C/2007 D2 (Spacewatch)
| 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) |
| 2026-02-03 00:00 |
04:26:45.85 |
+20:40:04.8 |
HIP 20785 |
20.02 |
| 2026-02-03 12:00 |
04:26:44.23 |
+20:40:02.0 |
HIP 20785 |
20.17 |
| 2026-02-04 00:00 |
04:26:42.63 |
+20:39:59.2 |
HIP 20785 |
20.31 |
| 2026-02-04 12:00 |
04:26:41.06 |
+20:39:56.5 |
HIP 20785 |
20.47 |
| 2026-02-05 00:00 |
04:26:39.52 |
+20:39:53.9 |
HIP 20785 |
20.62 |
| 2026-02-05 12:00 |
04:26:38.01 |
+20:39:51.3 |
HIP 20785 |
20.77 |
| 2026-02-06 00:00 |
04:26:36.53 |
+20:39:48.8 |
HIP 20785 |
20.93 |
| 2026-02-06 12:00 |
04:26:35.07 |
+20:39:46.3 |
HIP 20785 |
21.09 |
| 2026-02-07 00:00 |
04:26:33.65 |
+20:39:44.0 |
HIP 20785 |
21.24 |
| 2026-02-07 12:00 |
04:26:32.26 |
+20:39:41.7 |
HIP 20785 |
21.40 |
| 2026-02-08 00:00 |
04:26:30.90 |
+20:39:39.4 |
HIP 20785 |
21.56 |
| 2026-02-08 12:00 |
04:26:29.56 |
+20:39:37.3 |
HIP 20785 |
21.72 |
| 2026-02-09 00:00 |
04:26:28.26 |
+20:39:35.2 |
HIP 20785 |
21.88 |
| 2026-02-09 12:00 |
04:26:26.98 |
+20:39:33.1 |
HIP 20785 |
22.03 |
| 2026-02-10 00:00 |
04:26:25.74 |
+20:39:31.2 |
HIP 20785 |
22.19 |
| 2026-02-10 12:00 |
04:26:24.53 |
+20:39:29.3 |
HIP 20785 |
22.34 |
| 2026-02-11 00:00 |
04:26:23.34 |
+20:39:27.5 |
HIP 20785 |
22.50 |
| 2026-02-11 12:00 |
04:26:22.19 |
+20:39:25.7 |
HIP 20785 |
22.65 |
| 2026-02-12 00:00 |
04:26:21.07 |
+20:39:24.0 |
HIP 20785 |
22.79 |
| 2026-02-12 12:00 |
04:26:19.97 |
+20:39:22.4 |
HIP 20785 |
22.94 |
| 2026-02-13 00:00 |
04:26:18.91 |
+20:39:20.8 |
HIP 20785 |
23.08 |
| 2026-02-13 12:00 |
04:26:17.88 |
+20:39:19.4 |
HIP 20785 |
23.22 |
| 2026-02-14 00:00 |
04:26:16.88 |
+20:39:18.0 |
HIP 20785 |
23.36 |
| 2026-02-14 12:00 |
04:26:15.90 |
+20:39:16.6 |
HIP 20785 |
23.50 |
| 2026-02-15 00:00 |
04:26:14.96 |
+20:39:15.4 |
HIP 20785 |
23.63 |
| 2026-02-15 12:00 |
04:26:14.05 |
+20:39:14.2 |
HIP 20785 |
23.76 |
| 2026-02-16 00:00 |
04:26:13.17 |
+20:39:13.0 |
HIP 20785 |
23.88 |
| 2026-02-16 12:00 |
04:26:12.33 |
+20:39:12.0 |
HIP 20785 |
24.00 |
| 2026-02-17 00:00 |
04:26:11.51 |
+20:39:11.0 |
HIP 20785 |
24.12 |
| 2026-02-17 12:00 |
04:26:10.72 |
+20:39:10.1 |
HIP 20785 |
24.23 |
| 2026-02-18 00:00 |
04:26:09.96 |
+20:39:09.2 |
HIP 20785 |
24.34 |
| 2026-02-18 12:00 |
04:26:09.24 |
+20:39:08.4 |
HIP 20785 |
24.44 |
| 2026-02-19 00:00 |
04:26:08.54 |
+20:39:07.7 |
HIP 20785 |
24.54 |
| 2026-02-19 12:00 |
04:26:07.88 |
+20:39:07.1 |
HIP 20785 |
24.64 |
| 2026-02-20 00:00 |
04:26:07.24 |
+20:39:06.5 |
HIP 20785 |
24.73 |
| 2026-02-20 12:00 |
04:26:06.64 |
+20:39:06.0 |
HIP 20785 |
24.82 |
| 2026-02-21 00:00 |
04:26:06.07 |
+20:39:05.6 |
HIP 20785 |
24.90 |
| 2026-02-21 12:00 |
04:26:05.53 |
+20:39:05.2 |
HIP 20785 |
24.98 |
| 2026-02-22 00:00 |
04:26:05.02 |
+20:39:05.0 |
HIP 20785 |
25.05 |
| 2026-02-22 12:00 |
04:26:04.54 |
+20:39:04.7 |
HIP 20785 |
25.12 |
| 2026-02-23 00:00 |
04:26:04.09 |
+20:39:04.6 |
HIP 20785 |
25.18 |
| 2026-02-23 12:00 |
04:26:03.67 |
+20:39:04.5 |
HIP 20785 |
25.24 |
| 2026-02-24 00:00 |
04:26:03.28 |
+20:39:04.5 |
HIP 20785 |
25.30 |