| 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) |
| 2026-09-20 00:00 |
06:48:41.61 |
-65:03:46.0 |
HIP 32529 |
9.21 |
| 2026-09-20 12:00 |
06:48:43.09 |
-65:04:19.4 |
HIP 32529 |
9.29 |
| 2026-09-21 00:00 |
06:48:44.52 |
-65:04:52.9 |
HIP 32529 |
9.39 |
| 2026-09-21 12:00 |
06:48:45.90 |
-65:05:26.4 |
HIP 32529 |
9.53 |
| 2026-09-22 00:00 |
06:48:47.24 |
-65:06:00.0 |
HIP 32529 |
9.69 |
| 2026-09-22 12:00 |
06:48:48.54 |
-65:06:33.7 |
HIP 32529 |
9.88 |
| 2026-09-23 00:00 |
06:48:49.79 |
-65:07:07.4 |
HIP 32529 |
10.09 |
| 2026-09-23 12:00 |
06:48:50.99 |
-65:07:41.2 |
HIP 32529 |
10.33 |
| 2026-09-24 00:00 |
06:48:52.14 |
-65:08:15.0 |
HIP 32529 |
10.59 |
| 2026-09-24 12:00 |
06:48:53.25 |
-65:08:48.9 |
HIP 32529 |
10.86 |
| 2026-09-25 00:00 |
06:48:54.31 |
-65:09:22.8 |
HIP 32529 |
11.16 |
| 2026-09-25 12:00 |
06:48:55.33 |
-65:09:56.8 |
HIP 32529 |
11.47 |
| 2026-09-26 00:00 |
06:48:56.30 |
-65:10:30.8 |
HIP 32529 |
11.80 |
| 2026-09-26 12:00 |
06:48:57.22 |
-65:11:04.9 |
HIP 32529 |
12.15 |
| 2026-09-27 00:00 |
06:48:58.10 |
-65:11:39.0 |
HIP 32529 |
12.51 |
| 2026-09-27 12:00 |
06:48:58.93 |
-65:12:13.2 |
HIP 32529 |
12.87 |
| 2026-09-28 00:00 |
06:48:59.71 |
-65:12:47.3 |
HIP 32529 |
13.25 |
| 2026-09-28 12:00 |
06:49:00.44 |
-65:13:21.6 |
HIP 32529 |
13.64 |
| 2026-09-29 00:00 |
06:49:01.13 |
-65:13:55.8 |
HIP 32529 |
14.04 |
| 2026-09-29 12:00 |
06:49:01.77 |
-65:14:30.1 |
HIP 32529 |
14.45 |
| 2026-09-30 00:00 |
06:49:02.36 |
-65:15:04.4 |
HIP 32529 |
14.87 |
| 2026-09-30 12:00 |
06:49:02.90 |
-65:15:38.7 |
HIP 32529 |
15.29 |
| 2026-10-01 00:00 |
06:49:03.40 |
-65:16:13.0 |
HIP 32529 |
15.72 |
| 2026-10-01 12:00 |
06:49:03.85 |
-65:16:47.4 |
HIP 32529 |
16.15 |
| 2026-10-02 00:00 |
06:49:04.25 |
-65:17:21.8 |
HIP 32529 |
16.59 |
| 2026-10-02 12:00 |
06:49:04.60 |
-65:17:56.2 |
HIP 32529 |
17.03 |
| 2026-10-03 00:00 |
06:49:04.90 |
-65:18:30.6 |
HIP 32529 |
17.48 |
| 2026-10-03 12:00 |
06:49:05.16 |
-65:19:05.0 |
HIP 32529 |
17.93 |
| 2026-10-04 00:00 |
06:49:05.37 |
-65:19:39.4 |
HIP 32529 |
18.39 |
| 2026-10-04 12:00 |
06:49:05.52 |
-65:20:13.8 |
HIP 32529 |
18.85 |
| 2026-10-05 00:00 |
06:49:05.63 |
-65:20:48.3 |
HIP 32529 |
19.31 |
| 2026-10-05 12:00 |
06:49:05.69 |
-65:21:22.7 |
HIP 32529 |
19.78 |
| 2026-10-06 00:00 |
06:49:05.70 |
-65:21:57.1 |
HIP 32529 |
20.24 |
| 2026-10-06 12:00 |
06:49:05.67 |
-65:22:31.5 |
HIP 32529 |
20.72 |
| 2026-10-07 00:00 |
06:49:05.58 |
-65:23:05.9 |
HIP 32529 |
21.19 |
| 2026-10-07 12:00 |
06:49:05.44 |
-65:23:40.3 |
HIP 32529 |
21.66 |
| 2026-10-08 00:00 |
06:49:05.26 |
-65:24:14.7 |
HIP 32950 |
21.33 |
| 2026-10-08 12:00 |
06:49:05.02 |
-65:24:49.1 |
HIP 32950 |
21.01 |
| 2026-10-09 00:00 |
06:49:04.74 |
-65:25:23.4 |
HIP 32950 |
20.70 |
| 2026-10-09 12:00 |
06:49:04.41 |
-65:25:57.7 |
HIP 32950 |
20.40 |
| 2026-10-10 00:00 |
06:49:04.02 |
-65:26:32.0 |
HIP 32950 |
20.13 |
| 2026-10-10 12:00 |
06:49:03.59 |
-65:27:06.2 |
HIP 32950 |
19.87 |
| 2026-10-11 00:00 |
06:49:03.11 |
-65:27:40.5 |
HIP 32950 |
19.62 |