| Parameter |
Value |
| Designation |
C/1999 S4 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2000-07-26T03:54:28.607040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:02Z |
| Obs used |
1230 |
| NEO |
- |
| M1 |
9.600 |
| K1 |
6.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2000-02-13.0000000 |
| e |
1.00010829 |
| q (au) |
0.765089 |
| a (au) |
-7064.946187 |
| i (deg) |
149.384928 |
| Ω (om, deg) |
83.180585 |
| ω (w, deg) |
151.049994 |
| M (ma, deg) |
-0.000272 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.703 + 2.930\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.703 |
| n |
2.930 |
| gf |
0.800 |
| gb |
-0.588 |
| k |
0.800 |
| δ90 |
1.000 |
| 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 |
| 1999-09-27 |
1999-12-05 |
+5.1833 |
-3.118 |
| 1999-12-05 |
2000-06-22 |
+2.2171 |
-1.141 |
| 2000-06-22 |
2000-07-26 |
-14.5391 |
-1.393 |
| 2000-07-26 |
2000-08-30 |
+15.4677 |
+2.517 |
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 |
07:55:27.79 |
-00:14:54.6 |
HIP 38653 |
31.76 |
| 2026-03-26 12:00 |
07:55:26.81 |
-00:14:39.0 |
HIP 38653 |
31.94 |
| 2026-03-27 00:00 |
07:55:25.84 |
-00:14:23.5 |
HIP 38653 |
32.13 |
| 2026-03-27 12:00 |
07:55:24.90 |
-00:14:08.0 |
HIP 38653 |
32.32 |
| 2026-03-28 00:00 |
07:55:23.98 |
-00:13:52.5 |
HIP 38653 |
32.51 |
| 2026-03-28 12:00 |
07:55:23.08 |
-00:13:37.0 |
HIP 38653 |
32.70 |
| 2026-03-29 00:00 |
07:55:22.20 |
-00:13:21.5 |
HIP 38653 |
32.90 |
| 2026-03-29 12:00 |
07:55:21.34 |
-00:13:06.1 |
HIP 38653 |
33.11 |
| 2026-03-30 00:00 |
07:55:20.50 |
-00:12:50.6 |
HIP 38653 |
33.31 |
| 2026-03-30 12:00 |
07:55:19.68 |
-00:12:35.3 |
HIP 38653 |
33.52 |
| 2026-03-31 00:00 |
07:55:18.88 |
-00:12:19.9 |
HIP 38653 |
33.73 |
| 2026-03-31 12:00 |
07:55:18.10 |
-00:12:04.6 |
HIP 38653 |
33.94 |
| 2026-04-01 00:00 |
07:55:17.34 |
-00:11:49.2 |
HIP 38653 |
34.16 |
| 2026-04-01 12:00 |
07:55:16.60 |
-00:11:34.0 |
HIP 38653 |
34.37 |
| 2026-04-02 00:00 |
07:55:15.88 |
-00:11:18.7 |
HIP 38653 |
34.59 |
| 2026-04-02 12:00 |
07:55:15.18 |
-00:11:03.5 |
HIP 38653 |
34.81 |
| 2026-04-03 00:00 |
07:55:14.50 |
-00:10:48.3 |
HIP 38653 |
35.03 |
| 2026-04-03 12:00 |
07:55:13.85 |
-00:10:33.2 |
HIP 38653 |
35.26 |
| 2026-04-04 00:00 |
07:55:13.21 |
-00:10:18.1 |
HIP 38653 |
35.48 |
| 2026-04-04 12:00 |
07:55:12.60 |
-00:10:03.0 |
HIP 38653 |
35.71 |
| 2026-04-05 00:00 |
07:55:12.00 |
-00:09:47.9 |
HIP 38573 |
35.83 |
| 2026-04-05 12:00 |
07:55:11.43 |
-00:09:32.9 |
HIP 38573 |
35.54 |
| 2026-04-06 00:00 |
07:55:10.87 |
-00:09:18.0 |
HIP 38573 |
35.26 |
| 2026-04-06 12:00 |
07:55:10.34 |
-00:09:03.1 |
HIP 38573 |
34.98 |
| 2026-04-07 00:00 |
07:55:09.83 |
-00:08:48.2 |
HIP 38573 |
34.70 |
| 2026-04-07 12:00 |
07:55:09.34 |
-00:08:33.3 |
HIP 38573 |
34.43 |
| 2026-04-08 00:00 |
07:55:08.87 |
-00:08:18.5 |
HIP 38573 |
34.16 |
| 2026-04-08 12:00 |
07:55:08.42 |
-00:08:03.8 |
HIP 38573 |
33.89 |
| 2026-04-09 00:00 |
07:55:07.99 |
-00:07:49.1 |
HIP 38573 |
33.63 |
| 2026-04-09 12:00 |
07:55:07.58 |
-00:07:34.4 |
HIP 38573 |
33.37 |
| 2026-04-10 00:00 |
07:55:07.19 |
-00:07:19.8 |
HIP 38573 |
33.11 |
| 2026-04-10 12:00 |
07:55:06.82 |
-00:07:05.2 |
HIP 38573 |
32.86 |
| 2026-04-11 00:00 |
07:55:06.48 |
-00:06:50.7 |
HIP 38573 |
32.61 |
| 2026-04-11 12:00 |
07:55:06.15 |
-00:06:36.2 |
HIP 38573 |
32.37 |
| 2026-04-12 00:00 |
07:55:05.85 |
-00:06:21.8 |
HIP 38573 |
32.13 |
| 2026-04-12 12:00 |
07:55:05.57 |
-00:06:07.4 |
HIP 38573 |
31.89 |
| 2026-04-13 00:00 |
07:55:05.30 |
-00:05:53.1 |
HIP 38573 |
31.66 |
| 2026-04-13 12:00 |
07:55:05.06 |
-00:05:38.9 |
HIP 38573 |
31.43 |
| 2026-04-14 00:00 |
07:55:04.84 |
-00:05:24.6 |
HIP 38573 |
31.21 |
| 2026-04-14 12:00 |
07:55:04.64 |
-00:05:10.5 |
HIP 38573 |
30.99 |
| 2026-04-15 00:00 |
07:55:04.46 |
-00:04:56.4 |
HIP 38573 |
30.77 |
| 2026-04-15 12:00 |
07:55:04.31 |
-00:04:42.4 |
HIP 38573 |
30.56 |
| 2026-04-16 00:00 |
07:55:04.17 |
-00:04:28.4 |
HIP 38573 |
30.35 |