C/2017 T1 (Heinze)
| Parameter |
Value |
| Designation |
C/2017 T1 (Heinze) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-02-21T16:59:46.164480Z |
| Orbit solution date (soln_date, UTC) |
2019-05-15T15:10:09Z |
| Obs used |
1005 |
| NEO |
- |
| M1 |
11.900 |
| K1 |
14.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-12-14.0000000 |
| e |
1.00034579 |
| q (au) |
0.580655 |
| a (au) |
-1679.227553 |
| i (deg) |
96.833756 |
| Ω (om, deg) |
102.315945 |
| ω (w, deg) |
96.916279 |
| M (ma, deg) |
-0.000998 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.768 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.768 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.678 |
| k |
0.867 |
| 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 |
| 2017-09-28 |
2017-12-30 |
-3.8094 |
+0.571 |
| 2017-12-30 |
2018-01-19 |
+22.8584 |
-1.570 |
| 2018-01-19 |
2018-02-21 |
+13.5134 |
-1.215 |
| 2018-02-23 |
2018-04-23 |
+0.3225 |
-0.954 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
06:59:08.00 |
-81:08:52.6 |
HIP 33308 |
20.26 |
| 2026-02-03 12:00 |
06:58:37.64 |
-81:08:09.6 |
HIP 33308 |
19.15 |
| 2026-02-04 00:00 |
06:58:07.52 |
-81:07:25.8 |
HIP 33308 |
18.07 |
| 2026-02-04 12:00 |
06:57:37.64 |
-81:06:41.3 |
HIP 33308 |
17.02 |
| 2026-02-05 00:00 |
06:57:08.01 |
-81:05:56.1 |
HIP 33308 |
16.01 |
| 2026-02-05 12:00 |
06:56:38.63 |
-81:05:10.1 |
HIP 33308 |
15.05 |
| 2026-02-06 00:00 |
06:56:09.50 |
-81:04:23.5 |
HIP 33308 |
14.15 |
| 2026-02-06 12:00 |
06:55:40.63 |
-81:03:36.0 |
HIP 33308 |
13.32 |
| 2026-02-07 00:00 |
06:55:12.01 |
-81:02:47.9 |
HIP 33308 |
12.57 |
| 2026-02-07 12:00 |
06:54:43.66 |
-81:01:59.1 |
HIP 33308 |
11.93 |
| 2026-02-08 00:00 |
06:54:15.57 |
-81:01:09.5 |
HIP 33308 |
11.40 |
| 2026-02-08 12:00 |
06:53:47.74 |
-81:00:19.3 |
HIP 33308 |
11.01 |
| 2026-02-09 00:00 |
06:53:20.19 |
-80:59:28.3 |
HIP 33308 |
10.77 |
| 2026-02-09 12:00 |
06:52:52.90 |
-80:58:36.7 |
HIP 33308 |
10.69 |
| 2026-02-10 00:00 |
06:52:25.89 |
-80:57:44.4 |
HIP 33308 |
10.77 |
| 2026-02-10 12:00 |
06:51:59.16 |
-80:56:51.4 |
HIP 33308 |
11.01 |
| 2026-02-11 00:00 |
06:51:32.70 |
-80:55:57.8 |
HIP 33308 |
11.40 |
| 2026-02-11 12:00 |
06:51:06.52 |
-80:55:03.5 |
HIP 33308 |
11.93 |
| 2026-02-12 00:00 |
06:50:40.63 |
-80:54:08.6 |
HIP 32564 |
12.09 |
| 2026-02-12 12:00 |
06:50:15.02 |
-80:53:13.0 |
HIP 32564 |
12.34 |
| 2026-02-13 00:00 |
06:49:49.70 |
-80:52:16.8 |
HIP 32564 |
12.73 |
| 2026-02-13 12:00 |
06:49:24.66 |
-80:51:19.9 |
HIP 32564 |
13.27 |
| 2026-02-14 00:00 |
06:48:59.92 |
-80:50:22.5 |
HIP 32564 |
13.93 |
| 2026-02-14 12:00 |
06:48:35.47 |
-80:49:24.4 |
HIP 32564 |
14.71 |
| 2026-02-15 00:00 |
06:48:11.31 |
-80:48:25.7 |
HIP 32564 |
15.57 |
| 2026-02-15 12:00 |
06:47:47.45 |
-80:47:26.4 |
HIP 32564 |
16.51 |
| 2026-02-16 00:00 |
06:47:23.88 |
-80:46:26.5 |
HIP 32564 |
17.52 |
| 2026-02-16 12:00 |
06:47:00.62 |
-80:45:26.0 |
HIP 31897 |
17.06 |
| 2026-02-17 00:00 |
06:46:37.65 |
-80:44:25.0 |
HIP 31897 |
16.42 |
| 2026-02-17 12:00 |
06:46:14.98 |
-80:43:23.4 |
HIP 31897 |
15.88 |
| 2026-02-18 00:00 |
06:45:52.62 |
-80:42:21.2 |
HIP 31897 |
15.46 |
| 2026-02-18 12:00 |
06:45:30.56 |
-80:41:18.5 |
HIP 31897 |
15.16 |
| 2026-02-19 00:00 |
06:45:08.81 |
-80:40:15.2 |
HIP 31897 |
14.99 |
| 2026-02-19 12:00 |
06:44:47.36 |
-80:39:11.4 |
HIP 31897 |
14.96 |
| 2026-02-20 00:00 |
06:44:26.22 |
-80:38:07.0 |
HIP 31897 |
15.07 |
| 2026-02-20 12:00 |
06:44:05.38 |
-80:37:02.2 |
HIP 31897 |
15.32 |
| 2026-02-21 00:00 |
06:43:44.86 |
-80:35:56.8 |
HIP 31897 |
15.69 |
| 2026-02-21 12:00 |
06:43:24.64 |
-80:34:50.9 |
HIP 31897 |
16.18 |
| 2026-02-22 00:00 |
06:43:04.73 |
-80:33:44.5 |
HIP 31897 |
16.78 |
| 2026-02-22 12:00 |
06:42:45.13 |
-80:32:37.7 |
HIP 31897 |
17.48 |
| 2026-02-23 00:00 |
06:42:25.84 |
-80:31:30.3 |
HIP 31897 |
18.26 |
| 2026-02-23 12:00 |
06:42:06.86 |
-80:30:22.5 |
HIP 31897 |
19.12 |
| 2026-02-24 00:00 |
06:41:48.19 |
-80:29:14.2 |
HIP 31897 |
20.05 |