Fundamental properties of the pre-main sequence eclipsing stars of MML 53 and the mass of the tertiary
Por:
Maqueo Chew, Y. Gomez, Hebb, L., Stempels, H. C., Paat, A., Stassun, K. G., Faedi, F., Street, R. A., Rohn, G., Hellier, C., Anderson, D. R.
Publicada:
26 feb 2019
Resumen:
We present the most comprehensive analysis to date of the Upper
Centaurus Lupus eclipsing binary MML 53 (with P-EB = 2.097892 d), and
for the first time, confirm the bound-nature of the third star (in a P-3
similar to 9 yr orbit) by constraining its mass dynamically. Our
analysis is based on new and archival spectra and time-series
photometry, spanning 80% of one orbit of the outer component. From the
spectroscopic analysis, 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% (M-1 = 1.0400 +/- 0.0067 M-circle dot and M-2 =
0.8907 +/- 0.0058 M-circle dot), their radii within 4.5% (R-1 = 1.283
+/- 0.043 R-circle dot and R-2 = 1.107 +/- 0.049 R-circle dot), and the
temperature of the secondary star (T-eff,T-2 = 4379 +/- 100 K). 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 M-circle dot (with a
20% uncertainty). The age we derived from the evolution of the
temperature ratio between the eclipsing components is fully consistent
with previous, independent estimates of the age of Upper Centaurus Lupus
(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 the stars' evolution. The eclipsing
components of MML 53 roughly follow the same theoretical isochrone, but
appear to be inflated in radius (by 20% for the primary and 10% for
the secondary) with respect to recent evolutionary models. However, our
radius measurement of the 1.04 M-circle dot primary star of MML 53 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.
Filiaciones:
Maqueo Chew, Y. Gomez:
Univ Nacl Autonoma Mexico, Inst Astron, Ciudad Univ, Mexico City 04510, DF, Mexico
Hebb, L.:
Hobart & William Smith Coll, Dept Phys, Geneva, NY 14456 USA
Stempels, H. C.:
Uppsala Univ, Dept Phys & Astron, Box 516, S-75120 Uppsala, Sweden
Paat, A.:
Natl Opt Astron Observ, 950 N Cherry Ave, Tucson, AZ 85719 USA
Stassun, K. G.:
Vanderbilt Univ, Dept Phys, Nashville, TN 37235 USA
Fisk Univ, Dept Phys, Nashville, TN USA
Faedi, F.:
Osserv Astrofis Catania, INAF, Via S Sofia 78, I-95123 Catania, Italy
Univ Warwick, Dept Phys, Gibbet Hill Rd, Coventry CV4 7AL, W Midlands, England
Street, R. A.:
Las Cumbres Observ Global Telescope Network, 6740 Cortona Dr Suite 102, Goleta, CA 93117 USA
Rohn, G.:
SUNY Coll Cortland, Dept Phys, Cortland, NY 13045 USA
Hellier, C.:
Keele Univ, Astrophys Grp, Keele ST5 5BG, Staffs, England
Anderson, D. R.:
Keele Univ, Astrophys Grp, Keele ST5 5BG, Staffs, England
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