| 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
$$
M_a = (6.721 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.721 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
17:00:59.95 |
-29:18:47.5 |
HIP 83258 |
21.51 |
| 2026-09-20 12:00 |
17:01:07.14 |
-29:18:37.0 |
HIP 83258 |
21.72 |
| 2026-09-21 00:00 |
17:01:14.44 |
-29:18:26.6 |
HIP 83258 |
22.04 |
| 2026-09-21 12:00 |
17:01:21.86 |
-29:18:16.5 |
HIP 83258 |
22.47 |
| 2026-09-22 00:00 |
17:01:29.39 |
-29:18:06.5 |
HIP 83258 |
23.01 |
| 2026-09-22 12:00 |
17:01:37.04 |
-29:17:56.8 |
HIP 83378 |
22.26 |
| 2026-09-23 00:00 |
17:01:44.80 |
-29:17:47.2 |
HIP 83378 |
21.33 |
| 2026-09-23 12:00 |
17:01:52.68 |
-29:17:37.9 |
HIP 83378 |
20.48 |
| 2026-09-24 00:00 |
17:02:00.66 |
-29:17:28.7 |
HIP 83378 |
19.75 |
| 2026-09-24 12:00 |
17:02:08.77 |
-29:17:19.7 |
HIP 83378 |
19.16 |
| 2026-09-25 00:00 |
17:02:16.98 |
-29:17:11.0 |
HIP 83378 |
18.71 |
| 2026-09-25 12:00 |
17:02:25.31 |
-29:17:02.4 |
HIP 83378 |
18.42 |
| 2026-09-26 00:00 |
17:02:33.75 |
-29:16:54.0 |
HIP 83378 |
18.33 |
| 2026-09-26 12:00 |
17:02:42.30 |
-29:16:45.8 |
HIP 83378 |
18.42 |
| 2026-09-27 00:00 |
17:02:50.96 |
-29:16:37.8 |
HIP 83378 |
18.71 |
| 2026-09-27 12:00 |
17:02:59.73 |
-29:16:30.0 |
HIP 83378 |
19.20 |
| 2026-09-28 00:00 |
17:03:08.61 |
-29:16:22.4 |
HIP 83378 |
19.88 |
| 2026-09-28 12:00 |
17:03:17.60 |
-29:16:15.0 |
HIP 83378 |
20.73 |
| 2026-09-29 00:00 |
17:03:26.70 |
-29:16:07.8 |
HIP 83378 |
21.74 |
| 2026-09-29 12:00 |
17:03:35.90 |
-29:16:00.7 |
HIP 83378 |
22.91 |
| 2026-09-30 00:00 |
17:03:45.22 |
-29:15:53.9 |
HIP 83378 |
24.20 |
| 2026-09-30 12:00 |
17:03:54.64 |
-29:15:47.2 |
HIP 83378 |
25.61 |
| 2026-10-01 00:00 |
17:04:04.17 |
-29:15:40.8 |
HIP 83378 |
27.12 |
| 2026-10-01 12:00 |
17:04:13.80 |
-29:15:34.5 |
HIP 83378 |
28.72 |
| 2026-10-02 00:00 |
17:04:23.54 |
-29:15:28.4 |
HIP 83592 |
29.12 |
| 2026-10-02 12:00 |
17:04:33.39 |
-29:15:22.5 |
HIP 83592 |
28.64 |
| 2026-10-03 00:00 |
17:04:43.34 |
-29:15:16.7 |
HIP 83708 |
27.93 |
| 2026-10-03 12:00 |
17:04:53.40 |
-29:15:11.2 |
HIP 83708 |
26.09 |
| 2026-10-04 00:00 |
17:05:03.56 |
-29:15:05.8 |
HIP 83708 |
24.29 |
| 2026-10-04 12:00 |
17:05:13.83 |
-29:15:00.6 |
HIP 83708 |
22.55 |
| 2026-10-05 00:00 |
17:05:24.20 |
-29:14:55.6 |
HIP 83708 |
20.90 |
| 2026-10-05 12:00 |
17:05:34.67 |
-29:14:50.8 |
HIP 83708 |
19.36 |
| 2026-10-06 00:00 |
17:05:45.24 |
-29:14:46.2 |
HIP 83708 |
17.97 |
| 2026-10-06 12:00 |
17:05:55.92 |
-29:14:41.7 |
HIP 83708 |
16.78 |
| 2026-10-07 00:00 |
17:06:06.70 |
-29:14:37.4 |
HIP 83708 |
15.84 |
| 2026-10-07 12:00 |
17:06:17.58 |
-29:14:33.3 |
HIP 83708 |
15.21 |
| 2026-10-08 00:00 |
17:06:28.56 |
-29:14:29.3 |
HIP 83708 |
14.94 |
| 2026-10-08 12:00 |
17:06:39.64 |
-29:14:25.6 |
HIP 83708 |
15.05 |
| 2026-10-09 00:00 |
17:06:50.82 |
-29:14:22.0 |
HIP 83708 |
15.56 |
| 2026-10-09 12:00 |
17:07:02.10 |
-29:14:18.5 |
HIP 83708 |
16.43 |
| 2026-10-10 00:00 |
17:07:13.48 |
-29:14:15.3 |
HIP 83708 |
17.62 |
| 2026-10-10 12:00 |
17:07:24.95 |
-29:14:12.2 |
HIP 83708 |
19.08 |
| 2026-10-11 00:00 |
17:07:36.52 |
-29:14:09.3 |
HIP 83708 |
20.75 |