DOI: 10.24378/exe.1683
title: Exploring the M-dwarf Luminosity - Temperature - Radius Relationships using Gaia DR2 (dataset)

description: Corrected file versions uploaded on 06-03-2020, 11-08-2020, and 15-10-2020
description: There is growing evidence that M-dwarf stars suffer radius inflation when compared to theoretical models, suggesting that models are missing some key physics required to completely describe stars at effective temperatures (TSED) less than about 4000K. The advent of Gaia DR2 distances finally makes available large datasets to determine the nature and extent of this effect. We employ an all-sky sample, comprising of &gt;15 000 stars, to determine empirical relation- ships between luminosity, temperature and radius. This is accomplished using only geometric distances and multiwave-band photometry, by utilising a modified spectral energy distribution fitting method. The radii we measure show an inflation of 3 − 7% compared to models, but no more than a 1−2% intrinsic spread in the inflated sequence. We show that we are currently able to determine M-dwarf radii to an accuracy of 2.4% using our method. However, we determine that this is limited by the precision of metallicity measurements, which contribute 1.7% to the measured radius scatter. We also present evidence that stellar magnetism is currently unable to explain radius inflation in M-dwarfs.
description: (Morrell+, 2019) ================================================================================ Exploring the M-dwarf Luminosity - Temperature - Radius Relationships using Gaia DR2 Morrell S.A.F, Naylor T. = ================================================================================ Keywords: techniques: photometric – stars: low-mass – stars: late- type – stars: fundamental parameters Abstract: There is growing evidence that M-dwarf stars suffer radius inflation when compared to theoretical models, suggesting that models are missing some key physics required to completely describe stars at effective temperatures (TSED) less than about 4000K. The advent of Gaia DR2 distances finally makes available large datasets to determine the nature and extent of this effect.We employ an all-sky sample, comprising of&gt;15 000 stars, to determine empirical relation-ships between luminosity, temperature and radius.This is accomplished using only geometric distances and multiwave-band photometry, by utilising a modified spectral energy distribution fitting method. The radii we measure show an inflation of3−7%compared to models, but nomore than a 1−2% intrinsic spread in the inflated sequence. We show that we are currently able to determine M-dwarf radii to an accuracy of 2.4% using our method. However, we determine that this is limited by the precision of metallicity measurements, which contribute 1.7% to the measured radius scatter. We also present evidence that stellar magnetism is currently unable to explain radius inflation in M-dwarfs. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . this file mdwarf-properties.dat 822 15765 Input data and fitted properties for stars in our sample. tsed-r-relation.dat 64 1401 A tabulated form of our T_SED - R relation for M-dwarf stars. lsed-r-relation.dat 141 98 A tabulated form of our L_SED - R relation for M-dwarf stars. table3-tabulated-feh-corrections.dat 43 97 A electronic version of Table 3, which are the tabulated values of F(L_SED) in equation 16. mdwarf-properties.fits 822 15765 A FITS version of our main