Fundamental properties of the pre-main sequence eclipsing stars of MML 53 and the mass of the tertiary. (arXiv:1901.10611v1 [astro-ph.SR])
<a href="http://arxiv.org/find/astro-ph/1/au:+Chew_Y/0/1/0/all/0/1">Y. Gómez Maqueo Chew</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hebb_L/0/1/0/all/0/1">L. Hebb</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stempels_H/0/1/0/all/0/1">H.C. Stempels</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Paat_A/0/1/0/all/0/1">A. Paat</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Stassun_K/0/1/0/all/0/1">K.G. Stassun</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Faedi_F/0/1/0/all/0/1">F. Faedi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Street_R/0/1/0/all/0/1">R.A. Street</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rohn_G/0/1/0/all/0/1">G. Rohn</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hellier_C/0/1/0/all/0/1">C. Hellier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Anderson_D/0/1/0/all/0/1">D.R. Anderson</a>
We present the most comprehensive analysis to date of the Upper Centaurus
Lupus eclipsing binary MML 53 (2.097892 d), and for the first time, confirm the
bound-nature of the third star (~9yr orbit). Our analysis uses new and archival
spectra and time-series photometry. We determined the temperature of the
primary star to be 4880+-100 K. The study of the close binary incorporated
treatment of spots and dilution by the tertiary in the light curves, allowing
for the robust measurement of the masses of the eclipsing components within 1%
(M1=1.0400+-0.0067 and M2=0.8907+-0.0058 Msun), their radii within 4.5%
(R1=1.283+-0.043 and R2=1.107+-0.049 Rsun), and the secondary temperature
(4379+-100K). From the analysis of the eclipse timings, and the change in
systemic velocity of the eclipsing binary and the radial velocities of the
third star, we measured the mass of the outer companion to be 0.7 Msun within
20%. The age we derived from the evolution of the temperature ratio between the
eclipsing components is fully consistent with previous estimates of the age of
UCL (16+-2 Myr). At this age, the tightening of the MML 53 eclipsing binary has
already occurred, thus supporting close-binary formation mechanisms that act
early in their evolution. The eclipsing stars roughly follow the same
theoretical isochrone, but appear to be inflated in radius (by 20% for the
primary and 10% for the secondary). However, our primary radius measurement of
is in full agreement with the independent measurement of the secondary of NP
Per which has the same mass and a similar age. The eclipsing stars of MML 53
are found to be larger but not cooler than predicted by non-magnetic models, it
is not clear what is the mechanism that is causing the radius inflation given
that activity, spots and/or magnetic fields slowing their contraction, require
the inflated stars to be cooler to remain in thermal equilibrium.
We present the most comprehensive analysis to date of the Upper Centaurus
Lupus eclipsing binary MML 53 (2.097892 d), and for the first time, confirm the
bound-nature of the third star (~9yr orbit). Our analysis uses new and archival
spectra and time-series photometry. We determined the temperature of the
primary star to be 4880+-100 K. The study of the close binary incorporated
treatment of spots and dilution by the tertiary in the light curves, allowing
for the robust measurement of the masses of the eclipsing components within 1%
(M1=1.0400+-0.0067 and M2=0.8907+-0.0058 Msun), their radii within 4.5%
(R1=1.283+-0.043 and R2=1.107+-0.049 Rsun), and the secondary temperature
(4379+-100K). From the analysis of the eclipse timings, and the change in
systemic velocity of the eclipsing binary and the radial velocities of the
third star, we measured the mass of the outer companion to be 0.7 Msun within
20%. The age we derived from the evolution of the temperature ratio between the
eclipsing components is fully consistent with previous estimates of the age of
UCL (16+-2 Myr). At this age, the tightening of the MML 53 eclipsing binary has
already occurred, thus supporting close-binary formation mechanisms that act
early in their evolution. The eclipsing stars roughly follow the same
theoretical isochrone, but appear to be inflated in radius (by 20% for the
primary and 10% for the secondary). However, our primary radius measurement of
is in full agreement with the independent measurement of the secondary of NP
Per which has the same mass and a similar age. The eclipsing stars of MML 53
are found to be larger but not cooler than predicted by non-magnetic models, it
is not clear what is the mechanism that is causing the radius inflation given
that activity, spots and/or magnetic fields slowing their contraction, require
the inflated stars to be cooler to remain in thermal equilibrium.
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