| 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 |
-14.5392 |
-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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
07:56:19.25 |
+00:11:14.7 |
HIP 38796 |
21.06 |
| 2026-06-03 00:00 |
07:56:20.85 |
+00:11:19.6 |
HIP 38796 |
20.96 |
| 2026-06-03 12:00 |
07:56:22.46 |
+00:11:24.5 |
HIP 38796 |
20.86 |
| 2026-06-04 00:00 |
07:56:24.08 |
+00:11:29.2 |
HIP 38796 |
20.78 |
| 2026-06-04 12:00 |
07:56:25.72 |
+00:11:33.9 |
HIP 38796 |
20.70 |
| 2026-06-05 00:00 |
07:56:27.37 |
+00:11:38.4 |
HIP 38905 |
20.34 |
| 2026-06-05 12:00 |
07:56:29.04 |
+00:11:42.8 |
HIP 38905 |
19.92 |
| 2026-06-06 00:00 |
07:56:30.71 |
+00:11:47.1 |
HIP 38905 |
19.50 |
| 2026-06-06 12:00 |
07:56:32.41 |
+00:11:51.2 |
HIP 38905 |
19.08 |
| 2026-06-07 00:00 |
07:56:34.11 |
+00:11:55.3 |
HIP 38905 |
18.65 |
| 2026-06-07 12:00 |
07:56:35.82 |
+00:11:59.2 |
HIP 38905 |
18.23 |
| 2026-06-08 00:00 |
07:56:37.55 |
+00:12:03.0 |
HIP 38905 |
17.80 |
| 2026-06-08 12:00 |
07:56:39.29 |
+00:12:06.7 |
HIP 38905 |
17.36 |
| 2026-06-09 00:00 |
07:56:41.05 |
+00:12:10.3 |
HIP 38905 |
16.93 |
| 2026-06-09 12:00 |
07:56:42.81 |
+00:12:13.7 |
HIP 38905 |
16.50 |
| 2026-06-10 00:00 |
07:56:44.59 |
+00:12:17.0 |
HIP 38905 |
16.06 |
| 2026-06-10 12:00 |
07:56:46.38 |
+00:12:20.3 |
HIP 38905 |
15.62 |
| 2026-06-11 00:00 |
07:56:48.18 |
+00:12:23.4 |
HIP 38905 |
15.18 |
| 2026-06-11 12:00 |
07:56:49.99 |
+00:12:26.3 |
HIP 38905 |
14.74 |
| 2026-06-12 00:00 |
07:56:51.81 |
+00:12:29.2 |
HIP 38905 |
14.30 |
| 2026-06-12 12:00 |
07:56:53.65 |
+00:12:31.9 |
HIP 38905 |
13.86 |
| 2026-06-13 00:00 |
07:56:55.50 |
+00:12:34.6 |
HIP 38905 |
13.42 |
| 2026-06-13 12:00 |
07:56:57.35 |
+00:12:37.1 |
HIP 38905 |
12.98 |
| 2026-06-14 00:00 |
07:56:59.22 |
+00:12:39.4 |
HIP 38905 |
12.53 |
| 2026-06-14 12:00 |
07:57:01.10 |
+00:12:41.7 |
HIP 38905 |
12.09 |
| 2026-06-15 00:00 |
07:57:02.99 |
+00:12:43.8 |
HIP 38905 |
11.65 |
| 2026-06-15 12:00 |
07:57:04.89 |
+00:12:45.9 |
HIP 38905 |
11.21 |
| 2026-06-16 00:00 |
07:57:06.80 |
+00:12:47.8 |
HIP 38905 |
10.77 |
| 2026-06-16 12:00 |
07:57:08.72 |
+00:12:49.5 |
HIP 38905 |
10.33 |
| 2026-06-17 00:00 |
07:57:10.66 |
+00:12:51.2 |
HIP 38905 |
9.90 |
| 2026-06-17 12:00 |
07:57:12.60 |
+00:12:52.7 |
HIP 38905 |
9.47 |
| 2026-06-18 00:00 |
07:57:14.55 |
+00:12:54.1 |
HIP 38905 |
9.05 |
| 2026-06-18 12:00 |
07:57:16.51 |
+00:12:55.4 |
HIP 38905 |
8.63 |
| 2026-06-19 00:00 |
07:57:18.48 |
+00:12:56.6 |
HIP 38905 |
8.22 |
| 2026-06-19 12:00 |
07:57:20.46 |
+00:12:57.7 |
HIP 38905 |
7.81 |
| 2026-06-20 00:00 |
07:57:22.45 |
+00:12:58.6 |
HIP 38905 |
7.42 |
| 2026-06-20 12:00 |
07:57:24.44 |
+00:12:59.4 |
HIP 38905 |
7.04 |
| 2026-06-21 00:00 |
07:57:26.45 |
+00:13:00.1 |
HIP 38905 |
6.68 |
| 2026-06-21 12:00 |
07:57:28.47 |
+00:13:00.7 |
HIP 38905 |
6.33 |
| 2026-06-22 00:00 |
07:57:30.49 |
+00:13:01.2 |
HIP 38905 |
6.01 |