catalogue. tsed-r-relation.fits 64 1401 A FITS version of our tabulated T_SED - R relation. lsed-r-relation.fits 141 98 A FITS version of our tabulated L_SED - R relation. table3-tabulated-feh-corrections.fits 43 97 A FITS version of our tabulated values of F(L_SED). See also: I/345 : Gaia DR2 (Gaia Collaboration, 2018) II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003) II/328 : AllWISE Data Release (Cutri+ 2013) I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018) IV/35 : Gaia DR2-WISE Galactic Plane Matches (Wilson+, 2018) J/MNRAS/432/1203 : Rotation periods of M-dwarf stars (McQuillan+, 2013) J/ApJS/211/24 : Rotation periods of Kepler MS stars (McQuillan+, 2014) IX/50 : XMM-Newton Serendipitous Source Catalogue 3XMM-DR6 (XMM-SSC, 2016) II/321 : IPHAS DR2 Source Catalogue (Barentsen+, 2014) II/341 : VPHAS+ DR2 survey (Drew+, 2016) J/MNRAS/443/2561 : CONCH-SHELL catalog of nearby M dwarfs (Gaidos+, 2014) J/ApJS/220/16 : SpeX NIR survey of 886 nearby M dwarfs (Terrien+, 2015) -------------------------------------------------------------------------------- Byte-by-byte Description of file: mdwarf-properties.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 I5 --- id [1.0/15765.0]? Internal identifier for the object within our catalogue. 7- 28 F22.18 deg ra [0.0/360.0]? Right ascension of the source as given in the Gaia DR2 catalogue. 30- 52 F23.19 deg dec [-89.7/88.7]? Declination of the source as given in the Gaia DR2 catalogue. 54- 72 I19 --- source_id Unique source indentifier of the star within Gaia DR2. 74- 83 F10.7 mag phot_g_mean_mag [9.0/18.1]? G-band mean magnitude of the star in the Gaia DR2 catalogue. 85- 94 F10.7 mag phot_bp_mean_mag [9.9/20.7]? Integrated BP mean magnitude of the star in the Gaia DR2 catalogue. 96-105 F10.7 mag phot_rp_mean_mag [8.2/16.4]? Integrated RP mean magnitude of the star in the Gaia DR2 catalogue. 107-127 F21.19 mag phot_bp_mean_mag_err [0.0/0.3]? Uncertainty of the BP mean magnitude of the star in the Gaia DR2 catalogue. 129-150 F22.20 mag phot_rp_mean_mag_err [0.0/0.2]? Uncertainty of the RP mean magnitude of the star in the Gaia DR2 catalogue. 152-173 F22.14 'electron'.s**-1 phot_bp_mean_flux [70.8/1558645.7]? Integrated BP mean flux of the star in the Gaia DR2 catalogue. 175-195 F21.13 'electron'.s**-1 phot_rp_mean_flux [2151.7/4289144.1]? Integrated RP mean flux of the star in the Gaia DR2 catalogue. 197-217 F21.13 'electron'.s**-1 phot_g_mean_flux [1119.5/4568808.6]? G-band mean flux of the star in the Gaia DR2 catalogue. 219-230 F12.6 --- astrometric_chi2_al [56.3/24146.0]? Astrometric goodness of fit in the Gaia DR2 catalogue. 232-234 I3 --- astrometric_n_good_obs_al [66.0/916.0]? No. CCD transits not downweighted in the astrometric solution in the Gaia DR2 Catalogue. 236-241 F6.3 mag Jmag_cds [6.9/13.9]? $J$ band magnitude of the star in 2MASS. 243-247 F5.3 mag e_Jmag_cds [0.0/0.1]? Uncertainty in $J$ band magnitude of the star in 2MASS. 249-254 F6.3 mag Hmag_cds [6.3/13.4]? $H$ band magnitude of the star in 2MASS. 256-260 F5.3 mag e_Hmag_cds [0.0/0.1]? Uncertainty in $H$ band magnitude of the star in 2MASS. 262-267 F6.3 mag Kmag_cds [6.1/13.1]? $K_s$ band magnitude of the star in 2MASS. 269-273 F5.3 mag e_Kmag_cds [0.0/0.1]? Uncertainty in $K_s$ band magnitude of the star in 2MASS. 275-280 F6.3 mag W1mag_cds [6.0/11.9]? $W_1$ band magnitude of the star in AllWISE. 282-286 F5.3 mag e_W1mag_cds [0.0/0.1]? Uncertainty in $W_1$ band magnitude of the star in AllWISE. 