J/ApJS/253/19 Halpha and other EWs of LAMOST M-type stars (Zhang+, 2021)
Chromospheric activity of M stars based on LAMOST low- and medium-resolution
spectral surveys.
Zhang L.-Y., Meng G., Long L., Shi J., Zhong M., Han X.L., Misra P., Wang H.
<Astrophys. J. Suppl. Ser., 253, 19 (2021)>
=2021ApJS..253...19Z 2021ApJS..253...19Z
ADC_Keywords: Stars, M-type; Equivalent widths; Spectral types;
Radial velocities; Photometry, SDSS
Keywords: Stellar activity ; Stellar chromospheres ; M stars
Abstract:
We have used the Large Sky Area Multi-Object Fibre Spectroscopic
Telescope (LAMOST) low-resolution and medium-resolution spectroscopic
surveys to explore the chromospheric statistical properties and
variations of M stars. There are 738477 LAMOST low-resolution spectra
of 622523 M stars. We have calculated equivalent widths of the CaII H&K,
Hα, Hβ, Hγ, Hδ, HeI D3, and CaII infrared
triplet lines. Based on the Hα EWs, we found that 33374 objects
showed Hα emissions. We revised the relationship between the
active fraction and spectral subtype, and confirmed that the active
fractions increased from M0 to M3, and possibly declined from M4 to
subsequent types. Among 86005 objects with repeated spectra,
19422 objects showed Hα variations. The variation fraction of
stars with M4 and subsequent types with a fully convective envelope
was higher than those of M0-M3 with a partially convective envelope.
By combining the distances from Gaia, we have determined the positions
of the M dwarfs in the catalog for M stars. The active fraction
decreased rapidly in the height range of 0-400pc above and below the
Galactic plane, and maintained a steady trend in 400-1000pc. We
cross-matched the M catalog of the LAMOST low-resolution survey with
LAMOST medium-resolution spectra. We obtained 272181 spectra of
13355 M objects and calculated the Hα EWs. Among them,
3813 stars show variations, which might be caused by chromospheric
activity evolution with orbital phase or time. The Hα emission
for 972 objects shows variations over short and long timescales,
especially on short timescales of 20 minutes.
Description:
The Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST)
(also known as the Guoshoujing telescope) is a reflecting Schmidt
optical telescope with a field of view of about 25° and an
effective aperture of 3.6-4.9m, which is located at the Xinglong
Station of the National Astronomical Observatories of China (NAOC).
There are 738477 spectra of 622523 M stars from the LAMOST
low-resolution spectra DR7 survey (up to 2019 June).
We have cross-matched the M stars of the LAMOST low-resolution
spectral survey with the catalog obtained from the LAMOST
medium-resolution (R∼7500) spectra survey.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 199 738476 Parameters of M stars catalog observed in LAMOST
low-resolution spectral survey DR7
table3.dat 316 738476 Parameters of other chromospheric indicators
(besides Hα) and several molecular bands of
M stars from LAMOST low resolution spectra
table5.dat 74 80565 Parameters of M stars catalog from LAMOST
medium-resolution survey, the parameter of
Hα line and its variations in short and
long time scales
table6.dat 107 85992 Parameters of M stars catalog with repeated LAMOST
low-resolution observations
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See also:
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
V/153 : LAMOST DR4 catalogs (Luo+, 2018)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
