J/ApJ/827/50 Kepler faint red giants (Mathur+, 2016)
Probing the deep end of the Milky Way with Kepler: asteroseismic analysis
of 854 faint red giants misclassified as cool dwarfs.
Mathur S., Garcia R.A., Huber D., Regulo C., Stello D., Beck P.G.,
Houmani K., Salabert D.
<Astrophys. J., 827, 50-50 (2016)>
=2016ApJ...827...50M 2016ApJ...827...50M (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Effective temperatures ; Stars, masses ;
Stars, distances
Keywords: asteroseismology; methods: data analysis; methods: numerical;
stars: distances; stars: fundamental parameters;
stars: oscillations , including pulsations
Abstract:
Asteroseismology has proven to be an excellent tool to determine not
only global stellar properties with good precision, but also to infer
the stellar structure, dynamics, and evolution for a large sample of
Kepler stars. Prior to the launch of the mission, the properties of
Kepler targets were inferred from broadband photometry, leading to the
Kepler Input Catalog (KIC). The KIC was later revised in the Kepler
Star Properties Catalog, based on literature values and an
asteroseismic analysis of stars that were unclassified in the KIC.
Here, we present an asteroseismic analysis of 45400 stars that were
classified as dwarfs in the Kepler Star Properties Catalog. We found
that around 2% of the sample shows acoustic modes in the typical
frequency range that put them in the red-giant category rather than
the cool dwarf category. We analyze the asteroseismic properties of
these stars, derive their surface gravities, masses, and radii, and
present updated effective temperatures and distances. We show that the
sample is significantly fainter than the previously known oscillating
giants in the Kepler field, with the faintest stars reaching down to a
Kepler magnitude of Kp∼16. We demonstrate that 404 stars are at
distances beyond 5kpc and that the stars are significantly less
massive than for the original Kepler red-giant sample, consistent with
a population of distant halo giants. A comparison with a galactic
population model shows that up to 40 stars might be genuine halo
giants, which would increase the number of known asteroseismic halo
stars by a factor of 4. The detections presented here will provide a
valuable sample for galactic archeology studies.
Description:
From the H14 catalog (Huber+, 2014, J/ApJS/211/2), we selected GKM
dwarfs according to the following criteria: logg≥4.25 and
Teff≤5500K. We also added a few tens of stars from the asteroseismic
sample of solar-like stars from Chaplin et al. (2011ApJ...732...54C 2011ApJ...732...54C)
where red-giant-like oscillations were detected. These additional
stars have Teff>5500K.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 146 824 Seismic and fundamental parameters of the
misclassified red giants obtained for the
A2Z+ pipeline (Mathur+ 2010A&A...511A..46M 2010A&A...511A..46M)
table2.dat 94 741 Seismic and fundamental parameters of the
misclassified red giants obtained for the
SYD pipeline (Huber+ 2009CoAst.160...74H 2009CoAst.160...74H)
table3.dat 59 31 Properties of the red giants with modes near or
above the Nyquist frequency from the
A2Z+ pipeline
table4.dat 23 279 Evolutionary stage and period spacing for
279 misclassified red giants
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
J/ApJS/211/2 : Revised properties of Q1-16 Kepler targets (Huber+, 2014)
J/ApJ/767/127 : Asteroseismic solutions for 77 Kepler stars (Huber+, 2013)
J/ApJ/767/95 : Improved parameters of smallest KIC stars (Dressing+, 2013)
J/ApJ/765/L41 : Asteroseismic classification of KIC objects (Stello+, 2013)
J/ApJ/753/90 : Parameters of K5 and later type Kepler stars (Mann+, 2012)
J/A+A/543/A160 : Normalized spectra of 82 Kepler red giants (Thygesen+, 2012)
J/MNRAS/423/122 : Abundances of 93 solar-type Kepler targets (Bruntt+, 2012)
J/A+A/540/A143 : Oscillations of red giants observed by Kepler (Mosser+, 2012)
J/ApJS/199/30 : Eff. temperature scale for KIC stars (Pinsonneault+, 2012)
J/AJ/142/112 : KIC photometric calibration (Brown+, 2011)
J/A+A/530/A138 : Geneva-Copenhagen survey re-analysis (Casagrande+, 2011)
http://exoplanetarchive.ipac.caltech.edu/ : NASA exoplanet archive
http://archive.stsci.edu/kepler/ : MAST Kepler home page
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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2- 9 I8 --- KIC [893233/12833657] Kepler Input Catalog number
12- 15 F4.1 mag Kpmag [7.4/17] Kepler Magnitude
18- 21 I4 K Teff [3225/5876] Effective Temperature
from Huber et al. (2014, J/ApJS/211/2)
25- 27 I3 K E_Teff [0/611] Upper Uncertainty in Teff
31- 33 I3 K e_Teff [0/627] Lower Uncertainty in Teff
36- 39 I4 K Teffr [3838/6182]? Revised Effective Temperature (1)
43- 45 I3 K E_Teffr [78/746]? Upper Uncertainty in Teffr
49- 51 I3 K e_Teffr [76/736]? Lower Uncertainty in Teffr
54- 58 F5.2 uHz dnu [0.2/20.3]? Frequency Separation (G1)
61- 64 F4.2 uHz e_dnu [0/4]? Uncertainty in dnu
67- 71 F5.1 uHz numax [1/269.3] Maximum power mode (G1)
74- 77 F4.1 uHz e_numax [0.1/39] Uncertainty in numax
80- 83 F4.2 [cm/s2] logg [0.9/3.4] Log surface gravity
from scaling relations
86- 89 F4.2 [cm/s2] e_logg [0.01/0.2] Uncertainty in logg
92- 95 F4.2 Msun Mass [0.3/4.7]? Stellar Mass from scaling relations
98-101 F4.2 Msun e_Mass [0.05/2.5]? Uncertainty in Mass
103-108 F6.2 Rsun Rad [3/102]? Stellar Radius from scaling relations
111-115 F5.2 Rsun e_Rad [0.1/64]? Uncertainty in Rad
119-122 F4.2 --- Crowd [0.3/6.5]? Crowding (G2)
124-128 A5 --- Flag Flag (2)
130-134 F5.2 kpc Dist [0.2/42.6]? Distance from isochrone fitting (1)
136-140 F5.2 kpc e_Dist [0.02/15]? Lower Uncertainty in Dist
142-146 F5.2 kpc E_Dist [0.01/23]? Upper Uncertainty in Dist
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Note (1): To determine revised temperatures and distances for the sample,
we used broadband photometry, asteroseismic observables, and a grid of
Parsec isochrones (Bressan et al. 2012MNRAS.427..127B 2012MNRAS.427..127B).
