C/2015 Y1 (LINEAR)
| Parameter |
Value |
| Designation |
C/2015 Y1 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2016-05-15T04:24:32.302080Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:21Z |
| Obs used |
573 |
| NEO |
- |
| M1 |
6.500 |
| K1 |
21.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2016-02-29.0000000 |
| e |
0.99138537 |
| q (au) |
2.514054 |
| a (au) |
291.835567 |
| i (deg) |
71.219035 |
| Ω (om, deg) |
135.777778 |
| ω (w, deg) |
24.710558 |
| M (ma, deg) |
359.984939 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.720 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.720 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.760 |
| k |
0.996 |
| 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 |
| 2015-12-16 |
2016-05-09 |
+4.9888 |
-2.111 |
| 2016-05-21 |
2017-04-20 |
+9.2347 |
-4.331 |
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 |
20:43:12.87 |
-05:54:59.2 |
HIP 102322 |
10.42 |
| 2026-02-03 12:00 |
20:43:17.96 |
-05:54:44.6 |
HIP 102322 |
9.26 |
| 2026-02-04 00:00 |
20:43:23.05 |
-05:54:29.9 |
HIP 102322 |
8.13 |
| 2026-02-04 12:00 |
20:43:28.13 |
-05:54:15.0 |
HIP 102322 |
7.05 |
| 2026-02-05 00:00 |
20:43:33.20 |
-05:54:00.0 |
HIP 102322 |
6.06 |
| 2026-02-05 12:00 |
20:43:38.27 |
-05:53:44.9 |
HIP 102322 |
5.21 |
| 2026-02-06 00:00 |
20:43:43.33 |
-05:53:29.7 |
HIP 102322 |
4.56 |
| 2026-02-06 12:00 |
20:43:48.39 |
-05:53:14.3 |
HIP 102322 |
4.23 |
| 2026-02-07 00:00 |
20:43:53.43 |
-05:52:58.9 |
HIP 102322 |
4.26 |
| 2026-02-07 12:00 |
20:43:58.48 |
-05:52:43.3 |
HIP 102322 |
4.67 |
| 2026-02-08 00:00 |
20:44:03.51 |
-05:52:27.7 |
HIP 102322 |
5.36 |
| 2026-02-08 12:00 |
20:44:08.53 |
-05:52:11.9 |
HIP 102322 |
6.24 |
| 2026-02-09 00:00 |
20:44:13.55 |
-05:51:56.0 |
HIP 102322 |
7.23 |
| 2026-02-09 12:00 |
20:44:18.56 |
-05:51:40.0 |
HIP 102322 |
8.31 |
| 2026-02-10 00:00 |
20:44:23.56 |
-05:51:23.9 |
HIP 102322 |
9.43 |
| 2026-02-10 12:00 |
20:44:28.55 |
-05:51:07.7 |
HIP 102322 |
10.59 |
| 2026-02-11 00:00 |
20:44:33.53 |
-05:50:51.4 |
HIP 102322 |
11.76 |
| 2026-02-11 12:00 |
20:44:38.50 |
-05:50:35.0 |
HIP 102322 |
12.96 |
| 2026-02-12 00:00 |
20:44:43.46 |
-05:50:18.6 |
HIP 102322 |
14.16 |
| 2026-02-12 12:00 |
20:44:48.41 |
-05:50:02.0 |
HIP 102322 |
15.38 |
| 2026-02-13 00:00 |
20:44:53.35 |
-05:49:45.3 |
HIP 102322 |
16.59 |
| 2026-02-13 12:00 |
20:44:58.27 |
-05:49:28.5 |
HIP 102322 |
17.82 |
| 2026-02-14 00:00 |
20:45:03.19 |
-05:49:11.6 |
HIP 102322 |
19.04 |
| 2026-02-14 12:00 |
20:45:08.09 |
-05:48:54.7 |
HIP 102322 |
20.27 |
| 2026-02-15 00:00 |
20:45:12.99 |
-05:48:37.6 |
HIP 102421 |
20.85 |
| 2026-02-15 12:00 |
20:45:17.87 |
-05:48:20.5 |
HIP 102421 |
21.13 |
| 2026-02-16 00:00 |
20:45:22.73 |
-05:48:03.3 |
HIP 102421 |
21.48 |
| 2026-02-16 12:00 |
20:45:27.59 |
-05:47:46.0 |
HIP 102421 |
21.90 |
| 2026-02-17 00:00 |
20:45:32.43 |
-05:47:28.6 |
HIP 102421 |
22.38 |
| 2026-02-17 12:00 |
20:45:37.25 |
-05:47:11.2 |
HIP 102421 |
22.91 |
| 2026-02-18 00:00 |
20:45:42.06 |
-05:46:53.7 |
HIP 102421 |
23.50 |
| 2026-02-18 12:00 |
20:45:46.86 |
-05:46:36.0 |
HIP 102421 |
24.14 |
| 2026-02-19 00:00 |
20:45:51.64 |
-05:46:18.4 |
HIP 102421 |
24.82 |
| 2026-02-19 12:00 |
20:45:56.41 |
-05:46:00.6 |
HIP 102421 |
25.54 |
| 2026-02-20 00:00 |
20:46:01.16 |
-05:45:42.8 |
HIP 102421 |
26.30 |
| 2026-02-20 12:00 |
20:46:05.90 |
-05:45:24.9 |
HIP 102421 |
27.09 |
| 2026-02-21 00:00 |
20:46:10.62 |
-05:45:07.0 |
HIP 102421 |
27.91 |
| 2026-02-21 12:00 |
20:46:15.32 |
-05:44:48.9 |
HIP 102421 |
28.76 |
| 2026-02-22 00:00 |
20:46:20.01 |
-05:44:30.9 |
HIP 102421 |
29.63 |
| 2026-02-22 12:00 |
20:46:24.68 |
-05:44:12.7 |
HIP 102421 |
30.52 |
| 2026-02-23 00:00 |
20:46:29.33 |
-05:43:54.5 |
HIP 102655 |
30.67 |
| 2026-02-23 12:00 |
20:46:33.96 |
-05:43:36.3 |
HIP 102655 |
29.91 |
| 2026-02-24 00:00 |
20:46:38.58 |
-05:43:18.0 |
HIP 102655 |
29.18 |