J/ApJ/818/153 MEarth photometry: nearby M-dwarf magnitudes (Dittmann+, 2016)
Calibration of the MEarth photometric system: optical magnitudes and photometric
metallicity estimates for 1802 nearby M-dwarfs.
Dittmann J.A., Irwin J.M., Charbonneau D., Newton E.R.
<Astrophys. J., 818, 153 (2016)>
=2016ApJ...818..153D 2016ApJ...818..153D (SIMBAD/NED BibCode)
ADC_Keywords: Stars, M-type ; Photometry ; Abundances, [Fe/H] ;
Infrared sources ; Surveys
Keywords: catalogs; solar neighborhood; stars: abundances;
stars: fundamental parameters; stars: low-mass;
techniques: photometric
Abstract:
The MEarth Project is a photometric survey systematically searching
the smallest stars near the Sun for transiting rocky planets. Since
2008, MEarth has taken approximately two million images of 1844 stars
suspected to be mid-to-late M dwarfs. We have augmented this survey by
taking nightly exposures of photometric standard stars and have
utilized this data to photometrically calibrate the MEarth system,
identify photometric nights, and obtain an optical magnitude with 1.5%
precision for each M dwarf system. Each optical magnitude is an
average over many years of data, and therefore should be largely
immune to stellar variability and flaring. We combine this with
trigonometric distance measurements, spectroscopic metallicity
measurements, and 2MASS infrared magnitude measurements in order to
derive a color-magnitude-metallicity relation across the mid-to-late M
dwarf spectral sequence that can reproduce spectroscopic metallicity
determinations to a precision of 0.1 dex. We release optical
magnitudes and metallicity estimates for 1567 M dwarfs, many of which
did not have an accurate determination of either prior to this work.
For an additional 277 stars without a trigonometric parallax, we
provide an estimate of the distance, assuming solar neighborhood
metallicity. We find that the median metallicity for a volume-limited
sample of stars within 20pc of the Sun is [Fe/H]=-0.03±0.008, and
that 29/565 of these stars have a metallicity of [Fe/H]=-0.5 or lower,
similar to the low-metallicity distribution of nearby G dwarfs. When
combined with the results of ongoing and future planet surveys
targeting these objects, the metallicity estimates presented here will
be important for assessing the significance of any putative
planet-metallicity correlation.
Description:
We used data from MEarth-North observatory at the Fred Lawrence
Whipple Observatory on Mount Hopkins, Arizona, from the 2011 to 2014
seasons. See section 2 for further explanations.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 22 36 Quantum Efficiency (QE) of the MEarth CCD, and
filter throughput
table2.dat 41 3039 Nightly photometric coefficients
table3.dat 22 70 MEarth magnitudes of Landolt standards
table4.dat 227 1802 Observed properties of the MEarth targets
table5.dat 17 248 Color-magnitude sequence at [Fe/H]=-0.1 and
[Fe/H]=0.0
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See also:
I/298 : LSPM-North Catalog (Lepine+ 2005)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/A+A/577/A128 : CARMENES input catalog of M dwarfs. I (Alonso-Floriano+, 2015)
J/ApJ/812/3 : MEarth mid-to-late M dwarfs rotation+kinematics (West+, 2015)
J/ApJ/800/85 : Teff, radii and luminosities of cool dwarfs (Newton+, 2015)
J/ApJS/216/7 : Planets Around Low-Mass Stars (PALMS). IV. (Bowler+, 2015)
J/MNRAS/443/2561 : CONCH-SHELL catalog of nearby M dwarfs (Gaidos+, 2014)
J/AJ/147/85 : Solar neighborhood. XXXIII. 45 M dwarfs (Riedel+, 2014)
J/AJ/147/20 : Spectroscopy of 447 nearby M dwarfs (Newton+, 2014)
J/AJ/146/156 : APOGEE M-dwarf survey. I. 1st yr velocities (Deshpande+, 2013)
J/ApJ/771/107 : Spectroscopy of faint KOI stars (Everett+, 2013)
J/AJ/145/102 : Bright M dwarf spectro. in the northern sky (Lepine+, 2013)
J/AJ/145/52 : Abundances of late K&M dwarfs in binary systems (Mann+, 2013)
J/A+A/549/A109 : HARPS XXXI. The M-dwarf sample (Bonfils+, 2013)
J/ApJ/758/56 : Young M dwarfs within 25pc. II. Kinematics (Shkolnik+, 2012)
J/ApJ/754/44 : The AstraLux Large M-dwarf Survey (Janson+ 2012)
J/ApJ/753/90 : Stellar param. of K5 and later type Kepler stars (Mann+, 2012)
J/ApJ/748/93 : K-band spectra for 133 nearby M dwarfs (Rojas-Ayala+, 2012)
J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)
J/ApJ/704/975 : Rotational velocities for M dwarfs (Jenkins+, 2009)
J/ApJ/699/649 : Young M dwarfs within 25pc. I. (Shkolnik+, 2009)
J/AJ/136/1290 : Ultracool dwarfs from the 2MASS (Reid+, 2008)
J/AJ/136/452 : Astrometric studies of GAT stars (Gatewood, 2008)
J/AJ/133/2825 : Star beyond the NLTT catalog (Reid+, 2007)
J/AJ/133/439 : Luminosity function of M7-L8 ultracool dwarfs (Cruz+, 2007)
J/AJ/132/866 : New M dwarfs in solar neighborhood (Riaz+, 2006)
