C/2019 T2 (Lemmon)
| Parameter |
Value |
| Designation |
C/2019 T2 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-04-22T06:32:53.350080Z |
| Orbit solution date (soln_date, UTC) |
2023-08-06T18:12:27Z |
| Obs used |
187 |
| NEO |
- |
| M1 |
12.700 |
| K1 |
5.750 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2019-10-09T03:16:41.376000Z |
| Discovery magnitude (MPC) |
20.60 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-02-26.0000000 |
| e |
0.99872185 |
| q (au) |
2.645893 |
| a (au) |
2070.091183 |
| i (deg) |
111.488095 |
| Ω (om, deg) |
155.641811 |
| ω (w, deg) |
239.386315 |
| M (ma, deg) |
359.999422 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.950 + 3.858\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.950 |
| n |
3.858 |
| gf |
1.000 |
| gb |
-0.704 |
| k |
0.800 |
| 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 |
| 2019-08-26 |
2019-11-30 |
+22.3714 |
-17.071 |
| 2019-11-30 |
2020-07-16 |
-0.1476 |
-0.346 |
| 2020-07-16 |
2020-10-26 |
-4.8324 |
+2.665 |
| 2020-10-26 |
2021-04-11 |
-2.5155 |
+1.291 |
| 2021-05-22 |
2022-09-09 |
-4.5730 |
+3.129 |
| 2022-09-09 |
2023-06-14 |
+12.5899 |
-9.404 |
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 |
10:36:16.90 |
+16:52:45.2 |
HIP 51965 |
24.67 |
| 2026-02-03 12:00 |
10:36:08.57 |
+16:54:03.2 |
HIP 51965 |
24.40 |
| 2026-02-04 00:00 |
10:36:00.19 |
+16:55:21.1 |
HIP 51965 |
24.36 |
| 2026-02-04 12:00 |
10:35:51.79 |
+16:56:39.1 |
HIP 51965 |
24.56 |
| 2026-02-05 00:00 |
10:35:43.36 |
+16:57:57.0 |
HIP 51965 |
25.00 |
| 2026-02-05 12:00 |
10:35:34.89 |
+16:59:14.9 |
HIP 51965 |
25.66 |
| 2026-02-06 00:00 |
10:35:26.40 |
+17:00:32.8 |
HIP 51965 |
26.52 |
| 2026-02-06 12:00 |
10:35:17.87 |
+17:01:50.7 |
HIP 51965 |
27.58 |
| 2026-02-07 00:00 |
10:35:09.32 |
+17:03:08.5 |
HIP 51965 |
28.80 |
| 2026-02-07 12:00 |
10:35:00.74 |
+17:04:26.3 |
HIP 51965 |
30.18 |
| 2026-02-08 00:00 |
10:34:52.13 |
+17:05:44.0 |
HIP 51965 |
31.69 |
| 2026-02-08 12:00 |
10:34:43.50 |
+17:07:01.7 |
HIP 51677 |
33.11 |
| 2026-02-09 00:00 |
10:34:34.84 |
+17:08:19.3 |
HIP 51677 |
30.89 |
| 2026-02-09 12:00 |
10:34:26.16 |
+17:09:36.9 |
HIP 51677 |
28.71 |
| 2026-02-10 00:00 |
10:34:17.45 |
+17:10:54.4 |
HIP 51677 |
26.58 |
| 2026-02-10 12:00 |
10:34:08.72 |
+17:12:11.8 |
HIP 51677 |
24.50 |
| 2026-02-11 00:00 |
10:33:59.97 |
+17:13:29.2 |
HIP 51677 |
22.50 |
| 2026-02-11 12:00 |
10:33:51.20 |
+17:14:46.4 |
HIP 51677 |
20.60 |
| 2026-02-12 00:00 |
10:33:42.40 |
+17:16:03.6 |
HIP 51677 |
18.82 |
| 2026-02-12 12:00 |
10:33:33.59 |
+17:17:20.6 |
HIP 51677 |
17.21 |
| 2026-02-13 00:00 |
10:33:24.76 |
+17:18:37.6 |
HIP 51677 |
15.83 |
| 2026-02-13 12:00 |
10:33:15.91 |
+17:19:54.4 |
HIP 51677 |
14.74 |
| 2026-02-14 00:00 |
10:33:07.04 |
+17:21:11.1 |
HIP 51677 |
14.01 |
| 2026-02-14 12:00 |
10:32:58.16 |
+17:22:27.7 |
HIP 51677 |
13.69 |
| 2026-02-15 00:00 |
10:32:49.27 |
+17:23:44.2 |
HIP 51677 |
13.82 |
| 2026-02-15 12:00 |
10:32:40.35 |
+17:25:00.5 |
HIP 51677 |
14.38 |
| 2026-02-16 00:00 |
10:32:31.43 |
+17:26:16.7 |
HIP 51677 |
15.33 |
| 2026-02-16 12:00 |
10:32:22.49 |
+17:27:32.8 |
HIP 51677 |
16.60 |
| 2026-02-17 00:00 |
10:32:13.54 |
+17:28:48.7 |
HIP 51677 |
18.13 |
| 2026-02-17 12:00 |
10:32:04.58 |
+17:30:04.4 |
HIP 51677 |
19.85 |
| 2026-02-18 00:00 |
10:31:55.61 |
+17:31:20.0 |
HIP 51677 |
21.73 |
| 2026-02-18 12:00 |
10:31:46.64 |
+17:32:35.4 |
HIP 51677 |
23.71 |
| 2026-02-19 00:00 |
10:31:37.65 |
+17:33:50.7 |
HIP 51677 |
25.79 |
| 2026-02-19 12:00 |
10:31:28.66 |
+17:35:05.7 |
HIP 51579 |
25.83 |
| 2026-02-20 00:00 |
10:31:19.66 |
+17:36:20.6 |
HIP 51579 |
25.50 |
| 2026-02-20 12:00 |
10:31:10.65 |
+17:37:35.3 |
HIP 51579 |
25.41 |
| 2026-02-21 00:00 |
10:31:01.64 |
+17:38:49.7 |
HIP 51579 |
25.57 |
| 2026-02-21 12:00 |
10:30:52.63 |
+17:40:04.0 |
HIP 51579 |
25.96 |
| 2026-02-22 00:00 |
10:30:43.61 |
+17:41:18.1 |
HIP 51579 |
26.59 |
| 2026-02-22 12:00 |
10:30:34.60 |
+17:42:31.9 |
HIP 51579 |
27.42 |
| 2026-02-23 00:00 |
10:30:25.58 |
+17:43:45.6 |
HIP 51579 |
28.45 |
| 2026-02-23 12:00 |
10:30:16.56 |
+17:44:59.0 |
HIP 51318 |
27.75 |
| 2026-02-24 00:00 |
10:30:07.55 |
+17:46:12.1 |
HIP 51318 |
25.40 |