| Parameter |
Value |
| Designation |
C/1899 S1 (Giacobini) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1899-09-15T08:49:19.871040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:57Z |
| Obs used |
36 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1899-10-29.0000000 |
| e |
1.00000000 |
| q (au) |
1.785616 |
| a (au) |
- |
| i (deg) |
76.948955 |
| Ω (om, deg) |
273.627412 |
| ω (w, deg) |
10.751760 |
| M (ma, deg) |
- |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
06:12:24.55 |
+25:32:26.0 |
HIP 29454 |
1.17 |
| 2026-03-26 12:00 |
06:12:24.58 |
+25:32:25.4 |
HIP 29454 |
1.16 |
| 2026-03-27 00:00 |
06:12:24.61 |
+25:32:24.7 |
HIP 29454 |
1.15 |
| 2026-03-27 12:00 |
06:12:24.65 |
+25:32:24.1 |
HIP 29454 |
1.15 |
| 2026-03-28 00:00 |
06:12:24.71 |
+25:32:23.4 |
HIP 29454 |
1.15 |
| 2026-03-28 12:00 |
06:12:24.77 |
+25:32:22.7 |
HIP 29454 |
1.15 |
| 2026-03-29 00:00 |
06:12:24.84 |
+25:32:22.1 |
HIP 29454 |
1.15 |
| 2026-03-29 12:00 |
06:12:24.91 |
+25:32:21.4 |
HIP 29454 |
1.15 |
| 2026-03-30 00:00 |
06:12:25.00 |
+25:32:20.8 |
HIP 29454 |
1.15 |
| 2026-03-30 12:00 |
06:12:25.09 |
+25:32:20.1 |
HIP 29454 |
1.15 |
| 2026-03-31 00:00 |
06:12:25.19 |
+25:32:19.4 |
HIP 29454 |
1.16 |
| 2026-03-31 12:00 |
06:12:25.30 |
+25:32:18.8 |
HIP 29454 |
1.17 |
| 2026-04-01 00:00 |
06:12:25.41 |
+25:32:18.1 |
HIP 29454 |
1.18 |
| 2026-04-01 12:00 |
06:12:25.54 |
+25:32:17.4 |
HIP 29454 |
1.19 |
| 2026-04-02 00:00 |
06:12:25.67 |
+25:32:16.7 |
HIP 29454 |
1.20 |
| 2026-04-02 12:00 |
06:12:25.81 |
+25:32:16.1 |
HIP 29454 |
1.22 |
| 2026-04-03 00:00 |
06:12:25.95 |
+25:32:15.4 |
HIP 29454 |
1.23 |
| 2026-04-03 12:00 |
06:12:26.11 |
+25:32:14.7 |
HIP 29454 |
1.25 |
| 2026-04-04 00:00 |
06:12:26.27 |
+25:32:14.0 |
HIP 29454 |
1.27 |
| 2026-04-04 12:00 |
06:12:26.44 |
+25:32:13.4 |
HIP 29454 |
1.30 |
| 2026-04-05 00:00 |
06:12:26.62 |
+25:32:12.7 |
HIP 29454 |
1.32 |
| 2026-04-05 12:00 |
06:12:26.81 |
+25:32:12.0 |
HIP 29454 |
1.35 |
| 2026-04-06 00:00 |
06:12:27.00 |
+25:32:11.3 |
HIP 29454 |
1.38 |
| 2026-04-06 12:00 |
06:12:27.21 |
+25:32:10.6 |
HIP 29454 |
1.41 |
| 2026-04-07 00:00 |
06:12:27.42 |
+25:32:09.9 |
HIP 29454 |
1.45 |
| 2026-04-07 12:00 |
06:12:27.64 |
+25:32:09.2 |
HIP 29454 |
1.48 |
| 2026-04-08 00:00 |
06:12:27.86 |
+25:32:08.5 |
HIP 29454 |
1.52 |
| 2026-04-08 12:00 |
06:12:28.09 |
+25:32:07.9 |
HIP 29454 |
1.56 |
| 2026-04-09 00:00 |
06:12:28.34 |
+25:32:07.2 |
HIP 29454 |
1.61 |
| 2026-04-09 12:00 |
06:12:28.58 |
+25:32:06.5 |
HIP 29454 |
1.65 |
| 2026-04-10 00:00 |
06:12:28.84 |
+25:32:05.8 |
HIP 29454 |
1.70 |
| 2026-04-10 12:00 |
06:12:29.11 |
+25:32:05.1 |
HIP 29454 |
1.75 |
| 2026-04-11 00:00 |
06:12:29.38 |
+25:32:04.4 |
HIP 29454 |
1.81 |
| 2026-04-11 12:00 |
06:12:29.66 |
+25:32:03.7 |
HIP 29454 |
1.86 |
| 2026-04-12 00:00 |
06:12:29.94 |
+25:32:03.0 |
HIP 29454 |
1.92 |
| 2026-04-12 12:00 |
06:12:30.24 |
+25:32:02.3 |
HIP 29454 |
1.98 |
| 2026-04-13 00:00 |
06:12:30.54 |
+25:32:01.6 |
HIP 29454 |
2.04 |
| 2026-04-13 12:00 |
06:12:30.85 |
+25:32:00.9 |
HIP 29454 |
2.10 |
| 2026-04-14 00:00 |
06:12:31.17 |
+25:32:00.2 |
HIP 29454 |
2.17 |
| 2026-04-14 12:00 |
06:12:31.49 |
+25:31:59.5 |
HIP 29454 |
2.24 |
| 2026-04-15 00:00 |
06:12:31.82 |
+25:31:58.8 |
HIP 29454 |
2.31 |
| 2026-04-15 12:00 |
06:12:32.16 |
+25:31:58.1 |
HIP 29454 |
2.38 |
| 2026-04-16 00:00 |
06:12:32.51 |
+25:31:57.4 |
HIP 29454 |
2.45 |