Low-Mass and Sub-stellar Eclipsing Binaries in Stellar Clusters

Lodieu, N.; Paunzen, E.; Zejda, Miloslav

doi:10.1007/978-3-030-38509-5_8

Cited by 3 publications

(1 citation statement)

References 233 publications

(264 reference statements)

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“…We assumed an age of 10 Myr for USco based on the comparison of these models with the masses derived from eclipsing binaries identified in the association thanks to the Kepler K2 mission (Borucki et al 2010;Lissauer et al 2014;Batalha 2014) over the past years (Alonso et al 2015;Kraus et al 2015;Lodieu et al 2015;David et al 2016bDavid et al , 2019. The BT-Settl models at 10 Myr reproduce relatively well the sequence of USco eclipsing binaries in the mass-radius diagram (Lodieu et al 2020). The age of USco might well be as young as 5 Myr from isochrone fitting of the lowest mass stars (Preibisch & Zinnecker 1999;Preibisch et al 2001;Song et al 2012;David et al 2019) with an upper limit of about 10 Myr (Pecaut et al 2012).…”

Section: The Usco Imf In the Planetary-mass Regimementioning

confidence: 99%

Exploring the planetary-mass population in the Upper Scorpius association

Lodieu,

Hambly,

Cross

2021

Preprint

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We aim at identifying very low-mass isolated planetary-mass member candidates in the nearest OB association to the Sun, Upper Scorpius (145 pc; 5-10 Myr), to constrain the form and shape of the luminosity function and mass spectrum in this regime. We conducted a deep multi-band (𝑌 = 21.2, 𝐽 = 20.5, 𝑍 = 22.0 mag) photometric survey of six square degrees in the central region of Upper Scorpius. We extend the current sequence of astrometric and spectroscopic members by about two magnitudes in 𝑌 and one magnitude in 𝐽, reaching potentially T-type free-floating members in the association with predicted masses below 5 Jupiter masses, well into the planetary-mass regime. We extracted a sample of 57 candidates in this area and present infrared spectroscopy confirming two of them as young L-type members with characteristic spectral features of 10 Myr-old brown dwarfs. Among the 57 candidates, we highlight 10 new candidates fainter than the coolest members previously confirmed spectroscopically. We do not see any obvious sign of decrease in the mass spectrum of the association, suggesting that star processes can form substellar objects with masses down to 4-5 Jupiter masses.

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Section: The Usco Imf In the Planetary-mass Regimementioning

confidence: 99%

Exploring the planetary-mass population in the Upper Scorpius association

Lodieu,

Hambly,

Cross

2021

Preprint

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The CARMENES search for exoplanets around M dwarfs

Baroch

Morales

Ribas

et al. 2021

A&A

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Context. M dwarfs are ideal targets for the search of Earth-size planets in the habitable zone using the radial velocity method, and are attracting the attention of many ongoing surveys. One of the expected results of these surveys is that new multiple-star systems have also been found. This is the case also for the CARMENES survey, thanks to which nine new double-line spectroscopic binary systems have already been announced. Aims. Throughout the five years of the survey the accumulation of new observations has resulted in the detection of several new multiple-stellar systems with long periods and low radial-velocity amplitudes. Here we newly characterise the spectroscopic orbits and constrain the masses of eight systems and update the properties of a system that we had reported earlier. Methods. We derived the radial velocities of the stars using two-dimensional cross-correlation techniques and template matching. The measurements were modelled to determine the orbital parameters of the systems. We combined CARMENES spectroscopic observations with archival high-resolution spectra from other instruments to increase the time span of the observations and improve our analysis. When available, we also added archival photometric, astrometric, and adaptive optics imaging data to constrain the rotation periods and absolute masses of the components. Results. We determined the spectroscopic orbits of nine multiple systems, eight of which are presented for the first time. The sample is composed of five single-line binaries, two double-line binaries, and two triple-line spectroscopic triple systems. The companions of two of the single-line binaries, GJ 3626 and GJ 912, have minimum masses below the stellar boundary, and thus could be brown dwarfs. We found a new white dwarf in a close binary orbit around the M star GJ 207.1, located at a distance of 15.79 pc. From a global fit to radial velocities and astrometric measurements, we were able to determine the absolute masses of the components of GJ 282 C, which is one of the youngest systems with measured dynamical masses.

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A young spectroscopic binary in a quintuple system part of the Local Association

Guillén

Lodieu

Béjar

et al. 2021

A&A

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Context. Double-lined spectroscopic (SB2) binaries allow us to obtain a direct determination of the masses of their components, which is essential to test stellar models. Although these objects only provide a lower limit for the mass, they are more abundant than their eclipsing counterparts as they are not as strongly limited by the inclination of their orbit. Aims. Our aim is to derive the orbital and physical parameters of GJ 1284, a young SB2. We also revise the membership of this system and its two wide co-moving companions, GJ 898 and GJ 897AB, to a young moving group to assess, along with other youth indicators, their age. Afterwards, we compare the results from these analyses and the photometry of these systems with several pre-main-sequence evolutionary models. Methods. We use high-resolution spectra to determine the radial velocity of each component of GJ 1284 and the orbit of the system alongside its systemic velocity. Additionally, we use TESS photometry to derive the rotational period of the GJ 1284 and its two wide companions. Results. GJ 1284 is a binary system located at approximately 16 pc with an eccentric orbit (e = 0.505) of 11.83 d period made up of an M2–M2.5 + M3–M3.5 with minimum masses of M sin 3i = 0.141 ± 0.003 and 0.1189 ± 0.003 M⊙, respectively. The revised systemic velocity of γ = 0.84 ± 0.14 km s−1 suggests that it is a member of the Local Association. The kinematics together with other activity and youth indicators imply an age of 110–800 Myr for this system and its two companions. Conclusions. The isochronal ages derived from the comparison of the photometry with several evolutionary models are younger than the age estimated from the activity indicators for the three co-moving systems. The masses for the components of GJ 1284, derived from their luminosity and age using the different models, are not consistent with the masses derived from the photometry, except for the PARSEC models, but are compatible with dynamical masses of double-lined eclipsing binaries with similar ages and spectral types. The effect of magnetic activity in the form of spots can reconcile to some extent the photometric and dynamical masses, but is not considered in most of the evolutionary models.

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Low-Mass and Sub-stellar Eclipsing Binaries in Stellar Clusters

Cited by 3 publications

References 233 publications

Exploring the planetary-mass population in the Upper Scorpius association

Exploring the planetary-mass population in the Upper Scorpius association

The CARMENES search for exoplanets around M dwarfs

A young spectroscopic binary in a quintuple system part of the Local Association

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