |
HIP 80770 |
17.63 |
| 2026-05-25 00:00 |
16:28:34.83 |
-33:33:35.7 |
HIP 80770 |
18.10 |
| 2026-05-25 12:00 |
16:28:30.19 |
-33:33:28.1 |
HIP 80770 |
18.60 |
| 2026-05-26 00:00 |
16:28:25.55 |
-33:33:20.3 |
HIP 80770 |
19.14 |
| 2026-05-26 12:00 |
16:28:20.90 |
-33:33:12.4 |
HIP 80770 |
19.72 |
| 2026-05-27 00:00 |
16:28:16.26 |
-33:33:04.4 |
HIP 80770 |
20.32 |
| 2026-05-27 12:00 |
16:28:11.61 |
-33:32:56.2 |
HIP 80770 |
20.95 |
| 2026-05-28 00:00 |
16:28:06.96 |
-33:32:47.9 |
HIP 80770 |
21.61 |
| 2026-05-28 12:00 |
16:28:02.31 |
-33:32:39.5 |
HIP 80770 |
22.29 |
| 2026-05-29 00:00 |
16:27:57.66 |
-33:32:31.0 |
HIP 80770 |
22.99 |
| 2026-05-29 12:00 |
16:27:53.00 |
-33:32:22.3 |
HIP 80770 |
23.71 |
| 2026-05-30 00:00 |
16:27:48.35 |
-33:32:13.5 |
HIP 80770 |
24.45 |
| 2026-05-30 12:00 |
16:27:43.70 |
-33:32:04.6 |
HIP 80486 |
24.77 |
| 2026-05-31 00:00 |
16:27:39.05 |
-33:31:55.5 |
HIP 80486 |
23.82 |
| 2026-05-31 12:00 |
16:27:34.39 |
-33:31:46.4 |
HIP 80486 |
22.87 |
| 2026-06-01 00:00 |
16:27:29.74 |
-33:31:37.1 |
HIP 80486 |
21.92 |
| 2026-06-01 12:00 |
16:27:25.10 |
-33:31:27.7 |
HIP 80486 |
20.98 |
| 2026-06-02 00:00 |
16:27:20.45 |
-33:31:18.2 |
HIP 80486 |
20.04 |