288-293 F6.3 mag W2mag_cds [5.8/11.8]? $W_2$ band magnitude of the star in AllWISE. 295-299 F5.3 mag e_W2mag_cds [0.0/0.1]? Uncertainty in $W_2$ band magnitude of the star in AllWISE. 301-306 F6.3 mag W3mag_cds [5.8/11.3]? $W_3$ band magnitude of the star in AllWISE. 308-312 F5.3 mag e_W3mag_cds [0.0/0.1]? Uncertainty in $W_3$ band magnitude of the star in AllWISE. 314-317 I4 --- model_no [0.0/3535.0]? Number of the best fitting model in our grid. 319-336 F18.15 --- norm [45.0/51.0]? Magnitude normalisation calculated by the code to scale $Z_i$ to $m_{i, \text{syn}}$. 338-360 F23.18 --- chisq [0.0/3248.6]? Goodness of fit for the best fitting model. 362-383 F22.18 --- reduced_chisq [0.0/406.1]? Goodness of fit per degree of freedom for the best fitting model. 385-405 F21.19 --- prob [0.0/1.0]? The corresponding probability of being the best fitting model. 407-428 E22.17 --- rsqr_on_dsqr Measured radius squared on distance squared of the target. 430-448 F19.17 solRad radius [0.0/1.3]? Our measured radius of the target (in units of $R_{\odot}$). 450-466 F17.14 pc dist [9.5/100.0]? Estimated distance (in pc) to the target. 468-484 F17.14 pc dist_lbound [9.5/99.7]? Lower bound on the confidence interval of the estimated distance (in pc). 486-503 F18.14 pc dist_ubound [9.5/100.5]? Upper bound on the confidence interval of the estimated distance (in pc). 505-505 I1 --- nphot [8.0]? The number of photometric data points used for the SED fitting. 507-512 F6.1 K Teff [2900.0/5100.0]? Our measured SED temperature of the target. 514-516 F3.1 dex Log(g) [4.0/5.5]? Our measured surface gravity of the target. 518-522 E5.4 --- bad_phot Flag showing whether source is consistent with contaminated photometry in Gaia DR2. 524-528 E5.4 --- bad_astr Flag indicating whether source is consistent with contaminated astrometry in Gaia DR2. 530-534 E5.4 --- bad_teff Flag indicating that the measured $T_{\rm SED}$ is at a grid boundary. 536-540 E5.4 --- good True if none of \textbf{bad\_phot}, \textbf{bad\_astr} or \textbf{bad\_teff} are true for the source. 542-547 F6.1 K teff_lbound Lower bound on the confidence interval of our measured $T_{\rm SED}$. 549-554 F6.1 K teff_ubound Upper bound on the confidence interval of our measured $T_{\rm SED}$. 556-567 F12.8 dex logg_lbound Lower bound on the confidence interval of our measured $\log(g)$. 569-580 F12.8 dex logg_ubound Upper bound on the confidence interval of our measured $\log(g)$. 582-594 F13.9 solRad radius_lbound Lower bound on the confidence interval of our measured radius. 596-608 F13.9 solRad radius_ubound Upper bound on the confidence interval of our measured radius. 610-624 F15.10 --- tau_sq_68_contour Value of $\chi^2$ within which 68\% of the confidence is bounded within the cube. 626-631 A6 --- uncer_sample Sample for which the uncertainties correspond. For this publication, it will be 'random'. 633-655 F23.19 --- d08_inflation [-44.8/50.3]? Radius inflation (in \%) from the \citet{Dotter:2008aa} 4Gyr solar metallicity isochrone. 657-680 E24.17 solRad d08_lum_corr_radius Radius residual when corrected for our luminosity - radius relation. 682-703 F22.18 solLum lum Luminosity measured for the source when correcting the radius for metallicity. 705-725 F21.17 solRad corrected_radius Radius of the star when corrected for the effects of metallicity. 727-747 F21.17 solRad corrected_radius_lbound Lower bound on the confidence interval of our metallicity corrected radius. 