J/AJ/159/52 M dwarfs at high spectral-resolution in Y band (Muirhead+, 2020)
Magnetic inflation and stellar mass.
V. Intensification and saturation of M-dwarf absorption lines with
Rossby number.
Muirhead P.S., Veyette M.J., Newton E.R., Theissen C.A., Mann A.W.
<Astron. J., 159, 52 (2020)>
=2020AJ....159...52M 2020AJ....159...52M
ADC_Keywords: Spectra, infrared; Equivalent widths; Stars, masses;
Stars, dwarfs; Stars, M-type; Proper motions; Spectral types
Keywords: M dwarf stars ; Stellar rotation ; Stellar properties ;
Stellar activity ; Magnetic fields ; High resolution spectroscopy ;
Spectroscopy ; Infrared astronomy ; Near infrared astronomy
Abstract:
In young Sun-like stars and field M-dwarf stars, chromospheric and
coronal magnetic activity indicators such as Hα, X-ray, and
radio emission are known to saturate with low Rossby number (Ro≲0.1),
defined as the ratio of rotation period to convective turnover time.
The mechanism for the saturation is unclear. In this paper, we use
photospheric TiI and CaI absorption lines in the Y band to investigate
magnetic field strength in M dwarfs for Rossby numbers between 0.01
and 1.0. The equivalent widths of the lines are magnetically enhanced
by photospheric spots, a global field, or a combination of the two.
The equivalent widths behave qualitatively similar to the
chromospheric and coronal indicators: we see increasing equivalent
widths (increasing absorption) with decreasing Ro and saturation of
the equivalent widths for Ro≲0.1. The majority of M dwarfs in this
study are fully convective. The results add to mounting evidence that
the magnetic saturation mechanism occurs at or beneath the stellar
photosphere.
Description:
We collected spectra using one night of observation with the Near
Infrared Spectrograph (NIRSPEC) on the 10m Keck II Telescope located
on the summit of Maunakea in Hawaii, and combine them with publicly
available data from the Calar Alto high-Resolution search for M dwarfs
with Exoearths with Near-infrared and optical Echelle Spectrographs
(CARMENES) M-dwarf survey (Reiners+, 2018, J/A+A/612/A49).
Of the 102 M dwarf targets identified for NIRSPEC observations, we
observed 30 on UT 2018 December 18 (Y band, roughly 9800-11000Å;
R=25000).
The near-infrared spectrograph in CARMENES covers 9600 to 17100Å
with a resolving power of 80400. We downloaded the CARMENES
near-infrared spectra from the CARMENES data archive.
Following our selection cuts, we were left with 44 M dwarfs in the
CARMENES sample. Four of the 30 targets observed by NIRSPEC also have
CARMENES data -- HD285968, G99-49, V*YZCMi, and G195-36 -- resulting
in 70 total objects with spectra in this work.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 106 70 Details on M dwarf stars in this work
table3.dat 113 74 Equivalent widths
fits/* . Individual spectrum file in FITS format
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+, 2003)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/ApJS/85/315 : F, G and K dwarf stars of the Pleiades (Soderblom+ 1993)
J/A+A/397/147 : Activity-rotation relationship in stars (Pizzolato+ 2003)
J/ApJ/648/629 : Radio observations of late M, L, and T dwarfs (Berger+,2006)
J/ApJ/743/48 : Stars rotat. periods & X-ray luminosities (Wright+,2011)
J/ApJ/754/44 : The AstraLux Large M-dwarf Survey (Janson+ 2012)
J/ApJ/784/156 : Parallaxes for nearby mid-to-late M dwarfs (Dittmann+, 2014)
J/ApJ/791/54 : Nearby M Dwarfs parameters (Gaidos+, 2014)
J/ApJ/795/161 : Activity & rotation in Praesepe & the Hyades (Douglas+,2014)
J/ApJ/804/64 : Empirical and model parameters of 183 M dwarfs (Mann+, 2015)
J/ApJ/800/85 : Teff, radii and luminosities of cool dwarfs (Newton+, 2015)
