J/MNRAS/517/2165 Star-spots properties of Pleiades and M67 stars (Cao+, 2022)
Star-spots and magnetism testing the activity paradigm in the Pleiades and M67.
Cao L., Pinsonneault M.H.
<Mon. Not. R. Astron. Soc. 517, 2165-2189 (2022)>
=2022MNRAS.517.2165C 2022MNRAS.517.2165C (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Stars, activity ; Spectroscopy ; Infrared ;
Positional data ; Effective temperatures ; Abundances ;
Rotational velocities ; Velocity dispersion ; Magnetic fields ;
X-ray sources ; Optical
Keywords: stars: activity - stars: fundamental parameters - stars: late-type -
stars: magnetic field - stars: rotation; star-spots
Abstract:
We measure star-spot filling fractions for 240 stars in the Pleiades
and M67 open star clusters using APOGEE high-resolution H-band
spectra. For this work, we developed a modified spectroscopic pipeline
which solves for star-spot filling fraction and star-spot temperature
contrast. We exclude binary stars, finding that the large majority of
binaries in these clusters (80 per cent) can be identified from Gaia
DR3 and APOGEE criteria - important for field star applications. Our
data agree well with independent activity proxies, indicating that
this technique recovers real star-spot signals. In the Pleiades,
filling fractions saturate at a mean level of 0.248 ± 0.005 for
active stars with a decline at slower rotation; we present fitting
functions as a function of Rossby number. In M67, we recover low mean
filling fractions of 0.030 ± 0.008 and 0.003 ± 0.002 for main
sequence GK stars and evolved red giants, respectively, confirming
that the technique does not produce spurious spot signals in inactive
stars. Star-spots also modify the derived spectroscopic effective
temperatures and convective overturn time-scales. Effective
temperatures for active stars are offset from inactive ones by
-109 ± 11 K, in agreement with the Pecaut & Mamajek empirical scale.
Star-spot filling fractions at the level measured in active stars
changes their inferred overturn time-scale, which biases the derived
threshold for saturation. Finally, we identify a population of stars
statistically discrepant from mean activity-Rossby relations and
present evidence that these are genuine departures from a Rossby
scaling. Our technique is applicable to the full APOGEE catalogue,
with broad applications to stellar, galactic, and exoplanetary
astrophysics.
Description:
We present a method of inferring independent spectroscopic star-spot
measurements using our two-temperature method for open clusters,
publish star-spot constraint relations, and identify trends with
activity. As explained in section 2, we used APOGEE pipeline
stars-spots fitting spectra analysis code to construct star-spot grid
models and infer properties. Next, as detection of a star-spot
signature with spectra is confounded by the presence of a companion as
binaries can be physical two-temperature spectroscopic solutions, thus
we construct binary flag to examine sample contaminations.
As detailed in section 3, we test the precision of our model on APOGEE
DR16 H-band reduced spectra for two open clusters Pleaides and M67.
More, we complete our observational data with Hα and Ca lines
chromospheric activity emissions from LAMOST, X-ray from ROSAT and
Einstein catalogues, UV from GALEX data, membership and kinematics
from Gaia DR3 and 2MASS cross-matchs.
We ran our pipeline over the literature assigned members with an
APOGEE spectrum, including 214 stars in the Pleiades and 227 stars in
M67 yielding to spectroscopic properties inferences (Teff, logg,
vsini, Vt, [M/H], fspot, xspot, Prot, B). All results are available in
table1.dat and table3.dat for 214 Pleiades stars and 227 M67 stars
respectively (i.e see spots analysis an results details in section 4
and 5).
