| 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) |
| 2026-07-29 00:00 |
08:00:13.74 |
+00:08:17.4 |
HIP 39093 |
21.29 |
| 2026-07-29 12:00 |
08:00:15.98 |
+00:08:09.5 |
HIP 39093 |
21.58 |
| 2026-07-30 00:00 |
08:00:18.22 |
+00:08:01.6 |
HIP 39093 |
21.87 |
| 2026-07-30 12:00 |
08:00:20.46 |
+00:07:53.6 |
HIP 39093 |
22.18 |
| 2026-07-31 00:00 |
08:00:22.70 |
+00:07:45.5 |
HIP 39262 |
22.38 |
| 2026-07-31 12:00 |
08:00:24.93 |
+00:07:37.3 |
HIP 39262 |
21.82 |
| 2026-08-01 00:00 |
08:00:27.16 |
+00:07:28.9 |
HIP 39262 |
21.26 |
| 2026-08-01 12:00 |
08:00:29.38 |
+00:07:20.6 |
HIP 39262 |
20.70 |
| 2026-08-02 00:00 |
08:00:31.60 |
+00:07:12.1 |
HIP 39262 |
20.14 |
| 2026-08-02 12:00 |
08:00:33.82 |
+00:07:03.5 |
HIP 39262 |
19.58 |
| 2026-08-03 00:00 |
08:00:36.04 |
+00:06:54.8 |
HIP 39262 |
19.03 |
| 2026-08-03 12:00 |
08:00:38.24 |
+00:06:46.0 |
HIP 39262 |
18.47 |
| 2026-08-04 00:00 |
08:00:40.45 |
+00:06:37.2 |
HIP 39262 |
17.92 |
| 2026-08-04 12:00 |
08:00:42.65 |
+00:06:28.2 |
HIP 39262 |
17.37 |
| 2026-08-05 00:00 |
08:00:44.85 |
+00:06:19.2 |
HIP 39262 |
16.81 |
| 2026-08-05 12:00 |
08:00:47.04 |
+00:06:10.1 |
HIP 39262 |
16.27 |
| 2026-08-06 00:00 |
08:00:49.22 |
+00:06:00.9 |
HIP 39262 |
15.72 |
| 2026-08-06 12:00 |
08:00:51.40 |
+00:05:51.6 |
HIP 39262 |
15.17 |
| 2026-08-07 00:00 |
08:00:53.58 |
+00:05:42.2 |
HIP 39262 |
14.63 |
| 2026-08-07 12:00 |
08:00:55.75 |
+00:05:32.7 |
HIP 39262 |
14.09 |
| 2026-08-08 00:00 |
08:00:57.92 |
+00:05:23.2 |
HIP 39262 |
13.55 |
| 2026-08-08 12:00 |
08:01:00.08 |
+00:05:13.5 |
HIP 39262 |
13.01 |
| 2026-08-09 00:00 |
08:01:02.23 |
+00:05:03.8 |
HIP 39262 |
12.47 |
| 2026-08-09 12:00 |
08:01:04.38 |
+00:04:54.0 |
HIP 39262 |
11.94 |
| 2026-08-10 00:00 |
08:01:06.52 |
+00:04:44.1 |
HIP 39262 |
11.41 |
| 2026-08-10 12:00 |
08:01:08.66 |
+00:04:34.1 |
HIP 39262 |
10.89 |
| 2026-08-11 00:00 |
08:01:10.78 |
+00:04:24.1 |
HIP 39262 |
10.37 |
| 2026-08-11 12:00 |
08:01:12.91 |
+00:04:14.0 |
HIP 39262 |
9.85 |
| 2026-08-12 00:00 |
08:01:15.02 |
+00:04:03.7 |
HIP 39262 |
9.34 |
| 2026-08-12 12:00 |
08:01:17.13 |
+00:03:53.4 |
HIP 39262 |
8.83 |
| 2026-08-13 00:00 |
08:01:19.23 |
+00:03:43.1 |
HIP 39262 |
8.33 |
| 2026-08-13 12:00 |
08:01:21.33 |
+00:03:32.6 |
HIP 39262 |
7.84 |
| 2026-08-14 00:00 |
08:01:23.41 |
+00:03:22.1 |
HIP 39262 |
7.36 |
| 2026-08-14 12:00 |
08:01:25.49 |
+00:03:11.5 |
HIP 39262 |
6.89 |
| 2026-08-15 00:00 |
08:01:27.56 |
+00:03:00.8 |
HIP 39262 |
6.43 |
| 2026-08-15 12:00 |
08:01:29.63 |
+00:02:50.0 |
HIP 39262 |
5.98 |
| 2026-08-16 00:00 |
08:01:31.68 |
+00:02:39.2 |
HIP 39262 |
5.55 |
| 2026-08-16 12:00 |
08:01:33.73 |
+00:02:28.3 |
HIP 39262 |
5.15 |
| 2026-08-17 00:00 |
08:01:35.77 |
+00:02:17.3 |
HIP 39262 |
4.77 |
| 2026-08-17 12:00 |
08:01:37.80 |
+00:02:06.3 |
HIP 39262 |
4.42 |
| 2026-08-18 00:00 |
08:01:39.82 |
+00:01:55.2 |
HIP 39262 |
4.12 |
| 2026-08-18 12:00 |
08:01:41.83 |
+00:01:44.0 |
HIP 39262 |
3.87 |
| 2026-08-19 00:00 |
08:01:43.84 |
+00:01:32.7 |
HIP 39262 |
3.67 |