| 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) |
| 2026-05-12 00:00 |
06:12:59.80 |
+25:31:20.8 |
HIP 29454 |
8.55 |
| 2026-05-12 12:00 |
06:13:00.49 |
+25:31:20.1 |
HIP 29454 |
8.71 |
| 2026-05-13 00:00 |
06:13:01.18 |
+25:31:19.4 |
HIP 29454 |
8.86 |
| 2026-05-13 12:00 |
06:13:01.87 |
+25:31:18.7 |
HIP 29454 |
9.02 |
| 2026-05-14 00:00 |
06:13:02.57 |
+25:31:18.0 |
HIP 29454 |
9.18 |
| 2026-05-14 12:00 |
06:13:03.27 |
+25:31:17.4 |
HIP 29454 |
9.34 |
| 2026-05-15 00:00 |
06:13:03.98 |
+25:31:16.7 |
HIP 29454 |
9.50 |
| 2026-05-15 12:00 |
06:13:04.69 |
+25:31:16.0 |
HIP 29454 |
9.66 |
| 2026-05-16 00:00 |
06:13:05.41 |
+25:31:15.3 |
HIP 29454 |
9.82 |
| 2026-05-16 12:00 |
06:13:06.14 |
+25:31:14.6 |
HIP 29454 |
9.98 |
| 2026-05-17 00:00 |
06:13:06.86 |
+25:31:14.0 |
HIP 29454 |
10.15 |
| 2026-05-17 12:00 |
06:13:07.60 |
+25:31:13.3 |
HIP 29454 |
10.31 |
| 2026-05-18 00:00 |
06:13:08.33 |
+25:31:12.6 |
HIP 29454 |
10.48 |
| 2026-05-18 12:00 |
06:13:09.08 |
+25:31:12.0 |
HIP 29454 |
10.65 |
| 2026-05-19 00:00 |
06:13:09.82 |
+25:31:11.3 |
HIP 29454 |
10.82 |
| 2026-05-19 12:00 |
06:13:10.57 |
+25:31:10.6 |
HIP 29454 |
10.99 |
| 2026-05-20 00:00 |
06:13:11.33 |
+25:31:09.9 |
HIP 29454 |
11.16 |
| 2026-05-20 12:00 |
06:13:12.09 |
+25:31:09.3 |
HIP 29454 |
11.33 |
| 2026-05-21 00:00 |
06:13:12.85 |
+25:31:08.6 |
HIP 29454 |
11.50 |
| 2026-05-21 12:00 |
06:13:13.62 |
+25:31:08.0 |
HIP 29454 |
11.68 |
| 2026-05-22 00:00 |
06:13:14.39 |
+25:31:07.3 |
HIP 29454 |
11.85 |
| 2026-05-22 12:00 |
06:13:15.17 |
+25:31:06.6 |
HIP 29454 |
12.03 |
| 2026-05-23 00:00 |
06:13:15.95 |
+25:31:06.0 |
HIP 29454 |
12.20 |
| 2026-05-23 12:00 |
06:13:16.73 |
+25:31:05.3 |
HIP 29454 |
12.38 |
| 2026-05-24 00:00 |
06:13:17.52 |
+25:31:04.7 |
HIP 29454 |
12.56 |
| 2026-05-24 12:00 |
06:13:18.32 |
+25:31:04.0 |
HIP 29454 |
12.74 |
| 2026-05-25 00:00 |
06:13:19.11 |
+25:31:03.4 |
HIP 29454 |
12.92 |
| 2026-05-25 12:00 |
06:13:19.91 |
+25:31:02.7 |
HIP 29454 |
13.10 |
| 2026-05-26 00:00 |
06:13:20.71 |
+25:31:02.1 |
HIP 29454 |
13.28 |
| 2026-05-26 12:00 |
06:13:21.52 |
+25:31:01.5 |
HIP 29454 |
13.46 |
| 2026-05-27 00:00 |
06:13:22.33 |
+25:31:00.8 |
HIP 29454 |
13.64 |
| 2026-05-27 12:00 |
06:13:23.15 |
+25:31:00.2 |
HIP 29454 |
13.83 |
| 2026-05-28 00:00 |
06:13:23.97 |
+25:30:59.5 |
HIP 29454 |
14.01 |
| 2026-05-28 12:00 |
06:13:24.79 |
+25:30:58.9 |
HIP 29454 |
14.20 |
| 2026-05-29 00:00 |
06:13:25.61 |
+25:30:58.3 |
HIP 29454 |
14.38 |
| 2026-05-29 12:00 |
06:13:26.44 |
+25:30:57.7 |
HIP 29454 |
14.57 |
| 2026-05-30 00:00 |
06:13:27.27 |
+25:30:57.0 |
HIP 29454 |
14.76 |
| 2026-05-30 12:00 |
06:13:28.10 |
+25:30:56.4 |
HIP 29454 |
14.95 |
| 2026-05-31 00:00 |
06:13:28.94 |
+25:30:55.8 |
HIP 29454 |
15.14 |
| 2026-05-31 12:00 |
06:13:29.78 |
+25:30:55.2 |
HIP 29454 |
15.33 |
| 2026-06-01 00:00 |
06:13:30.63 |
+25:30:54.5 |
HIP 29454 |
15.52 |
| 2026-06-01 12:00 |
06:13:31.47 |
+25:30:53.9 |
HIP 29454 |
15.71 |
| 2026-06-02 00:00 |
06:13:32.32 |
+25:30:53.3 |
HIP 29454 |
15.90 |