J/MNRAS/476/3245 M dwarfs in the Pleiades (Jackson+, 2018)
The inflated radii of M dwarfs in the Pleiades.
Jackson R.J., Deliyannis C.P., Jeffries R.D.
<Mon. Not. R. Astron. Soc., 476, 3245-3262 (2018)>
=2018MNRAS.476.3245J 2018MNRAS.476.3245J (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, M-type ; Stars, masses ;
Photometry, infrared ; Optical ; Rotational velocities
Keywords: stars: activity - stars: evolution - stars: low-mass -
stars: pre-main-sequence - open clusters and associations: general
Abstract:
Rotation periods obtained with the Kepler satellite have been combined
with precise measurements of projected rotation velocity from the WIYN
3.5-m telescope to determine the distribution of projected radii for
several hundred low-mass (0.1≤M/M☉≤0.8), fast-rotating members
of the Pleiades cluster. A maximum likelihood modelling technique,
that takes account of observational uncertainties, selection effects
and censored data, and considers the effects of differential rotation
and unresolved binarity, has been used to find that the average radius
of these stars is 14±2 per cent larger at a given luminosity than
predicted by current evolutionary models of Dotter et al. and Baraffe
et al. The same models are a reasonable match to the interferometric
radii of older, magnetically inactive field M dwarfs, suggesting that
the over-radius may be associated with the young, magnetically active
nature of the Pleiades objects. No evidence is found for any change in
this over-radius above and below the boundary marking the transition
to full convection. Published evolutionary models that incorporate
either the effects of magnetic inhibition of convection or the
blocking of flux by dark star-spots do not individually explain the
radius inflation, but a combination of the two effects might. The
distribution of projected radii is consistent with the adopted
hypothesis of a random spatial orientation of spin axes; strong
alignments of the spin vectors into cones with an opening semi-angle
<30° can be ruled out. Any plausible but weaker alignment would
increase the inferred over-radius.
Description:
The WIYN hydra multi-object spectrograph consists of a robotic
positioner that can position up to 83 fibres, each with a 3 arcsec
diameter (we used the blue fibre cable), across a 1° diameter
unvignetted field of view at the Nasmyth focus of the 3.5-m WIYN
telescope.
The observing program was performed over nine nights during a 6 month
period from 2016 September to 2017 February, although poor weather
restricted the total observing time available.
The names, coordinates, photometry, rotation periods, estimated
masses, and radii (from the Baraffe et al. (2015A&A...577A..42B 2015A&A...577A..42B)
models) and derived luminosities for the 324 individual Pleiades
targets that were actually observed are listed in Table 2.
Table 4 gives the measured RV and FWHM and estimated uncertainties of
the 314 Pleiades targets with well-defined CCFs that can be used to
determine stellar vsini.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 90 319 Properties of observed science targets in the
Pleiades and reference slow rotators in Praesepe
(corrected version, 16-Apr-2024)
table4.dat 85 319 Measured values of relative RV, FWHM, vsini,
and Rsini
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- 2MASS 2MASS name (JHHMMSSss+DDMMSS)
19- 20 I2 h RAh Right ascension (J2000)
22- 23 I2 min RAm Right ascension (J2000)
25- 30 F6.3 s RAs Right ascension (J2000)
32 A1 --- DE- Declination sign (J2000)
33- 34 I2 deg DEd Declination (J2000)
36- 37 I2 arcmin DEm Declination (J2000)
39- 43 F5.2 arcsec DEs Declination (J2000)
45- 49 F5.2 mag Kmag 2MASS K magnitude
51- 54 F4.2 mag (V-K)0 Deredenned V-K colour index
56- 61 F6.3 d Per Period
63 I1 --- r_Per [1/3] Period reference (1)
65- 68 F4.2 mag BCK Bolometric correction
70- 74 F5.2 [Lsun] logL Luminosity
76- 79 F4.2 [Msun] logM Mass (2)
81- 84 F4.2 [Rsun] logR Radius (2)
86- 90 F5.1 km/s vsini Predicted equatorial velocity
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Note (1): References as follows:
1 = Rebull et al. (2016AJ....152..113R 2016AJ....152..113R, Cat. J/AJ/152/113)
2 = Covey et al. (2016ApJ...822...81C 2016ApJ...822...81C, Cat. J/ApJ/822/81)
3 = Hartman et al. (2010MNRAS.408..475H 2010MNRAS.408..475H, Cat. J/MNRAS/408/475)
Note (2): Masses and radii are estimated from the models of Baraffe et al.
(2015A&A...577A..42B 2015A&A...577A..42B).
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- 2MASS 2MASS name (JHHMMSSss+DDMMSS)
19- 22 F4.2 mag KMAG Absolute 2MASS K magnitude
24- 28 F5.2 [Lsun] logL Luminosity
30- 35 F6.3 d Per Period
37- 41 F5.1 --- S/N Signal-to-noise ratio
43- 48 F6.1 km/s RV Radial velocity
50- 52 F3.1 km/s e_RV Radial velocity error
54- 58 F5.1 km/s FWHM FWHM
60- 62 F3.1 km/s e_FWHM FWHM error
64- 67 F4.1 km/s FWHM0 Deredenned error
69 A1 --- l_vsini Limit flag on vsini
70- 74 F5.1 km/s vsini Rotational velocity
76- 78 F3.1 km/s SVsini ?=- Precision in vsini
80 A1 --- l_Rsini Limit flag on Rsini
81- 85 F5.3 Rsun Rsini Radius
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History:
10-Oct-2023: From electronic version of the journal
16-Apr-2024: Erroneous positions in table2 corrected with 2MASS ones
(End) Patricia Vannier [CDS] 23-Sep-2023