| Parameter |
Value |
| Designation |
109P/Swift-Tuttle |
| Type |
P |
| Perihelion (tp_cal, UTC) |
1992-12-11T23:59:41.389440Z |
| Orbit solution date (soln_date, UTC) |
2001-10-09T15:34:49Z |
| Obs used |
652 |
| NEO |
Yes |
| M1 |
4.500 |
| K1 |
15.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1995-10-10.0000000 |
| e |
0.96322576 |
| q (au) |
0.959516 |
| a (au) |
26.092069 |
| i (deg) |
113.453817 |
| Ω (om, deg) |
139.381192 |
| ω (w, deg) |
152.982168 |
| M (ma, deg) |
7.631696 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.031 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.031 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.861 |
| k |
0.996 |
| δ90 |
10.000 |
| 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 |
| 1992-01-03 |
1992-12-11 |
+4.1490 |
-0.126 |
| 1992-12-12 |
1993-03-09 |
+2.1256 |
-0.154 |
| 1993-03-09 |
1995-04-05 |
-0.7717 |
+0.720 |
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 |
09:34:24.34 |
-18:32:35.5 |
HIP 46972 |
12.55 |
| 2026-05-12 12:00 |
09:34:24.30 |
-18:32:11.6 |
HIP 46972 |
12.95 |
| 2026-05-13 00:00 |
09:34:24.28 |
-18:31:47.8 |
HIP 46972 |
13.34 |
| 2026-05-13 12:00 |
09:34:24.29 |
-18:31:24.1 |
HIP 46972 |
13.74 |
| 2026-05-14 00:00 |
09:34:24.32 |
-18:31:00.6 |
HIP 46972 |
14.13 |
| 2026-05-14 12:00 |
09:34:24.37 |
-18:30:37.1 |
HIP 46972 |
14.52 |
| 2026-05-15 00:00 |
09:34:24.44 |
-18:30:13.7 |
HIP 46972 |
14.91 |
| 2026-05-15 12:00 |
09:34:24.54 |
-18:29:50.5 |
HIP 46972 |
15.30 |
| 2026-05-16 00:00 |
09:34:24.67 |
-18:29:27.3 |
HIP 46972 |
15.68 |
| 2026-05-16 12:00 |
09:34:24.81 |
-18:29:04.3 |
HIP 46972 |
16.07 |
| 2026-05-17 00:00 |
09:34:24.98 |
-18:28:41.4 |
HIP 46972 |
16.45 |
| 2026-05-17 12:00 |
09:34:25.18 |
-18:28:18.6 |
HIP 46972 |
16.83 |
| 2026-05-18 00:00 |
09:34:25.39 |
-18:27:55.9 |
HIP 46972 |
17.21 |
| 2026-05-18 12:00 |
09:34:25.63 |
-18:27:33.4 |
HIP 46972 |
17.58 |
| 2026-05-19 00:00 |
09:34:25.90 |
-18:27:11.0 |
HIP 46972 |
17.96 |
| 2026-05-19 12:00 |
09:34:26.18 |
-18:26:48.7 |
HIP 46972 |
18.33 |
| 2026-05-20 00:00 |
09:34:26.49 |
-18:26:26.5 |
HIP 46972 |
18.70 |
| 2026-05-20 12:00 |
09:34:26.82 |
-18:26:04.4 |
HIP 46972 |
19.07 |
| 2026-05-21 00:00 |
09:34:27.18 |
-18:25:42.5 |
HIP 46972 |
19.44 |
| 2026-05-21 12:00 |
09:34:27.56 |
-18:25:20.7 |
HIP 46972 |
19.80 |
| 2026-05-22 00:00 |
09:34:27.96 |
-18:24:59.1 |
HIP 46972 |
20.17 |
| 2026-05-22 12:00 |
09:34:28.38 |
-18:24:37.6 |
HIP 46972 |
20.53 |
| 2026-05-23 00:00 |
09:34:28.83 |
-18:24:16.2 |
HIP 46972 |
20.89 |
| 2026-05-23 12:00 |
09:34:29.29 |
-18:23:54.9 |
HIP 46972 |
21.25 |
| 2026-05-24 00:00 |
09:34:29.78 |
-18:23:33.8 |
HIP 46972 |
21.61 |
| 2026-05-24 12:00 |
09:34:30.30 |
-18:23:12.8 |
HIP 46972 |
21.97 |
| 2026-05-25 00:00 |
09:34:30.83 |
-18:22:51.9 |
HIP 46972 |
22.32 |
| 2026-05-25 12:00 |
09:34:31.39 |
-18:22:31.2 |
HIP 46972 |
22.67 |
| 2026-05-26 00:00 |
09:34:31.97 |
-18:22:10.7 |
HIP 46972 |
23.03 |
| 2026-05-26 12:00 |
09:34:32.57 |
-18:21:50.3 |
HIP 46972 |
23.38 |
| 2026-05-27 00:00 |
09:34:33.20 |
-18:21:30.0 |
HIP 46972 |
23.73 |
| 2026-05-27 12:00 |
09:34:33.85 |
-18:21:09.8 |
HIP 46972 |
24.07 |
| 2026-05-28 00:00 |
09:34:34.51 |
-18:20:49.8 |
HIP 46972 |
24.42 |
| 2026-05-28 12:00 |
09:34:35.20 |
-18:20:30.0 |
HIP 46972 |
24.76 |
| 2026-05-29 00:00 |
09:34:35.92 |
-18:20:10.3 |
HIP 46972 |
25.11 |
| 2026-05-29 12:00 |
09:34:36.65 |
-18:19:50.7 |
HIP 46972 |
25.45 |
| 2026-05-30 00:00 |
09:34:37.40 |
-18:19:31.3 |
HIP 46972 |
25.79 |
| 2026-05-30 12:00 |
09:34:38.18 |
-18:19:12.1 |
HIP 46972 |
26.13 |
| 2026-05-31 00:00 |
09:34:38.98 |
-18:18:53.0 |
HIP 46972 |
26.47 |
| 2026-05-31 12:00 |
09:34:39.80 |
-18:18:34.0 |
HIP 46972 |
26.81 |
| 2026-06-01 00:00 |
09:34:40.64 |
-18:18:15.3 |
HIP 46972 |
27.15 |
| 2026-06-01 12:00 |
09:34:41.50 |
-18:17:56.6 |
HIP 46972 |
27.49 |
| 2026-06-02 00:00 |
09:34:42.39 |
-18:17:38.1 |
HIP 46972 |
27.82 |