Lithium Depletion of Nearby Young Stellar Associations

Mentuch, Erin; Brandeker, Alexis; Kerkwijk, M. H. van; Jayawardhana, Ray; Hauschildt, P. H.

doi:10.1086/592764

Cited by 163 publications

(207 citation statements)

References 38 publications

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“…However, statistically speaking, Li abundances derived in a homogeneous way as done in this paper can be used to determine relative ages of the young associations provided that the associations possess enough members cooler than 5000−4500 K. Our conclusions are similar to those of Mentuch et al (2008), who also found qualitatively good agreement between the Li abundances and the isochronal ages of a small number of stars belonging to the five associations studied here.…”

Section: Lithium Depletion Pattern and The Relative Agessupporting

confidence: 82%

Search for associations containing young stars (SACY)

Silva¹,

Torres

Reza³

et al. 2009

A&A

152

150

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Context. Our study is a follow-up of the SACY project, an extended high spectral resolution survey of more than two thousand optical counterparts to X-ray sources in the southern hemisphere targeted to search for young nearby association. Nine associations have either been newly identified, or have had their member list revised. Groups belonging to the Sco-Cen-Oph complex are not considered in the present study. Aims. These nine associations, with ages of between about 6 Myr and 70 Myr, form an excellent sample to study the Li depletion in the pre-main sequence (PMS) evolution. In the present paper, we investigate the use of Li abundances as an independent clock to constrain the PMS evolution. Methods. Using our measurements of the equivalent widths of the Li resonance line and assuming fixed metallicities and microturbulence, we calculated the LTE Li abundances for 376 members of various young associations. In addition, we considered the effects of their projected stellar rotation. Results. We present the Li depletion as a function of age in the first hundred million years for the first time for the most extended sample of Li abundances in young stellar associations. Conclusions. A clear Li depletion can be measured in the temperature range from 5000 K to 3500 K for the age span covered by the nine associations studied in this paper. The age sequence based on the Li-clock agrees well with the isochronal ages, the Cha association being the only possible exception. The lithium depletion patterns for the associations presented here resemble those of the young open clusters with similar ages, strengthening the notion that the members proposed for these loose young associations have indeed a common physical origin. The observed scatter in the Li abundances hampers the use of Li in determining reliable ages for individual stars. For velocities above 20 km s −1 , rotation seems to play an important role in inhibiting the Li depletion.

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Section: Lithium Depletion Pattern and The Relative Agessupporting

confidence: 82%

Search for associations containing young stars (SACY)

Silva¹,

Torres

Reza³

et al. 2009

A&A

152

150

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“…The EW of Li in J024902 A is weaker than in M1−M2 type members of the ≈ 10 Myr TW Hydrae association, but stronger than members of the ≈ 40 Myr old Tucana-Horologium association (Kraus et al 2014). The Li strength is consistent with that of early-M stars in the β Pic MG, suggesting a similar age of ≈ 20 Myr (Mentuch et al 2008;Mamajek & Bell 2014).…”

Section: Feros Observations Of the J024902 Systemsupporting

confidence: 54%

Characterization of close visual binaries from the AstraLux Large M Dwarf Survey

Bergfors¹,

Brandner²,

Bonnefoy³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present VLT/SINFONI J, H + K spectra of seven close visual pairs in M dwarf binary/triple systems, discovered or observed by the AstraLux M dwarf survey. We determine the spectral types to within ±1.0 subclasses from comparison to template spectra and the strength of K-band water absorption, and derive effective temperatures. The results are compared to optical spectral types of the unresolved binary/multiple systems, and we confirm that our photometric method to derive spectral types in the AstraLux M dwarf survey is accurate. We look for signs of youth such as chromospheric activity and low surface gravity, and find an age in the range 0.25 − 1 Gyr for the GJ 852 system. Strong Li absorption is detected in optical spectra of the triple system J024902 obtained with FEROS at the ESO-MPG 2.2 m telescope. The equivalent width of the absorption suggests an age consistent with the β Pic moving group. However, further observations are needed to establish group membership. Ongoing orbital monitoring will provide dynamical masses and thus calibration of evolutionary models for low mass stars.

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“…This indicates that both stars are young and have an age younger than that of the Pleiades. According to Mentuch et al (2008) early G-type stars in the β Pic moving group and in the Tucanae-Horologium association have similar Li EW to that of TYC 2627-638-1A and TYC 2627-638-1B, and from this we may estimate an age of about 25 Myr with an uncertainty of at least 10 Myr for our objects.…”

Section: Age Estimates Of the Systemsupporting

confidence: 52%

Young solar type active stars: the TYC 2627-638-1 system

Oláh

Korhonen²,

Vida

et al. 2010

A&A

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We present BV(RI) C and JHK s photometry and low-and high-resolution spectroscopy of the 11th mag G-type star TYC 2627-638-1. Our investigation reveals that the target is separated into two young, early-G-type main-sequence (or late pre-main-sequence) stars, which are most probably bound and form a wide binary system. A substellar body orbits the brighter component as implied by radial velocity variations. The brighter component possibly also has a faint, later type stellar companion.Both components of the wide binary have clear emission cores in the Ca ii H&K lines and filled-in Hα absorption, indicating that both stars are chromospherically active. Our photometric time series reveals clear but only a few hundredths of a magnitude amplitude rotational modulation, which is most likely due to cool starspots. Two distinct periods, near 3.5 and 3.7 days, are found in the brightness variations. Photometry obtained separately of the two components of the wide binary show that these periodicities belong to the brighter star. The fainter component shows a much slower light variation of about 0.3 mag. amplitude. In addition, long-term changes in the brightness of both stars are seen. The spectral energy distribution shows a strong near-infrared excess in the fainter component of the wide binary.

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Lithium Depletion of Nearby Young Stellar Associations

Cited by 163 publications

References 38 publications

Search for associations containing young stars (SACY)

Search for associations containing young stars (SACY)

Characterization of close visual binaries from the AstraLux Large M Dwarf Survey

Young solar type active stars: the TYC 2627-638-1 system

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