Two close binaries across the hydrogen-burning limit in the Praesepe open 
cluster

Lodieu, N; Burgo, C del; Manjavacas, E; Osorio, M R Zapatero; Alvarez, C; Béjar, V J S; Boudreault, Steve; Lyke, J; Rebolo, R; Chinchilla, P

doi:10.1093/mnras/staa2538

Item

ITEM ACTIONSEXPORT

Add to Basket

Local TagsRelease HistoryDetailsSummary

Released

Journal Article

Two close binaries across the hydrogen-burning limit in the Praesepe open cluster

MPS-Authors

/persons/resource/persons192380

Boudreault, Steve
Department Planets and Comets, Max Planck Institute for Solar System Research, Max Planck Society;

External Resource

No external resources are shared

Fulltext (restricted access)

There are currently no full texts shared for your IP range.

Fulltext (public)

There are no public fulltexts stored in PuRe

Supplementary Material (public)

There is no public supplementary material available

Citation

Lodieu, N., Burgo, C. d., Manjavacas, E., Osorio, M. R. Z., Alvarez, C., Béjar, V. J. S., et al. (2020). Two close binaries across the hydrogen-burning limit in the Praesepe open cluster. Monthly Notices of the Royal Astronomical Society, 498(3), 3964-3974. doi:10.1093/mnras/staa2538.

Cite as: https://hdl.handle.net/21.11116/0000-0007-20CC-F

Abstract

We present Keck I/OSIRIS and Keck II/NIRC2 adaptive optics imaging of two member candidates of the Praesepe stellar cluster (d = 186.18±0.11 pc; 590–790 Myr), UGCS J08451066+2148171 (L1.5±0.5) and UGCS J08301935+2003293 (no spectroscopic classification). We resolved UGCS J08451066+2148171 into a binary system in the near-infrared, with a K-band wavelength flux ratio of 0.89±0.04, a projected separation of 60.3±1.3 mas (11.2±0.7 au; 1σ). We also resolved UGCS J08301935+2003293 into a binary system with a flux ratio of 0.46±0.03 and a separation of 62.5±0.9 mas. Assuming zero eccentricity, we estimate minimum orbital periods of ∼100 years for both systems. According to theoretical evolutionary models, we derive masses in the range of 0.074–0.078 M⊙ and 0.072–0.076 M⊙ for the primary and secondary of UGCS J08451066+2148171 for an age of 700±100 Myr. In the case of UGCS J08301935+2003293, the primary is a low-mass star at the stellar/substellar boundary (0.070–0.078 M⊙) while the companion candidate might be a brown dwarf (0.051–0.065 M⊙). These are the first two binaries composed of L dwarfs in Praesepe. They are benchmark systems to derive the location of the substellar limit at the age and metallicity of Praesepe, determine the age of the cluster based on the lithium depletion boundary test, derive dynamical masses, and improve low-mass stellar and substellar evolutionary models at a well-known age and metallicity.