Gaia DR4 pre-release¶
[1]:
import matplotlib.pyplot as plt
import numpy as np
[2]:
from exogaia.data import EpochAstrometry
from exogaia.leastsq import LeastSquares
[3]:
np.random.seed(42)
[4]:
source_id = 1457486023639239296 # Gaia-4
primary_mass = (0.644, 0.025) # (Msun)
[5]:
epoch_astrom = EpochAstrometry(primary_mass=primary_mass, gaia_release="DR4", verbose=True)
epoch_astrom.retrieve_dr4_prelease(source_id=source_id, exclude_outliers=True, combine_ccds=True)
----------------
Epoch astrometry
----------------
Gaia release: DR4
Reference epoch: 2017.5
Primary mass (Msun): 0.64 +/- 0.03
---------------
Querying source
---------------
Gaia release: DR3
Source ID: 1457486023639239296
INFO: Query finished. [astroquery.utils.tap.core]
RA = 209.506 deg +/- 0.013 mas
Dec = 31.695 deg +/- 0.013 mas
Parallax = 13.545 +/- 0.021 mas
Proper motion in RA = -75.412 +/- 0.020 mas/yr
Proper motion in Dec = 18.063 +/- 0.016 mas/yr
G-band magnitude = 11.909
Pseudocolor = 1.39 um-1
UWE = 1.97
RUWE = 1.50
Astrometric excess noise (mas) = 0.1563 +/- 0.0045
Non single star = 1
---------------------------
Retrieving epoch astrometry
---------------------------
Gaia release: DR4
Reference epoch: 2017.5
Source ID: 1457486023639239296
Primary mass (Msun): 0.64 +/- 0.03
Data file: /Users/tomasstolker/.exogaia/GAIA_DR4_PRERELEASE_EPOCH_ASTROMETRY_RAW.xml
Data shape: (1008, 37)
[6]:
epoch_astrom.data_table.info()
<class 'pandas.DataFrame'>
RangeIndex: 93 entries, 0 to 92
Data columns (total 39 columns):
# Column Non-Null Count Dtype
--- ------ -------------- -----
0 solution_id 93 non-null int64
1 source_id 93 non-null int64
2 transit_id 93 non-null int64
3 ra0 93 non-null float64
4 dec0 93 non-null float64
5 agis_source_excess_noise 93 non-null float32
6 obs_time_tcb 93 non-null float64
7 obs_time_bary_corr 93 non-null float32
8 scan_pos_angle 93 non-null float64
9 zeta 93 non-null float32
10 parallax_factor_al 93 non-null float32
11 parallax_factor_ac 93 non-null float32
12 colour_factor_al 93 non-null float64
13 colour_factor_ac 93 non-null float64
14 nu_eff_used_in_astrometry 93 non-null float32
15 nu_eff_error 93 non-null float32
16 centroid_pos_al 93 non-null float64
17 calculated_pos_ac 93 non-null float64
18 centroid_pos_error_al 93 non-null float64
19 used_by_agis_al 93 non-null bool
20 used_by_agis_ac 93 non-null bool
21 transit_acq_flags 93 non-null int16
22 transit_proc_flags 93 non-null int16
23 ccd_proc_flags 93 non-null int64
24 multipeak 93 non-null bool
25 blended 93 non-null bool
26 ipd_error_al 93 non-null float64
27 ipd_error_ac 93 non-null float64
28 g_mag 93 non-null float32
29 g_class 93 non-null int16
30 gates 93 non-null int64
31 source_dist_to_last_ci 93 non-null float64
32 ac_rate 93 non-null float32
33 sub_pixel_coord 93 non-null float64
34 mu 93 non-null float64
35 sin_scan_ang 93 non-null float64
36 cos_scan_ang 93 non-null float64
37 relative_time_year 93 non-null float64
38 relative_time_day 93 non-null float64
dtypes: bool(4), float32(9), float64(18), int16(3), int64(5)
memory usage: 21.0 KB
[7]:
leastsq = LeastSquares(epoch_astrometry=epoch_astrom)
[8]:
fig = leastsq.orbit_grid(map_type='ruwe', plot_file='plot.png', n_points=30)
--------------------------
Orbit grid (12-parameters)
--------------------------
Best-fit RUWE = 1.843
Best-fit stellar track:
- RA offset (mas) = -0.031 +/- 0.008
- Dec offset (mas) = 0.107 +/- 0.009
- Parallax (mas) = 13.659 +/- 0.010
- mu in RA (mas/yr) = -75.533 +/- 0.005
- mu in Dec (mas/yr) = 17.957 +/- 0.005
Best-fit orbit:
- Period (days) = 528.966
- Eccentricity = 0.267
- Relative time of periastron = 0.90
- Thiele-Innes A = 0.221 +/- 0.011
- Thiele-Innes B = 0.018 +/- 0.010
- Thiele-Innes F = 0.101 +/- 0.010
- Thiele-Innes G = -0.092 +/- 0.009
Derived parameters:
- Semi-major axis of photocenter (mas) = 0.244 +/- 0.011
- Relative semi-major axis (au) = 1.111
- Mass function (Msun) = 2.712e-06
- Companion mass (Msun) = 1.051e-02
Conversion to campbell elements:
- Period = 528.966 days
- Eccentricity = 0.267
- Relative time of periastron = 0.900
- Semi-major axis of photocenter (mas) = 0.244
- Inclination (deg) = 111.734
- Argument of periastron (deg) = 153.163
- PA of ascending node (deg) = 174.030
[9]:
fig = leastsq.orbit_fit(inc_jitter=False, plot_file='plot.png')
-------------------------
Orbit fit (12 parameters)
-------------------------
Reduced chi^2: 0.925
RUWE: 0.731
Best-fit stellar track:
- RA offset (mas) = -0.041 +/- 0.013
- Dec offset (mas) = 0.129 +/- 0.019
- Parallax (mas) = 13.629 +/- 0.007
- mu in RA (mas/yr) = -75.532 +/- 0.003
- mu in Dec (mas/yr) = 17.966 +/- 0.003
Best-fit orbit:
- Period (days) = 573.087 +/- 2.673
- Eccentricity = 0.295 +/- 0.050
- Relative time of periastron = 1.000 +/- 0.029
- Semi-major axis of photocenter (mas) = 0.247 +/- 0.007
- Inclination (deg) = 122.355 +/- 2.272
- Argument of periastron (deg) = 180.410 +/- 10.870
- PA of ascending node (deg) = 173.516 +/- 2.217
Number of function evaluations: 9
Number of Jacobian evaluations: 9
Derived parameters:
- Relative semi-major axis (au) = 1.172
- Mass function (Msun) = 2.411e-06
- Companion mass (Msun) = 1.010e-02
[10]:
print(leastsq)
LeastSquares(Δα = -0.040749 mas, Δδ = 0.129385 mas, ϖ = 13.6287 mas, μ_α = -75.5319 mas/yr, μ_δ = 17.9662 mas/yr, P = 573.087 days, e = 0.294848, τ = 1, a = 0.246776 mas, i = 2.1355 rad, ω = 3.14875 rad, Ω = 3.02842 rad)