OC Binary Explorer

A website to explore results from the BASE-9 Open Cluster project

Explanation of the data

Users can interact with the data from our papers in multiple ways within the associated interactive website and can also download the data directly from Zenodo here. Data files are stored in sqlite format. Each cluster has a database file, and there is also a summary database with information on all available clusters in our survey. Below we describe the tables in each database file and the columns in each table.

cluster_summary.db : the summary database

This file contains one table : cluster_parameters, with the following columns:

• Cluster : cluster name
• Center_RA_hr, Center_Dec_deg : central right ascension (in hours) and declination (in degrees) for the cluster
• Age_Gyr, Age_16_Gyr, Age_84_Gyr , : median, 16th percentile and 84th percentile of the age posterior in Gyr for the cluster derived from our BASE-9 analysis
• [Fe/H], [Fe/H]_16, [Fe/H]_84 : median, 16th percentile and 84th percentile of the metallicity posterior for the cluster derived from our BASE-9 analysis
• Distance_m-M, Distance_16_m-M_16, Distance_84_m-M : median, 16th percentile and 84th percentile of the distance modulus posterior in magnitudes for the cluster derived from our BASE-9 analysis
• Distance_pc : median distance to the cluster in parsecs derived from our BASE-9 analysis
• Av_mag, Av_16_mag, Av_84_mag : median, 16th percentile and 84th percentile of the extinction posterior in magnitudes for the cluster derived from our BASE-9 analysis
• r_h_deg, r_h_pc : cluster half-mass radius in degrees and parsecs (2D projection)
• r_eff_arcmin : cluster effective radius in arcminutes
• r_core_arcmin, r_core_pc, sig_r_core_arcmin : cluster core radius in arcminutes and parsecs, and the 1 sigma error on the cluster core radius in arcminutes, derived from a King model fit to the MLMS sample (and assuming the median distance to the cluster)
• r_tidal_arcmin, sig_r_tidal_arcmin : cluster tidal radius and the 1 sigma error on the cluster tidal radius in arcminutes aderived from a King model fit to the MLMS sample
• N, N_MLMS : total number of objects (single and binary) and the number of MLMS objects in the cluster
• N_bin, N_bin_MLMS : total number of binaries and the number of MLMS binaries in the cluster
• N1, N1_MLMS : number of objects (single and binary) and the number of MLMS objects within one core radius from the cluster center
• central_rho_N1_per_arcmin2, central_rho_N1_per_pc2, central_rho_16_N1_per_pc2, central_rho_84_N1_per_pc2 : stellar number density within 1 core radius from the cluster center in units of N/arcmin^2 and N/pc^2 (respectively) and the 16th and 84th percentiles for this density
• fb_i, sig_fb_i : raw binary fraction for all objects in our sample and the 1 sigma uncertainty on that value for the cluster
• fb_MLMS_i, sig_fb_MLMS_i : raw binary fraction for the MLMS stars and the 1 sigma uncertainty on that value for the cluster
• fb_MLMS_c, sig_fb_MLMS_c : incompleteness corrected binary fraction for the MLMS stars and the 1 sigma uncertainty on that value for the cluster
• fb_MLMS_c_big_q, sig_fb_MLMS_c_big_q : incompleteness corrected binary fraction for the MLMS stars, including only binaries with q > 0.4, and the 1 sigma uncertainty on that value for the cluster
• tot_mass_M_Sun, tot_mass_16_M_Sun, tot_mass_84_M_Sun : total cluster mass (counting all stars in our sample) in solar masses and the 16th and 84th percentiles of the total mass
• tr_Myr, tr_16_Myr, tr_84_Myr : half-mass relaxation time for the cluster in Myr and the 16th and 84th percentiles for that value
• mean_RV_km_per_s : mean radial velocity from Gaia in km/s for cluster members
• mean_pmracosdec_mas_per_yr : mean proper motion in RA*cos(Dec) from Gaia in mas/yr for cluster members
• mean_pmdec_mas_per_yr : : mean proper motion in Dec from Gaia in mas/yr for cluster members
• mean_distance_pc: mean distance from inverting the Gaia parallax in pc for cluster members

