| 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) |
| 2026-07-29 00:00 |
07:39:09.12 |
+24:02:56.3 |
HIP 37269 |
10.43 |
| 2026-07-29 12:00 |
07:39:11.66 |
+24:02:50.2 |
HIP 37269 |
10.51 |
| 2026-07-30 00:00 |
07:39:14.21 |
+24:02:44.2 |
HIP 37269 |
10.63 |
| 2026-07-30 12:00 |
07:39:16.74 |
+24:02:38.2 |
HIP 37269 |
10.77 |
| 2026-07-31 00:00 |
07:39:19.27 |
+24:02:32.2 |
HIP 37269 |
10.94 |
| 2026-07-31 12:00 |
07:39:21.80 |
+24:02:26.2 |
HIP 37269 |
11.14 |
| 2026-08-01 00:00 |
07:39:24.32 |
+24:02:20.3 |
HIP 37269 |
11.37 |
| 2026-08-01 12:00 |
07:39:26.84 |
+24:02:14.4 |
HIP 37269 |
11.62 |
| 2026-08-02 00:00 |
07:39:29.35 |
+24:02:08.5 |
HIP 37269 |
11.89 |
| 2026-08-02 12:00 |
07:39:31.85 |
+24:02:02.6 |
HIP 37269 |
12.18 |
| 2026-08-03 00:00 |
07:39:34.35 |
+24:01:56.7 |
HIP 37269 |
12.49 |
| 2026-08-03 12:00 |
07:39:36.84 |
+24:01:50.9 |
HIP 37269 |
12.82 |
| 2026-08-04 00:00 |
07:39:39.33 |
+24:01:45.1 |
HIP 37269 |
13.17 |
| 2026-08-04 12:00 |
07:39:41.81 |
+24:01:39.3 |
HIP 37269 |
13.53 |
| 2026-08-05 00:00 |
07:39:44.28 |
+24:01:33.6 |
HIP 37269 |
13.90 |
| 2026-08-05 12:00 |
07:39:46.75 |
+24:01:27.8 |
HIP 37269 |
14.29 |
| 2026-08-06 00:00 |
07:39:49.21 |
+24:01:22.1 |
HIP 37269 |
14.68 |
| 2026-08-06 12:00 |
07:39:51.66 |
+24:01:16.5 |
HIP 37269 |
15.09 |
| 2026-08-07 00:00 |
07:39:54.11 |
+24:01:10.8 |
HIP 37269 |
15.51 |
| 2026-08-07 12:00 |
07:39:56.54 |
+24:01:05.2 |
HIP 37269 |
15.93 |
| 2026-08-08 00:00 |
07:39:58.97 |
+24:00:59.6 |
HIP 37269 |
16.36 |
| 2026-08-08 12:00 |
07:40:01.40 |
+24:00:54.0 |
HIP 37269 |
16.79 |
| 2026-08-09 00:00 |
07:40:03.81 |
+24:00:48.5 |
HIP 37269 |
17.24 |
| 2026-08-09 12:00 |
07:40:06.22 |
+24:00:43.0 |
HIP 37269 |
17.68 |
| 2026-08-10 00:00 |
07:40:08.62 |
+24:00:37.5 |
HIP 37269 |
18.13 |
| 2026-08-10 12:00 |
07:40:11.01 |
+24:00:32.0 |
HIP 37269 |
18.59 |
| 2026-08-11 00:00 |
07:40:13.39 |
+24:00:26.6 |
HIP 37269 |
19.05 |
| 2026-08-11 12:00 |
07:40:15.76 |
+24:00:21.2 |
HIP 37269 |
19.51 |
| 2026-08-12 00:00 |
07:40:18.13 |
+24:00:15.8 |
HIP 37269 |
19.97 |
| 2026-08-12 12:00 |
07:40:20.48 |
+24:00:10.5 |
HIP 37269 |
20.44 |
| 2026-08-13 00:00 |
07:40:22.83 |
+24:00:05.2 |
HIP 37269 |
20.91 |
| 2026-08-13 12:00 |
07:40:25.16 |
+23:59:59.9 |
HIP 37269 |
21.38 |
| 2026-08-14 00:00 |
07:40:27.49 |
+23:59:54.7 |
HIP 37517 |
21.41 |
| 2026-08-14 12:00 |
07:40:29.81 |
+23:59:49.4 |
HIP 37517 |
20.90 |
| 2026-08-15 00:00 |
07:40:32.12 |
+23:59:44.3 |
HIP 37517 |
20.39 |
| 2026-08-15 12:00 |
07:40:34.41 |
+23:59:39.1 |
HIP 37517 |
19.89 |
| 2026-08-16 00:00 |
07:40:36.70 |
+23:59:34.0 |
HIP 37517 |
19.39 |
| 2026-08-16 12:00 |
07:40:38.98 |
+23:59:28.9 |
HIP 37517 |
18.90 |
| 2026-08-17 00:00 |
07:40:41.24 |
+23:59:23.9 |
HIP 37517 |
18.40 |
| 2026-08-17 12:00 |
07:40:43.50 |
+23:59:18.9 |
HIP 37517 |
17.92 |
| 2026-08-18 00:00 |
07:40:45.74 |
+23:59:13.9 |
HIP 37517 |
17.43 |
| 2026-08-18 12:00 |
07:40:47.98 |
+23:59:09.0 |
HIP 37517 |
16.95 |
| 2026-08-19 00:00 |
07:40:50.20 |
+23:59:04.0 |
HIP 37517 |
16.48 |