Objects:
----------------------------------------------------------------------------
RA (2000) DE Designation(s)
----------------------------------------------------------------------------
03 46 37.96 +24 10 41.1 NAME Pleiades = Cl Melotte 22
08 51 23.51 +11 48 54.0 M 67 = NGC 2682
----------------------------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 243 214 Physical, photometric and spectroscopic
informations of Pleiades star sources
table3.dat 186 227 Physical, photometric and spectroscopic
informations of M67 star sources
--------------------------------------------------------------------------------
See also:
J/MNRAS/513/5727 : Lithium study with GESiDR6's PMS stars cluster
(Binks+, 2022)
J/MNRAS/476/908 : Chromospheric activity in 4 open clusters (Fang+, 2018)
J/MNRAS/448/484 : MgII UV feature in T Tauri stars (Lopez-Martinez+, 2015)
J/MNRAS/441/2361 : Stellar magnetism, age and rotation (Vidotto+, 2014)
J/A+A/662/A41 : Magnetic fields in 292 M dwarfs. (Reiners+, 2022)
J/A+A/657/A7 : Stellar and substellar companions from Gaia EDR3
(Kervella+, 2022)
J/A+A/656/A103 : NGC 3532 stars chromospheric activity (Fritzewski+, 2021)
J/A+A/627/A119 : Extended halo of NGC 2682 (M 67) (Carrera+ 2019)
J/A+A/613/A63 : Lithium content for 148 Pleiades stars (Bouvier+, 2018)
J/A+A/605/A102 : Stellar models. 0.85<M<6, Z=0.0001-0.014 (Charbonnel+, 2017)
J/A+A/589/A113 : PMS stars in h Per (Argiroffi+, 2016)
J/A+A/586/A52 : NGC 2264, NGC 2547 and NGC 2516 stellar radii
(Jackson+, 2016)
J/A+A/541/A150 : Lithium in M67 and Hyades (Pace+, 2012)
J/A+A/510/A46 : Pre-main sequence evolutionary tracks (Landin+, 2010)
J/A+A/484/609 : BVI photometry and proper motions in M67 (Yadav+, 2008)
J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)
J/A+A/341/751 : ROSAT HRI observations of the Pleiades (Micela+ 1999)
J/ApJ/931/45 : The factory & the beehive. IV. Praesepe & Hyades
(Nunez+, 2022)
J/ApJ/924/84 : λ Orionis PMS stars with Gaia & SPOTS (Cao+, 2022)
J/ApJ/921/53 : IGRINS YSO survey. I. PMS stars in Tau-Aur
(Lopez-Valdivia+, 2021)
J/ApJ/916/66 : K2 LCs analysis of Sun-like stars in the Pleiades
(Brown+, 2021)
J/ApJ/893/67 : Smoothed amplitudes from Kepler, K2 and TESS phot.
(Morris, 2020)
J/ApJ/874/97 : Chemical abundances from APOGEE. II. M67 stars (Souto+,2019)
J/ApJ/871/174 : Kepler rapid rotators and Ks-band excesses (Simonian+, 2019)
J/ApJ/869/9 : Machine-learning investigation of the open cluster M67
(Gao, 2018)
J/ApJ/834/85 : Hα emission in nearby M dwarfs (Newton+, 2017)
J/ApJ/794/125 : IN-SYNC. I. APOGEE stellar parameters (Cottaar+, 2014)
J/ApJ/776/67 : Rotational tracks (van Saders+, 2013)
J/ApJ/743/48 : Stars with rotation periods and X-ray luminosities
(Wright+, 2011)
J/ApJ/348/557 : X-ray studies of stars in the Pleiades (Micela+, 1990)
J/ApJ/315/687 : X-Ray emission from solar-type stars: F and G (Maggio+,1987)
J/ApJS/244/21 : Surface rotation & activity of Kepler stars. I.