749-769 F21.17 solRad corrected_radius_ubound Upper bound on the confidence interval of our metallicity corrected radius. 771-777 F7.2 dex fe_h Measured metallicity of the target. 779-797 A19 --- fe_h_bibcode The bibcode corresponding to the source of the metallicity measurement. 799-822 F24.19 solRad rad_corr The correction applied to our measured radius to correct for metallicity, measured in $R_\odot$. -------------------------------------------------------------------------------- Byte-by-byte Description of file: tsed-r-relation.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 4 I4 K tsed [3000.0/4400.0]? SED temperature of the source. 6-24 F19.17 solRad radius [0.2/0.7]? Radius prescribed by the relation at tempertature T_SED. 26-44 F19.17 solRad radius_lbound [0.2/0.6]? Lower bound radius prescribed by the relation at tempertature T_SED. 46-64 F19.17 solRad radius_ubound [0.3/0.7]? Upper bound radius prescribed by the relation at tempertature T_SED. -------------------------------------------------------------------------------- Byte-by-byte Description of file: lsed-r-relation.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 20 F20.18 solLum lsed [0.0/0.1]? Luminosity of the source from a SED fit. 22- 41 F20.18 solRad radius_correction [0.0/0.0]? Radius correction to the D08 4Gyr isochrone at luminosity L_SED. 43- 61 F19.17 solRad radius_correction_lbound [0.2/0.6]? Description 63- 81 F19.17 solRad radius_correction_ubound [0.2/0.7]? Description 83-101 F19.17 solRad radius [0.2/0.6]? Radius prescribed by the relation at luminosity L_SED. 103-121 F19.17 solRad radius_lbound [0.2/0.6]? Lower bound radius prescribed by the relation at luminosity L_SED. 123-141 F19.17 solRad radius_ubound [0.2/0.7]? Upper bound radius prescribed by the relation at luminosity L_SED. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3-tabulated-feh-corrections.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-21 F21.19 solLum lum [0.0/0.1]? Luminosity of the source from a SED fit. 23-43 F21.18 --- f_lum [-0.1/-0.0]? Gradient of F(L_SED) at the given luminosity L_SED. -------------------------------------------------------------------------------- Byte-by-byte Description of file: mdwarf-properties.fits -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 5 I5 --- id [1.0/15765.0]? Internal identifier for the object within our catalogue. 7- 28 F22.18 deg ra [0.0/360.0]? Right ascension of the source as given in the Gaia DR2 catalogue. 30- 52 F23.19 deg dec [-89.7/88.7]? Declination of the source as given in the Gaia DR2 catalogue. 54- 72 I19 --- source_id Unique source indentifier of the star within Gaia DR2. 74- 83 F10.7 mag phot_g_mean_mag [9.0/18.1]? G-band mean magnitude of the star in the Gaia DR2 catalogue. 85- 94 F10.7 mag phot_bp_mean_mag [9.9/20.7]? Integrated BP mean magnitude of the star in the Gaia DR2 catalogue. 96-105 F10.7 mag phot_rp_mean_mag [8.2/16.4]? Integrated RP mean magnitude of the star in the Gaia DR2 catalogue. 107-127 F21.19 mag phot_bp_mean_mag_err [0.0/0.3]? Uncertainty of the BP mean magnitude of the star in the Gaia DR2 catalogue. 129-150 F22.20 mag phot_rp_mean_mag_err [0.0/0.2]? Uncertainty of the RP mean magnitude of the star in the Gaia DR2 catalogue. 152-173 F22.14 'electron'.s**-1 phot_bp_mean_flux [70.8/1558645.7]? Integrated BP mean flux of the star in the Gaia DR2 catalogue. 175-195 F21.13 'electron'.s**-1 phot_rp_mean_flux [2151.7/4289144.1]? Integrated RP mean flux of the star in the Gaia DR2 catalogue. 