| Parameter |
Value |
| Designation |
C/1997 J2 (Meunier-Dupouy) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1998-03-10T10:24:04.697280Z |
| Orbit solution date (soln_date, UTC) |
2022-02-03T20:42:52Z |
| Obs used |
1420 |
| NEO |
- |
| M1 |
8.400 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1998-01-22.0000000 |
| e |
1.00055829 |
| q (au) |
3.051149 |
| a (au) |
-5465.167454 |
| i (deg) |
91.273399 |
| Ω (om, deg) |
148.844533 |
| ω (w, deg) |
122.671679 |
| M (ma, deg) |
-0.000116 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.859 + 3.586\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.859 |
| n |
3.586 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 1997-05-07 |
1998-03-10 |
-1.5585 |
+0.533 |
| 1998-03-10 |
1999-10-09 |
+7.0916 |
-3.331 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
06:31:59.35 |
-64:21:09.6 |
HIP 30901 |
19.59 |
| 2026-06-01 12:00 |
06:32:04.42 |
-64:20:52.4 |
HIP 30901 |
20.01 |
| 2026-06-02 00:00 |
06:32:09.51 |
-64:20:35.4 |
HIP 30901 |
20.44 |
| 2026-06-02 12:00 |
06:32:14.62 |
-64:20:18.6 |
HIP 30901 |
20.89 |
| 2026-06-03 00:00 |
06:32:19.74 |
-64:20:02.1 |
HIP 30901 |
21.35 |
| 2026-06-03 12:00 |
06:32:24.89 |
-64:19:45.9 |
HIP 30901 |
21.82 |
| 2026-06-04 00:00 |
06:32:30.05 |
-64:19:29.9 |
HIP 30901 |
22.30 |
| 2026-06-04 12:00 |
06:32:35.23 |
-64:19:14.2 |
HIP 30901 |
22.79 |
| 2026-06-05 00:00 |
06:32:40.42 |
-64:18:58.8 |
HIP 30901 |
23.28 |
| 2026-06-05 12:00 |
06:32:45.63 |
-64:18:43.6 |
HIP 30901 |
23.79 |
| 2026-06-06 00:00 |
06:32:50.86 |
-64:18:28.7 |
HIP 30901 |
24.31 |
| 2026-06-06 12:00 |
06:32:56.10 |
-64:18:14.0 |
HIP 31335 |
24.67 |
| 2026-06-07 00:00 |
06:33:01.36 |
-64:17:59.6 |
HIP 31335 |
24.26 |
| 2026-06-07 12:00 |
06:33:06.64 |
-64:17:45.5 |
HIP 31335 |
23.85 |
| 2026-06-08 00:00 |
06:33:11.92 |
-64:17:31.7 |
HIP 31335 |
23.45 |
| 2026-06-08 12:00 |
06:33:17.23 |
-64:17:18.1 |
HIP 31335 |
23.08 |
| 2026-06-09 00:00 |
06:33:22.55 |
-64:17:04.8 |
HIP 31335 |
22.71 |
| 2026-06-09 12:00 |
06:33:27.88 |
-64:16:51.7 |
HIP 31335 |
22.36 |
| 2026-06-10 00:00 |
06:33:33.22 |
-64:16:39.0 |
HIP 31335 |
22.03 |
| 2026-06-10 12:00 |
06:33:38.58 |
-64:16:26.5 |
HIP 31335 |
21.71 |
| 2026-06-11 00:00 |
06:33:43.95 |
-64:16:14.3 |
HIP 31335 |
21.41 |
| 2026-06-11 12:00 |
06:33:49.34 |
-64:16:02.3 |
HIP 31335 |
21.13 |
| 2026-06-12 00:00 |
06:33:54.73 |
-64:15:50.7 |
HIP 31335 |
20.87 |
| 2026-06-12 12:00 |
06:34:00.14 |
-64:15:39.3 |
HIP 31335 |
20.63 |
| 2026-06-13 00:00 |
06:34:05.56 |
-64:15:28.2 |
HIP 31335 |
20.40 |
| 2026-06-13 12:00 |
06:34:11.00 |
-64:15:17.3 |
HIP 31335 |
20.20 |
| 2026-06-14 00:00 |
06:34:16.44 |
-64:15:06.8 |
HIP 31335 |
20.03 |
| 2026-06-14 12:00 |
06:34:21.89 |
-64:14:56.5 |
HIP 31335 |
19.87 |
| 2026-06-15 00:00 |
06:34:27.35 |
-64:14:46.5 |
HIP 31335 |
19.74 |
| 2026-06-15 12:00 |
06:34:32.83 |
-64:14:36.8 |
HIP 31335 |
19.63 |
| 2026-06-16 00:00 |
06:34:38.31 |
-64:14:27.3 |
HIP 31335 |
19.54 |
| 2026-06-16 12:00 |
06:34:43.80 |
-64:14:18.2 |
HIP 31335 |
19.48 |
| 2026-06-17 00:00 |
06:34:49.30 |
-64:14:09.3 |
HIP 31335 |
19.44 |
| 2026-06-17 12:00 |
06:34:54.81 |
-64:14:00.7 |
HIP 31335 |
19.43 |
| 2026-06-18 00:00 |
06:35:00.33 |
-64:13:52.4 |
HIP 31335 |
19.44 |
| 2026-06-18 12:00 |
06:35:05.86 |
-64:13:44.4 |
HIP 31335 |
19.48 |
| 2026-06-19 00:00 |
06:35:11.39 |
-64:13:36.6 |
HIP 31335 |
19.54 |
| 2026-06-19 12:00 |
06:35:16.93 |
-64:13:29.2 |
HIP 31335 |
19.62 |
| 2026-06-20 00:00 |
06:35:22.47 |
-64:13:22.0 |
HIP 31335 |
19.73 |
| 2026-06-20 12:00 |
06:35:28.02 |
-64:13:15.1 |
HIP 31335 |
19.86 |
| 2026-06-21 00:00 |
06:35:33.58 |
-64:13:08.5 |
HIP 31335 |
20.02 |
| 2026-06-21 12:00 |
06:35:39.15 |
-64:13:02.2 |
HIP 31335 |
20.20 |
| 2026-06-22 00:00 |
06:35:44.72 |
-64:12:56.1 |
HIP 31335 |
20.39 |