J/AJ/113/806 : M-Subdwarfs (Gizis 1997)
J/A+A/337/403 : Low-mass stars evolutionary models (Baraffe+ 1998)
J/AJ/128/426 : Subdwarfs in the SDSS (West+, 2004)
J/AJ/135/785 : SDSS-DR5 low-mass star spectroscopic sample (West+, 2008)
J/AJ/140/1402 : M dwarf flares from SDSS spectra (Hilton+, 2010)
J/AJ/141/97 : SDSS DR7 M dwarfs (West+, 2011)
J/A+A/581/A52 : Gaia-ESO Survey: Hα emission stars (Traven+, 2015)
J/ApJ/821/93 : Rotation & Galactic kinematics of mid M dwarfs (Newton+, 2016)
J/ApJ/834/85 : Hα emission in nearby M dwarfs (Newton+, 2017)
J/ApJ/835/61 : Chromospherically active stars in RAVE. II. (Zerjal+, 2017)
J/other/RAA/18.68 : Cataclysmic variables from LAMOST DR3 (Han+, 2018)
J/ApJS/235/5 : EA-type eclipsing binaries observed by LAMOST (Qian+, 2018)
J/AJ/158/155 : SB candidates from the RAVE & Gaia DR2 surveys (Birko+, 2019)
J/ApJS/243/28 : M star magnetic activities from LAMOST & Kepler (Lu+, 2019)
J/ApJ/877/75 : BVRI photom. of DV Psc and known short-period EBs (Pi+, 2019)
J/ApJS/244/27 : Radial velocity measurements in LAMOST-II (Wang+, 2019)
J/ApJS/240/31 : M-subdwarf research. I. LAMOST DR4 spectra obs. (Zhang+, 2019)
http://dr7.lamost.org/ : LAMOST DR7 home page
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [LAMOST]
8- 26 A19 --- LAMOST LAMOST identifier (JHHMMSS.ss+DDMMSS.s)
29- 39 F11.5 d HJD [55858.8/58643.11]?=0 Heliocentric Julian Date
of observation; HJD-2400000 (G1)
41- 47 F7.1 s Exp [500/9000]?=-9999 Exposure time
49- 50 A2 --- SpT Spectral type
52- 58 F7.1 --- SNr [-9999/999] Signal to noise in r filter
60- 66 F7.1 km/s RVel [-9999/93341]? Radial velocity
68- 75 F8.1 km/s e_RVel [0/999619]? Uncertainty in RVel
77- 95 A19 --- SDSS SDSS DR 12 identifier (JHHMMSS.ss+DDMMSS.s)
97-102 F6.3 mag umag [10.3/32.6]? Apparent SDSS u band AB magnitude
104-109 F6.3 mag e_umag [0/82]? Uncertainty in umag
111-116 F6.3 mag gmag [7.9/36.1]? Apparent SDSS g band AB magnitude
118-123 F6.3 mag e_gmag [0/68]? Uncertainty in gmag
125-130 F6.3 mag rmag [6.5/31.1]? Apparent SDSS r band AB magnitude
132-137 F6.3 mag e_rmag [0/37]? Uncertainty in rmag
139-144 F6.3 mag imag [6.1/37.6]? Apparent SDSS i band AB magnitude
146-151 F6.3 mag e_imag [0/58]? Uncertainty in imag
153-158 F6.3 mag zmag [5/32.6]? Apparent SDSS z band AB magnitude
160-165 F6.3 mag e_zmag [0/59]? Uncertainty in zmag
167-174 F8.3 0.1nm EWHa [-984/7873]? Hα equivalent width; Angstroms
176-181 F6.1 --- SNHa [-753/9856]? Signal to noise of Hα line
183-190 F8.3 0.1nm e_EWHa [0/9975]? Uncertainty in EWHa
192-197 F6.1 0.1nm Height [0/1104]? Height of Hα
199-199 A1 --- E Hα activity criteria; (Y)es or (N)o
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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 identifier (JHHMMSS.ss+DDMMSS.s)
29- 39 F11.5 d HJD [55858.8/58643.2]?=0 Heliocentric Julian Date
of observation; HJD-2400000 (G1)
41- 49 F9.3 0.1nm EWCaH [-9732/93048]? CaII H line equivalent width;
in Angstrom units
51- 60 F10.3 0.1nm e_EWCaH [0.003/996907]? Uncertainty in EWCaH
62 A1 --- f_EWCaH Activity flag for EWCaH (1)
64- 71 F8.3 0.1nm EWHb [-945/7740]? Hβ line equivalent width;
in Angstrom units
73- 80 F8.3 0.1nm e_EWHb [0/9990]? Uncertainty in EWHb
82 A1 --- f_EWHb Activity flag for EWHb (1)
84- 92 F9.3 0.1nm EWHg [-9397/98764]? Hγ line equivalent width;
in Angstrom units
94-104 F11.3 0.1nm e_EWHg [0.001/1546892]? Uncertainty in EWHg
106 A1 --- f_EWHg Activity flag for EWHg (1)
108-115 F8.3 0.1nm EWHd [-1000/9981]? Hδ line equivalent width;
