The Lithium Depletion Boundary and the Age of the Hyades Cluster<sup>∗</sup>

Martín, E. L.; Lodieu, N.; Pavlenko, Ya. V.; Béjar, V. J. S.

doi:10.3847/1538-4357/aaaeb8

Cited by 104 publications

(111 citation statements)

References 53 publications

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“…To illustrate the effect of segregation in a more quantitative manner, we compute the ratio R of stars to brown dwarfs as defined by Andersen et al (2008): the sum of all objects in the interval 0.08-1.0 M is divided by the number of brown dwarfs (0.03-0.08 M ). We emphasise that the bin of brown dwarfs is yet incomplete in the Hyades because the coolest members are early-T dwarfs with model-dependent masses of the order of 0.05 M (Bouvier et al 2008) and confirmed L-type brown dwarf with lithium in absorption at 6707.8Å and masses in the range 0.05-0.06 M Martín et al 2018). The 0.03-0.05 M bin remains currently unexplored in the Hyades cluster; thus all number are upper limits.…”

Section: Mass Segregationmentioning

confidence: 73%

“…The role of rotation at such ages leads to an age of 750±100 Myr (Brandt & Huang 2015). Recently, the method using the lithium depletion boundary at the stellar/sub-stellar limit prompted an age of 650±70 Myr consistent with the canonical age of the cluster Martín et al 2018).…”

Section: Introductionmentioning

confidence: 90%

“…Compared to this uncertainty, the Gaia photometric and parallax errors are negligible for these relatively bright stars. When considering all eight single WDs in Table 6 ;Maeder & Mermilliod 1981;Mermilliod 1981) and the lithium depletion boundary method (650±70 Myr; Lodieu et al 2018;Martín et al 2018). However, it is on the lower side of older ages determined from evolutionary models with enhanced convective overshooting (upper limit of 1.2 Gyr; Mazzei & Pigatto 1988) and models with rotation (750±100 Myr; Brandt & Huang 2015).…”

Section: White Dwarfsmentioning

confidence: 99%

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A 3D view of the Hyades stellar and sub-stellar population

Lodieu

Smart

Pérez‐Garrido

et al. 2019

A&A

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Aims. Our scientific goal is to provide a 3D map of the nearest open cluster to the Sun, the Hyades, combining the recent release of Gaia astrometric data, ground-based parallaxes of sub-stellar member candidates and photometric data from surveys which cover large areas of the cluster. Methods. We combined the second Gaia release with ground-based H-band parallaxes obtained with the infrared camera on the 2-m robotic Liverpool telescope to astrometrically identify stellar and sub-stellar members of the Hyades, the nearest open cluster to the Sun. Results. We find 1764 objects within 70 • radius from the cluster center from the Gaia second data release, whose kinematic properties are consistent with the Hyades. We limit our study to 30 pc from the cluster center (47.03±0.20 pc) where we identify 710 candidate members, including 85 and 385 in the core and tidal radius, respectively. We determine proper motions and parallaxes of eight candidate brown dwarf members and confirm their membership. Using the 3D positions and a model-based mass-luminosity relation we derive a luminosity and mass function in the 0.04 to 2.5 M range. We confirm evidence for mass segregation in the Hyades and find a dearth of brown dwarfs in the core of the cluster. From the white dwarf members we estimate an age of 640 +67 −49 Myr. Conclusions. We identify a list of members in the Hyades cluster from the most massive stars down to the brown dwarfs. We produce for the first time a 3D map of the Hyades cluster in the stellar and sub-stellar regimes and make available the list of candidate members.

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Section: Mass Segregationmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 90%

Section: White Dwarfsmentioning

confidence: 99%

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A 3D view of the Hyades stellar and sub-stellar population

Lodieu

Smart

Pérez‐Garrido

et al. 2019

A&A

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“…Clearly, a reduction of the error on the Hyades age determined from the Gaia CMD is required, to reduce the uncertainty on the slope of the cluster IFMR. We just recall here that other recent estimates of the Hyades agenot based on DR2 data-have provided 650±70 Myr from the lithium depletion boundary technique applied to cluster brown dwarfs (Martín et al 2018), 750±100 Myr from a Bayesian fit of rotating stellar models to the Hipparcos CMD of the cluster (Brandt & Huang 2015), and 700±100 Myr from non-rotating isochrone fitting to an optical CMD using the mean distance modulus from Gaia Data Release 1 (Hidalgo et al 2018).…”

