J/ApJS/243/28 M-type star magnetic activities from LAMOST & Kepler (Lu+, 2019)
Magnetic activities of M-type stars based on LAMOST DR5 and Kepler and K2
missions.
Lu H.-P., Zhang L.-Y., Shi J., Han X.L., Fan D., Long L., Pi Q.
<Astrophys. J. Suppl. Ser., 243, 28 (2019)>
=2019ApJS..243...28L 2019ApJS..243...28L
ADC_Keywords: Stars, M-type; Spectral types; Stars, flare; Equivalent widths;
Photometry, ugriz
Keywords: stars: activity; stars: chromospheres; stars: flare; stars: low-mass;
stars: rotation
Abstract:
We performed a statistical study of magnetic activities of M-type
stars by combining the spectra of LAMOST DR5 with light curves from
the Kepler and K2 missions. We mainly want to study the relationship
between chromospheric activity and flares, and their relations of
magnetic activity and rotation period. We have obtained the maximum
catalog of 516688 M-type stellar spectra of 480912 M stars from
LAMOST-DR5 and calculated their equivalent widths of chromospheric
activity indicators (Hα, Hβ, Hγ, Hδ, CaII H&K,
and HeI D3). Using the Hα indicator, 40464 spectra of 38417 M
stars show chromospheric activity, and 1791 of these 5499 M-type stars
with repeated observations have Hα variability. We used an
automatic detection plus visual inspection method to detect 17432
flares on 8964 M-type stars from the catalog by cross-matching LAMOST
DR5 and the Kepler and K2 databases. We used the Lomb-Scargle method
to calculate their rotation periods. We find that the flare frequency
is consistent with the ratio of activities of these chromospheric
activity indicators as a function of spectral type in M0-M3. We find
the equivalent widths of Hα and CaII H have a significant
statistical correlation with the flare amplitude in M-type stars. We
confirm that the stellar flare is affected by both the stellar
magnetic activity and the rotation period. Finally, using the Hα
equivalent width equal to 0.75Å and using the rotation period equal
to 10 days as the threshold for the M-type stellar flare time
frequency are almost equivalent.
Description:
LAMOST (also known as Guoshoujing Telescope), located in Xinglong
Station of the National Astronomical Observatories of the Chinese
Academy of Sciences (NAOC), is a special meridian reflecting Schmidt
telescope with about 4m effective aperture and a 5° field of view.
LAMOST can obtain about 4000 spectra with a wavelength range of
3650-9000Å and a resolution R∼1800 in one single exposure.
The five-year regular survey ended on 2017 June 16, and all spectra
were provided through the LAMOST DR5.
There are also some overlaps between the observation areas of the
LAMOST and Kepler K2 missions.
The Kepler spacecraft was equipped with a telescope with a 95cm
aperture and 105deg2 field of view.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 86 516688 M-type stellar spectral parameters in LAMOST DR5
table3.dat 239 516688 EWs of the special lines of the LAMOST M-type spectra
table5.dat 93 5499 Hα variability of LAMOST M-type stars
table6.dat 166 8964 Parameters of 8964 M-type stars (observed by
LAMOST and Kepler)
table7.dat 85 17432 Flare parameters
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See also:
III/159 : Ca II H and K Measurements Made at MWO (Duncan+ 1991)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
V/146 : LAMOST DR1 catalogs (Luo+, 2015)
IV/34 : K2 Ecliptic Plane Input Catalog (EPIC) (Huber+, 2017)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
J/AJ/128/426 : Subdwarfs in the SDSS (West+, 2004)
J/AJ/134/2398 : Stellar SEDs in SDSS and 2MASS filters (Covey+, 2007)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/AJ/141/50 : White-light flares on cool Kepler stars (Walkowicz+, 2011)
J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)
J/other/Nat/485.478 : Superflares on solar-type stars (Maehara+, 2012)
J/ApJS/209/5 : Superflares of Kepler stars. I. (Shibayama+, 2013)
J/ApJS/211/2 : Revised properties of Q1-16 Kepler targets (Huber+, 2014)
J/ApJS/220/19 : LAMOST obs. in the Kepler field. I. (De Cat+, 2015)
J/ApJS/224/2 : K2 EPIC stellar properties for 138600 targets (Huber+, 2016)
J/ApJS/232/26 : Catalog of Kepler flare stars (Van Doorsselaere+, 2017)
J/ApJ/849/36 : Flaring activity of M dwarfs in the Kepler field (Yang+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- --- [LAMOST]
8- 26 A19 --- LAMOST LAMOST spectral name (JHHMMSS.ss+DDMMSS.s)
28- 33 F6.3 mag rmag [7.6/32.2]? r band magnitude (1)
35- 40 F6.3 mag imag [5.3/32.3]? i band magnitude (1)
42- 47 F6.3 mag zmag [9.6/31.2]? z band magnitude (1)
49- 56 F8.3 s Exp [500/9000]? Spectral exposure time
58- 76 A19 "datime" Date Starting exposure time of spectrum,
ISO 8601 combined
78- 79 A2 --- SpT Spectral type
81- 86 F6.2 --- SNR-R [0/999] Spectrum Signal to noise ratio
in the R band
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Note (1): Null values (blanks) indicates that LAMOST does not give
this parameter.