See section 3.3 for further explanations.
Please, note that distances are taken from the erratum published
in 2016, ApJ, 833, 294 (note added by CDS).
Note (2): Flags as follows:
PB = Possible Blend;
CR = Crowding;
PP = Possible Pollution;
SNR = low Signal-to-Noise Ratio;
PM = Possible M dwarf.
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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- 8 I8 --- KIC [893233/12833657] Kepler Input Catalog number
10- 13 I4 K Teffr [3766/6103] Revised Effective Temperature
15- 18 I4 K E_Teffr [77/1023] Upper Uncertainty in Teffr
20- 22 I3 K e_Teffr [75/846] Lower Uncertainty in Teffr
24- 28 F5.2 uHz dnu [0.2/19.1] Frequency Separation (G1)
30- 33 F4.2 uHz e_dnu [0.01/0.7] Uncertainty in dnu
35- 39 F5.1 uHz numax [1/249] Maximum power mode (G1)
41- 44 F4.1 uHz e_numax [0/13] Uncertainty in numax
46- 49 F4.2 [cm/s2] logg [0.8/3.4] Log surface gravity
from scaling relations
51- 54 F4.2 [cm/s2] e_logg [0.01/0.08] Uncertainty in logg
56- 59 F4.2 Msun Mass [0.3/4.1] Stellar Mass from scaling relations
61- 64 F4.2 Msun e_Mass [0.02/0.6] Uncertainty in Mass
66- 70 F5.2 Rsun Rad [3.7/69.2] Stellar Radius from scaling relations
72- 76 F5.2 Rsun e_Rad [0.07/13] Uncertainty in Rad
78- 82 F5.2 kpc Dist [0.2/40.3] Distance from isochrone fitting (1)
84- 88 F5.2 kpc e_Dist [0.01/12] Lower Uncertainty in Dist
90- 94 F5.2 kpc E_Dist [0.01/19] Upper Uncertainty in Dist
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Note (1): Note that distances are taken from the erratum published
in 2016, ApJ, 833, 294 (note added by CDS).
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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- 8 I8 --- KIC [1296817/11666333] Kepler Input Catalog number
10- 13 F4.1 mag Kpmag [11.1/15.4] Kepler Magnitude
15- 18 I4 K Teff [4750/5385] Effective Temperature
20- 22 I3 K e_Teff [95/107] Uncertainty in Teff
24- 28 F5.2 uHz dnu [14.3/26.4] Frequency Separation (G1)
30- 33 F4.2 uHz e_dnu [0.08/3] Uncertainty in dnu
35- 39 F5.1 uHz numax [285/370] Maximum power mode (G1)
41- 44 F4.1 uHz e_numax [20/25] Uncertainty in numax
46- 49 F4.2 [cm/s2] logg [3.3/3.5] Log surface gravity
51- 54 F4.2 [cm/s2] e_logg [0.03] Uncertainty in logg
56- 59 F4.2 --- Crowd [0.6/1] Crowding (G2)
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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- 8 I8 --- KIC [1160684/12690972] Kepler Input Catalog number
10- 14 F5.1 s dPer [10.5/304.8] Median Period Spacing
16- 23 A8 --- Stage Evolutionary Stage (1)
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Note (1): Evolutionary Stage as follows:
RC/2ndRC = Red Clump or 2nd Red Clump stars (127 sources);
RGB = Red Giant Branch stage (152 sources).
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Globla notes:
Note (G1): Values for numax (νmax) and the dnu (Δν) values for
each model were calculated using the scaling relations
(Kjeldsen & Bedding 1995A&A...293...87K 1995A&A...293...87K), assuming solar reference values
of numax=3090uHz and dnu=135.1uHz (Huber+ 2011ApJ...743..143H 2011ApJ...743..143H).
Note (G2): The crowding is provided on the MAST and is defined as the ratio of
the target flux to the total flux in the optimal aperture. The optimal
aperture is computed by the NASA Pre-search Data Conditioning (for more
details see Jenkins+ 2010ApJ...713L..87J 2010ApJ...713L..87J).
In this paper, we define a crowding value of 1 when all of the flux belongs
to the main target. See section 3.2 for further explanations.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Nov-2016