Section: Comparisons With Previous Resultsmentioning

confidence: 99%

A Gaia DR2 view of white dwarfs in the Hyades

Salaris

Bedin

2018

Monthly Notices of the Royal Astronomical Society

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We have exploited the very precise parallaxes, proper motions and photometry of Gaia Data Release 2 to study white dwarf members of the Hyades star cluster. Gaia photometry and parallaxes for the eight DA white dwarfs confirmed members have been then used to compute absolute magnitudes and colours. These were compared to three independent sets of white dwarf evolutionary tracks, to derive cooling times and white dwarf (final) masses. All sets of models provide the same mass values, with only small differences in the cooling ages. The precision in the derived masses and cooling ages is typically 1-3%. Our derived masses are generally consistent with spectroscopic estimates from the literature, whilst cooling ages are generally larger. The recent estimate of the cluster age from the Gaia Data Release 2 main sequence turn off colour-magnitude-diagram (790 Myr) has been employed to derive progenitor (initial) masses. We find a slope of the initial-final mass relation for the Hyades white dwarfs (masses between ∼0.67 and ∼ 0.84M ⊙ ) steeper than that derived for the same mass range from global estimates -averaged over the whole spectrum of white dwarf masses-irrespectively of the cooling models adopted. However, when considering the error in this age estimate ( +160 −100 Myr), a definitive conclusion on this issue cannot be reached yet. The lower limit of 690 Myr (closer to the classical Hyades age of 600-650 Myr) would provide a slope of the initial-final mass relation closer to the global determinations. We also find hints of an intrinsic spread of the cluster initial-final mass relation for the cluster.

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“…In this Section we present the RV measurements of the star HD 285507, a member of the Hyades open cluster (age=625 ± 50 Myr, Perryman et al 1997, or a more recent estimation of 650 ± 70 Myr, Martín et al 2018). It is a K4.5 star, with magnitudes V=10.5, J=8.…”

Section: Hd 285507mentioning

confidence: 98%

The GAPS Programme at TNG

Carleo

Malavolta

Lanza

et al. 2020

A&A

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Context. The existence of hot Jupiters is still not well understood. Two main channels are thought to be responsible for their current location: a smooth planet migration through the proto-planetary disk or the circularization of an initial high eccentric orbit by tidal dissipation leading to a strong decrease of the semimajor axis. Different formation scenarios result in different observable effects, such as orbital parameters (obliquity/eccentricity), or frequency of planets at different stellar ages. Aims. In the context of the GAPS Young-Objects project, we are carrying out a radial velocity survey with the aim to search and characterize young hot-Jupiter planets. Our purpose is to put constraints on evolutionary models and establish statistical properties, such as the frequency of these planets from a homogeneous sample. Methods. Since young stars are in general magnetically very active, we performed multi-band (visible and near-infrared) spectroscopy with simultaneous GIANO-B + HARPS-N (GIARPS) observing mode at TNG. This helps to deal with stellar activity and distinguish the nature of radial velocity variations: stellar activity will introduce a wavelength-dependent radial velocity amplitude, whereas a Keplerian signal is achromatic. As a pilot study, we present here the cases of two already claimed hot Jupiters orbiting young stars: HD 285507 b and AD Leo b. Results. Our analysis of simultaneous high-precision GIARPS spectroscopic data confirms the Keplerian nature of HD285507's radial velocities variation and refines the orbital parameters of the hot Jupiter, obtaining an eccentricity consistent with a circular orbit. On the other hand, our analysis does not confirm the signal previously attributed to a planet orbiting AD Leo. This demonstrates the power of the multi-band spectroscopic technique when observing active stars.

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The Lithium Depletion Boundary and the Age of the Hyades Cluster^∗

Cited by 104 publications

References 53 publications

A 3D view of the Hyades stellar and sub-stellar population

A 3D view of the Hyades stellar and sub-stellar population

A Gaia DR2 view of white dwarfs in the Hyades

The GAPS Programme at TNG

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The Lithium Depletion Boundary and the Age of the Hyades Cluster∗

Cited by 104 publications

References 53 publications

A 3D view of the Hyades stellar and sub-stellar population

A 3D view of the Hyades stellar and sub-stellar population

A Gaia DR2 view of white dwarfs in the Hyades

The GAPS Programme at TNG

Contact Info

Product

Resources

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The Lithium Depletion Boundary and the Age of the Hyades Cluster^∗