| 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) |
| 2026-05-12 00:00 |
04:30:11.11 |
+20:49:47.4 |
HIP 20994 |
2.90 |
| 2026-05-12 12:00 |
04:30:14.11 |
+20:49:54.0 |
HIP 20994 |
3.05 |
| 2026-05-13 00:00 |
04:30:17.12 |
+20:50:00.7 |
HIP 20994 |
3.35 |
| 2026-05-13 12:00 |
04:30:20.14 |
+20:50:07.5 |
HIP 20994 |
3.76 |
| 2026-05-14 00:00 |
04:30:23.17 |
+20:50:14.2 |
HIP 20994 |
4.26 |
| 2026-05-14 12:00 |
04:30:26.20 |
+20:50:20.9 |
HIP 20994 |
4.81 |
| 2026-05-15 00:00 |
04:30:29.24 |
+20:50:27.6 |
HIP 20994 |
5.40 |
| 2026-05-15 12:00 |
04:30:32.29 |
+20:50:34.3 |
HIP 20994 |
6.03 |
| 2026-05-16 00:00 |
04:30:35.34 |
+20:50:41.1 |
HIP 20994 |
6.67 |
| 2026-05-16 12:00 |
04:30:38.40 |
+20:50:47.8 |
HIP 20994 |
7.33 |
| 2026-05-17 00:00 |
04:30:41.47 |
+20:50:54.6 |
HIP 20994 |
8.00 |
| 2026-05-17 12:00 |
04:30:44.54 |
+20:51:01.3 |
HIP 20994 |
8.68 |
| 2026-05-18 00:00 |
04:30:47.62 |
+20:51:08.0 |
HIP 20994 |
9.37 |
| 2026-05-18 12:00 |
04:30:50.70 |
+20:51:14.8 |
HIP 20994 |
10.07 |
| 2026-05-19 00:00 |
04:30:53.79 |
+20:51:21.5 |
HIP 20994 |
10.77 |
| 2026-05-19 12:00 |
04:30:56.89 |
+20:51:28.3 |
HIP 20994 |
11.48 |
| 2026-05-20 00:00 |
04:30:59.99 |
+20:51:35.0 |
HIP 20994 |
12.19 |
| 2026-05-20 12:00 |
04:31:03.09 |
+20:51:41.8 |
HIP 20994 |
12.90 |
| 2026-05-21 00:00 |
04:31:06.20 |
+20:51:48.5 |
HIP 20994 |
13.62 |
| 2026-05-21 12:00 |
04:31:09.31 |
+20:51:55.3 |
HIP 20994 |
14.34 |
| 2026-05-22 00:00 |
04:31:12.43 |
+20:52:02.0 |
HIP 20994 |
15.06 |
| 2026-05-22 12:00 |
04:31:15.55 |
+20:52:08.8 |
HIP 20994 |
15.79 |
| 2026-05-23 00:00 |
04:31:18.68 |
+20:52:15.5 |
HIP 20994 |
16.52 |
| 2026-05-23 12:00 |
04:31:21.80 |
+20:52:22.2 |
HIP 20994 |
17.24 |
| 2026-05-24 00:00 |
04:31:24.94 |
+20:52:28.9 |
HIP 20994 |
17.97 |
| 2026-05-24 12:00 |
04:31:28.07 |
+20:52:35.7 |
HIP 20994 |
18.71 |
| 2026-05-25 00:00 |
04:31:31.21 |
+20:52:42.4 |
HIP 20994 |
19.44 |
| 2026-05-25 12:00 |
04:31:34.35 |
+20:52:49.1 |
HIP 20994 |
20.17 |
| 2026-05-26 00:00 |
04:31:37.49 |
+20:52:55.8 |
HIP 20994 |
20.91 |
| 2026-05-26 12:00 |
04:31:40.63 |
+20:53:02.5 |
HIP 20994 |
21.64 |
| 2026-05-27 00:00 |
04:31:43.78 |
+20:53:09.2 |
HIP 20994 |
22.38 |
| 2026-05-27 12:00 |
04:31:46.92 |
+20:53:15.9 |
HIP 20994 |
23.12 |
| 2026-05-28 00:00 |
04:31:50.07 |
+20:53:22.6 |
HIP 20994 |
23.86 |
| 2026-05-28 12:00 |
04:31:53.22 |
+20:53:29.2 |
HIP 20994 |
24.60 |
| 2026-05-29 00:00 |
04:31:56.37 |
+20:53:35.9 |
HIP 20994 |
25.34 |
| 2026-05-29 12:00 |
04:31:59.52 |
+20:53:42.6 |
HIP 20994 |
26.07 |
| 2026-05-30 00:00 |
04:32:02.67 |
+20:53:49.2 |
HIP 21256 |
26.79 |
| 2026-05-30 12:00 |
04:32:05.83 |
+20:53:55.8 |
HIP 21256 |
26.13 |
| 2026-05-31 00:00 |
04:32:08.98 |
+20:54:02.5 |
HIP 21256 |
25.47 |
| 2026-05-31 12:00 |
04:32:12.13 |
+20:54:09.1 |
HIP 21256 |
24.81 |
| 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 |