J/ApJ/836/167 K2 planetary syst. around low-mass stars. I. (Dressing+, 2017)
Characterizing K2 candidate planetary systems orbiting low-mass stars.
I. Classifying low-mass host stars observed during Campaigns 1-7.
Dressing C.D., Newton E.R., Schlieder J.E., Charbonneau D., Knutson H.A.,
Vanderburg A., Sinukoff E.
<Astrophys. J., 836, 167 (2017)>
=2017ApJ...836..167D 2017ApJ...836..167D
ADC_Keywords: Stars, masses; Spectral types; Effective temperatures; Abundances;
Equivalent widths; Radial velocities; Stars, diameters
Keywords: planetary systems ; planets and satellites: fundamental parameters ;
stars: fundamental parameters ; stars: late-type ; stars: low-mass ;
techniques: spectroscopic
Abstract:
We present near-infrared spectra for 144 candidate planetary systems
identified during Campaigns 1-7 of the NASA K2 Mission. The goal of
the survey was to characterize planets orbiting low-mass stars, but
our Infrared Telescope Facility/SpeX and Palomar/TripleSpec
spectroscopic observations revealed that 49% of our targets were
actually giant stars or hotter dwarfs reddened by interstellar
extinction. For the 72 stars with spectra consistent with
classification as cool dwarfs (spectral types K3-M4), we refined their
stellar properties by applying empirical relations based on stars with
interferometric radius measurements. Although our revised temperatures
are generally consistent with those reported in the Ecliptic Plane
Input Catalog (EPIC), our revised stellar radii are typically
0.13R☉ (39%) larger than the EPIC values, which were based on
model isochrones that have been shown to underestimate the radii of
cool dwarfs. Our improved stellar characterizations will enable more
efficient prioritization of K2 targets for follow-up studies.
Description:
We conducted our observations using the SpeX instrument on the NASA
Infrared Telescope Facility (IRTF) over 15 partial nights during the
2015A, 2015B, 2016A, and 2016B semesters and the TripleSpec instrument
on the Palomar 200" over four full nights during the 2016A semester.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 71 24 Observations of K2 targets classified as giant stars
table4.dat 71 56 Observations of K2 targets classified as
hotter dwarfs
table5.dat 52 82 Observation dates, spectral types, and radial
velocities for stars classified as cool dwarfs
table6.dat 101 82 Inferred stellar parameters for low-mass dwarfs
table7.dat 98 82 Equivalent widths and metallicities for cool dwarfs
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See also:
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/317 : The PPMXL Catalog (Roeser+ 2010)
III/272 : RAVE 4th data release (Kordopatis+, 2013)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
V/146 : LAMOST DR1 catalogs (Luo+, 2015)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
J/A+AS/141/371 : Low-mass stars evolutionary tracks (Girardi+, 2000)
J/ApJ/728/117 : Kepler planetary candidates. I. (Borucki+, 2011)
J/ApJ/736/19 : Kepler planetary candidates. II. (Borucki+, 2011)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/ApJ/757/112 : Stellar diameters. II. K and M-stars (Boyajian+, 2012)
J/ApJ/753/90 : Parameters of K5 and later type Kepler stars (Mann+, 2012)
J/ApJ/750/L37 : Stellar parameters of low-mass KOIs (Muirhead+, 2012)
J/ApJ/748/93 : K-band spectra for 133 nearby M dwarfs (Rojas-Ayala+, 2012)
J/ApJS/204/24 : Kepler planetary candidates. III. (Batalha+, 2013)
J/ApJ/767/95 : Improved parameters of smallest KIC stars (Dressing+, 2013)
J/ApJ/770/90 : Candidate planets in the habitable zones (Gaidos, 2013)
J/AJ/145/52 : Abundances of late K & M dwarfs in bin. systems (Mann+, 2013)
J/ApJ/779/188 : Spectra of nearby late K and M Kepler stars (Mann+, 2013)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/A+A/562/A71 : Abundances of solar neighbourhood dwarfs (Bensby+, 2014)
J/ApJS/210/19 : Kepler planetary candidates. IV. 22 months (Burke+, 2014)
J/MNRAS/437/3133 : Candidate Neptunes around late-type dwarfs (Gaidos+, 2014)