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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- 6 A6 --- --- [LAMOST]
8- 26 A19 --- LAMOST LAMOST spectral name (JHHMMSS.ss+DDMMSS.s)
28- 46 A19 "datime" Date Starting exposure time of spectrum,
ISO 8601 combined
48- 49 A2 --- SpT Spectral type
51- 58 F8.3 0.1nm EWHa [-208/337]? Equivalent Width, Hα (1)
60- 66 F7.3 0.1nm e_EWHa [0/248]? Uncertainty in EWHa (1)
68- 68 A1 --- ActHa Activity criteria, Ha (G1)
70- 77 F8.3 0.1nm EWHb [-190/432]? Equivalent Width, Hβ (1)
79- 85 F7.3 0.1nm e_EWHb [0.001/250]? Uncertainty in EWHb (1)
87- 87 A1 --- ActHb Activity criteria, Hb (G1)
89- 96 F8.3 0.1nm EWHg [-124/5619]? Equivalent Width, Hγ (1)
98-105 F8.3 0.1nm e_EWHg [0.001/1096]? Uncertainty in EWHg (1)
107-107 A1 --- ActHg Activity criteria, Hg (G1)
109-115 F7.3 0.1nm EWHd [-91/359]? Equivalent Width, Hδ (1)
117-123 F7.3 0.1nm e_EWHd [0.002/250]? Uncertainty in EWHd (1)
125-125 A1 --- ActHd Activity criteria, Hd (G1)
127-135 F9.3 0.1nm EWCaH [-132/17672]? Equivalent Width, Ca II H (1)
137-144 F8.3 0.1nm e_EWCaH [0/1906]? Uncertainty in EWCaH (1)
146-146 A1 --- ActCaH Activity criteria, CaH (G1)
148-155 F8.3 0.1nm EWCaK [-188/5907]? Equivalent Width, Ca II K (1)
157-163 F7.3 0.1nm e_EWCaK [0.006/657]? Uncertainty in EWCaK (1)
165-165 A1 --- ActCaK Activity criteria, CaK (G1)
167-173 F7.3 0.1nm EWCa84 [-54/212]? Equivalent Width, Ca II 8498A (1)
175-181 F7.3 0.1nm e_EWCa84 [0/245]? Uncertainty in EWCa84 (1)
183-183 A1 --- ActCa84 Activity criteria, Ca84 (G1)
185-192 F8.3 0.1nm EWCa85 [-38/1022]? Equivalent Width, Ca II 8542A (1)
194-200 F7.3 0.1nm e_EWCa85 [0/237]? Uncertainty in EWCa85 (1)
202-202 A1 --- ActCa85 Activity criteria, Ca85 (G1)
204-210 F7.3 0.1nm EWCa86 [-42/119]? Equivalent Width, Ca II 8662A (1)
212-218 F7.3 0.1nm e_EWCa86 [0/250]? Uncertainty in EWCa86 (1)
220-220 A1 --- ActCa86 Activity criteria, Ca86 (G1)
222-229 F8.3 0.1nm EWHeI [-140/238]? Equivalent Width, He I D3 (1)
231-237 F7.3 0.1nm e_EWHeI [0/250]? Uncertainty in EWHeI (1)
239-239 A1 --- ActHeI Activity criteria, HeI (G1)
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Note (1): Null values (blanks) indicates that the EW of the line cannot be
calculated because the S/N around the line is too low.
