| Parameter |
Value |
| Designation |
C/2019 D1 (Flewelling) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-05-11T20:12:52.110720Z |
| Orbit solution date (soln_date, UTC) |
2022-07-19T01:12:15Z |
| Obs used |
797 |
| NEO |
- |
| M1 |
11.900 |
| K1 |
15.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2019-02-26T15:28:50.505600Z |
| Discovery magnitude (MPC) |
16.75 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-06-19.0000000 |
| e |
0.98854927 |
| q (au) |
1.577555 |
| a (au) |
137.768888 |
| i (deg) |
34.098372 |
| Ω (om, deg) |
231.717805 |
| ω (w, deg) |
70.477432 |
| M (ma, deg) |
0.023257 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.316 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.316 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.999 |
| 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 |
| 2019-02-26 |
2019-05-11 |
+2.3057 |
-1.095 |
| 2019-05-12 |
2019-07-27 |
+16.0844 |
-3.717 |
| 2019-07-27 |
2019-12-04 |
-2.5143 |
+1.033 |
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 |
05:36:59.21 |
+04:06:06.6 |
HIP 26522 |
23.36 |
| 2026-06-01 12:00 |
05:37:05.44 |
+04:06:13.1 |
HIP 26522 |
21.88 |
| 2026-06-02 00:00 |
05:37:11.67 |
+04:06:19.4 |
HIP 26522 |
20.41 |
| 2026-06-02 12:00 |
05:37:17.91 |
+04:06:25.4 |
HIP 26522 |
18.96 |
| 2026-06-03 00:00 |
05:37:24.15 |
+04:06:31.2 |
HIP 26522 |
17.53 |
| 2026-06-03 12:00 |
05:37:30.41 |
+04:06:36.8 |
HIP 26522 |
16.12 |
| 2026-06-04 00:00 |
05:37:36.67 |
+04:06:42.2 |
HIP 26522 |
14.74 |
| 2026-06-04 12:00 |
05:37:42.95 |
+04:06:47.3 |
HIP 26522 |
13.41 |
| 2026-06-05 00:00 |
05:37:49.23 |
+04:06:52.1 |
HIP 26522 |
12.13 |
| 2026-06-05 12:00 |
05:37:55.51 |
+04:06:56.7 |
HIP 26522 |
10.92 |
| 2026-06-06 00:00 |
05:38:01.81 |
+04:07:01.1 |
HIP 26522 |
9.83 |
| 2026-06-06 12:00 |
05:38:08.11 |
+04:07:05.3 |
HIP 26522 |
8.88 |
| 2026-06-07 00:00 |
05:38:14.41 |
+04:07:09.2 |
HIP 26522 |
8.13 |
| 2026-06-07 12:00 |
05:38:20.72 |
+04:07:12.8 |
HIP 26522 |
7.63 |
| 2026-06-08 00:00 |
05:38:27.04 |
+04:07:16.2 |
HIP 26522 |
7.45 |
| 2026-06-08 12:00 |
05:38:33.36 |
+04:07:19.4 |
HIP 26575 |
6.66 |
| 2026-06-09 00:00 |
05:38:39.69 |
+04:07:22.3 |
HIP 26575 |
5.10 |
| 2026-06-09 12:00 |
05:38:46.02 |
+04:07:25.0 |
HIP 26575 |
3.55 |
| 2026-06-10 00:00 |
05:38:52.35 |
+04:07:27.5 |
HIP 26575 |
2.04 |
| 2026-06-10 12:00 |
05:38:58.69 |
+04:07:29.7 |
HIP 26575 |
0.87 |
| 2026-06-11 00:00 |
05:39:05.03 |
+04:07:31.6 |
HIP 26575 |
1.53 |
| 2026-06-11 12:00 |
05:39:11.38 |
+04:07:33.3 |
HIP 26594 |
0.27 |
| 2026-06-12 00:00 |
05:39:17.73 |
+04:07:34.8 |
HIP 26594 |
1.67 |
| 2026-06-12 12:00 |
05:39:24.08 |
+04:07:36.0 |
HIP 26594 |
3.24 |
| 2026-06-13 00:00 |
05:39:30.43 |
+04:07:37.0 |
HIP 26594 |
4.82 |
| 2026-06-13 12:00 |
05:39:36.78 |
+04:07:37.7 |
HIP 26594 |
6.40 |
| 2026-06-14 00:00 |
05:39:43.13 |
+04:07:38.1 |
HIP 26594 |
7.98 |
| 2026-06-14 12:00 |
05:39:49.49 |
+04:07:38.4 |
HIP 26594 |
9.57 |
| 2026-06-15 00:00 |
05:39:55.84 |
+04:07:38.3 |
HIP 26594 |
11.15 |
| 2026-06-15 12:00 |
05:40:02.20 |
+04:07:38.1 |
HIP 26594 |
12.73 |
| 2026-06-16 00:00 |
05:40:08.55 |
+04:07:37.5 |
HIP 26594 |
14.32 |
| 2026-06-16 12:00 |
05:40:14.90 |
+04:07:36.8 |
HIP 26767 |
15.26 |
| 2026-06-17 00:00 |
05:40:21.26 |
+04:07:35.8 |
HIP 26767 |
13.86 |
| 2026-06-17 12:00 |
05:40:27.61 |
+04:07:34.5 |
HIP 26767 |
12.52 |
| 2026-06-18 00:00 |
05:40:33.95 |
+04:07:33.0 |
HIP 26767 |
11.24 |
| 2026-06-18 12:00 |
05:40:40.30 |
+04:07:31.2 |
HIP 26767 |
10.05 |
| 2026-06-19 00:00 |
05:40:46.64 |
+04:07:29.2 |
HIP 26767 |
8.99 |
| 2026-06-19 12:00 |
05:40:52.98 |
+04:07:26.9 |
HIP 26767 |
8.10 |
| 2026-06-20 00:00 |
05:40:59.32 |
+04:07:24.4 |
HIP 26767 |
7.45 |
| 2026-06-20 12:00 |
05:41:05.65 |
+04:07:21.6 |
HIP 26767 |
7.11 |
| 2026-06-21 00:00 |
05:41:11.97 |
+04:07:18.6 |
HIP 26767 |
7.11 |
| 2026-06-21 12:00 |
05:41:18.30 |
+04:07:15.4 |
HIP 26767 |
7.46 |
| 2026-06-22 00:00 |
05:41:24.61 |
+04:07:11.9 |
HIP 26767 |
8.10 |