| 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 |
-0.500 |
| 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) |
| 2026-05-12 00:00 |
06:28:55.25 |
-64:36:01.0 |
HIP 30624 |
18.08 |
| 2026-05-12 12:00 |
06:28:59.33 |
-64:35:34.2 |
HIP 30624 |
18.45 |
| 2026-05-13 00:00 |
06:29:03.43 |
-64:35:07.7 |
HIP 30624 |
18.84 |
| 2026-05-13 12:00 |
06:29:07.56 |
-64:34:41.4 |
HIP 30624 |
19.24 |
| 2026-05-14 00:00 |
06:29:11.73 |
-64:34:15.3 |
HIP 30624 |
19.66 |
| 2026-05-14 12:00 |
06:29:15.92 |
-64:33:49.4 |
HIP 30901 |
19.59 |
| 2026-05-15 00:00 |
06:29:20.15 |
-64:33:23.7 |
HIP 30901 |
19.18 |
| 2026-05-15 12:00 |
06:29:24.41 |
-64:32:58.3 |
HIP 30901 |
18.79 |
| 2026-05-16 00:00 |
06:29:28.69 |
-64:32:33.0 |
HIP 30901 |
18.42 |
| 2026-05-16 12:00 |
06:29:33.00 |
-64:32:08.0 |
HIP 30901 |
18.06 |
| 2026-05-17 00:00 |
06:29:37.35 |
-64:31:43.2 |
HIP 30901 |
17.72 |
| 2026-05-17 12:00 |
06:29:41.72 |
-64:31:18.7 |
HIP 30901 |
17.40 |
| 2026-05-18 00:00 |
06:29:46.12 |
-64:30:54.3 |
HIP 30901 |
17.11 |
| 2026-05-18 12:00 |
06:29:50.54 |
-64:30:30.2 |
HIP 30901 |
16.83 |
| 2026-05-19 00:00 |
06:29:55.00 |
-64:30:06.3 |
HIP 30901 |
16.58 |
| 2026-05-19 12:00 |
06:29:59.48 |
-64:29:42.7 |
HIP 30901 |
16.36 |
| 2026-05-20 00:00 |
06:30:03.99 |
-64:29:19.2 |
HIP 30901 |
16.16 |
| 2026-05-20 12:00 |
06:30:08.52 |
-64:28:56.1 |
HIP 30901 |
15.98 |
| 2026-05-21 00:00 |
06:30:13.08 |
-64:28:33.1 |
HIP 30901 |
15.84 |
| 2026-05-21 12:00 |
06:30:17.67 |
-64:28:10.4 |
HIP 30901 |
15.72 |
| 2026-05-22 00:00 |
06:30:22.28 |
-64:27:47.9 |
HIP 30901 |
15.63 |
| 2026-05-22 12:00 |
06:30:26.92 |
-64:27:25.7 |
HIP 30901 |
15.58 |
| 2026-05-23 00:00 |
06:30:31.58 |
-64:27:03.7 |
HIP 30901 |
15.55 |
| 2026-05-23 12:00 |
06:30:36.27 |
-64:26:41.9 |
HIP 30901 |
15.55 |
| 2026-05-24 00:00 |
06:30:40.98 |
-64:26:20.4 |
HIP 30901 |
15.58 |
| 2026-05-24 12:00 |
06:30:45.71 |
-64:25:59.1 |
HIP 30901 |
15.64 |
| 2026-05-25 00:00 |
06:30:50.47 |
-64:25:38.1 |
HIP 30901 |
15.73 |
| 2026-05-25 12:00 |
06:30:55.25 |
-64:25:17.3 |
HIP 30901 |
15.85 |
| 2026-05-26 00:00 |
06:31:00.05 |
-64:24:56.7 |
HIP 30901 |
15.99 |
| 2026-05-26 12:00 |
06:31:04.88 |
-64:24:36.4 |
HIP 30901 |
16.17 |
| 2026-05-27 00:00 |
06:31:09.72 |
-64:24:16.4 |
HIP 30901 |
16.37 |
| 2026-05-27 12:00 |
06:31:14.59 |
-64:23:56.6 |
HIP 30901 |
16.59 |
| 2026-05-28 00:00 |
06:31:19.48 |
-64:23:37.0 |
HIP 30901 |
16.85 |
| 2026-05-28 12:00 |
06:31:24.40 |
-64:23:17.7 |
HIP 30901 |
17.12 |
| 2026-05-29 00:00 |
06:31:29.33 |
-64:22:58.6 |
HIP 30901 |
17.41 |
| 2026-05-29 12:00 |
06:31:34.28 |
-64:22:39.8 |
HIP 30901 |
17.73 |
| 2026-05-30 00:00 |
06:31:39.26 |
-64:22:21.3 |
HIP 30901 |
18.07 |
| 2026-05-30 12:00 |
06:31:44.25 |
-64:22:03.0 |
HIP 30901 |
18.42 |
| 2026-05-31 00:00 |
06:31:49.26 |
-64:21:45.0 |
HIP 30901 |
18.80 |
| 2026-05-31 12:00 |
06:31:54.30 |
-64:21:27.2 |
HIP 30901 |
19.19 |
| 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 |