J/ApJ/818/153 : MEarth photometry: nearby M-dwarf mag (Dittmann+,2016)
J/MNRAS/463/1844 : M dwarfs rotation-activity relation (Stelzer+, 2016)
J/ApJ/836/124 : 2yrs of eclipse data & RVs for LP661-13 (Dittmann+,2017)
J/ApJ/834/85 : Hα emission in nearby M dwarfs (Newton+, 2017)
J/ApJ/851/26 : Teff, metallicity & Ti abundance of M dwarfs (Veyette+,2017)
J/AJ/155/225 : M dwarf stars rotational broadening measure. (Kesseli+,2018)
J/A+A/612/A49 : 324 CARMENES M dwarfs velocities (Reiners+, 2018)
J/A+A/629/A83 : Complexity of magnetic fields on red dwarfs (Afram+, 2019)
J/A+A/621/A126 : CARMENES input catalogue M dwarfs. IV. (Diez Alonso+,2019)
J/A+A/627/A161 : CARMENES stars multi wavelength measurem. (Passegger+,2019)
J/AJ/157/216 : Stellar multiplicity rate of M dwarfs 25 pc (Winters+, 2019)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 23 A23 --- Name SIMBAD identifier
25- 26 I2 h RAh Hour of right ascension (J2000)
28- 29 I2 min RAm Minute of right ascension (J2000)
31- 35 F5.2 s RAs Second of right ascension (J2000)
37 A1 --- DE- [-/+] Sign of the declination (J2000)
38- 39 I2 deg DEd Degree of declination (J2000)
41- 42 I2 arcmin DEm Arcminute of declination (J2000)
44- 48 F5.2 arcsec DEs Arcsecond of declination (J2000)
50- 57 F8.2 mas/yr pmRA [-4411/2892] Gaia DR2 proper motion along RA (1)
59- 66 F8.2 mas/yr pmDE [-145574/943] Gaia DR2 proper motion along DE (1)
68- 73 F6.2 mas plx [22/337] Gaia DR2 parallax (π) (1)
75- 79 F5.2 mag Ksmag [4/11] 2MASS Ks band magnitude (2)
81- 84 F4.2 Msun Mass [0.14/0.58] Mass (3)
86- 91 A6 --- SpType Spectral type from SIMBAD
93- 98 F6.2 d Prot [1/163] Rotational period (4)
100-104 F5.2 [-] logRo [-3/0.29] log Rossby number
106 A1 --- Inst Instrument code (5)
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Note (1): All astrometric data are from Gaia DR2
(Gaia Collaboration, 2018, I/345) in ICRS and epoch 2000.
Note (2): Point Source Catalog : Cutri+, 2003, II/246
and Skrutskie+, 2006, VII/233.
Note (3): Calculated using using MK-to-mass relations of
Mann+, 2019ApJ...871...63M 2019ApJ...871...63M.
Note (4): Rotation periods are from Newton+, 2017, J/ApJ/834/85 for
targets with NIRSPEC observations and from
Diez Alonso+, 2019, J/A+A/621/A126 for CARMENES data. For targets with
both, we default to the Newton+ rotation periods.
Convective turnover time was calculated using the mass-dependent
relation from Wright+, 2011, J/ApJ/743/48.
Note (5): Code as follows:
C = CARMENES (40 occurrences);
N = NIRSPEC (26 occurrences);
B = both NIRSPEC and CARMENES (4 occurrences).
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 23 A23 --- Name SIMBAD identifier
25- 30 F6.4 0.1nm EWTi1 [0.22/0.42] Equivalent width TiI 10396.802Å line
32- 37 F6.4 0.1nm EWTi2 [0.21/0.4] Equivalent width TiI 10496.113Å line
39- 44 F6.4 0.1nm EWTi3 [0.21/0.38] Equivalent width TiI 10584.633Å line
46- 51 F6.4 0.1nm EWTi4 [0.09/0.27] Equivalent width TiI 10677.047Å line
53- 58 F6.4 0.1nm EWTi5 [0.2/0.32]? Equivalent width TiI 10726.391Å line
60- 65 F6.4 0.1nm EWTi6 [0.1/0.34] Equivalent width TiI 10774.866Å line
67- 72 F6.4 0.1nm EWCa [0.54/0.8] Equivalent width CaI 10343.8194Å line
74- 81 A8 --- Inst Instrument used ("CARMENES" or "NIRSPEC")
82-113 A32 --- File Name of the FITS file in subdirectory fits;
column added by CDS
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History:
From electronic version of the journal
References:
Han et al. Paper I. 2017AJ....154..100H 2017AJ....154..100H
Kesseli et al. Paper II. 2018AJ....155..225K 2018AJ....155..225K Cat. J/AJ/155/225
Healy et al. Paper III. 2019AJ....158...89H 2019AJ....158...89H
Han et al. Paper IV. 2019AJ....158..111H 2019AJ....158..111H
(End) Prepared by [AAS], Coralie Fix [CDS], 06-Mar-2020