J/A+A/590/A78 NGC2264 weak-line T Tauri lithium abundances (Bouvier+, 2016)
The Gaia-ESO survey: A lithium-rotation connection at 5 Myr?
Bouvier J., Lanzafame A., Venuti L., Klutsch A., Jeffries R., Frasca A.,
Moraux E., Biazzo K., Messina S., Micela G., Randich S., Stauffer J.,
Cody A.M., Flaccomio E., Gilmore G., Bayo A., Bensby T., Bragaglia A.,
Carraro C., Casey A., Costado M.T., Damiani F., Delgado Mena E., Donati P.,
Franciosini E., Hourihane A., Koposov S., Lardo C., Lewis J., Magrini L.,
Monaco L., Morbidelli L., Prisinzano L., Sacco G., Sbordone L., Sousa S.G.,
Vallenari A., Worley C.C., Zaggia S., Zwitter T.
<Astron. Astrophys. 590, A78 (2016)>
=2016A&A...590A..78B 2016A&A...590A..78B (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, pre-main sequence ; Abundances
Keywords: stars: abundances - stars: pre-main sequence - stars: rotation -
open clusters and associations: individual: NGC 2264
Abstract:
The evolution of lithium abundance in cool dwarfs provides a unique
probe of non-standard processes in stellar evolution. Aims. We
investigate here the lithium content of young low-mass stars in the 5
Myr-old star forming region NGC 2264 and its relationship with
rotation.
We combine lithium equivalent width measurements (EW(Li)) from the
Gaia-ESO Survey with the determination of rotational periods from the
CSI 2264 survey. We consider only bona fide non accreting cluster
members in order to minimize uncertainties on EW(Li).
We report the existence of a relationship between lithium content and
rotation in NGC 2264 at an age of 5Myr. The Li-rotation connection is
seen over a restricted temperature range (Teff=800-4400K) where
fast rotators are Li-rich compared to slow ones. This correlation is
similar to, albeit of lower amplitude than, the Li-rotation connection
previously reported for K dwarfs in the 125Myr-old Pleiades cluster.
We investigate whether the non-standard pre-main sequence models
developed so far to explain the Pleiades results, which are based on
episodic accretion, pre-main sequence core-envelope decoupling, and/or
radius inflation due to enhanced magnetic activity, can account for an
early development of the Li-rotation connection. While radius
inflation appears to be the most promising possibility, each of these
models has issues. We therefore also discuss external causes that
might operate during the first few Myr of pre-main sequence evolution,
such as planet engulfment and/or steady disk accretion, as possible
candidates for the common origin for Li-excess and fast rotation in
young low-mass pre-main sequence stars.
Description:
The table contains 201 weak-line T Tauri stars of the NGC 2264 star
forming region with litihum and rotational period measurements.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 105 201 Lithium and rotation measurements
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- CSI CSI designation (CSIMon-NNNNNN)
15- 30 A16 --- GES GES designation (HHMMSSss+DDMMSSs)
32- 40 F9.5 deg RAdeg Right ascension (J2000)
42- 49 F8.5 deg DEdeg Declination (J2000)
51- 54 I4 deg Teff Effective temperature
56- 58 I3 deg e_Teff Error on Teff
60- 64 F5.1 0.1nm EWLi Lithium equivalent width
66- 69 F4.1 0.1nm e_EWLi Error on EW(Li)
71 I1 --- f_EWLi [1/3] Flag on EW(Li) (1)
73- 77 F5.2 d Per Rotational period
79- 82 A4 --- r_Per Period reference (2)
84- 87 F4.1 km/s RV ?=- Radial velocity
89- 92 F4.1 km/s e_RV ?=- Error on RV
94- 98 F5.1 km/s Vsini ?=- Projected rotational velocity
100-103 F4.1 km/s e_Vsini ?=- Error on vsini
105 I1 --- Note [1/3]? Notes (3)
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Note (1): Flag on EW(Li) as follows:
1 = EW(Li) is corrected from line blends contribution using stellar models
(see text)
2 = EW(Li) is measured separately from line blends (UVES spectra only)
3 = Only an EW(Li) upper limit could be derived.
Note (2): References as follows:
A+13 = Affer et al. (2013, Cat. J/MNRAS/430/1433)
L+04 = Lamm et al. (2004, Cat. J/A+A/417/557)
LRpv = L. Rebull, priv. comm.
M+04 = Makidon et al. (2004, Cat. J/AJ/127/2228)
V+16 = Venuti et al. (in prep.)
Note (3): Note as follows:
1 = This source has low EW(Li) for its Teff and a discrepant Vrad (see text)
2 = This source has low EW(Li) for its Teff (see text)
3 = This source has multiple periods detected in its light-curve (see text).
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Acknowledgements:
Jerome Bouvier, jerome.bouvier(at)univ-grenoble-alpes.fr
(End) Jerome Bouvier [UGA], Patricia Vannier [CDS] 28-Apr-2016