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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- 4 I4 --- Seq [1/5499] Sequential running number
6- 11 A6 --- --- [LAMOST]
13- 31 A19 --- LAMOST LAMOST spectral name (JHHMMSS.ss+DDMMSS.s)
33- 34 A2 --- SpT Spectral type
36- 37 I2 --- NObs [2/21] Number of spectra observed by LAMOST
39- 45 F7.3 0.1nm Max(EWHa) [0.7/337] Maximum Hα equivalent width
47- 52 F6.3 0.1nm e_Max(EWHa) [0.01/88] Uncertainty in Max(EWHa)
54- 60 F7.3 0.1nm Min(EWHa) [0.7/192] Minumum Hα equivalent width
62- 67 F6.3 0.1nm e_Min(EWHa) [0.01/25] Uncertainty in Min(EWHa)
69- 74 F6.3 --- REW [1/24.2] Ratio, Max(EWHa)/Min(EWHa)
76- 82 F7.3 0.1nm dEW [0/265] Difference, Max(EWHa)-Min(EWHa)
84- 89 F6.3 0.1nm e_dEW [0.02/88.5] Uncertainty, dEW
91- 93 A3 --- Var [Yes, No] Is Hα variable?
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Kepler/K2(EPIC) name (KIC NNNNNNNN or
EPIC NNNNNNNNN)
16- 21 A6 --- --- [LAMOST]
23- 41 A19 --- LAMOST LAMOST spectral name (JHHMMSS.ss+DDMMSS.s)
43- 61 A19 "datime" Date Starting exposure time of LAMOST spectrum,
ISO 8601 combined
63- 64 A2 --- SpT Spectral type
66- 73 F8.3 d KTime [9.7/1425] Kepler's total observation time
for the star (1)
75- 78 I4 K Teff [0/8007]? Literature Effective temperature (2)
80- 83 I4 K e_Teff [0/3335]? Uncertainty in Teff
85- 91 F7.3 Rsun Rstar [0.0/300.749]? Literature stellar radius (2)
93- 99 F7.3 Rsun e_Rstar [0.0/191.378]? Uncertainty in Rstar
101-107 F7.3 0.1nm EWHa [-24.5/69]? Equivalent Width, Hα (3)
109-114 F6.3 0.1nm e_EWHa [0/75]? Uncertainty in EWHa (3)
116-116 A1 --- ActHa Activity criteria, Ha (G1)
118-124 F7.3 0.1nm EWCaH [-81/101]? Equivalent Width, Ca II H (3)
126-132 F7.3 0.1nm e_EWCaH [0.01/250]? Uncertainty in EWCaH (3)
134-134 A1 --- ActCaH Activity criteria, CaH (G1)
136-142 F7.3 0.1nm EWHeI [-40/112]? Equivalent Width, He I D3 (3)
144-150 F7.3 0.1nm e_EWHeI [0.001/236]? Uncertainty in EWHeI (3)
152-152 A1 --- ActHeI Activity criteria, HeI (G1)
154-156 I3 --- Nfl [0/140] Number of flares detected in this star
158-166 F9.6 d Per [0.07/65]? Derived Stellar Rotation Period
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Note (1): The total number of days Kepler observed the star.
Note (2): The stellar effective temperatures and stellar radii from the
literature, Huber+ (2014, J/ApJS/211/2 and 2016, J/ApJS/224/2).
Note (3): Null values (blanks) indicates that the EW of the line cannot be
calculated because the S/N around the line is too low.
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Byte-by-byte Description of file: table7.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Kepler/K2(EPIC) name
16- 27 F12.7 d Start [120.9/3410.7] Flare start time; BJD-2454833
29- 39 F11.6 d Peak [120.9/3410.8] Flare peak time; BJD-2454833
41- 52 F12.7 d End [121/3411] Flare end time; BJD-2454833
54- 61 F8.6 d Dur [0.06/0.5] Flare duration time
63- 70 F8.6 --- Amp [4e-5/2] Flare amplitude, normalized as
in Equation 3
(Fnorm=(FPDC-Faverage)/Faverage) (1)
72- 85 E14.8 10-7J Energy [2e+30/2.6e+40] Flare Energy; in erg units
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Note (1): PDC stands for presearch data conditioning.
See section 3 for further explanations on the Kepler and K2 data.
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Global notes:
Note (G1): A "Y" indicates that the corresponding line meets the activity
criteria, and "N" indicates that the corresponding line does not meet
the activity criteria (or that the EW could not be derived). The
activity criteria are: a. the EW of any one of the special lines is
greater than the corresponding threshold (the activity threshold for
these lines are shown in the last column of Table 2); b. the value of
the EW is greater than three times its uncertainty; c. the height of the
emission line must be larger than 3 times the noise in the emission line
center.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 27-Dec-2019