J/AJ/147/20 Spectroscopy of 447 nearby M dwarfs (Newton+, 2014)
Near-infrared metallicities, radial velocities, and spectral types for 447
nearby M dwarfs.
Newton E.R., Charbonneau D., Irwin J., Berta-Thompson Z.K., Rojas-Ayala B.,
Covey K., Lloyd J.P.
<Astron. J., 147, 20 (2014)>
=2014AJ....147...20N 2014AJ....147...20N
ADC_Keywords: Stars, M-type ; Stars, dwarfs ; Parallaxes, spectroscopic ;
Equivalent widths ; Proper motions ; Abundances, [Fe/H] ;
Radial velocities ; Spectral types
Keywords: stars: abundances - stars: fundamental parameters -
stars: kinematics and dynamics - stars: late-type - stars: low-mass
Abstract:
We present metallicities, radial velocities, and near-infrared (NIR)
spectral types for 447 M dwarfs determined from moderate resolution
(R~2000) NIR spectra obtained with the NASA Infrared Telescope
Facility (IRTF)/SpeX. These M dwarfs are primarily targets of the
MEarth Survey, a transiting planet survey searching for super Earths
around mid-to-late M dwarfs within 33pc. We present NIR spectral types
for each star and new spectral templates for the IRTF in the Y, J, H,
and K-bands, created using M dwarfs with near-solar metallicities. We
developed two spectroscopic distance calibrations that use NIR
spectral type or an index based on the curvature of the K-band
continuum. Our distance calibration has a scatter of 14%. We searched
27 NIR spectral lines and 10 spectral indices for metallicity
sensitive features, taking into account correlated noise in our
estimates of the errors on these parameters. We calibrated our
relation using 36 M dwarfs in common proper pairs with an F-, G-, or
K-type star of known metallicity. We validated the physical
association of these pairs using proper motions, radial velocities,
and spectroscopic distance estimates. Our resulting metallicity
calibration uses the sodium doublet at 2.2µm as the sole indicator
for metallicity. It has an accuracy of 0.12dex inferred from the
scatter between the metallicities of the primaries and the estimated
metallicities of the secondaries. Our relation is valid for NIR
spectral types from M1V to M5V and for -1.0dex<[Fe/H]<+0.35dex. We
present a new color-color metallicity relation using J-H and J-K
colors that directly relates two observables: the distance from the M
dwarf main sequence and equivalent width of the sodium line at
2.2µm. We used radial velocities of M dwarf binaries, observations
at different epochs, and comparison between our measurements and
precisely measured radial velocities to demonstrate a 4km/s accuracy.
Description:
Our sample consists of 447 M dwarfs targeted by the MEarth transiting
planet survey and 46 M dwarfs in common proper motion (CPM) pairs with
an F, G, or K star of known metallicity.
We conducted our observations with the SpeX instrument on the NASA
Infrared Telescope Facility (IRTF). We used the short cross dispersed
mode with the 0.3*15" slit. This yielded spectra with R~2000
covering 0.8-2.4µm. Our observations spanned 25 partial nights over
4 semesters (2011 May 15-2011 May 18; 2011 Jun 9, 2011 Aug 11-2011 Aug
14, 2011 Oct 7-2011 Oct 9; 2012 Feb 14-Feb 16, 2012 Feb 24, 2012 Feb
27, 2012 Feb 28, 2012 May 1, 2012 May 2; 2012 Aug 14, 2012 Aug 26,
2012 Aug 27, 2012 Jan 26, 2012 Jan 27).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 123 46 Observational properties of M dwarf common proper
motion (CPM) pairs
table3.dat 145 46 Measured properties of M dwarf CPM pairs
table6.dat 189 447 All stars from our rotation and nearby samples
table7.dat 193 133 M dwarfs observed by Rojas-Ayala et al.
