| 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) |
| 2026-09-20 00:00 |
04:38:02.97 |
+21:03:47.3 |
HIP 21639 |
20.47 |
| 2026-09-20 12:00 |
04:38:01.82 |
+21:03:44.2 |
HIP 21639 |
20.58 |
| 2026-09-21 00:00 |
04:38:00.64 |
+21:03:41.0 |
HIP 21639 |
20.69 |
| 2026-09-21 12:00 |
04:37:59.43 |
+21:03:37.7 |
HIP 21639 |
20.81 |
| 2026-09-22 00:00 |
04:37:58.20 |
+21:03:34.4 |
HIP 21639 |
20.94 |
| 2026-09-22 12:00 |
04:37:56.93 |
+21:03:31.1 |
HIP 21639 |
21.08 |
| 2026-09-23 00:00 |
04:37:55.64 |
+21:03:27.7 |
HIP 21639 |
21.22 |
| 2026-09-23 12:00 |
04:37:54.32 |
+21:03:24.2 |
HIP 21639 |
21.37 |
| 2026-09-24 00:00 |
04:37:52.97 |
+21:03:20.7 |
HIP 21639 |
21.52 |
| 2026-09-24 12:00 |
04:37:51.59 |
+21:03:17.1 |
HIP 21639 |
21.68 |
| 2026-09-25 00:00 |
04:37:50.19 |
+21:03:13.5 |
HIP 21639 |
21.85 |
| 2026-09-25 12:00 |
04:37:48.75 |
+21:03:09.8 |
HIP 21639 |
22.03 |
| 2026-09-26 00:00 |
04:37:47.29 |
+21:03:06.1 |
HIP 21639 |
22.22 |
| 2026-09-26 12:00 |
04:37:45.80 |
+21:03:02.3 |
HIP 21639 |
22.41 |
| 2026-09-27 00:00 |
04:37:44.29 |
+21:02:58.5 |
HIP 21639 |
22.61 |
| 2026-09-27 12:00 |
04:37:42.74 |
+21:02:54.6 |
HIP 21639 |
22.82 |
| 2026-09-28 00:00 |
04:37:41.17 |
+21:02:50.6 |
HIP 21639 |
23.03 |
| 2026-09-28 12:00 |
04:37:39.57 |
+21:02:46.7 |
HIP 21639 |
23.26 |
| 2026-09-29 00:00 |
04:37:37.95 |
+21:02:42.6 |
HIP 21604 |
23.37 |
| 2026-09-29 12:00 |
04:37:36.29 |
+21:02:38.5 |
HIP 21604 |
23.45 |
| 2026-09-30 00:00 |
04:37:34.61 |
+21:02:34.4 |
HIP 21604 |
23.55 |
| 2026-09-30 12:00 |
04:37:32.91 |
+21:02:30.2 |
HIP 21604 |
23.65 |
| 2026-10-01 00:00 |
04:37:31.17 |
+21:02:25.9 |
HIP 21604 |
23.76 |
| 2026-10-01 12:00 |
04:37:29.41 |
+21:02:21.6 |
HIP 21604 |
23.88 |
| 2026-10-02 00:00 |
04:37:27.62 |
+21:02:17.2 |
HIP 21604 |
24.01 |
| 2026-10-02 12:00 |
04:37:25.80 |
+21:02:12.8 |
HIP 21604 |
24.15 |
| 2026-10-03 00:00 |
04:37:23.96 |
+21:02:08.4 |
HIP 21604 |
24.29 |
| 2026-10-03 12:00 |
04:37:22.09 |
+21:02:03.8 |
HIP 21604 |
24.45 |
| 2026-10-04 00:00 |
04:37:20.20 |
+21:01:59.3 |
HIP 21604 |
24.62 |
| 2026-10-04 12:00 |
04:37:18.28 |
+21:01:54.7 |
HIP 21604 |
24.79 |
| 2026-10-05 00:00 |
04:37:16.33 |
+21:01:50.0 |
HIP 21604 |
24.98 |
| 2026-10-05 12:00 |
04:37:14.35 |
+21:01:45.3 |
HIP 21604 |
25.17 |
| 2026-10-06 00:00 |
04:37:12.35 |
+21:01:40.5 |
HIP 21604 |
25.38 |
| 2026-10-06 12:00 |
04:37:10.32 |
+21:01:35.7 |
HIP 21604 |
25.59 |
| 2026-10-07 00:00 |
04:37:08.27 |
+21:01:30.9 |
HIP 21604 |
25.82 |
| 2026-10-07 12:00 |
04:37:06.19 |
+21:01:25.9 |
HIP 21604 |
26.05 |
| 2026-10-08 00:00 |
04:37:04.09 |
+21:01:21.0 |
HIP 21604 |
26.30 |
| 2026-10-08 12:00 |
04:37:01.96 |
+21:01:16.0 |
HIP 21604 |
26.56 |
| 2026-10-09 00:00 |
04:36:59.80 |
+21:01:10.9 |
HIP 21604 |
26.82 |
| 2026-10-09 12:00 |
04:36:57.62 |
+21:01:05.8 |
HIP 21604 |
27.10 |
| 2026-10-10 00:00 |
04:36:55.41 |
+21:01:00.6 |
HIP 21604 |
27.39 |
| 2026-10-10 12:00 |
04:36:53.18 |
+21:00:55.4 |
HIP 21604 |
27.69 |
| 2026-10-11 00:00 |
04:36:50.93 |
+21:00:50.2 |
HIP 21604 |
27.99 |