197-217 F21.13 'electron'.s**-1 phot_g_mean_flux [1119.5/4568808.6]? G-band mean flux of the star in the Gaia DR2 catalogue. 219-230 F12.6 --- astrometric_chi2_al [56.3/24146.0]? Astrometric goodness of fit in the Gaia DR2 catalogue. 232-234 I3 --- astrometric_n_good_obs_al [66.0/916.0]? No. CCD transits not downweighted in the astrometric solution in the Gaia DR2 Catalogue. 236-241 F6.3 mag Jmag_cds [6.9/13.9]? $J$ band magnitude of the star in 2MASS. 243-247 F5.3 mag e_Jmag_cds [0.0/0.1]? Uncertainty in $J$ band magnitude of the star in 2MASS. 249-254 F6.3 mag Hmag_cds [6.3/13.4]? $H$ band magnitude of the star in 2MASS. 256-260 F5.3 mag e_Hmag_cds [0.0/0.1]? Uncertainty in $H$ band magnitude of the star in 2MASS. 262-267 F6.3 mag Kmag_cds [6.1/13.1]? $K_s$ band magnitude of the star in 2MASS. 269-273 F5.3 mag e_Kmag_cds [0.0/0.1]? Uncertainty in $K_s$ band magnitude of the star in 2MASS. 275-280 F6.3 mag W1mag_cds [6.0/11.9]? $W_1$ band magnitude of the star in AllWISE. 282-286 F5.3 mag e_W1mag_cds [0.0/0.1]? Uncertainty in $W_1$ band magnitude of the star in AllWISE. 288-293 F6.3 mag W2mag_cds [5.8/11.8]? $W_2$ band magnitude of the star in AllWISE. 295-299 F5.3 mag e_W2mag_cds [0.0/0.1]? Uncertainty in $W_2$ band magnitude of the star in AllWISE. 301-306 F6.3 mag W3mag_cds [5.8/11.3]? $W_3$ band magnitude of the star in AllWISE. 308-312 F5.3 mag e_W3mag_cds [0.0/0.1]? Uncertainty in $W_3$ band magnitude of the star in AllWISE. 314-317 I4 --- model_no [0.0/3535.0]? Number of the best fitting model in our grid. 319-336 F18.15 --- norm [45.0/51.0]? Magnitude normalisation calculated by the code to scale $Z_i$ to $m_{i, \text{syn}}$. 338-360 F23.18 --- chisq [0.0/3248.6]? Goodness of fit for the best fitting model. 362-383 F22.18 --- reduced_chisq [0.0/406.1]? Goodness of fit per degree of freedom for the best fitting model. 385-405 F21.19 --- prob [0.0/1.0]? The corresponding probability of being the best fitting model. 407-428 E22.17 --- rsqr_on_dsqr Measured radius squared on distance squared of the target. 430-448 F19.17 solRad radius [0.0/1.3]? Our measured radius of the target (in units of $R_{\odot}$). 450-466 F17.14 pc dist [9.5/100.0]? Estimated distance (in pc) to the target. 468-484 F17.14 pc dist_lbound [9.5/99.7]? Lower bound on the confidence interval of the estimated distance (in pc). 486-503 F18.14 pc dist_ubound [9.5/100.5]? Upper bound on the confidence interval of the estimated distance (in pc). 505-505 I1 --- nphot [8.0]? The number of photometric data points used for the SED fitting. 507-512 F6.1 K Teff [2900.0/5100.0]? Our measured SED temperature of the target. 514-516 F3.1 dex Log(g) [4.0/5.5]? Our measured surface gravity of the target. 518-522 E5.4 --- bad_phot Flag showing whether source is consistent with contaminated photometry in Gaia DR2. 524-528 E5.4 --- bad_astr Flag indicating whether source is consistent with contaminated astrometry in Gaia DR2. 530-534 E5.4 --- bad_teff Flag indicating that the measured $T_{\rm SED}$ is at a grid boundary. 536-540 E5.4 --- good True if none of \textbf{bad\_phot}, \textbf{bad\_astr} or \textbf{bad\_teff} are true for the source. 542-547 F6.1 K teff_lbound Lower bound on the confidence interval of our measured $T_{\rm SED}$. 549-554 F6.1 K teff_ubound Upper bound on the confidence interval of our measured $T_{\rm SED}$. 556-567 F12.8 dex logg_lbound Lower bound on the confidence interval of our measured $\log(g)$. 569-580 F12.8 dex logg_ubound Upper bound on the confidence interval of our measured $\log(g)$. 