NGC_*.db : the cluster database

Each cluster has its own database file (e.g., NGC_188.db). Within each of these files are multiple tables. Each table and the columns they contain are described below.

cluster_posterior : posterior distribution from our BASE-9 singlePopMcmc analysis

• iteration : iteration number in the MCMC chain
• logAge : posterior value at each iteration for the log_10 age [Gyr] of the cluster
• FeH : posterior value at each iteration for the metallicity of the cluster
• modulus : posterior value at each iteration for the distance modulus of the cluster in magnitudes
• absorption : posterior value at each iteration for the Av value of the cluster in magnitudes
• logPost : unnormalized value of the log-posterior density evaluated at the parameter values given in the previous columns
• stage : analysis stage (see the BASE-9 documentation for a detailed explanation)

posterior_for_id_* : posterior distribution from our BASE-9 sampleMass analysis for each star. The * should be replaced by a source_id for cluster members

• iteration : iteration number in the MCMC chain
• mass : posterior value at each iteration for the stellar mass in solar masses
• massRatio : posterior value at each iteration for the mass ratio (m2/m1)
• membership : posterior value at each iteration for the cluster membership probatility (binary value, 1 for member and 0 for non-member)

parsec_isochrone : PARSEC isochrone produced from the median values of the cluster posterior distribution using BASE-9's makeCMD tool

Columns here should be self explanatory (each contains the magnitude in the given filter, except for the column labelled Mass which contains the stellar mass in solar units); see the PARSEC website for more information.

stars_summary : summary information for each star in our sample

• source_id : Gaia source ID of the star
• ra, dec : the right ascension and declination of the star in degrees
• pmra, pmdec : the proper motion measurements of the star in right ascension (ra*cos(dec)) and declination in mas/yr
• radial_velocity : the RV measurement of the star in km/s
• G, phot_g_mean_flux_over_error, G_BP, phot_bp_mean_flux_over_error, G_RP, phot_rp_mean_flux_over_error : the Gaia photometric measurements and errors taken in Gaia G, G_BP, and G_RP bandpasses
• distance_1_per_parallax_arcsec : the distance to the star, calculated as 1/parallax(arcsec)
• teff_gspphot : the effective temperature estimate from Gaia
• ruwe : the ruwe value from Gaia
• number_of_neighbours, number_of_mates : ancillary data from Gaia catalog matching
• g_ps, sigg_ps, r_ps, sigr_ps, i_ps, sigi_ps, z_ps, sigz_ps, y_ps, sigy_ps : the photometric measurments and errors for the Pan-STARRS g, r, i, z, and y bandpasses, respectively
• J_2M, sigJ_2M, H_2M, sigH_2M, Ks_2M, sigKs_2M : the photometric measurements and errors for the 2MASS survery in the J, H, and Ks bandpasses, respectively
• rCenter : the angular distance from the star from the cluster center in degrees
• sig_E(B-V), E(B-V) : the error and reddening value taken from the Bayestarr reddening map.
• PPa : the probability the star is a cluster member as determined by its Gaia parallax measurment calaculated within our code
• PRV : the probability the star is a cluster member as determined by its Gaia radial-velocity measurement calculated within our code
• PM_ra, PM_dec, PPM : the probabilities the star is a cluster member as determined by its Gaia proper motion in the right ascension, proper motion in declination and combined probability for proper motion measuremnts calculated within our code
• CMprior : the final cluster membership probability we feed to BASE-9 (calculated from our code)
• member, binary : (True/False) our final identification of cluster members and binaries, resulting from our analysis of BASE-9 results
• m1Median, m1Std, m1_16, m1_84 : the median, standard deviation, 16th and 84th percentiles of the BASE-9 posterior distribution for primary mass
• qMedian,qStd, q_16, q_84 : the median, standard deviation, 16th and 84th percentiles of the BASE-9 posterior distribution for mass ratio.