(Santos+, 2019)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars
(Pecaut+, 2013)
J/ApJS/91/625 : ROSAT survey of the Pleiades (Stauffer+ 1994)
J/ApJS/85/315 : F, G and K dwarf stars of the Pleiades (Soderblom+ 1993)
J/AJ/163/257 : Properties of 125 M-dwarfs in the southern CVZ
(Anthony+, 2022)
J/AJ/161/190 : Radial Velocities of binary population in M67 (Geller+,2021)
J/AJ/153/101 : Pleiades members stellar properties (Somers+, 2017)
J/AJ/152/115 : Pleiades members with K2 light curves. III. (Stauffer+,2016)
J/AJ/152/114 : Pleiades members with K2 light curves. II. (Rebull+, 2016)
J/AJ/152/113 : Pleiades members with K2 light curves. I. Periods
(Rebull+, 2016)
J/AJ/151/144 : ASPCAP weights for the 15 APOGEE chemical elements
(Garcia+, 2016)
J/AJ/106/1059 : Lithium in the Pleiades (Soderblom+, 1993)
VII/233 : 2MASS All-Sky Extended Source Catalog (XSC)
(IPAC-UMass, 2003-2006)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16)
(Ahumada+, 2020)
III/284 : APOGEE-2 data from DR16 (Johnsson+, 2020)
II/335 : Revised catalog of GALEX UV sources (GUVcat_AIS GR6+7)
(Bianchi+ 2017)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- 2MASS 2MASS designation as 2MHHMMSSss+DDMMSSs
(APOGEE_ID)
20- 27 F8.5 deg RAdeg Right ascension (J2000) (RA_J2000)
29- 36 F8.5 deg DEdeg Declination (J2000) (Dec_J2000)
38- 44 F7.4 d Prot Rotation period (Prot) (1)
46- 52 F7.5 --- Ro ? Rossby number (Ro) (2)
54- 58 A5 --- Glob Global binarity flag computed from section
2.3 Binary rejection (Bin_Flag)
60- 64 A5 --- Phot Photometric binary flag computed from
section 2.3.1 Photometric binary cut
(Bin_Photometric)
66- 70 A5 --- GaiaRV Gaia radial velocity DR3 variance flag
for binarity from section 2.3.2 Gaia DR3
radial velocity cut (BinGaiaRV)
72- 76 A5 --- APORV APOGEE RV flag for binarity from section
2.3.2 APOGEE radial velocity cut
(BinaryAPOGEERV_Flag)
78- 82 A5 --- RUWE RUWE flag for binarity as defined in
sec. 2.3.3 Gaia RUWE Cut (BinGaiaRUWE)
84- 88 A5 --- GaiaMult Multiple source flag for binarity from
section 2.3.4 Gaia multiple source cut
(BinGaiaMultiple)
90- 96 F7.2 K Teff ? Two-temperature effective temperature
as defined in equation 1 of section 2.2
Grid construction (Teff)
98-102 F5.3 --- fspot ? Two-temperature star-spot filling
fraction as explicited in section 2.2
Grid construction (fspot)
104-108 F5.3 --- xspot ? Two-temperature star-spot temperature
contrast as explicited in section 2.2
Grid construction (xspot)
110-114 F5.3 [cm/s2] logg ? Logarithm of surface gravity dertived
from two-temperature method explicited in
section 2.2 Grid construction (logg)
116-120 F5.3 [-] [M/H] ? Metallicity derived from
two-temperature method explicited in
section 2.2 Grid construction ([M/H])
122-127 F6.3 km/s vsini ? Rotational velocity derived from
