| 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 |
-0.998 |
| 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) |
| 2026-09-20 00:00 |
19:08:34.04 |
+39:36:56.6 |
HIP 93989 |
27.94 |
| 2026-09-20 12:00 |
19:08:31.05 |
+39:35:45.5 |
HIP 93989 |
26.69 |
| 2026-09-21 00:00 |
19:08:28.12 |
+39:34:34.3 |
HIP 93989 |
25.44 |
| 2026-09-21 12:00 |
19:08:25.26 |
+39:33:23.0 |
HIP 93989 |
24.20 |
| 2026-09-22 00:00 |
19:08:22.46 |
+39:32:11.4 |
HIP 93989 |
22.97 |
| 2026-09-22 12:00 |
19:08:19.72 |
+39:30:59.8 |
HIP 93989 |
21.74 |
| 2026-09-23 00:00 |
19:08:17.04 |
+39:29:48.0 |
HIP 93989 |
20.52 |
| 2026-09-23 12:00 |
19:08:14.44 |
+39:28:36.1 |
HIP 93989 |
19.31 |
| 2026-09-24 00:00 |
19:08:11.89 |
+39:27:24.1 |
HIP 93989 |
18.11 |
| 2026-09-24 12:00 |
19:08:09.41 |
+39:26:12.0 |
HIP 93989 |
16.92 |
| 2026-09-25 00:00 |
19:08:06.99 |
+39:24:59.8 |
HIP 93989 |
15.75 |
| 2026-09-25 12:00 |
19:08:04.64 |
+39:23:47.4 |
HIP 93989 |
14.59 |
| 2026-09-26 00:00 |
19:08:02.35 |
+39:22:35.0 |
HIP 93989 |
13.46 |
| 2026-09-26 12:00 |
19:08:00.13 |
+39:21:22.5 |
HIP 93989 |
12.34 |
| 2026-09-27 00:00 |
19:07:57.97 |
+39:20:09.9 |
HIP 93989 |
11.26 |
| 2026-09-27 12:00 |
19:07:55.88 |
+39:18:57.2 |
HIP 93989 |
10.23 |
| 2026-09-28 00:00 |
19:07:53.85 |
+39:17:44.5 |
HIP 93989 |
9.24 |
| 2026-09-28 12:00 |
19:07:51.88 |
+39:16:31.6 |
HIP 93989 |
8.33 |
| 2026-09-29 00:00 |
19:07:49.98 |
+39:15:18.8 |
HIP 93989 |
7.51 |
| 2026-09-29 12:00 |
19:07:48.15 |
+39:14:05.8 |
HIP 93989 |
6.83 |
| 2026-09-30 00:00 |
19:07:46.38 |
+39:12:52.8 |
HIP 93989 |
6.31 |
| 2026-09-30 12:00 |
19:07:44.67 |
+39:11:39.8 |
HIP 93989 |
6.01 |
| 2026-10-01 00:00 |
19:07:43.03 |
+39:10:26.7 |
HIP 93989 |
5.96 |
| 2026-10-01 12:00 |
19:07:41.46 |
+39:09:13.6 |
HIP 93989 |
6.15 |
| 2026-10-02 00:00 |
19:07:39.95 |
+39:08:00.5 |
HIP 93989 |
6.57 |
| 2026-10-02 12:00 |
19:07:38.50 |
+39:06:47.3 |
HIP 93989 |
7.18 |
| 2026-10-03 00:00 |
19:07:37.12 |
+39:05:34.2 |
HIP 93989 |
7.92 |
| 2026-10-03 12:00 |
19:07:35.80 |
+39:04:21.0 |
HIP 93989 |
8.78 |
| 2026-10-04 00:00 |
19:07:34.55 |
+39:03:07.8 |
HIP 93954 |
7.86 |
| 2026-10-04 12:00 |
19:07:33.37 |
+39:01:54.6 |
HIP 93954 |
6.80 |
| 2026-10-05 00:00 |
19:07:32.25 |
+39:00:41.4 |
HIP 93954 |
5.82 |
| 2026-10-05 12:00 |
19:07:31.19 |
+38:59:28.3 |
HIP 93954 |
4.94 |
| 2026-10-06 00:00 |
19:07:30.20 |
+38:58:15.1 |
HIP 93954 |
4.24 |
| 2026-10-06 12:00 |
19:07:29.28 |
+38:57:02.0 |
HIP 93954 |
3.81 |
| 2026-10-07 00:00 |
19:07:28.42 |
+38:55:48.9 |
HIP 93954 |
3.73 |
| 2026-10-07 12:00 |
19:07:27.63 |
+38:54:35.8 |
HIP 93954 |
4.04 |
| 2026-10-08 00:00 |
19:07:26.90 |
+38:53:22.8 |
HIP 93954 |
4.64 |
| 2026-10-08 12:00 |
19:07:26.24 |
+38:52:09.9 |
HIP 93954 |
5.45 |
| 2026-10-09 00:00 |
19:07:25.64 |
+38:50:57.0 |
HIP 93954 |
6.38 |
| 2026-10-09 12:00 |
19:07:25.10 |
+38:49:44.2 |
HIP 93954 |
7.39 |
| 2026-10-10 00:00 |
19:07:24.64 |
+38:48:31.4 |
HIP 93954 |
8.45 |
| 2026-10-10 12:00 |
19:07:24.23 |
+38:47:18.7 |
HIP 93954 |
9.54 |
| 2026-10-11 00:00 |
19:07:23.89 |
+38:46:06.1 |
HIP 93954 |
10.64 |