| Parameter |
Value |
| Designation |
55P/Tempel-Tuttle |
| Type |
P |
| Perihelion (tp_cal, UTC) |
1998-02-28T02:20:44.226240Z |
| Orbit solution date (soln_date, UTC) |
2002-01-03T16:05:39Z |
| Obs used |
392 |
| NEO |
Yes |
| M1 |
10.000 |
| K1 |
25.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1998-08-15.0000000 |
| e |
0.90555272 |
| q (au) |
0.976428 |
| a (au) |
10.338338 |
| i (deg) |
162.486575 |
| Ω (om, deg) |
235.270989 |
| ω (w, deg) |
172.500274 |
| M (ma, deg) |
4.978340 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.795 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.795 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
1.000 |
| 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 |
| 1996-05-12 |
1998-01-01 |
-1.9145 |
+1.548 |
| 1998-01-01 |
1998-01-27 |
+5.5017 |
-0.086 |
| 1998-01-27 |
1998-02-28 |
+19.7139 |
-0.354 |
| 1998-02-28 |
1998-07-05 |
+8.1609 |
-1.479 |
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 |
14:29:46.83 |
-10:44:15.0 |
HIP 70867 |
10.94 |
| 2026-07-29 12:00 |
14:29:45.20 |
-10:44:12.1 |
HIP 70867 |
10.76 |
| 2026-07-30 00:00 |
14:29:43.65 |
-10:44:09.5 |
HIP 70867 |
10.60 |
| 2026-07-30 12:00 |
14:29:42.17 |
-10:44:07.4 |
HIP 70867 |
10.47 |
| 2026-07-31 00:00 |
14:29:40.77 |
-10:44:05.6 |
HIP 70867 |
10.36 |
| 2026-07-31 12:00 |
14:29:39.45 |
-10:44:04.2 |
HIP 70867 |
10.27 |
| 2026-08-01 00:00 |
14:29:38.21 |
-10:44:03.2 |
HIP 70867 |
10.20 |
| 2026-08-01 12:00 |
14:29:37.05 |
-10:44:02.6 |
HIP 70867 |
10.14 |
| 2026-08-02 00:00 |
14:29:35.96 |
-10:44:02.3 |
HIP 70867 |
10.10 |
| 2026-08-02 12:00 |
14:29:34.96 |
-10:44:02.5 |
HIP 70867 |
10.08 |
| 2026-08-03 00:00 |
14:29:34.03 |
-10:44:02.9 |
HIP 70867 |
10.07 |
| 2026-08-03 12:00 |
14:29:33.18 |
-10:44:03.8 |
HIP 70867 |
10.07 |
| 2026-08-04 00:00 |
14:29:32.40 |
-10:44:05.1 |
HIP 70867 |
10.09 |
| 2026-08-04 12:00 |
14:29:31.70 |
-10:44:06.7 |
HIP 70867 |
10.11 |
| 2026-08-05 00:00 |
14:29:31.08 |
-10:44:08.7 |
HIP 70867 |
10.15 |
| 2026-08-05 12:00 |
14:29:30.54 |
-10:44:11.0 |
HIP 70867 |
10.19 |
| 2026-08-06 00:00 |
14:29:30.08 |
-10:44:13.8 |
HIP 70867 |
10.23 |
| 2026-08-06 12:00 |
14:29:29.69 |
-10:44:16.9 |
HIP 70867 |
10.29 |
| 2026-08-07 00:00 |
14:29:29.38 |
-10:44:20.3 |
HIP 70867 |
10.35 |
| 2026-08-07 12:00 |
14:29:29.14 |
-10:44:24.2 |
HIP 70867 |
10.42 |
| 2026-08-08 00:00 |
14:29:28.99 |
-10:44:28.4 |
HIP 70867 |
10.49 |
| 2026-08-08 12:00 |
14:29:28.91 |
-10:44:32.9 |
HIP 70867 |
10.57 |
| 2026-08-09 00:00 |
14:29:28.90 |
-10:44:37.9 |
HIP 70867 |
10.65 |
| 2026-08-09 12:00 |
14:29:28.98 |
-10:44:43.1 |
HIP 70867 |
10.73 |
| 2026-08-10 00:00 |
14:29:29.13 |
-10:44:48.8 |
HIP 70867 |
10.83 |
| 2026-08-10 12:00 |
14:29:29.35 |
-10:44:54.8 |
HIP 70867 |
10.92 |
| 2026-08-11 00:00 |
14:29:29.65 |
-10:45:01.2 |
HIP 70867 |
11.03 |
| 2026-08-11 12:00 |
14:29:30.03 |
-10:45:07.9 |
HIP 70867 |
11.14 |
| 2026-08-12 00:00 |
14:29:30.48 |
-10:45:15.0 |
HIP 70867 |
11.25 |
| 2026-08-12 12:00 |
14:29:31.01 |
-10:45:22.4 |
HIP 70867 |
11.37 |
| 2026-08-13 00:00 |
14:29:31.62 |
-10:45:30.1 |
HIP 70867 |
11.50 |
| 2026-08-13 12:00 |
14:29:32.30 |
-10:45:38.3 |
HIP 70867 |
11.64 |
| 2026-08-14 00:00 |
14:29:33.05 |
-10:45:46.7 |
HIP 70867 |
11.79 |
| 2026-08-14 12:00 |
14:29:33.88 |
-10:45:55.6 |
HIP 70867 |
11.94 |
| 2026-08-15 00:00 |
14:29:34.78 |
-10:46:04.7 |
HIP 70867 |
12.11 |
| 2026-08-15 12:00 |
14:29:35.76 |
-10:46:14.2 |
HIP 70867 |
12.29 |
| 2026-08-16 00:00 |
14:29:36.81 |
-10:46:24.0 |
HIP 70867 |
12.47 |
| 2026-08-16 12:00 |
14:29:37.93 |
-10:46:34.2 |
HIP 70867 |
12.67 |
| 2026-08-17 00:00 |
14:29:39.13 |
-10:46:44.7 |
HIP 70867 |
12.89 |
| 2026-08-17 12:00 |
14:29:40.40 |
-10:46:55.5 |
HIP 70867 |
13.12 |
| 2026-08-18 00:00 |
14:29:41.74 |
-10:47:06.7 |
HIP 70867 |
13.36 |
| 2026-08-18 12:00 |
14:29:43.16 |
-10:47:18.2 |
HIP 70867 |
13.62 |
| 2026-08-19 00:00 |
14:29:44.65 |
-10:47:30.0 |
HIP 70867 |
13.89 |