two-temperature method explicited in
section 2.2 Grid construction (vsini)
129-133 F5.3 km/s Vt ? Microturbulence velocity from
two-temperature method explicited in
section 2.2 Grid construction (vdop)
135-140 F6.3 K e_Teff ? Mean error in derived Teff (e_Teff)
142-146 F5.3 --- e_fspot ? Mean error in derived fspot (e_fspot)
148-152 F5.3 --- e_xspot ? Mean error in derived xspot (e_xspot)
154-158 F5.3 [cm/s2] e_logg ? Mean error in derived logg (e_logg)
160-164 F5.3 [-] e_[M/H] ? Mean error in derived [M/H] (e_[M/H])
166-172 F7.3 km/s e_vsini ? Mean error in derived vsini (e_vsini)
174-178 F5.3 km/s e_Vt ? Mean error in derived microturbulence
(e_vdop)
180-184 F5.1 gauss Bmean ? Derived surface mean equipartition B
as defined in equation 7 of section 4.2.2
(Beqpmean)
186-189 F4.1 gauss e_Bmean ? Mean error of Bmean (eBeqp_mean)
191-196 F6.1 gauss Bmax ? Derived equipartition magnetic field
(Beqpmax) (3)
198-201 F4.1 gauss e_Bmax ? Mean error of Bmax (eBeqp_max)
203-208 F6.3 [-] logLX/Lbol ? Logarithm of the fractional X-ray
emission as defined in section 4.2.3
Activity-Star-spot Relations (logLxLbol)
210-214 F5.3 [-] e_logLX/Lbol ? Reported mean error in X-ray emission
(elogLx_Lbol)
216 A1 --- l_logLX/Lbol Upper limit flag in X-ray emission for
logLx/Lbol values (llogLx_Lbol)
218 A1 --- r_logLX/Lbol Reference for X-ray data (ReflogLx_Lbol)
(4)
220-225 F6.3 --- logR'Ha ? Logarithm of the excess chromospheric
Hα emission isolating activity
emission as in Appendix B (log_R'Ha)
227 A1 --- r_logR'Ha Reference for logR'Ha (ReflogR'Ha) (5)
229-234 F6.3 --- logR'CaIRT ? Logarithm of th excess chromospheric
Ca II infrared triplet isolated activity
emission as in Appendix B (log_R'CaIRT)
236 A1 --- r_logR'CaIRT Reference for logR'CaIRT (ReflogR'CaIRT)
(5)
238-243 F6.4 --- F10/F90 Fractional flux difference F10/F90
10th to 90th percentile as in equation 8
of the section 4.2.3 (fracflux10_90)
--------------------------------------------------------------------------------
Note (1): As detailed in section 3.2, our source for rotation periods for the
Pleiades are from targeted observations in K2 of Rebull et al.
(2016AJ....152..113R 2016AJ....152..113R, Cat. J/AJ/152/113).
Note (2): As defined in section 2.5, Ro = Prot/τCZ, with our
measurements of spectroscopic star-spot filling fractions it is now
possible to self-consistently infer theoretical convective turnover
time-scales with a SPOTS model (Somers et al. 2020ApJ...891...29S 2020ApJ...891...29S)
isochrone, matching the star-spot parameter between our observations
and appropriate theoretical models.
Note (3): As maximal field strength within an star-spot to be in equipartition
with the stellar photosphere as in equation 6 of the section 4.2.2
Equipartition Magnetic Field-Rossby Relation.