J/ApJS/211/2 : Revised properties of Q1-16 Kepler targets (Huber+, 2014)
J/ApJ/791/10 : Distribution of planets around cool stars (Morton+, 2014)
J/ApJS/213/5 : Cool KOIs. VI. H- and K- band spectra (Muirhead+, 2014)
J/AJ/147/20 : Spectroscopy of 447 nearby M dwarfs (Newton+, 2014)
J/ApJ/807/45 : Habitable planet cand. around M dwarfs (Dressing+, 2015)
J/ApJ/804/64 : Empirical and model parameters of 183 M dwarfs (Mann+, 2015)
J/ApJ/809/25 : Stellar & planet properties for K2 candidates (Montet+, 2015)
J/ApJ/800/85 : Teff, radii and luminosities of cool dwarfs (Newton+, 2015)
J/AJ/149/5 : Solar neighborhood. XXXV. M dwarfs (Winters+, 2015)
J/A+A/594/A100 : K2 new planetary and EB candidates (Barros+, 2016)
J/ApJS/226/7 : Planet cand. discovered using K2's 1st yr (Crossfield+, 2016)
J/MNRAS/457/2877 : Kepler M dwarf stars revised properties (Gaidos+, 2016)
J/ApJS/224/2 : K2 EPIC stellar properties for 138600 targets (Huber+, 2016)
J/ApJS/222/14 : Planetary cand. from 1st yr K2 mission (Vanderburg+, 2016)
J/AJ/154/207 : K2 planetary syst. around low-mass stars (Dressing+, 2017)
J/ApJS/239/5 : Variable stars and cand. planets from K2 (Crossfield+, 2018)
Byte-by-byte Description of file: table[34].dat
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Bytes Format Units Label Explanations
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1- 9 I9 --- EPIC [201754305/219114906] EPIC number
11 A1 --- f_EPIC [cd] Flag on EPIC (1)
13- 23 A11 "Y/M/D" Date Observation date (UT)
25- 29 A5 --- Inst Instrument (SpeX or TSPEC)
31- 35 A5 --- SpT MK spectral type (G1)
36 A1 --- f_SpT [b] Flag on SpT (1)
38- 38 I1 --- Camp [1/7] Campaign number
40- 43 I4 K Teff [3330/6237]? Effective temperature
45- 48 I4 K E_Teff [33/1219]? Teff positive uncertainty
50- 53 I4 K e_Teff [33/1432]? Teff negative uncertainty
55- 59 F5.3 [cm/s2] logg [0.08/4.9]? Log of surface gravity
61- 65 F5.3 [cm/s2] E_logg [0.02/2.4]? logg positive uncertainty
67- 71 F5.3 [cm/s2] e_logg [0.02/1.4]? logg negative uncertainty
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Note (1): Flag as follows:
b = In general, we list stars with spectral types of K3V or later in the
cool dwarf sample rather than the hotter dwarf sample. However, these
stars had estimated temperatures >4800K or estimated radii >0.8R☉,
which are beyond the validity range of the Newton+ (2015, J/ApJ/800/85)
relations.
c = Possible fainter nearby star identified in the Gemini AO image acquired
by D. Ciardi
(https://exofop.ipac.caltech.edu/k2/edit_target.php?id=210414957).
d = Characterized by Osborn+ (2017A&A...604A..19O 2017A&A...604A..19O) as a K3 dwarf
with M*=0.739±0.017M☉, R*=0.713±0.020R☉, Teff=5010±48K,
and [Fe/H]=-0.343±0.032.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- EPIC [201205469/217941732] EPIC number
10 A1 --- m_EPIC [AB] EPIC component
11 A1 --- n_EPIC [e] Flag on EPIC (1)
13- 13 I1 --- Camp [1/7] Campaign number
15- 25 A11 "Y/M/D" Date Observation date
27- 31 A5 --- Inst Instrument (SpeX or TSPEC)
33- 35 A3 --- SpT MK spectral type (G1)
37- 40 F4.2 --- Ind [0.85/1.1] H2O-K2 index
(Rojas-Ayala+ 2012, J/ApJ/748/93) (2)
42- 46 F5.2 --- HSpT [-1.2/5] H2O-K2 spectral type (3)
48- 52 F5.1 km/s RV [-83/79.1] Radial velocity (4)
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Note (1):
e = Keck AO imaging by D. Ciardi and Gemini speckle imaging by M. Everett
revealed that the star is actually a visual binary with a separation
of roughly 1.1"
(https://exofop.ipac.caltech.edu/k2/edit_target.php?id=211428897).
Note (2): Although we report H2O-K2 indices and index-based spectral types
for the full cool dwarf sample, these values are meaningless for the
hotter stars.
Note (3): Spectral type estimated using the H2O-K2 --spectral type relation
introduced by Newton+ (2014, J/AJ/147/20). On this scale, a spectral
type of 0 corresponds to MV0 and positive values indicate
correspondingly later M dwarf spectral types (e.g., 2 = M2V). Negative
values indicate K subtypes (i.e., -1 = K7V, -2 = K5V).
