| Parameter |
Value |
| Designation |
271P/van Houten-Lemmon |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2013-07-05T13:04:46.807680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:12Z |
| Obs used |
96 |
| NEO |
- |
| M1 |
7.200 |
| K1 |
15.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-09-26.0000000 |
| e |
0.39067132 |
| q (au) |
4.249690 |
| a (au) |
6.974381 |
| i (deg) |
6.856107 |
| Ω (om, deg) |
9.590375 |
| ω (w, deg) |
35.088457 |
| M (ma, deg) |
344.880647 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.743 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.743 |
| n |
6.000 |
| gf |
0.996 |
| gb |
-0.982 |
| k |
1.000 |
| δ90 |
9.986 |
| 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 |
17:28:09.46 |
-30:25:18.3 |
HIP 85413 |
31.19 |
| 2026-05-12 12:00 |
17:27:59.88 |
-30:25:28.5 |
HIP 85413 |
30.61 |
| 2026-05-13 00:00 |
17:27:50.22 |
-30:25:38.5 |
HIP 85413 |
30.16 |
| 2026-05-13 12:00 |
17:27:40.47 |
-30:25:48.1 |
HIP 85413 |
29.84 |
| 2026-05-14 00:00 |
17:27:30.63 |
-30:25:57.5 |
HIP 85413 |
29.66 |
| 2026-05-14 12:00 |
17:27:20.70 |
-30:26:06.5 |
HIP 85413 |
29.63 |
| 2026-05-15 00:00 |
17:27:10.69 |
-30:26:15.3 |
HIP 85413 |
29.74 |
| 2026-05-15 12:00 |
17:27:00.60 |
-30:26:23.8 |
HIP 85413 |
30.01 |
| 2026-05-16 00:00 |
17:26:50.43 |
-30:26:32.0 |
HIP 85413 |
30.44 |
| 2026-05-16 12:00 |
17:26:40.17 |
-30:26:39.9 |
HIP 85413 |
31.01 |
| 2026-05-17 00:00 |
17:26:29.84 |
-30:26:47.4 |
HIP 85413 |
31.73 |
| 2026-05-17 12:00 |
17:26:19.43 |
-30:26:54.7 |
HIP 85413 |
32.59 |
| 2026-05-18 00:00 |
17:26:08.94 |
-30:27:01.7 |
HIP 85281 |
33.13 |
| 2026-05-18 12:00 |
17:25:58.38 |
-30:27:08.4 |
HIP 85281 |
32.56 |
| 2026-05-19 00:00 |
17:25:47.74 |
-30:27:14.7 |
HIP 85281 |
32.14 |
| 2026-05-19 12:00 |
17:25:37.04 |
-30:27:20.8 |
HIP 85281 |
31.89 |
| 2026-05-20 00:00 |
17:25:26.26 |
-30:27:26.5 |
HIP 85281 |
31.80 |
| 2026-05-20 12:00 |
17:25:15.41 |
-30:27:31.9 |
HIP 85281 |
31.90 |
| 2026-05-21 00:00 |
17:25:04.49 |
-30:27:37.0 |
HIP 85281 |
32.17 |
| 2026-05-21 12:00 |
17:24:53.51 |
-30:27:41.8 |
HIP 85281 |
32.61 |
| 2026-05-22 00:00 |
17:24:42.47 |
-30:27:46.3 |
HIP 84982 |
33.12 |
| 2026-05-22 12:00 |
17:24:31.35 |
-30:27:50.4 |
HIP 84982 |
30.72 |
| 2026-05-23 00:00 |
17:24:20.18 |
-30:27:54.3 |
HIP 84982 |
28.32 |
| 2026-05-23 12:00 |
17:24:08.95 |
-30:27:57.8 |
HIP 84982 |
25.90 |
| 2026-05-24 00:00 |
17:23:57.66 |
-30:28:01.0 |
HIP 84982 |
23.47 |
| 2026-05-24 12:00 |
17:23:46.31 |
-30:28:03.9 |
HIP 84982 |
21.03 |
| 2026-05-25 00:00 |
17:23:34.90 |
-30:28:06.4 |
HIP 84982 |
18.58 |
| 2026-05-25 12:00 |
17:23:23.44 |
-30:28:08.6 |
HIP 84982 |
16.13 |
| 2026-05-26 00:00 |
17:23:11.92 |
-30:28:10.5 |
HIP 84982 |
13.66 |
| 2026-05-26 12:00 |
17:23:00.36 |
-30:28:12.1 |
HIP 84982 |
11.20 |
| 2026-05-27 00:00 |
17:22:48.74 |
-30:28:13.3 |
HIP 84982 |
8.73 |
| 2026-05-27 12:00 |
17:22:37.07 |
-30:28:14.3 |
HIP 84982 |
6.30 |
| 2026-05-28 00:00 |
17:22:25.36 |
-30:28:14.8 |
HIP 84982 |
3.95 |
| 2026-05-28 12:00 |
17:22:13.60 |
-30:28:15.1 |
HIP 84982 |
2.07 |
| 2026-05-29 00:00 |
17:22:01.79 |
-30:28:15.0 |
HIP 84982 |
2.42 |
| 2026-05-29 12:00 |
17:21:49.94 |
-30:28:14.6 |
HIP 84982 |
4.52 |
| 2026-05-30 00:00 |
17:21:38.05 |
-30:28:13.9 |
HIP 84982 |
6.95 |
| 2026-05-30 12:00 |
17:21:26.12 |
-30:28:12.8 |
HIP 84982 |
9.45 |
| 2026-05-31 00:00 |
17:21:14.14 |
-30:28:11.4 |
HIP 84982 |
11.99 |
| 2026-05-31 12:00 |
17:21:02.13 |
-30:28:09.7 |
HIP 84806 |
13.52 |
| 2026-06-01 00:00 |
17:20:50.09 |
-30:28:07.6 |
HIP 84806 |
10.97 |
| 2026-06-01 12:00 |
17:20:38.01 |
-30:28:05.3 |
HIP 84806 |
8.43 |
| 2026-06-02 00:00 |
17:20:25.89 |
-30:28:02.5 |
HIP 84806 |
5.95 |