| Parameter |
Value |
| Designation |
C/1997 P2 (Spacewatch) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1997-08-31T03:18:18.817920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:53Z |
| Obs used |
94 |
| NEO |
- |
| M1 |
10.200 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1997-08-29.0000000 |
| e |
1.02794485 |
| q (au) |
4.262988 |
| a (au) |
-152.550043 |
| i (deg) |
14.579088 |
| Ω (om, deg) |
302.910064 |
| ω (w, deg) |
24.504901 |
| M (ma, deg) |
-0.001118 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.430 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.430 |
| n |
2.000 |
| 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) |
| 2026-09-20 00:00 |
07:42:43.54 |
+23:55:15.8 |
HIP 37517 |
12.57 |
| 2026-09-20 12:00 |
07:42:44.77 |
+23:55:13.7 |
HIP 37517 |
12.82 |
| 2026-09-21 00:00 |
07:42:45.98 |
+23:55:11.7 |
HIP 37517 |
13.06 |
| 2026-09-21 12:00 |
07:42:47.17 |
+23:55:09.8 |
HIP 37517 |
13.29 |
| 2026-09-22 00:00 |
07:42:48.34 |
+23:55:07.9 |
HIP 37650 |
13.17 |
| 2026-09-22 12:00 |
07:42:49.50 |
+23:55:06.1 |
HIP 37650 |
12.94 |
| 2026-09-23 00:00 |
07:42:50.63 |
+23:55:04.3 |
HIP 37650 |
12.72 |
| 2026-09-23 12:00 |
07:42:51.75 |
+23:55:02.5 |
HIP 37650 |
12.50 |
| 2026-09-24 00:00 |
07:42:52.84 |
+23:55:00.8 |
HIP 37650 |
12.28 |
| 2026-09-24 12:00 |
07:42:53.92 |
+23:54:59.2 |
HIP 37650 |
12.08 |
| 2026-09-25 00:00 |
07:42:54.97 |
+23:54:57.6 |
HIP 37650 |
11.87 |
| 2026-09-25 12:00 |
07:42:56.01 |
+23:54:56.1 |
HIP 37650 |
11.67 |
| 2026-09-26 00:00 |
07:42:57.03 |
+23:54:54.6 |
HIP 37650 |
11.48 |
| 2026-09-26 12:00 |
07:42:58.02 |
+23:54:53.2 |
HIP 37650 |
11.30 |
| 2026-09-27 00:00 |
07:42:59.00 |
+23:54:51.8 |
HIP 37650 |
11.11 |
| 2026-09-27 12:00 |
07:42:59.96 |
+23:54:50.5 |
HIP 37650 |
10.94 |
| 2026-09-28 00:00 |
07:43:00.89 |
+23:54:49.2 |
HIP 37650 |
10.77 |
| 2026-09-28 12:00 |
07:43:01.81 |
+23:54:48.0 |
HIP 37650 |
10.60 |
| 2026-09-29 00:00 |
07:43:02.71 |
+23:54:46.9 |
HIP 37650 |
10.45 |
| 2026-09-29 12:00 |
07:43:03.58 |
+23:54:45.8 |
HIP 37650 |
10.29 |
| 2026-09-30 00:00 |
07:43:04.44 |
+23:54:44.7 |
HIP 37650 |
10.14 |
| 2026-09-30 12:00 |
07:43:05.27 |
+23:54:43.7 |
HIP 37650 |
10.00 |
| 2026-10-01 00:00 |
07:43:06.09 |
+23:54:42.8 |
HIP 37650 |
9.87 |
| 2026-10-01 12:00 |
07:43:06.88 |
+23:54:41.9 |
HIP 37650 |
9.73 |
| 2026-10-02 00:00 |
07:43:07.66 |
+23:54:41.0 |
HIP 37650 |
9.61 |
| 2026-10-02 12:00 |
07:43:08.41 |
+23:54:40.2 |
HIP 37650 |
9.49 |
| 2026-10-03 00:00 |
07:43:09.14 |
+23:54:39.5 |
HIP 37650 |
9.37 |
| 2026-10-03 12:00 |
07:43:09.85 |
+23:54:38.8 |
HIP 37650 |
9.26 |
| 2026-10-04 00:00 |
07:43:10.54 |
+23:54:38.2 |
HIP 37650 |
9.16 |
| 2026-10-04 12:00 |
07:43:11.21 |
+23:54:37.6 |
HIP 37650 |
9.06 |
| 2026-10-05 00:00 |
07:43:11.86 |
+23:54:37.1 |
HIP 37650 |
8.96 |
| 2026-10-05 12:00 |
07:43:12.49 |
+23:54:36.6 |
HIP 37650 |
8.87 |
| 2026-10-06 00:00 |
07:43:13.09 |
+23:54:36.2 |
HIP 37650 |
8.79 |
| 2026-10-06 12:00 |
07:43:13.68 |
+23:54:35.8 |
HIP 37650 |
8.71 |
| 2026-10-07 00:00 |
07:43:14.24 |
+23:54:35.5 |
HIP 37650 |
8.63 |
| 2026-10-07 12:00 |
07:43:14.79 |
+23:54:35.3 |
HIP 37650 |
8.56 |
| 2026-10-08 00:00 |
07:43:15.31 |
+23:54:35.1 |
HIP 37650 |
8.49 |
| 2026-10-08 12:00 |
07:43:15.80 |
+23:54:35.0 |
HIP 37650 |
8.43 |
| 2026-10-09 00:00 |
07:43:16.28 |
+23:54:34.9 |
HIP 37650 |
8.38 |
| 2026-10-09 12:00 |
07:43:16.74 |
+23:54:34.8 |
HIP 37650 |
8.32 |
| 2026-10-10 00:00 |
07:43:17.17 |
+23:54:34.9 |
HIP 37650 |
8.27 |
| 2026-10-10 12:00 |
07:43:17.58 |
+23:54:34.9 |
HIP 37650 |
8.23 |
| 2026-10-11 00:00 |
07:43:17.98 |
+23:54:35.1 |
HIP 37650 |
8.19 |