| Parameter |
Value |
| Designation |
C/1913 Y1 (Delavan) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1914-10-26T18:27:07.724160Z |
| Orbit solution date (soln_date, UTC) |
2024-04-15T15:43:28Z |
| Obs used |
157 |
| NEO |
- |
| M1 |
4.800 |
| K1 |
4.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1914-03-15.0000000 |
| e |
1.00014579 |
| q (au) |
1.104401 |
| a (au) |
-7575.468577 |
| i (deg) |
68.042932 |
| Ω (om, deg) |
60.397252 |
| ω (w, deg) |
97.469440 |
| M (ma, deg) |
-0.000337 |
Magnitude
Scatter + Global Linear
$$
M_a = (-2.437 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
-2.437 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
01:51:21.39 |
-69:58:01.0 |
HIP 8394 |
16.76 |
| 2026-05-12 12:00 |
01:51:23.73 |
-69:58:04.9 |
HIP 8394 |
16.92 |
| 2026-05-13 00:00 |
01:51:26.06 |
-69:58:09.0 |
HIP 8394 |
17.08 |
| 2026-05-13 12:00 |
01:51:28.38 |
-69:58:13.1 |
HIP 8394 |
17.25 |
| 2026-05-14 00:00 |
01:51:30.69 |
-69:58:17.3 |
HIP 8394 |
17.41 |
| 2026-05-14 12:00 |
01:51:33.00 |
-69:58:21.7 |
HIP 8394 |
17.57 |
| 2026-05-15 00:00 |
01:51:35.29 |
-69:58:26.1 |
HIP 8394 |
17.73 |
| 2026-05-15 12:00 |
01:51:37.58 |
-69:58:30.7 |
HIP 8394 |
17.89 |
| 2026-05-16 00:00 |
01:51:39.86 |
-69:58:35.3 |
HIP 8394 |
18.05 |
| 2026-05-16 12:00 |
01:51:42.14 |
-69:58:40.1 |
HIP 8394 |
18.21 |
| 2026-05-17 00:00 |
01:51:44.40 |
-69:58:44.9 |
HIP 8394 |
18.37 |
| 2026-05-17 12:00 |
01:51:46.66 |
-69:58:49.9 |
HIP 8394 |
18.53 |
| 2026-05-18 00:00 |
01:51:48.90 |
-69:58:55.0 |
HIP 8394 |
18.69 |
| 2026-05-18 12:00 |
01:51:51.14 |
-69:59:00.2 |
HIP 8394 |
18.85 |
| 2026-05-19 00:00 |
01:51:53.36 |
-69:59:05.5 |
HIP 8394 |
19.00 |
| 2026-05-19 12:00 |
01:51:55.58 |
-69:59:10.9 |
HIP 8394 |
19.16 |
| 2026-05-20 00:00 |
01:51:57.79 |
-69:59:16.3 |
HIP 8394 |
19.32 |
| 2026-05-20 12:00 |
01:51:59.99 |
-69:59:21.9 |
HIP 8394 |
19.48 |
| 2026-05-21 00:00 |
01:52:02.18 |
-69:59:27.6 |
HIP 8394 |
19.64 |
| 2026-05-21 12:00 |
01:52:04.36 |
-69:59:33.4 |
HIP 8394 |
19.79 |
| 2026-05-22 00:00 |
01:52:06.52 |
-69:59:39.3 |
HIP 8394 |
19.95 |
| 2026-05-22 12:00 |
01:52:08.68 |
-69:59:45.3 |
HIP 8834 |
19.82 |
| 2026-05-23 00:00 |
01:52:10.83 |
-69:59:51.4 |
HIP 8834 |
19.66 |
| 2026-05-23 12:00 |
01:52:12.96 |
-69:59:57.6 |
HIP 8834 |
19.49 |
| 2026-05-24 00:00 |
01:52:15.09 |
-70:00:03.9 |
HIP 8834 |
19.33 |
| 2026-05-24 12:00 |
01:52:17.21 |
-70:00:10.3 |
HIP 8834 |
19.17 |
| 2026-05-25 00:00 |
01:52:19.31 |
-70:00:16.8 |
HIP 8834 |
19.00 |
| 2026-05-25 12:00 |
01:52:21.40 |
-70:00:23.3 |
HIP 8834 |
18.84 |
| 2026-05-26 00:00 |
01:52:23.48 |
-70:00:30.0 |
HIP 8834 |
18.67 |
| 2026-05-26 12:00 |
01:52:25.55 |
-70:00:36.8 |
HIP 8834 |
18.51 |
| 2026-05-27 00:00 |
01:52:27.61 |
-70:00:43.7 |
HIP 8834 |
18.34 |
| 2026-05-27 12:00 |
01:52:29.66 |
-70:00:50.6 |
HIP 8834 |
18.18 |
| 2026-05-28 00:00 |
01:52:31.69 |
-70:00:57.7 |
HIP 8834 |
18.01 |
| 2026-05-28 12:00 |
01:52:33.71 |
-70:01:04.8 |
HIP 8834 |
17.85 |
| 2026-05-29 00:00 |
01:52:35.73 |
-70:01:12.1 |
HIP 8834 |
17.68 |
| 2026-05-29 12:00 |
01:52:37.72 |
-70:01:19.4 |
HIP 8834 |
17.52 |
| 2026-05-30 00:00 |
01:52:39.71 |
-70:01:26.9 |
HIP 8834 |
17.35 |
| 2026-05-30 12:00 |
01:52:41.68 |
-70:01:34.4 |
HIP 8834 |
17.18 |
| 2026-05-31 00:00 |
01:52:43.64 |
-70:01:42.0 |
HIP 8834 |
17.02 |
| 2026-05-31 12:00 |
01:52:45.59 |
-70:01:49.7 |
HIP 8834 |
16.85 |
| 2026-06-01 00:00 |
01:52:47.53 |
-70:01:57.5 |
HIP 8834 |
16.68 |
| 2026-06-01 12:00 |
01:52:49.45 |
-70:02:05.4 |
HIP 8834 |
16.51 |
| 2026-06-02 00:00 |
01:52:51.36 |
-70:02:13.3 |
HIP 8834 |
16.34 |