| 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) |
| 2026-05-12 00:00 |
07:55:24.94 |
+00:05:55.2 |
HIP 38573 |
27.16 |
| 2026-05-12 12:00 |
07:55:25.85 |
+00:06:04.9 |
HIP 38573 |
27.27 |
| 2026-05-13 00:00 |
07:55:26.78 |
+00:06:14.4 |
HIP 38573 |
27.39 |
| 2026-05-13 12:00 |
07:55:27.72 |
+00:06:23.9 |
HIP 38573 |
27.52 |
| 2026-05-14 00:00 |
07:55:28.69 |
+00:06:33.3 |
HIP 38573 |
27.65 |
| 2026-05-14 12:00 |
07:55:29.67 |
+00:06:42.5 |
HIP 38573 |
27.80 |
| 2026-05-15 00:00 |
07:55:30.67 |
+00:06:51.7 |
HIP 38573 |
27.95 |
| 2026-05-15 12:00 |
07:55:31.69 |
+00:07:00.7 |
HIP 38573 |
28.10 |
| 2026-05-16 00:00 |
07:55:32.72 |
+00:07:09.7 |
HIP 38796 |
28.23 |
| 2026-05-16 12:00 |
07:55:33.78 |
+00:07:18.5 |
HIP 38796 |
27.98 |
| 2026-05-17 00:00 |
07:55:34.85 |
+00:07:27.3 |
HIP 38796 |
27.73 |
| 2026-05-17 12:00 |
07:55:35.94 |
+00:07:35.9 |
HIP 38796 |
27.48 |
| 2026-05-18 00:00 |
07:55:37.04 |
+00:07:44.5 |
HIP 38796 |
27.23 |
| 2026-05-18 12:00 |
07:55:38.16 |
+00:07:52.9 |
HIP 38796 |
26.98 |
| 2026-05-19 00:00 |
07:55:39.30 |
+00:08:01.2 |
HIP 38796 |
26.73 |
| 2026-05-19 12:00 |
07:55:40.46 |
+00:08:09.4 |
HIP 38796 |
26.49 |
| 2026-05-20 00:00 |
07:55:41.63 |
+00:08:17.6 |
HIP 38796 |
26.25 |
| 2026-05-20 12:00 |
07:55:42.82 |
+00:08:25.6 |
HIP 38796 |
26.00 |
| 2026-05-21 00:00 |
07:55:44.03 |
+00:08:33.4 |
HIP 38796 |
25.76 |
| 2026-05-21 12:00 |
07:55:45.25 |
+00:08:41.2 |
HIP 38796 |
25.53 |
| 2026-05-22 00:00 |
07:55:46.49 |
+00:08:48.9 |
HIP 38796 |
25.29 |
| 2026-05-22 12:00 |
07:55:47.75 |
+00:08:56.5 |
HIP 38796 |
25.06 |
| 2026-05-23 00:00 |
07:55:49.02 |
+00:09:03.9 |
HIP 38796 |
24.83 |
| 2026-05-23 12:00 |
07:55:50.31 |
+00:09:11.3 |
HIP 38796 |
24.60 |
| 2026-05-24 00:00 |
07:55:51.61 |
+00:09:18.5 |
HIP 38796 |
24.37 |
| 2026-05-24 12:00 |
07:55:52.93 |
+00:09:25.6 |
HIP 38796 |
24.15 |
| 2026-05-25 00:00 |
07:55:54.26 |
+00:09:32.6 |
HIP 38796 |
23.94 |
| 2026-05-25 12:00 |
07:55:55.61 |
+00:09:39.5 |
HIP 38796 |
23.72 |
| 2026-05-26 00:00 |
07:55:56.98 |
+00:09:46.3 |
HIP 38796 |
23.51 |
| 2026-05-26 12:00 |
07:55:58.36 |
+00:09:53.0 |
HIP 38796 |
23.31 |
| 2026-05-27 00:00 |
07:55:59.76 |
+00:09:59.6 |
HIP 38796 |
23.11 |
| 2026-05-27 12:00 |
07:56:01.17 |
+00:10:06.0 |
HIP 38796 |
22.91 |
| 2026-05-28 00:00 |
07:56:02.60 |
+00:10:12.4 |
HIP 38796 |
22.72 |
| 2026-05-28 12:00 |
07:56:04.04 |
+00:10:18.6 |
HIP 38796 |
22.54 |
| 2026-05-29 00:00 |
07:56:05.50 |
+00:10:24.7 |
HIP 38796 |
22.36 |
| 2026-05-29 12:00 |
07:56:06.97 |
+00:10:30.7 |
HIP 38796 |
22.18 |
| 2026-05-30 00:00 |
07:56:08.45 |
+00:10:36.6 |
HIP 38796 |
22.02 |
| 2026-05-30 12:00 |
07:56:09.95 |
+00:10:42.4 |
HIP 38796 |
21.86 |
| 2026-05-31 00:00 |
07:56:11.47 |
+00:10:48.1 |
HIP 38796 |
21.71 |
| 2026-05-31 12:00 |
07:56:12.99 |
+00:10:53.6 |
HIP 38796 |
21.56 |
| 2026-06-01 00:00 |
07:56:14.54 |
+00:10:59.0 |
HIP 38796 |
21.42 |
| 2026-06-01 12:00 |
07:56:16.09 |
+00:11:04.4 |
HIP 38796 |
21.29 |
| 2026-06-02 00:00 |
07:56:17.66 |
+00:11:09.6 |
HIP 38796 |
21.17 |