Note (4): Reported absolute radial velocities are the median of the values
estimated by cross-correlating the telluric lines in our J-, H-, and
K-band spectra with a theoretical atmospheric transmission spectrum
using the tellrv framework developed by Newton+ (2014, J/AJ/147/20).
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Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- EPIC [201205469/217941732] EPIC number
10 A1 --- m_EPIC [AB] EPIC component
11 A1 --- f_EPIC [bc] Flag on EPIC (5)
13- 23 A11 "Y/M/D" Date Observation date
25- 27 A3 --- SpT MK spectral type (G1)
29- 32 I4 K Teff [3276/4753] Effective temperature
34- 36 I3 K e_Teff [73/211] Teff negative uncertainty
38- 40 I3 K E_Teff [73/202] Teff positive uncertainty
42- 46 F5.3 Rsun Rad [0.1/0.8] Radius
48- 52 F5.3 Rsun e_Rad [0.02/0.08] Rad negative uncertainty
54- 58 F5.3 Rsun E_Rad [0.02/0.2] Rad positive uncertainty
60- 64 F5.3 Msun Mass [0.1/0.8] Mass
66- 70 F5.3 Msun e_Mass [0.01/0.2] Mass negative uncertainty
72- 76 F5.3 Msun E_Mass [0.01/0.2] Mass positive uncertainty
78- 83 F6.3 [Lsun] logL [-2.4/-0.5] log of luminosity
85- 92 F8.6 [Lsun] e_logL [0.05/0.7] logL negative uncertainty
94-101 F8.6 [Lsun] E_logL [0.05/0.7] logL positive uncertainty
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Note (5): Flag as follows:
b = Star observed twice to check the repeatability of our analysis. These
are the higher precision estimates.
c = The Al-a EW for these stars are below the calibration range for the
Newton+ (2015, J/ApJ/800/85) relations. Adopted parameters are based
on the Mann+ (2013, J/AJ/145/52 ; 2013, J/ApJ/779/188 and
2015, J/ApJ/804/64) relations.
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Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- EPIC [201205469/217941732] EPIC number
10 A1 --- m_EPIC [AB] EPIC component
12- 22 A11 "Y/M/D" Date Observation date
24- 27 F4.2 0.1nm EWMg1 [1.2/9] Equivalent width of Mg 1.50um features
29- 32 F4.2 0.1nm e_EWMg1 [0.06/0.5] EWMg1 uncertainty
34- 37 F4.2 0.1nm EWMg2 [0.9/6.2] Equivalent width of Mg 1.57um features
39- 42 F4.2 0.1nm e_EWMg2 [0.06/0.6] EWMg2 uncertainty
44- 47 F4.2 0.1nm EWMg3 [0.9/5.1] Equivalent width of Mg 1.71um features
49- 52 F4.2 0.1nm e_EWMg3 [0.04/0.4] EWMg3 uncertainty
54- 57 F4.2 0.1nm EWAla [0.6/2.5] EW of Al 1.67um features a
59- 62 F4.2 0.1nm e_EWAla [0.04/0.3] EWAla uncertainty
64- 67 F4.2 0.1nm EWAlb [0.6/3.2] EW of Al 1.67um features b
69- 72 F4.2 0.1nm e_EWAlb [0.06/0.4] EWAlb uncertainty
74- 79 F6.3 [-] [Fe/H] [-0.5/0.6]? Metallicity [Fe/H] (6)
81- 85 F5.3 [-] e_[Fe/H] [0.08/0.3]? Uncertainty of [Fe/H]
87- 92 F6.3 [-] [M/H] [-0.4/0.4]? Metallicity [M/H] (6)
94- 98 F5.3 [-] e_[M/H] [0.08/0.2]? Uncertainty of [M/H]
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Note (6): Estimated by taking the average of the H-band and K-band estimates
determined using the spectral indices introduced by Mann+ (2013,
J/AJ/145/52). We do not report [Fe/H] and [M/H] for K3-K5 dwarfs
because the Mann+ (2013, J/AJ/145/52) relations are not valid for
those stars.
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Global notes:
Note (G1): Spectral types are coarse assignments based on visual inspection of
the near-infrared spectra collected in this paper. The assigned
spectral types have errors of roughly ±1 subtype.
See Section 4.1 for details.
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History:
From electronic version of the journal
References:
Dressing et al. Paper I. 2017ApJ...836..167D 2017ApJ...836..167D This catalog
Dressing et al. Paper II. 2017AJ....154..207D 2017AJ....154..207D Cat. J/AJ/154/207
Dressing et al. Paper III. 2018AJ....156...70D 2018AJ....156...70D
Dressing et al. Paper IV. 2019AJ....158...87D 2019AJ....158...87D
(End) Emmanuelle Perret [CDS] 24-Jan-2019