Note (4): As explained in section 3.2 Pleiades, we collect X-ray luminosities
using the published Pleiades catalogues as follows:
1 = Micela et al. 1990ApJ...348..557M 1990ApJ...348..557M, Cat. J/ApJ/348/557, Einstein,
23 sources in our sample
2 = Micela et al. 1999A&A...341..751M 1999A&A...341..751M, Cat. J/A+A/341/751, ROSAT,
34 sources in our sample
3 = Stauffer et al. 1994ApJS...91..625S 1994ApJS...91..625S, Cat. J/ApJS/91/625, ROSAT,
15 sources in our sample
Note (5): As explained in section 3.2 Pleiades, we collect line spectroscopic
measurements as follows:
1 = Fang et al. 2018MNRAS.476..908F 2018MNRAS.476..908F, Cat. J/MNRAS/476/908, LAMOST,
36 sources in our sample for logR'Ha and 28 for logR'CaIRT values
2 = Soderblom et al. 1993ApJS...85..315S 1993ApJS...85..315S, Cat. J/ApJS/85/315,
Hamilton Lick observatory, 28 sources in our sample and 29 for
logR'CaIRT values
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 18 A18 --- 2MASS 2MASS designation as 2MHHMMSSss+DDMMSSs
(APOGEE_ID)
20- 30 F11.7 deg RAdeg Right ascension (J2000) (RA_J2000)
32- 42 F11.8 deg DEdeg Declination (J2000) (Dec_J2000)
44- 55 A12 --- State Evolutionary state as defined in section 4.3
(Evstate) (1)
57- 61 A5 --- Glob Global binarity flag computed from section
2.3 Binary rejection (Bin_Flag)
63- 67 A5 --- Phot Photometric binary flag computed from section
2.3.1 Photometric binary cut (Bin_Photometric)
69- 73 A5 --- GaiaRV Gaia radial velocity DR3 variance flag for
binarity from section 2.3.2 Gaia DR3 radial
velocity cut (BinGaiaRV)
75- 79 A5 --- APORV APOGEE RV flag for binarity from section
2.3.2 APOGEE radial velocity cut
(BinaryAPOGEERV_Flag)
81- 85 A5 --- RUWE RUWE flag for binarity as defined in sec.
2.3.3 Gaia RUWE Cut (BinGaiaRUWE)
87- 91 A5 --- SL Single-lined binary flag from spectroscopic
selects of Geller et al. (2021AJ....161..190G 2021AJ....161..190G,
Cat. J/AJ/161/190) (BinGeller17sl)
93- 97 A5 --- DL Double-lined binary flag from spectroscopic
selects of Geller et al. (2021AJ....161..190G 2021AJ....161..190G,
Cat. J/AJ/161/190) (BinGeller17dl)
99-105 F7.2 K Teff ? Two-temperature effective temperature as
defined in equation 1 of section 2.2 Grid
construction (Teff)
107-111 F5.3 --- fspot ? Two-temperature star-spot filling fraction
as explicited in section 2.2 Grid construction
(fspot)
113-117 F5.3 --- xspot ? Two-temperature star-spot temperature
contrast as explicited in section 2.2 Grid
construction (xspot)
119-123 F5.3 [cm/s2] logg ? Logarithm of surface gravity dertived from
two-temperature method explicited in section
2.2 Grid construction (logg)
125-129 F5.3 [-] [M/H] ? Metallicity derived from two-temperature
method explicited in section 2.2 Grid
construction ([M/H])
131-136 F6.3 km/s vsini ? Rotational velocity derived from
two-temperature method explicited in section
2.2 Grid construction (vsini)
138-142 F5.3 km/s Vt ? Microturbulence velocity from
two-temperature method explicited in section
2.2 Grid construction (vdop)
144-148 F5.2 K e_Teff ? Mean error in derived Teff (e_Teff)
150-154 F5.3 --- e_fspot ? Mean error in derived fspot (e_fspot)
156-160 F5.3 --- e_xspot ? Mean error in derived xspot (e_xspot)
162-166 F5.3 [cm/s2] e_logg ? Mean error in derived logg (e_logg)
168-172 F5.3 [-] e_[M/H] ? Mean error in derived [M/H] (e_[M/H])
174-179 F6.3 km/s e_vsini ? Mean error in derived vsini (e_vsini)
181-186 F6.3 km/s e_Vt ? Mean error in derived microturbulence
(e_vdop)
--------------------------------------------------------------------------------
Note (1): Evolutionary state are separeted into different regimes as follows:
Giant = Giant stars, 37 sources in our M67 sample
MS = Main-sequence stars, 61 sources in our M67 sample
Sub-subgiant = Sub-Sub-giant stars, 2 sources in our M67 sample
Subgiant = Sub-giant stars, 49 sources in our M67 sample
Turnoff = Turnoff stars, 78 sources in our M67 sample
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History:
From electronic version of the journal
(End) Luc Trabelsi [CDS] 02-Oct-2025