J/AJ/153/101 Pleiades members stellar properties (Somers+, 2017)
A measurement of radius inflation in the Pleiades and its relation to rotation
and lithium depletion.
Somers G., Stassun K.G.
<Astron. J., 153, 101-101 (2017)>
=2017AJ....153..101S 2017AJ....153..101S (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Populations, stellar ; Photometry, UBV ;
Photometry, infrared ; Effective temperatures ; Stars, diameters
Keywords: stars: activity - stars: fundamental parameters - stars: rotation -
starspot
Abstract:
Precise measurements of eclipsing binary parameters and statistical
studies of young clusters have suggested that some magnetically active
low-mass dwarfs possess radii inflated by ∼5%-15% relative to
theoretical expectations. If true, this effect should be pronounced in
young open clusters, due to the rapid rotation and strong magnetic
activity of their most extreme members. We explore this possibility by
determining empirical radii for 83 members of the nearby Pleiades open
cluster, using spectral energy distribution fitting to establish Fbol
with a typical accuracy of ∼3% together with color and
spectro-photometric indices to determine Teff. We find several
Pleiades members with radii inflated above radius-Teff models from
state-of-the-art calculations, and apparent dispersions in radii for
the K-dwarfs of the cluster. Moreover, we demonstrate that this
putative radius inflation correlates strongly with rotation rate,
consistent with inflation of young stars by magnetic activity and/or
starspots. We argue that this signal is not a consequence of
starspot-induced color anomalies, binarity, or depth effects in the
cluster, employing Gaia DR1 distances as a check. Finally, we consider
the lithium abundances of these stars, demonstrating a triple
correlation between rotation rate, radius inflation, and enhanced
lithium abundance. Our result-already significant to ∼99.99%
confidence-provides strong support for a magnetic origin of the
inflated radii and lithium dispersion observed in young, low-mass stars.
Description:
We began with the newly assembled catalog of literature lithium
measurements reported by Barrado et al. (2016, J/A+A/596/A113), who
accepted only stars with membership probability >0.75. A small number
of Pleiads lie behind an HI cloud, and are thus far more extincted
than the rest (e.g., Gordon & Arny 1984AJ.....89..672G 1984AJ.....89..672G); for simplicity,
we discard these members. We then cross-correlated this sample with
the famous UBV photometric catalog of Johnson & Mitchell
(1958ApJ...128...31J 1958ApJ...128...31J), who produced homogeneous photometry for a large
sample of Pleiades members. We further selected stars with measured
rotation rates, either from the HATNet collaboration (Hartman et al.
2010, J/MNRAS/408/475), or the recent analysis of K2 data (Rebull et al.
2016, J/AJ/152/113, J/AJ/152/114; Stauffer et al. 2016, J/AJ/152/115),
preferring the latter for joint detections. Finally, we queried VizieR
(http://vizier.u-strasbg.fr/) to obtain KS-band magnitudes from the
Two-Micron All-Sky Survey (2MASS) catalog (Skrutskie et al. 2006,
Cat. VII/233), which detected every star in our reduced sample. These
criteria produced a total of 83 high-probability cluster members,
stretching from early-F to late-K type.
Objects:
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RA (ICRS) DE Designation(s)
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03 47 00 +24 07.0 Pleiades = Cl Melotte 22
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 96 83 Basic Pleiades Data
table2.dat 86 83 Derived Stellar Properties (V-KS)
table3.dat 86 83 Derived Stellar Properties (DANCe)
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See also:
I/258 : Pleiades positions and proper motions (Wang+, 1996)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/AJ/106/1059 : Lithium in the Pleiades (Soderblom+, 1993)
J/ApJS/172/663 : Infrared observations of the Pleiades (Stauffer+, 2007)
J/MNRAS/408/475 : HATNet Pleiades Rotation Period Catalogue (Hartman+, 2010)
J/AJ/148/30 : BVI photometry of 350 Pleiades stars (Kamai+, 2014)
J/A+A/596/A113 : The Seven Sisters DANCe. II. Pleiades (Barrado+, 2016)
J/AJ/152/113 : Pleiades members with K2 light curves. I. Periods
(Rebull+, 2016)
J/AJ/152/114 : Pleiades members with K2 light curves. II. (Rebull+, 2016)
J/AJ/152/115 : Pleiades members with K2 light curves. III. (Stauffer+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- HII [25/3187] The H II region identifier
6- 16 A11 --- Tycho Tycho-2 catalog (Cat. I/259) identifier
18- 33 A16 --- 2MASS 2MASS identifier (HHMMSSss+DDMMSSs)
35- 43 F9.6 deg RAdeg Right Ascension in decimal degrees (J2000)
45- 54 F10.6 deg DEdeg Declination in decimal degrees (J2000)
56- 61 F6.3 mag Vmag [8.83/13.52] V band magnitude (1)
63- 66 F4.2 mag B-V [0.38/1.22] The (B-V) color (1)
68- 71 F4.2 mag e_B-V [0.02/0.02] Uncertainty in B-V (1)
73- 77 F5.3 mag V-Ks [0.95/3.224] The (V-KS) color (2)
79- 83 F5.3 mag e_V-Ks [0.025/0.039] Uncertainty in V-Ks
85- 94 F10.8 d Prot [0.24/9.03288129]? Rotation period (3)
96 A1 --- Binary [NY] A binary system? (Y=Yes, N=No)
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Note (1): Vmag and B-V data from Johnson & Mitchell (1958ApJ...128...31J 1958ApJ...128...31J).
Note (2): KS data from Skrutskie et al. (2006, Cat. VII/233).
Note (3): Rotation periods with two decimal places are from the K2 Pleiades
campaign (Rebull et al. 2016, J/AJ/152/113, J/AJ/152/114;
Stauffer et al. 2016, J/AJ/152/115, and those with more decimals
places are from the HATNet campaign (Hartman et al. 2010,
J/MNRAS/408/475).
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Byte-by-byte Description of file: table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- HII [25/3187] The H II region identifier
6- 9 I4 K Teff [4192/7055] Effective temperature
11- 13 I3 K E_Teff [16/125] Upper uncertainty in Teff
15- 17 I3 K e_Teff [21/125] Lower uncertainty in Teff
19- 23 F5.2 10-13W/m2 Fbol [2.13/86.19] Bolometric flux
(in 10-10 erg/s/cm2)
25- 28 F4.2 10-13W/m2 e_Fbol [0/4.65] Lower uncertainty in Fbol
(in 10-10 erg/s/cm2)
30- 33 F4.2 10-13W/m2 E_Fbol [0/4.37] Upper uncertainty in Fbol
(in 10-10 erg/s/cm2)
35- 39 F5.2 --- chi2 [0.27/38.32] Model reduced χ2
41- 45 F5.2 10-2mas Diam [4.15/10.33] Angular diameter
47- 50 F4.2 10-2mas e_Diam [0.08/0.51] Lower uncertainty in Diam
52- 55 F4.2 10-2mas E_Diam [0.07/0.54] Upper uncertainty in Diam
57- 61 F5.3 Rsun Rad [0.598/1.487] Radius
63- 67 F5.3 Rsun e_Rad [0.019/0.08] Lower uncertainty in Rad
69- 73 F5.3 Rsun E_Rad [0.018/0.084] Upper uncertainty in Rad
75- 78 F4.1 % DelRad [-8/32.8] Percent difference in radius
80- 82 F3.1 % E_DelRad [2.7/8.7] Upper uncertainty in DelRad
84- 86 F3.1 % e_DelRad [2.7/8.3] Lower uncertainty in DelRad
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 13-Apr-2018