| Parameter |
Value |
| Designation |
C/1998 G1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1998-11-16T14:59:02.595840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:53Z |
| Obs used |
161 |
| NEO |
- |
| M1 |
13.800 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1998-04-21.0000000 |
| e |
0.82369261 |
| q (au) |
2.133379 |
| a (au) |
12.100336 |
| i (deg) |
109.714727 |
| Ω (om, deg) |
341.383665 |
| ω (w, deg) |
236.322318 |
| M (ma, deg) |
355.091490 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.797 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.797 |
| n |
6.000 |
| 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 |
| 1998-04-02 |
1998-11-16 |
+14.8291 |
-7.029 |
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 |
19:39:04.38 |
+37:59:43.4 |
HIP 96609 |
16.65 |
| 2026-03-26 12:00 |
19:39:06.10 |
+38:00:59.8 |
HIP 96609 |
17.95 |
| 2026-03-27 00:00 |
19:39:07.76 |
+38:02:16.2 |
HIP 96609 |
19.25 |
| 2026-03-27 12:00 |
19:39:09.37 |
+38:03:32.9 |
HIP 96609 |
20.55 |
| 2026-03-28 00:00 |
19:39:10.92 |
+38:04:49.6 |
HIP 96609 |
21.85 |
| 2026-03-28 12:00 |
19:39:12.42 |
+38:06:06.6 |
HIP 96609 |
23.15 |
| 2026-03-29 00:00 |
19:39:13.86 |
+38:07:23.6 |
HIP 96609 |
24.44 |
| 2026-03-29 12:00 |
19:39:15.24 |
+38:08:40.8 |
HIP 96609 |
25.74 |
| 2026-03-30 00:00 |
19:39:16.56 |
+38:09:58.1 |
HIP 96609 |
27.04 |
| 2026-03-30 12:00 |
19:39:17.82 |
+38:11:15.6 |
HIP 96609 |
28.34 |
| 2026-03-31 00:00 |
19:39:19.03 |
+38:12:33.1 |
HIP 96866 |
28.57 |
| 2026-03-31 12:00 |
19:39:20.17 |
+38:13:50.8 |
HIP 96866 |
27.71 |
| 2026-04-01 00:00 |
19:39:21.26 |
+38:15:08.6 |
HIP 96866 |
26.90 |
| 2026-04-01 12:00 |
19:39:22.29 |
+38:16:26.5 |
HIP 96866 |
26.15 |
| 2026-04-02 00:00 |
19:39:23.26 |
+38:17:44.5 |
HIP 96866 |
25.45 |
| 2026-04-02 12:00 |
19:39:24.18 |
+38:19:02.6 |
HIP 96866 |
24.81 |
| 2026-04-03 00:00 |
19:39:25.03 |
+38:20:20.7 |
HIP 96866 |
24.23 |
| 2026-04-03 12:00 |
19:39:25.82 |
+38:21:39.0 |
HIP 96866 |
23.73 |
| 2026-04-04 00:00 |
19:39:26.56 |
+38:22:57.3 |
HIP 96866 |
23.29 |
| 2026-04-04 12:00 |
19:39:27.23 |
+38:24:15.8 |
HIP 96866 |
22.94 |
| 2026-04-05 00:00 |
19:39:27.85 |
+38:25:34.2 |
HIP 96866 |
22.67 |
| 2026-04-05 12:00 |
19:39:28.40 |
+38:26:52.8 |
HIP 96866 |
22.49 |
| 2026-04-06 00:00 |
19:39:28.90 |
+38:28:11.4 |
HIP 96866 |
22.39 |
| 2026-04-06 12:00 |
19:39:29.33 |
+38:29:30.1 |
HIP 96866 |
22.38 |
| 2026-04-07 00:00 |
19:39:29.71 |
+38:30:48.8 |
HIP 96866 |
22.46 |
| 2026-04-07 12:00 |
19:39:30.02 |
+38:32:07.6 |
HIP 96727 |
21.96 |
| 2026-04-08 00:00 |
19:39:30.27 |
+38:33:26.4 |
HIP 96727 |
20.66 |
| 2026-04-08 12:00 |
19:39:30.46 |
+38:34:45.3 |
HIP 96727 |
19.36 |
| 2026-04-09 00:00 |
19:39:30.59 |
+38:36:04.2 |
HIP 96727 |
18.06 |
| 2026-04-09 12:00 |
19:39:30.66 |
+38:37:23.1 |
HIP 96727 |
16.77 |
| 2026-04-10 00:00 |
19:39:30.67 |
+38:38:42.0 |
HIP 96727 |
15.48 |
| 2026-04-10 12:00 |
19:39:30.62 |
+38:40:00.9 |
HIP 96727 |
14.20 |
| 2026-04-11 00:00 |
19:39:30.50 |
+38:41:19.9 |
HIP 96727 |
12.94 |
| 2026-04-11 12:00 |
19:39:30.32 |
+38:42:38.8 |
HIP 96727 |
11.68 |
| 2026-04-12 00:00 |
19:39:30.08 |
+38:43:57.8 |
HIP 96727 |
10.45 |
| 2026-04-12 12:00 |
19:39:29.78 |
+38:45:16.8 |
HIP 96727 |
9.25 |
| 2026-04-13 00:00 |
19:39:29.42 |
+38:46:35.7 |
HIP 96727 |
8.08 |
| 2026-04-13 12:00 |
19:39:28.99 |
+38:47:54.6 |
HIP 96727 |
6.98 |
| 2026-04-14 00:00 |
19:39:28.50 |
+38:49:13.5 |
HIP 96727 |
5.97 |
| 2026-04-14 12:00 |
19:39:27.95 |
+38:50:32.4 |
HIP 96727 |
5.12 |
| 2026-04-15 00:00 |
19:39:27.34 |
+38:51:51.2 |
HIP 96727 |
4.50 |
| 2026-04-15 12:00 |
19:39:26.66 |
+38:53:10.0 |
HIP 96727 |
4.24 |
| 2026-04-16 00:00 |
19:39:25.92 |
+38:54:28.8 |
HIP 96727 |
4.39 |