| 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) |
| 2026-07-29 00:00 |
17:00:12.62 |
-29:54:05.6 |
HIP 83258 |
17.39 |
| 2026-07-29 12:00 |
17:00:06.44 |
-29:53:39.7 |
HIP 83258 |
17.91 |
| 2026-07-30 00:00 |
17:00:00.37 |
-29:53:13.8 |
HIP 83258 |
18.51 |
| 2026-07-30 12:00 |
16:59:54.42 |
-29:52:48.0 |
HIP 83258 |
19.17 |
| 2026-07-31 00:00 |
16:59:48.59 |
-29:52:22.1 |
HIP 83258 |
19.89 |
| 2026-07-31 12:00 |
16:59:42.87 |
-29:51:56.3 |
HIP 83258 |
20.64 |
| 2026-08-01 00:00 |
16:59:37.28 |
-29:51:30.5 |
HIP 83080 |
20.60 |
| 2026-08-01 12:00 |
16:59:31.80 |
-29:51:04.7 |
HIP 83080 |
20.20 |
| 2026-08-02 00:00 |
16:59:26.44 |
-29:50:39.0 |
HIP 83080 |
19.88 |
| 2026-08-02 12:00 |
16:59:21.21 |
-29:50:13.3 |
HIP 83080 |
19.65 |
| 2026-08-03 00:00 |
16:59:16.09 |
-29:49:47.6 |
HIP 83080 |
19.50 |
| 2026-08-03 12:00 |
16:59:11.09 |
-29:49:22.0 |
HIP 83080 |
19.43 |
| 2026-08-04 00:00 |
16:59:06.22 |
-29:48:56.5 |
HIP 83080 |
19.44 |
| 2026-08-04 12:00 |
16:59:01.47 |
-29:48:31.0 |
HIP 83080 |
19.53 |
| 2026-08-05 00:00 |
16:58:56.84 |
-29:48:05.5 |
HIP 83080 |
19.68 |
| 2026-08-05 12:00 |
16:58:52.33 |
-29:47:40.1 |
HIP 83080 |
19.89 |
| 2026-08-06 00:00 |
16:58:47.95 |
-29:47:14.8 |
HIP 83080 |
20.16 |
| 2026-08-06 12:00 |
16:58:43.69 |
-29:46:49.5 |
HIP 83080 |
20.48 |
| 2026-08-07 00:00 |
16:58:39.55 |
-29:46:24.3 |
HIP 83080 |
20.85 |
| 2026-08-07 12:00 |
16:58:35.54 |
-29:45:59.2 |
HIP 83080 |
21.25 |
| 2026-08-08 00:00 |
16:58:31.66 |
-29:45:34.1 |
HIP 83080 |
21.69 |
| 2026-08-08 12:00 |
16:58:27.90 |
-29:45:09.2 |
HIP 83080 |
22.15 |
| 2026-08-09 00:00 |
16:58:24.27 |
-29:44:44.3 |
HIP 83080 |
22.64 |
| 2026-08-09 12:00 |
16:58:20.76 |
-29:44:19.5 |
HIP 83080 |
23.14 |
| 2026-08-10 00:00 |
16:58:17.39 |
-29:43:54.8 |
HIP 83080 |
23.66 |
| 2026-08-10 12:00 |
16:58:14.13 |
-29:43:30.2 |
HIP 83080 |
24.20 |
| 2026-08-11 00:00 |
16:58:11.01 |
-29:43:05.6 |
HIP 83080 |
24.74 |
| 2026-08-11 12:00 |
16:58:08.02 |
-29:42:41.2 |
HIP 83080 |
25.28 |
| 2026-08-12 00:00 |
16:58:05.15 |
-29:42:16.9 |
HIP 83080 |
25.83 |
| 2026-08-12 12:00 |
16:58:02.42 |
-29:41:52.7 |
HIP 83080 |
26.37 |
| 2026-08-13 00:00 |
16:57:59.81 |
-29:41:28.6 |
HIP 83080 |
26.92 |
| 2026-08-13 12:00 |
16:57:57.33 |
-29:41:04.6 |
HIP 83080 |
27.46 |
| 2026-08-14 00:00 |
16:57:54.99 |
-29:40:40.7 |
HIP 83080 |
28.00 |
| 2026-08-14 12:00 |
16:57:52.77 |
-29:40:17.0 |
HIP 83080 |
28.53 |
| 2026-08-15 00:00 |
16:57:50.68 |
-29:39:53.3 |
HIP 83080 |
29.05 |
| 2026-08-15 12:00 |
16:57:48.72 |
-29:39:29.8 |
HIP 83080 |
29.56 |
| 2026-08-16 00:00 |
16:57:46.90 |
-29:39:06.4 |
HIP 83080 |
30.06 |
| 2026-08-16 12:00 |
16:57:45.20 |
-29:38:43.2 |
HIP 83080 |
30.56 |
| 2026-08-17 00:00 |
16:57:43.64 |
-29:38:20.0 |
HIP 83080 |
31.04 |
| 2026-08-17 12:00 |
16:57:42.20 |
-29:37:57.0 |
HIP 83080 |
31.51 |
| 2026-08-18 00:00 |
16:57:40.90 |
-29:37:34.2 |
HIP 83080 |
31.97 |
| 2026-08-18 12:00 |
16:57:39.73 |
-29:37:11.4 |
HIP 83080 |
32.42 |
| 2026-08-19 00:00 |
16:57:38.69 |
-29:36:48.8 |
HIP 83080 |
32.85 |