| 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 |
0.999 |
| 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) |
| 2026-03-26 00:00 |
07:32:38.88 |
+24:23:42.9 |
HIP 36623 |
12.00 |
| 2026-03-26 12:00 |
07:32:38.26 |
+24:23:42.1 |
HIP 36623 |
11.89 |
| 2026-03-27 00:00 |
07:32:37.66 |
+24:23:41.2 |
HIP 36623 |
11.79 |
| 2026-03-27 12:00 |
07:32:37.09 |
+24:23:40.3 |
HIP 36623 |
11.69 |
| 2026-03-28 00:00 |
07:32:36.54 |
+24:23:39.3 |
HIP 36623 |
11.59 |
| 2026-03-28 12:00 |
07:32:36.01 |
+24:23:38.3 |
HIP 36623 |
11.50 |
| 2026-03-29 00:00 |
07:32:35.51 |
+24:23:37.2 |
HIP 36623 |
11.42 |
| 2026-03-29 12:00 |
07:32:35.02 |
+24:23:36.1 |
HIP 36623 |
11.34 |
| 2026-03-30 00:00 |
07:32:34.56 |
+24:23:34.9 |
HIP 36623 |
11.27 |
| 2026-03-30 12:00 |
07:32:34.12 |
+24:23:33.7 |
HIP 36623 |
11.20 |
| 2026-03-31 00:00 |
07:32:33.70 |
+24:23:32.5 |
HIP 36623 |
11.13 |
| 2026-03-31 12:00 |
07:32:33.31 |
+24:23:31.1 |
HIP 36623 |
11.08 |
| 2026-04-01 00:00 |
07:32:32.93 |
+24:23:29.8 |
HIP 36623 |
11.02 |
| 2026-04-01 12:00 |
07:32:32.58 |
+24:23:28.3 |
HIP 36623 |
10.97 |
| 2026-04-02 00:00 |
07:32:32.25 |
+24:23:26.9 |
HIP 36623 |
10.93 |
| 2026-04-02 12:00 |
07:32:31.94 |
+24:23:25.4 |
HIP 36623 |
10.89 |
| 2026-04-03 00:00 |
07:32:31.66 |
+24:23:23.8 |
HIP 36623 |
10.86 |
| 2026-04-03 12:00 |
07:32:31.40 |
+24:23:22.2 |
HIP 36623 |
10.83 |
| 2026-04-04 00:00 |
07:32:31.16 |
+24:23:20.5 |
HIP 36623 |
10.80 |
| 2026-04-04 12:00 |
07:32:30.94 |
+24:23:18.8 |
HIP 36623 |
10.78 |
| 2026-04-05 00:00 |
07:32:30.74 |
+24:23:17.0 |
HIP 36623 |
10.77 |
| 2026-04-05 12:00 |
07:32:30.57 |
+24:23:15.2 |
HIP 36623 |
10.75 |
| 2026-04-06 00:00 |
07:32:30.41 |
+24:23:13.4 |
HIP 36623 |
10.75 |
| 2026-04-06 12:00 |
07:32:30.28 |
+24:23:11.4 |
HIP 36623 |
10.75 |
| 2026-04-07 00:00 |
07:32:30.18 |
+24:23:09.5 |
HIP 36623 |
10.75 |
| 2026-04-07 12:00 |
07:32:30.09 |
+24:23:07.5 |
HIP 36623 |
10.76 |
| 2026-04-08 00:00 |
07:32:30.03 |
+24:23:05.4 |
HIP 36623 |
10.77 |
| 2026-04-08 12:00 |
07:32:29.99 |
+24:23:03.3 |
HIP 36623 |
10.79 |
| 2026-04-09 00:00 |
07:32:29.97 |
+24:23:01.2 |
HIP 36623 |
10.81 |
| 2026-04-09 12:00 |
07:32:29.97 |
+24:22:59.0 |
HIP 36623 |
10.83 |
| 2026-04-10 00:00 |
07:32:30.00 |
+24:22:56.7 |
HIP 36623 |
10.86 |
| 2026-04-10 12:00 |
07:32:30.05 |
+24:22:54.4 |
HIP 36623 |
10.89 |
| 2026-04-11 00:00 |
07:32:30.12 |
+24:22:52.1 |
HIP 36623 |
10.93 |
| 2026-04-11 12:00 |
07:32:30.21 |
+24:22:49.7 |
HIP 36623 |
10.97 |
| 2026-04-12 00:00 |
07:32:30.32 |
+24:22:47.3 |
HIP 36623 |
11.02 |
| 2026-04-12 12:00 |
07:32:30.46 |
+24:22:44.8 |
HIP 36623 |
11.07 |
| 2026-04-13 00:00 |
07:32:30.62 |
+24:22:42.3 |
HIP 36623 |
11.13 |
| 2026-04-13 12:00 |
07:32:30.80 |
+24:22:39.7 |
HIP 36623 |
11.19 |
| 2026-04-14 00:00 |
07:32:31.01 |
+24:22:37.1 |
HIP 36623 |
11.25 |
| 2026-04-14 12:00 |
07:32:31.23 |
+24:22:34.4 |
HIP 36623 |
11.32 |
| 2026-04-15 00:00 |
07:32:31.48 |
+24:22:31.7 |
HIP 36623 |
11.39 |
| 2026-04-15 12:00 |
07:32:31.75 |
+24:22:29.0 |
HIP 36623 |
11.47 |
| 2026-04-16 00:00 |
07:32:32.04 |
+24:22:26.1 |
HIP 36623 |
11.55 |