(2012, cat. J/ApJ/748/93)
refs.dat 83 38 References
--------------------------------------------------------------------------------
See also:
I/298 : LSPM-North Catalog (Lepine+ 2005)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
III/198 : Palomar/MSU nearby star spectroscopic survey (Hawley+ 1997)
J/ApJ/748/93 : K-band spectra for 133 nearby M dwarfs (Rojas-Ayala+, 2012)
J/AJ/142/138 : All-sky catalog of bright M dwarfs (Lepine+, 2011)
J/ApJ/697/544 : Planets orbiting metal-poor dwarfs. II. (Sozzetti+, 2009)
J/ApJS/159/141 : Spectroscopic properties of cool stars. I. (Valenti+, 2005)
J/A+A/415/1153 : [Fe/H] for 98 extra-solar planet-host stars (Santos+, 2004)
J/ApJ/582/1011 : Revised NLTT Catalog (Salim+, 2003)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- S M dwarfs sample (G3)
4- 27 A24 --- Name2 Name of the secondary in the M dwarf common
proper motion (CPM) pair
29 A1 --- f_Name2 [g] Flag on Name2 (1)
31- 32 I2 h RAh Hour of Right Ascension (J2000) (G1)
34- 35 I2 min RAm Minute of Right Ascension (J2000) (G1)
37- 42 F6.3 s RAs Second of Right Ascension (J2000) (G1)
44 A1 --- DE- Sign of the Declination (J2000) (G1)
45- 46 I2 deg DEd Degree of the Declination (J2000) (G1)
48- 49 I2 arcmin DEm Arcminute of Declination (J2000) (G1)
51- 54 F4.1 arcsec DEs Arcsecond of Declination (J2000) (G1)
56- 61 F6.3 arcsec/yr pmRA2 Secondary proper motion along Right Ascension
62 A1 --- f_pmRA2 [f] Flag for Hipparcos proper motion (2)
64- 69 F6.3 arcsec/yr pmDE2 Secondary proper motion along Declination
70 A1 --- f_pmDE2 [f] Flag for Hipparcos proper motion (2)
72- 79 A8 --- Ref Reference for astrometry; in refs.dat file (3)
81- 86 F6.3 mag Kmag Apparent 2MASS Ks magnitude (cat. II/246)
87 A1 --- u_Kmag [:] Uncertainty flag on Kmag
88 A1 --- f_Kmag [i] No Ks magnitude found for Gl 806.1B (4)
90- 91 I2 pc Dist2 Distance for secondary (5)
92 A1 --- u_Dist2 [:] Uncertainty flag on Dist
94-103 A10 --- Name1 Name of the primary in the M dwarf common
proper motion (CPM) pair
105-110 F6.3 arcsec/yr pmRA1 Primary proper motion along Right Ascension (6)
112-117 F6.3 arcsec/yr pmDE1 Primary proper motion along Declination (6)
119-121 I3 pc Dist1 Distance for primary (6)
122 A1 --- u_Dist1 [:] Uncertainty flag on Dist1
123 A1 --- f_Dist1 [h] Primary distance estimated with M(Ks)=6 (7)
--------------------------------------------------------------------------------
Note (1): LSPM-South (Lepine et al., 2010, priv. com.). We resolved this object
as a binary. Astrometry, proper motions, magnitude were derived jointly.
We assume the two components contribute equally to the luminosity in order
to estimate their spectroscopic distances.
Note (2): For CE 226 and Gl 376B, the Hipparcos proper motion for the primary
was found to be a better match to the observed motion of the secondary from
2MASS to recent epoch MEarth imaging than the proper motion given in Ruiz
et al. (2001, cat. J/ApJS/133/119; for CE 226) or in LSPM-North (Lepine et
al., 2005, cat. I/298; for Gl 376B). In these cases, the Hipparcos value
has been adopted in the table.
Note (3): If one reference is provided, it applies to both position and proper
motion; if two are provided, the first is for position and the second for
proper motion.
