| 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
$$
M_a = (15.769 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.769 |
| 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 |
-3.8045 |
+0.570 |
| 2017-12-30 |
2018-01-19 |
+22.8569 |
-1.570 |
| 2018-01-19 |
2018-02-21 |
+13.5047 |
-1.217 |
| 2018-02-23 |
2018-04-23 |
+0.3229 |
-0.952 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
06:56:54.91 |
-76:34:21.6 |
HIP 33418 |
4.24 |
| 2026-06-01 12:00 |
06:57:13.89 |
-76:33:35.0 |
HIP 33418 |
5.08 |
| 2026-06-02 00:00 |
06:57:32.95 |
-76:32:48.8 |
HIP 33418 |
6.10 |
| 2026-06-02 12:00 |
06:57:52.06 |
-76:32:03.1 |
HIP 33418 |
7.22 |
| 2026-06-03 00:00 |
06:58:11.23 |
-76:31:17.9 |
HIP 33418 |
8.41 |
| 2026-06-03 12:00 |
06:58:30.46 |
-76:30:33.2 |
HIP 33418 |
9.63 |
| 2026-06-04 00:00 |
06:58:49.75 |
-76:29:48.9 |
HIP 33418 |
10.87 |
| 2026-06-04 12:00 |
06:59:09.10 |
-76:29:05.1 |
HIP 33418 |
12.14 |
| 2026-06-05 00:00 |
06:59:28.51 |
-76:28:21.8 |
HIP 33418 |
13.41 |
| 2026-06-05 12:00 |
06:59:47.97 |
-76:27:39.0 |
HIP 33418 |
14.70 |
| 2026-06-06 00:00 |
07:00:07.48 |
-76:26:56.6 |
HIP 33418 |
15.99 |
| 2026-06-06 12:00 |
07:00:27.05 |
-76:26:14.7 |
HIP 33418 |
17.28 |
| 2026-06-07 00:00 |
07:00:46.68 |
-76:25:33.4 |
HIP 33418 |
18.58 |
| 2026-06-07 12:00 |
07:01:06.35 |
-76:24:52.5 |
HIP 33418 |
19.88 |
| 2026-06-08 00:00 |
07:01:26.08 |
-76:24:12.1 |
HIP 33418 |
21.19 |
| 2026-06-08 12:00 |
07:01:45.86 |
-76:23:32.1 |
HIP 33418 |
22.49 |
| 2026-06-09 00:00 |
07:02:05.68 |
-76:22:52.7 |
HIP 33418 |
23.80 |
| 2026-06-09 12:00 |
07:02:25.56 |
-76:22:13.8 |
HIP 33418 |
25.10 |
| 2026-06-10 00:00 |
07:02:45.48 |
-76:21:35.3 |
HIP 34381 |
25.71 |
| 2026-06-10 12:00 |
07:03:05.45 |
-76:20:57.4 |
HIP 34381 |
24.44 |
| 2026-06-11 00:00 |
07:03:25.46 |
-76:20:20.0 |
HIP 34381 |
23.19 |
| 2026-06-11 12:00 |
07:03:45.52 |
-76:19:43.0 |
HIP 34381 |
21.94 |
| 2026-06-12 00:00 |
07:04:05.63 |
-76:19:06.6 |
HIP 34381 |
20.71 |
| 2026-06-12 12:00 |
07:04:25.77 |
-76:18:30.7 |
HIP 34381 |
19.50 |
| 2026-06-13 00:00 |
07:04:45.96 |
-76:17:55.2 |
HIP 34381 |
18.32 |
| 2026-06-13 12:00 |
07:05:06.19 |
-76:17:20.3 |
HIP 34381 |
17.16 |
| 2026-06-14 00:00 |
07:05:26.46 |
-76:16:45.9 |
HIP 34381 |
16.04 |
| 2026-06-14 12:00 |
07:05:46.77 |
-76:16:12.0 |
HIP 34381 |
14.95 |
| 2026-06-15 00:00 |
07:06:07.12 |
-76:15:38.6 |
HIP 34381 |
13.92 |
| 2026-06-15 12:00 |
07:06:27.50 |
-76:15:05.8 |
HIP 34381 |
12.95 |
| 2026-06-16 00:00 |
07:06:47.92 |
-76:14:33.4 |
HIP 34381 |
12.06 |
| 2026-06-16 12:00 |
07:07:08.37 |
-76:14:01.6 |
HIP 34381 |
11.27 |
| 2026-06-17 00:00 |
07:07:28.86 |
-76:13:30.2 |
HIP 34381 |
10.59 |
| 2026-06-17 12:00 |
07:07:49.38 |
-76:12:59.4 |
HIP 34381 |
10.05 |
| 2026-06-18 00:00 |
07:08:09.93 |
-76:12:29.2 |
HIP 34381 |
9.68 |
| 2026-06-18 12:00 |
07:08:30.51 |
-76:11:59.4 |
HIP 34381 |
9.48 |
| 2026-06-19 00:00 |
07:08:51.12 |
-76:11:30.2 |
HIP 34381 |
9.49 |
| 2026-06-19 12:00 |
07:09:11.76 |
-76:11:01.4 |
HIP 34748 |
8.76 |
| 2026-06-20 00:00 |
07:09:32.43 |
-76:10:33.2 |
HIP 34748 |
7.57 |
| 2026-06-20 12:00 |
07:09:53.12 |
-76:10:05.6 |
HIP 34748 |
6.43 |
| 2026-06-21 00:00 |
07:10:13.84 |
-76:09:38.4 |
HIP 34748 |
5.37 |
| 2026-06-21 12:00 |
07:10:34.58 |
-76:09:11.8 |
HIP 34748 |
4.44 |
| 2026-06-22 00:00 |
07:10:55.35 |
-76:08:45.7 |
HIP 34748 |
3.75 |