| 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) |
| 2026-03-26 00:00 |
06:25:26.76 |
-65:28:53.7 |
HIP 30467 |
13.69 |
| 2026-03-26 12:00 |
06:25:26.86 |
-65:28:16.3 |
HIP 30467 |
14.23 |
| 2026-03-27 00:00 |
06:25:27.01 |
-65:27:39.0 |
HIP 30467 |
14.78 |
| 2026-03-27 12:00 |
06:25:27.22 |
-65:27:01.6 |
HIP 30467 |
15.34 |
| 2026-03-28 00:00 |
06:25:27.47 |
-65:26:24.3 |
HIP 30467 |
15.91 |
| 2026-03-28 12:00 |
06:25:27.77 |
-65:25:46.9 |
HIP 30467 |
16.48 |
| 2026-03-29 00:00 |
06:25:28.12 |
-65:25:09.6 |
HIP 30467 |
17.06 |
| 2026-03-29 12:00 |
06:25:28.53 |
-65:24:32.3 |
HIP 30467 |
17.64 |
| 2026-03-30 00:00 |
06:25:28.98 |
-65:23:55.0 |
HIP 30467 |
18.22 |
| 2026-03-30 12:00 |
06:25:29.48 |
-65:23:17.7 |
HIP 30467 |
18.81 |
| 2026-03-31 00:00 |
06:25:30.03 |
-65:22:40.4 |
HIP 30467 |
19.41 |
| 2026-03-31 12:00 |
06:25:30.62 |
-65:22:03.2 |
HIP 30467 |
20.01 |
| 2026-04-01 00:00 |
06:25:31.27 |
-65:21:26.0 |
HIP 30467 |
20.61 |
| 2026-04-01 12:00 |
06:25:31.97 |
-65:20:48.8 |
HIP 30467 |
21.21 |
| 2026-04-02 00:00 |
06:25:32.71 |
-65:20:11.7 |
HIP 30467 |
21.82 |
| 2026-04-02 12:00 |
06:25:33.50 |
-65:19:34.6 |
HIP 30467 |
22.42 |
| 2026-04-03 00:00 |
06:25:34.35 |
-65:18:57.5 |
HIP 30467 |
23.03 |
| 2026-04-03 12:00 |
06:25:35.24 |
-65:18:20.5 |
HIP 30467 |
23.65 |
| 2026-04-04 00:00 |
06:25:36.17 |
-65:17:43.5 |
HIP 30467 |
24.26 |
| 2026-04-04 12:00 |
06:25:37.16 |
-65:17:06.6 |
HIP 30467 |
24.87 |
| 2026-04-05 00:00 |
06:25:38.19 |
-65:16:29.7 |
HIP 30467 |
25.49 |
| 2026-04-05 12:00 |
06:25:39.28 |
-65:15:52.9 |
HIP 30467 |
26.11 |
| 2026-04-06 00:00 |
06:25:40.41 |
-65:15:16.1 |
HIP 30467 |
26.73 |
| 2026-04-06 12:00 |
06:25:41.58 |
-65:14:39.4 |
HIP 30467 |
27.35 |
| 2026-04-07 00:00 |
06:25:42.81 |
-65:14:02.7 |
HIP 30467 |
27.97 |
| 2026-04-07 12:00 |
06:25:44.08 |
-65:13:26.1 |
HIP 30467 |
28.59 |
| 2026-04-08 00:00 |
06:25:45.40 |
-65:12:49.5 |
HIP 30467 |
29.21 |
| 2026-04-08 12:00 |
06:25:46.77 |
-65:12:13.1 |
HIP 30467 |
29.83 |
| 2026-04-09 00:00 |
06:25:48.18 |
-65:11:36.6 |
HIP 30467 |
30.46 |
| 2026-04-09 12:00 |
06:25:49.64 |
-65:11:00.3 |
HIP 30467 |
31.08 |
| 2026-04-10 00:00 |
06:25:51.15 |
-65:10:24.0 |
HIP 30467 |
31.70 |
| 2026-04-10 12:00 |
06:25:52.70 |
-65:09:47.8 |
HIP 30467 |
32.33 |
| 2026-04-11 00:00 |
06:25:54.30 |
-65:09:11.7 |
HIP 30467 |
32.95 |
| 2026-04-11 12:00 |
06:25:55.94 |
-65:08:35.7 |
HIP 30467 |
33.58 |
| 2026-04-12 00:00 |
06:25:57.64 |
-65:07:59.7 |
HIP 30467 |
34.20 |
| 2026-04-12 12:00 |
06:25:59.37 |
-65:07:23.8 |
HIP 30624 |
34.23 |
| 2026-04-13 00:00 |
06:26:01.16 |
-65:06:48.0 |
HIP 30624 |
33.63 |
| 2026-04-13 12:00 |
06:26:02.99 |
-65:06:12.3 |
HIP 30624 |
33.03 |
| 2026-04-14 00:00 |
06:26:04.86 |
-65:05:36.7 |
HIP 30624 |
32.43 |
| 2026-04-14 12:00 |
06:26:06.78 |
-65:05:01.2 |
HIP 30624 |
31.84 |
| 2026-04-15 00:00 |
06:26:08.74 |
-65:04:25.8 |
HIP 30624 |
31.25 |
| 2026-04-15 12:00 |
06:26:10.75 |
-65:03:50.5 |
HIP 30624 |
30.66 |
| 2026-04-16 00:00 |
06:26:12.81 |
-65:03:15.3 |
HIP 30624 |
30.07 |