Note (4): We estimated a rough magnitude from 2MASS Atlas images using a 4 pixel
aperture radius (this value was chosen to reduce contamination from nearby
stars), and applied an aperture correction of 0.04mag, derived from stars
of similar K magnitude elsewhere in the field.
Note (5): Errors on the distance estimates are 14%.
Note (6): From from Hipparcos (van Leeuwen, 2007, cat. I/311) except when
otherwise noted.
Note (7): No parallax was available for the primary. Its distance was estimated
assuming an absolute Ks magnitude of 6, typical for an early K dwarf.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- S M dwarfs sample (G3)
4- 27 A24 --- Name2 Name of the secondary in the M dwarf common
proper motion (CPM) pair
29- 30 A2 --- SpT Near-infrared spectral type
32- 35 F4.2 0.1nm EWNa Na line equivalent width (2.21µm); in Å)
37- 40 F4.2 0.1nm e_EWNa Uncertainty in EWNa
42- 45 F4.2 0.1nm EWCa Ca line equivalent width (2.26µm); in Å)
47- 50 F4.2 0.1nm e_EWCa Uncertainty in EWCa
52- 56 F5.3 --- H2O-K2 Value of the H2O-K2 index
58- 62 F5.3 --- e_H2O-K2 Uncertainty in H2O-K2
64- 68 F5.2 [Sun] [Fe/H]2 Iron abundance for secondary
70- 73 F4.2 [Sun] e_[Fe/H]2 Uncertainty in [Fe/H]2
75- 79 F5.2 [Sun] [Fe/H]1 Iron abundance for primary
81- 84 F4.2 [Sun] e_[Fe/H]1 ? Uncertainty in [Fe/H]1
86- 90 A5 --- r_[Fe/H]1 Reference for [Fe/H]1; in refs.dat file
92- 96 F5.2 [Sun] [Fe/H]1b ? Alternative iron abundance for primary (8)
98-101 F4.2 [Sun] e_[Fe/H]1b ? Uncertainty in [Fe/H]1b
103-107 A5 --- r_[Fe/H]1b Reference for [Fe/H]1b; in refs.dat file
109-113 F5.2 [Sun] [Fe/H]1c ? Alternative iron abundance for primary (8)
115-118 F4.2 [Sun] e_[Fe/H]1c ? Uncertainty in [Fe/H]1c
120-124 A5 --- r_[Fe/H]1c Reference for [Fe/H]1c; in refs.dat file
126-129 I4 km/s RV2 Radial velocity for secondary
131 I1 km/s e_RV2 Uncertainty in RV2
133-138 F6.1 km/s RV1 Radial velocity for primary
140-145 A6 --- r_RV1 Reference for RV1; in refs.dat file
--------------------------------------------------------------------------------
Note (8): Alternative values for the primary iron abundance when more than one
value is available. Values from the SPOCS catalog (Valenti et al., 2005,
cat. J/ApJS/159/141) are preferred.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 23 A23 --- Name Name in LSPM Catalog (Lepine et al., 2005,
cat. I/298); except for 4 stars (LP 613-22,
2MASS J11414417-2312514, LP 794-19, and
LP 858-23)
25- 26 A2 --- m_Name Binary component (1)
28- 29 I2 h RAh Hour of Right Ascension (J2000) (2)
31- 32 I2 min RAm Minute of Right Ascension (J2000) (2)
34- 38 F5.2 s RAs Second of Right Ascension (J2000) (2)
40 A1 --- DE- Sign of the Declination (J2000) (2)
42- 43 I2 deg DEd Degree of Declination (J2000) (2)
45- 46 I2 arcmin DEm Arcminute of Declination (J2000) (2)
48- 51 F4.1 arcsec DEs Arcsecond of Declination (J2000) (2)
53- 58 F6.3 arcsec/yr pmRA Proper motion along Right Ascension (2)
60- 65 F6.3 arcsec/yr pmDE Proper motion along Declination (2)
67- 72 F6.3 mag Kmag ? Apparent 2MASS Ks magnitude (cat. II/246)
74 I1 --- f_Kmag [1]?=0 Poor quality 2MASS magnitudes (3)
76 I1 --- J1 [1]?=0 Flag for joint values for binaries (4)
78- 82 A5 --- SpT Near-infrared spectral type (5)
84- 88 A5 --- SpTp Spectral type from PMSU survey (G2)
