| Parameter |
Value |
| Designation |
C/2007 D2 (Spacewatch) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2006-11-24T08:05:07.175040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:05Z |
| Obs used |
72 |
| NEO |
- |
| M1 |
18.600 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2007-02-25.0000000 |
| e |
0.97763484 |
| q (au) |
1.245656 |
| a (au) |
55.696245 |
| i (deg) |
178.618011 |
| Ω (om, deg) |
297.125793 |
| ω (w, deg) |
65.126637 |
| M (ma, deg) |
0.219721 |
Magnitude
Scatter + Global Linear
$$
M_a = (18.407 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
18.407 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.715 |
| k |
0.989 |
| 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 |
04:32:15.28 |
+20:54:15.7 |
HIP 21256 |
24.16 |
| 2026-06-01 12:00 |
04:32:18.44 |
+20:54:22.3 |
HIP 21256 |
23.51 |
| 2026-06-02 00:00 |
04:32:21.59 |
+20:54:28.9 |
HIP 21256 |
22.87 |
| 2026-06-02 12:00 |
04:32:24.74 |
+20:54:35.4 |
HIP 21256 |
22.24 |
| 2026-06-03 00:00 |
04:32:27.89 |
+20:54:42.0 |
HIP 21256 |
21.61 |
| 2026-06-03 12:00 |
04:32:31.04 |
+20:54:48.5 |
HIP 21256 |
20.99 |
| 2026-06-04 00:00 |
04:32:34.18 |
+20:54:55.1 |
HIP 21256 |
20.39 |
| 2026-06-04 12:00 |
04:32:37.33 |
+20:55:01.6 |
HIP 21256 |
19.79 |
| 2026-06-05 00:00 |
04:32:40.47 |
+20:55:08.1 |
HIP 21256 |
19.20 |
| 2026-06-05 12:00 |
04:32:43.61 |
+20:55:14.6 |
HIP 21256 |
18.62 |
| 2026-06-06 00:00 |
04:32:46.75 |
+20:55:21.1 |
HIP 21256 |
18.05 |
| 2026-06-06 12:00 |
04:32:49.89 |
+20:55:27.5 |
HIP 21256 |
17.50 |
| 2026-06-07 00:00 |
04:32:53.02 |
+20:55:34.0 |
HIP 21256 |
16.97 |
| 2026-06-07 12:00 |
04:32:56.15 |
+20:55:40.4 |
HIP 21256 |
16.45 |
| 2026-06-08 00:00 |
04:32:59.28 |
+20:55:46.8 |
HIP 21256 |
15.94 |
| 2026-06-08 12:00 |
04:33:02.41 |
+20:55:53.2 |
HIP 21256 |
15.46 |
| 2026-06-09 00:00 |
04:33:05.53 |
+20:55:59.5 |
HIP 21256 |
15.00 |
| 2026-06-09 12:00 |
04:33:08.65 |
+20:56:05.9 |
HIP 21256 |
14.56 |
| 2026-06-10 00:00 |
04:33:11.76 |
+20:56:12.2 |
HIP 21256 |
14.15 |
| 2026-06-10 12:00 |
04:33:14.87 |
+20:56:18.6 |
HIP 21256 |
13.76 |
| 2026-06-11 00:00 |
04:33:17.98 |
+20:56:24.8 |
HIP 21256 |
13.41 |
| 2026-06-11 12:00 |
04:33:21.08 |
+20:56:31.1 |
HIP 21256 |
13.09 |
| 2026-06-12 00:00 |
04:33:24.17 |
+20:56:37.4 |
HIP 21256 |
12.80 |
| 2026-06-12 12:00 |
04:33:27.27 |
+20:56:43.6 |
HIP 21256 |
12.54 |
| 2026-06-13 00:00 |
04:33:30.35 |
+20:56:49.8 |
HIP 21256 |
12.33 |
| 2026-06-13 12:00 |
04:33:33.43 |
+20:56:56.0 |
HIP 21256 |
12.15 |
| 2026-06-14 00:00 |
04:33:36.51 |
+20:57:02.2 |
HIP 21256 |
12.02 |
| 2026-06-14 12:00 |
04:33:39.57 |
+20:57:08.3 |
HIP 21256 |
11.93 |
| 2026-06-15 00:00 |
04:33:42.64 |
+20:57:14.5 |
HIP 21256 |
11.89 |
| 2026-06-15 12:00 |
04:33:45.69 |
+20:57:20.5 |
HIP 21256 |
11.89 |
| 2026-06-16 00:00 |
04:33:48.74 |
+20:57:26.6 |
HIP 21256 |
11.93 |
| 2026-06-16 12:00 |
04:33:51.79 |
+20:57:32.7 |
HIP 21256 |
12.01 |
| 2026-06-17 00:00 |
04:33:54.82 |
+20:57:38.7 |
HIP 21256 |
12.14 |
| 2026-06-17 12:00 |
04:33:57.85 |
+20:57:44.7 |
HIP 21318 |
12.28 |
| 2026-06-18 00:00 |
04:34:00.87 |
+20:57:50.7 |
HIP 21318 |
11.71 |
| 2026-06-18 12:00 |
04:34:03.88 |
+20:57:56.6 |
HIP 21318 |
11.17 |
| 2026-06-19 00:00 |
04:34:06.89 |
+20:58:02.5 |
HIP 21318 |
10.64 |
| 2026-06-19 12:00 |
04:34:09.88 |
+20:58:08.4 |
HIP 21318 |
10.14 |
| 2026-06-20 00:00 |
04:34:12.87 |
+20:58:14.3 |
HIP 21318 |
9.66 |
| 2026-06-20 12:00 |
04:34:15.85 |
+20:58:20.1 |
HIP 21318 |
9.22 |
| 2026-06-21 00:00 |
04:34:18.82 |
+20:58:25.9 |
HIP 21318 |
8.81 |
| 2026-06-21 12:00 |
04:34:21.78 |
+20:58:31.7 |
HIP 21318 |
8.44 |
| 2026-06-22 00:00 |
04:34:24.74 |
+20:58:37.5 |
HIP 21318 |
8.11 |