in Angstrom units
117-125 F9.3 0.1nm e_EWHd [0.002/99944]? Uncertainty in EWHd
127 A1 --- f_EWHd Activity flag for EWHd (1)
129-137 F9.3 0.1nm EWHeI [-8872/48729]? HeI D3 line equivalent width;
in Angstrom units
139-146 F8.3 0.1nm e_EWHeI [0/9997]? Uncertainty in EWHeI
148 A1 --- f_EWHeI Activity flag for EWHeI
150-161 F12.3 0.1nm EWCaII-1 [-815931/77628000]? CaII 8498Å line
equivalent width; in Angstrom units
163-174 F12.3 0.1nm e_EWCaII-1 [0/48926900]? Uncertainty in EWCaII-1
176 A1 --- f_EWCaII-1 Activity flag for EWCaII-1
178-190 F13.3 0.1nm EWCaII-2 [-635707/749992000]? CaII 8542Å line
equivalent width; in Angstrom units
192-203 F12.3 0.1nm e_EWCaII-2 [0/87080000]? Uncertainty in EWCaII-2
205 A1 --- f_EWCaII-2 Activity flag for EWCaII-2
207-215 F9.3 0.1nm EWCaII-3 [-812/80842]? CaII 8662Å line equivalent
width; in Angstrom units
217-228 F12.3 0.1nm e_EWCaII-3 [0/49267000]? Uncertainty in EWCaII-3
230 A1 --- f_EWCaII-3 Activity flag for EWCaII-3
232-241 F10.3 0.1nm EWTiO5 [-900/999995]? TiO5 molecular line equivalent
width; in Angstrom units
243-253 F11.3 0.1nm e_EWTiO5 [0/1316216]? Uncertainty in EWTiO5
255-263 F9.3 0.1nm EWCaH1 [-3580/6399]? CaH1 molecular line equivalent
width; in Angstrom units
265-274 F10.3 0.1nm e_EWCaH1 [0/970780]? Uncertainty in EWCaH1
276-284 F9.3 0.1nm EWCaH2 [-1205/730]? CaH2 molecular line equivalent
width; in Angstrom units
286-294 F9.3 0.1nm e_EWCaH2 [0/99769]? Uncertainty in EWCaH2
296-303 F8.3 0.1nm EWCaH3 [-837/1777]? CaH3 molecular line equivalent
width; in Angstrom units
305-316 F12.3 0.1nm e_EWCaH3 [0/42079819]? Uncertainty in EWCaH3
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Note (1): Flas as follows:
Y = line meets the activity criteria;
N = line does not meet the activity criteria.
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 A6 --- --- [LAMOST]
8- 26 A19 --- LAMOST LAMOST identifier (JHHMMSS.ss+DDMMSS.s)
28- 29 A2 --- SpT Spectral type
31- 38 I8 min HJD [83555758/84454742]? Heliocentric Julian Date
in minutes
40- 43 I4 s Exp [319/1800]? Exposure time
45- 47 I3 --- SN [0/999] Signal to noise ratio
49- 56 F8.3 0.1nm EWHa [-578/571] Equivalent width of Hα;
in Angstrom units
58- 68 F11.3 0.1nm e_EWHa [0/241958] Uncertainty in EWHa
70 A1 --- Em [Y/N] Emission of Hα line? (No=absorption)
72 A1 --- L [Y/N] Hα variation on long time scale?
74 A1 --- S [Y/N] Hα variation on short time scale?
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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- 5 I5 --- Seq [1/85992] Internal object number
7- 12 A6 --- --- [LAMOST]
14- 32 A19 --- LAMOST LAMOST identifier (JHHMMSS.ss+DDMMSS.s)
34- 35 A2 --- SpT Spectral type
37- 38 I2 --- Rep [2/30] The repeated number of objects
40- 47 F8.3 0.1nm EWHa-Max [-86/1363] Maximum Hα equivalent width;
in Angstrom units
49- 56 F8.3 0.1nm e_EWHa-Max [0/8484] Uncertainty in EWHa-Max
58- 65 F8.3 0.1nm EWHa-Min [-498/318] Minimum Hα equivalent width;
in Angstrom units
67- 74 F8.3 0.1nm e_EWHa-Min [0/8928] Uncertainty in EWHa-Min
76- 85 F10.3 --- Ratio [-79107/24178] The EWHa-Max/EWHa-Min ratio
87- 94 F8.3 --- Diff [0/1360] The EWHa-Max - EWHa-Min difference
96-103 F8.3 --- e_Diff [0.002/8928] Uncertainty in Diff
105-107 A3 --- Var [Yes/No ] Variation of Hα line?
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Global notes:
Note (G1): A blank HJD indicates not published observation time in the
LAMOST survey.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-May-2021