90- 93 F4.2 0.1nm EWNa Na line equivalent width (2.21µm); in Å
95- 98 F4.2 0.1nm e_EWNa Error in EWNa; in Å
100-103 F4.2 0.1nm EWCa Ca line equivalent width (2.26µm); in Å
105-108 F4.2 0.1nm e_EWCa Error in EWCa; in Å
110-114 F5.3 --- H2O-K2 Value of the H2O-K2 index
116-120 F5.3 --- e_H2O-K2 Error in H2O-K2
122-126 F5.2 [Sun] [Fe/H] Iron abundance with respect to solar
128-131 F4.2 [Sun] e_[Fe/H] Error in iron abundance
133-136 I4 km/s RV Radial Velocity measured from NIR spectral
138-139 I2 km/s e_RV Error in RV
141-146 F6.1 km/s RVp ? Radial velocity from PMSU survey (G2)
148 I1 --- J2 [0/1]? Joint RVPMSU & SpTPMSU measurements (6)
150-151 I2 pc Dist ? Distance estimate using H2O-K2 index (7)
153 I1 --- f_Dist [1]?=0 Flag for distance estimate quality (8)
155-159 F5.1 mas plx ? Parallax
161-164 F4.1 mas e_plx ? Error in parallax
166 I1 --- f_plx [0/1]? 1=parallax assumed to be that of common
proper motion (CPM) primary
168-171 A4 --- r_plx Reference for plx; in refs.dat file
173-181 F9.1 --- JD Starting Julian date of observation
183-189 A7 --- Obs Observational sample (9)
--------------------------------------------------------------------------------
Note (1): For binaries which were not resolved in the LSPM catalogs but which
we resolve, we use the appropriate LSPM name in the first column and
identify the components in the second column.
Note (2): Astrometry is from LSPM-North (Lepine et al., 2005, cat. I/298) and
LSPM-South (Lepine et al., 2010, priv. com.). Positions are given in the
International Celestial Reference System (ICRS), and have been corrected to
epoch 2000.0 where necessary assuming the proper motions given in the
table.
Note (3): 1 = The 2MASS qual_flag was not AAA, the highest quality.
Note (4): 1 = The astrometry and magnitudes are for the joint system.
Note (5): Assigned by eye as described in Section 5.
Note (6): 1=PMSU spectral types and radial velocities are for the joint system.
Note (7): Spectroscopic distances were estimated using Section 4, relating the
H2O-K2 index to absolute Ks magnitude. For binaries where individual
magnitudes are not available, we assume the two components have equal
luminosities. Errors on estimated distances are 14%.
Note (8): 1 = The magnitude used in the spectroscopic distance estimate is
subject to uncertainty (see Notes 3, 4, and 6 in this Table).
Note (9): Observational samples as follows:
PotCal = Potential calibrators: 10 potential calibrators are in common proper
pair (CPM) with an F, G, or K star but do not have a metallicity
measurement available for the primary. We did not include these stars
in our metallicity calibration;
Nearby = Nearby sample: 257 M dwarfs drawn from the full MEarth sample, for
which no clear periodic photometric modulation was detected at the time
of selection. See Section 2.2 for additional details;
Rotator = Rotation sample: 181 M dwarfs with preliminary rotation periods
measured from MEarth photometry. These show periodic photometric
modulation presumed to be due to star spots rotating in and out of
view.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 16 A16 --- Name Name in LSPM catalog (Lepine et al., 2005,
cat. I/298)
18- 33 A16 --- Name2 Second LSPM name
35- 57 A23 --- OName Name in Rojas-Ayala et al.