582-594 F13.9 solRad radius_lbound Lower bound on the confidence interval of our measured radius. 596-608 F13.9 solRad radius_ubound Upper bound on the confidence interval of our measured radius. 610-624 F15.10 --- tau_sq_68_contour Value of $\chi^2$ within which 68\% of the confidence is bounded within the cube. 626-631 A6 --- uncer_sample Sample for which the uncertainties correspond. For this publication, it will be 'random'. 633-655 F23.19 --- d08_inflation [-44.8/50.3]? Radius inflation (in \%) from the \citet{Dotter:2008aa} 4Gyr solar metallicity isochrone. 657-680 E24.17 solRad d08_lum_corr_radius Radius residual when corrected for our luminosity - radius relation. 682-703 F22.18 solLum lum Luminosity measured for the source when correcting the radius for metallicity. 705-725 F21.17 solRad corrected_radius Radius of the star when corrected for the effects of metallicity. 727-747 F21.17 solRad corrected_radius_lbound Lower bound on the confidence interval of our metallicity corrected radius. 749-769 F21.17 solRad corrected_radius_ubound Upper bound on the confidence interval of our metallicity corrected radius. 771-777 F7.2 dex fe_h Measured metallicity of the target. 779-797 A19 --- fe_h_bibcode The bibcode corresponding to the source of the metallicity measurement. 799-822 F24.19 solRad rad_corr The correction applied to our measured radius to correct for metallicity, measured in $R_\odot$. -------------------------------------------------------------------------------- Byte-by-byte Description of file: tsed-r-relation.fits -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 4 I4 K tsed [3000.0/4400.0]? SED temperature of the source. 6-24 F19.17 solRad radius [0.2/0.7]? Radius prescribed by the relation at tempertature T_SED. 26-44 F19.17 solRad radius_lbound [0.2/0.6]? Lower bound radius prescribed by the relation at tempertature T_SED. 46-64 F19.17 solRad radius_ubound [0.3/0.7]? Upper bound radius prescribed by the relation at tempertature T_SED. -------------------------------------------------------------------------------- Byte-by-byte Description of file: lsed-r-relation.fits -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 20 F20.18 solLum lsed [0.0/0.1]? Luminosity of the source from a SED fit. 22- 41 F20.18 solRad radius_correction [0.0/0.0]? Radius correction to the D08 4Gyr isochrone at luminosity L_SED. 43- 61 F19.17 solRad radius_correction_lbound [0.2/0.6]? Description 63- 81 F19.17 solRad radius_correction_ubound [0.2/0.7]? Description 83-101 F19.17 solRad radius [0.2/0.6]? Radius prescribed by the relation at luminosity L_SED. 103-121 F19.17 solRad radius_lbound [0.2/0.6]? Lower bound radius prescribed by the relation at luminosity L_SED. 123-141 F19.17 solRad radius_ubound [0.2/0.7]? Upper bound radius prescribed by the relation at luminosity L_SED. -------------------------------------------------------------------------------- Byte-by-byte Description of file: table3-tabulated-feh-corrections.fits -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-21 F21.19 solLum lum [0.0/0.1]? Luminosity of the source from a SED fit. 23-43 F21.18 --- f_lum [-0.1/-0.0]? Gradient of F(L_SED) at the given luminosity L_SED. -------------------------------------------------------------------------------- ================================================================================
description: The article associated with this dataset is available in ORE at: http://hdl.handle.net/10871/38284