Bibcode
Lodieu, N.; Alonso, R.; González Hernández, J. I.; Sanchis-Ojeda, R.; Narita, N.; Kawashima, Y.; Kawauchi, K.; Suárez Mascareño, A.; Deeg, H. J.; Prieto Arranz, J.; Rebolo, R.; Pallé, E.; Béjar, V. J. S.; Ferragamo, A.; Rubiño-Martín, J. A.
Bibliographical reference
Astronomy and Astrophysics, Volume 584, id.A128, 15 pp.
Advertised on:
12
2015
Journal
Citations
27
Refereed citations
26
Description
Aims: We aim at constraining evolutionary models at low mass and
young ages by identifying interesting transiting system members of the
nearest OB association to the Sun, Upper Scorpius (USco), which has been
targeted by the Kepler mission. Methods: We produced light curves
for M-dwarf members of the USco region that has been surveyed during the
second campaign of the Kepler K2 mission. We identified by eye a
transiting system, USco J161630.68-251220.1 (=EPIC 203710387) with a
combined spectral type of M5.25, whose photometric, astrometric, and
spectroscopic properties makes it a member of USco. We conducted an
extensive photometric and spectroscopic follow-up of this transiting
system with a suite of telescopes and instruments to characterise the
properties of each component of the system. Results: We
calculated a transit duration of about 2.42 h that occurs every 2.88
days with a slight difference in transit depth and phase between the two
components. We estimated a mass ratio of 0.922 ± 0.015 from the
semi-amplitudes of the radial velocity curves for each component. We
derived masses of 0.091 ± 0.005M⊙ and 0.084
± 0.004M⊙, radii of 0.388 ±
0.008R⊙ and 0.380 ± 0.008R⊙,
luminosities of log (L/L⊙) =
-2.020-0.121+0.099 dex and
-2.032-0.121+0.099 dex, and effective temperatures
of 2901-172+199 K and
2908-172+199 K for the primary and secondary,
respectively. Conclusions: We present a complete photometric and
radial velocity characterisation of the least massive double-line
eclipsing binary system in the young USco association with two
components close to the stellar/substellar limit. This system falls in a
gap between the least massive eclipsing binaries in the low-mass and
substellar regimes at young ages and represents an important addition to
constraining evolutionary models at young ages.
Based on observations made with telescopes (GTC, WHT) installed in the
Spanish Observatorio del Roque de los Muchachos of the Instituto de
Astrofísica de Canarias, in the island of La Palma.
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