(2012, cat. J/ApJ/748/93)
59- 60 I2 h RAh Hour of Right Ascension (J2000) (G1)
62- 63 I2 min RAm Minute of Right Ascension (J2000) (G1)
65- 69 F5.2 s RAs Second of Right Ascension (J2000) (G1)
71 A1 --- DE- Sign of the Declination (J2000) (G1)
73- 74 I2 deg DEh Degree of Declination (J2000) (G1)
76- 77 I2 arcmin DEm Arcminute of Declination (J2000) (G1)
79- 82 F4.1 arcsec DEs Arcsecond of Declination (J2000) (G1)
84- 89 F6.3 arcsec/yr pmRA Proper motion along Right Ascension
91- 96 F6.3 arcsec/yr pmDE Proper motion along Right Ascension
98-101 A4 --- Ref Reference for Astrometry; in refs.dat file
103-108 F6.3 mag Kmag Apparent 2MASS Ks magnitude (cat. II/246)
110-112 A3 --- SpT NIR spectral type (1)
114-118 A5 --- SpTp Spectral type from PMSU survey (G2)
120-123 F4.2 0.1nm EWNa Equivalent width of Na line; 2.21µm (2)
125-128 F4.2 0.1nm e_EWNa Error in EWNa
130-133 F4.2 0.1nm EWCa Equivalent width of Ca line; 2.26µm (2)
135-138 F4.2 0.1nm e_EWCa Error in EWCa
140-144 F5.3 --- H2O-K2 Value of the H2O-K2 index
146-150 F5.3 --- e_H2O-K2 Error in H2O-K2
152-156 F5.2 [Sun] [Fe/H] Iron abundance with respect to solar (2)
158-161 F4.2 [Sun] e_[Fe/H] Error in [Fe/H]
163-168 F6.1 km/s RVp ? Radial velocity from PMSU survey (G2)
170-171 I2 pc Dist1 Distance estimate using H2O-K2 index (3)
173-176 F4.1 pc Dist2 ? Distance from parallax
178-181 A4 --- r_Dist2 Reference for Dist2; in refs.dat file
183-193 A11 --- Obs Observational sample listed in Rojas-Ayala et
al. (2012, cat. J/ApJ/748/93) (4)
--------------------------------------------------------------------------------
Note (1): Calculated from the H2O-K2 index using Equation (2):
SpT1=25.4-24.2(H2O-K2).
Note (2): The equivalent widths and [Fe/H] measurements have been converted
to their equivalent IRTF (NASA Infrared Telescope Facility) values, as
described in Section 6.6.
Note (3): Spectroscopic distances were estimated using Section 4, relating the
H2O-K2 index to absolute K magnitude. Errors on estimated distances are 14%.
Note (4): 8pc, Cal/8pc (=Calibrator/8pc), Cal/LSPM (Calibrator/LSPM), LSPM,
Planet/8pc, or Planet/LSPM.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- Ref Reference identifier
8- 26 A19 --- BibCode Bibliographic code
28- 48 A21 --- Aut Author's name
50- 83 A34 --- Cat Catalog
--------------------------------------------------------------------------------
Global notes:
Note (G1): Positions are given in the International Celestial Reference System
(ICRS), and have been corrected to epoch 2000.0 where necessary assuming
the proper motions given in the table.
Note (G2): PMSU = Palomar/Michigan State University (Reid et al., 1995; Hawley
et al., 1996, cat. III/198).
Note (G3): We divide our targets into the four following subsamples:
M1 = M dwarfs used to calibrate metallicity relation;
M2 = M0 dwarfs in a common proper motion (CPM) pair not used in our
metallicity calibration;
M3 = M dwarfs in a CPM pair where the primary has a metallicity measurement
from Sozzetti et al. (2009, cat. J/ApJ/697/544);
M4 = M dwarfs in a CPM pair that may not to be physically associated.
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 29-Aug-2014