J/AJ/130/1871 : Spectroscopic survey of M dwarfs (Bochanski+, 2005)
J/AJ/130/1680 : LSPM-North proper-motion catalog nearby stars (Lepine+, 2005)
J/AJ/126/2421 : 2MASS-Selected sample of ultracool dwarfs (Cruz+, 2003)
J/ApJ/476/311 : 2MASS M-dwarf discoveries (Kirkpatrick+ 1997)
J/AJ/113/806 : M-Subdwarfs (Gizis 1997)
http://www.cfa.harvard.edu/MEarth/Welcome.html : MEarth project home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 nm lambda [650/1000] Wavelength of filter (nanometer)
6- 10 F5.3 -- QE [0.15/0.91] Quantum Efficiency of the MEarth CCD
12- 16 F5.3 -- Trans [0/1] Transmission of the filter
18- 22 F5.3 -- Prod [0/0.8] Product
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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- 10 A10 "Y/M/D" Date Observing date
12- 18 F7.4 -- k2 [-1.93/13.3] Color coefficient, k2 (1)
20- 27 F8.3 -- k1 [-225.5/489.6] Airmass coefficient, k1 (1)
29- 35 F7.3 mag ZP [-80.5/322.6] Zero point, zi (1)
37- 41 A5 -- Tel MEarth telescope number (tel01-tel08)
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Note (1): We adopt the following model: Equation (1):
m*,MEarth=zi-2.5log10(fobs/texp_)
-AC-(k1,i+k2,i(m*,MEarth-m*,K))
x(X-1)
where m*,MEarth is the magnitude of the star in the MEarth band,
m*,K is the magnitude of the star in the 2MASS Ks band, zi is the
zero point of the telescope, fobs is the observed flux (in counts)
for the star, texp is the exposure time of the image, AC is the
aperture correction for the image, k1 and k2 are fitted coefficients
to correct for airmass and color effects, respectively, and X is the
airmass of the object. i denotes the night that the observation was
taken.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 9 A9 -- Name Name of Landolt standard
11- 16 F6.3 mag mag [9.2/13.3] MEarth magnitude
18- 22 F5.3 mag e_mag [0.02/0.07] MEarth magnitude error
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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- 16 A16 -- 2MASS 2MASS ID (HHMMSSss+DDMMSSs; J2000)
18- 28 A11 -- LSPM LSPM-North ID (JHHMM+DDMMW)
30- 35 F6.3 mag mag [6.6/15.2] MEarth magnitude
37- 41 F5.3 mag e_mag [0.005/0.2] MEarth magnitude error
43- 48 F6.3 mag Jmag [5.2/12.9] 2MASS J magnitude
50- 54 A5 mag e_Jmag ? 2MASS J error
56- 61 F6.3 mag Hmag [4.8/12.3] 2MASS H magnitude
63- 67 A5 mag e_Hmag ? 2MASS H error
69- 74 F6.3 mag Kmag [4.5/11.9] 2MASS Ks magnitude
76- 80 A5 mag e_Kmag ? 2MASS Ks error
82- 87 F6.3 arcsec Plx [0.007/0.6]? Trigonometric parallax
89- 96 F8.5 arcsec e_Plx [0/0.02]? Trigonometric parallax error
98-116 A19 -- r_Plx Reference for trigonometric parallax
118-123 A6 -- SpT MK spectral type
125-143 A19 -- r_SpT Reference for spectral type
145-150 F6.3 [Sun] FeHsp [-0.9/0.9]? Spectroscopic metallicity
152-156 F5.2 [Sun] e_FeHsp [0.1/0.3]? Spectroscopic metallicity error
158-163 F6.3 [Sun] FeHph [-1.1/0.7]? Metallicity from our photometric
relation
165-170 F6.3 -- DM [-0.7/4.8]? Distance modulus (assuming
metallicity =-0.1 from this work)
172-172 I1 -- F1 [0/1]? Flag 1 for possible contaminating light
(1=True) (1)
174-174 I1 -- F2 [0/1]? Flag 2 for possible contaminating light
(1=True) (2)
176-176 I1 -- F3 [0/1]? Flag 3 for possible contaminating light
(1=True) (3)
178-196 A19 -- r_F3 Source for flag 3
198-208 F11.3 -- FirstJD Julian date of 1st photometric data point
210-220 F11.3 -- LastJD Julian date of last photometric data point
222-225 I4 -- Ndata [14/7752] Total number of data points on
photometric nights
227-227 I1 -- Flag [0/1] Flag whether source appears to be over
luminous (1=True) (4)
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Note (1): Indicates whether the aperture contains any additional stars
other than the target star. This includes background objects as
well as close common proper motion pairs. In many cases, this
contamination is negligible, but we recommend assessing the
importance of the contaminating flux using the MEarth finder
charts available on the MEarth website.
Note (2): Objects that have two individual entries in the LSPM-North catalog
but are unresolved in the MEarth telescopes. Additionally, some of
these objects are also unresolved in 2MASS.
Note (3): Indicates a known blended object that also has only a single entry
in the LSPM-North catalog. A reference is provided, r_BlendFlag3.
Note (4): "OverLuminousFlag" if the metallicity interpolation predicts a higher
metallicity for a hypothetical star at the same absolute magnitude
but 0.25 magnitudes bluer.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 5 F5.3 -- Color [2.1/3.4] MEarth-2MASS K color index
7- 11 F5.3 mag K1Mag [6.4/10] Absolute 2MASS K magnitude
for -0.1 metallicity
13- 17 F5.3 mag K0Mag [5.9/10] Absolute 2MASS K magnitude
for 0.0 metallicity
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 02-May-2016