J/MNRAS/523/2193 TMTS flare study from the first two years (Liu+, 2023)
Minute-cadence observations of the LAMOST fields with the TMTS.
III. Statistic study of the flare stars from the first two years.
Liu Q., Lin J., Wang X., Gu S., Shi J., Zhang L., Xi G., Mo J., Cai Y.,
Chen L., Chen Z., Guo F., Jiang X., Li G., Li W., Lin H., Lin W., Liu J.,
Miao C., Ma X., Peng H., Xiang D., Yan S., Zhang J., Zhang X.
<Mon. Not. R. Astron. Soc. 523, 2193-2208 (2023)>
=2023MNRAS.523.2193L 2023MNRAS.523.2193L (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Stars, flare ; Optical ; Spectral types
Keywords: dynamo - surveys - stars: chromospheres - stars: flare -
stars: magnetic fields
Abstract:
Tsinghua University-Ma Huateng Telescopes for Survey (TMTS) aims to
detect fast-evolving transients in the Universe, which has led to
discovery of thousands of short period variables and eclipsing
binaries since 2020. In this paper, we present the observed properties
of 125 flare stars identified by the TMTS within the first two years,
with an attempt to constrain their eruption physics. As expected, most
of these flares were recorded in late-type red stars with
GBP-GRP>2.0mag, however, the flares associated with blue stars of
them tend to be on average more energetic and have broader profiles.
The peak flux (Fpeak) of the flare is found to depend strongly on
the equivalent duration (ED) of the energy release, i.e.,
Fpeak{pro.to}ED0.72±0.04, which is consistent with the results
derived from the Kepler and Evryscope samples. This relation is likely
related to the magnetic loop emission, while for the more popular
non-thermal electron heating model a specific time evolution may be
required to generate this relation. We notice that flares produced by
hotter stars have a flatter Fpeak{pro.to}ED relation compared to
that from cooler stars, which is related to the statistical
discrepancy in light-curve shape of flare events with different
colors. With the spectra from the LAMOST, we found that flare stars
have apparently stronger Hα emission than inactive stars,
especially at low temperature end, suggesting that chromospheric
activity plays an important role in producing flares. On the other
hand, the subclass having frequent flares are found to show Hα
emissions of similar strength in their spectra as that recorded with
only a single flare but similar effective temperature, implying that
the chromospheric activity may not be the only reason of triggering
eruptions.
Description:
TMTS is a multiple-tube telescope system consisting of four 40-cm
optical telescopes with a total field of view (FoV) of about 18 deg2
and a plate scale of 1.86-arcsec/pix. Luminous filters are used in the
TMTS observations, which cover the wavelength from 330nm to about
900nm. During the first two-year survey, TMTS found 125 flare stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 162 125 Summary of properties of 125 flare stars from
the first two-year survey of TMTS
table2.dat 139 132 Summary of the flare parameters for 125 flare
stars from the first two-year survey of TMTS
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See also:
J/MNRAS/523/2172 : TMTS delta Scuti stars (Lin+, 2023)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Name TMTS name of the source
(TMTS JHHMMSSss+DDMMSSs)
23 A1 --- n_Name [*] Note on Name (G1)
25- 37 F13.9 deg RAdeg [4.59/337.34] Right Ascension (J2000)
39- 50 F12.9 deg DEdeg [0.89/76.4] Declination (J2000)
52- 58 A7 --- SpType Spectra type
60- 65 F6.2 mas Plx [0.09/128.49]? Parallax of the source
67- 70 F4.2 mas e_Plx [0.02/1.29]? Uncertainty in parallax
73- 79 F7.5 kpc Dist [0.01/1.5]? Distance of the source
81- 87 F7.5 kpc e_Dist [0.0/0.3]? Uncertainty in distance
89- 95 F7.4 mag GMAG [4.3/12.317]? Absolute G-band magnitude
97-102 F6.4 mag e_GMAG [0.0011/0.4]? Uncertainty in
absolute G-band magnitude
104-108 F5.3 mag BP-RP [0.78/3.32]? Gaia color with reddening-removed
110-114 F5.3 mag e_BP-RP [0.0013/0.09]? Uncertainty in Gaia color
116-122 F7.2 K Teff [3202.26/5913.13]? Effective temperature
of the source
124-129 F6.2 K e_Teff [38.08/344.36]? Uncertainty in
effective temperature
131-134 F4.2 [cm/s2] logg [2.09/5.5]? logarithmic form of
surface gravity
136-139 F4.2 [cm/s2] e_logg [0.05/0.5]? Uncertainty in logg
141-145 F5.2 [-] [Fe/H] [-1.1/0.09]? Iron abundance
147-150 F4.2 [-] e_[Fe/H] [0.04/0.3]? Uncertainty in iron abundance
153-157 F5.2 0.1nm EWHa [-1.48/10.0]? Equivalent width of
Hα line
159-162 F4.2 0.1nm e_EWHa [0.06/0.9]? Uncertainty in EWHa
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 22 A22 --- Name TMTS name of the source
(TMTS JHHMMSSss+DDMMSSs)
23 A1 --- n_Name [*] Note on Name (G1)
25- 35 F11.5 d TimeStart [58856/59579]? Time when TMTS observation
started (MJD)
37- 42 F6.3 --- FPeak [0.053/33.36] Fractional flux of flare peak
44- 48 F5.3 --- e_FPeak [0.006/4.39] Uncertainty in Peak_flux
50- 57 F8.2 s t0 [-44/40973] Time of flare beginning
since TimeStart
59- 65 F7.2 s e_t0 [6.21/1546.88] Uncertainty in t0
67- 73 F7.2 s t1/2 [38.21/1699.98]? Full-time width
at half peak flux
75- 80 F6.2 s e_t1/2 [5.25/355.62]? Uncertainty in t1/2
82- 89 F8.2 s Dur [487.14/13787.71] Duration of the flare
91- 97 F7.2 s e_Dur [36.12/7718.42] Uncertainty in Dur
99-105 F7.2 s ED [12.98/6600.62] Equivalent duration
107-113 F7.2 s e_ED [1.96/2877.63] Uncertainty in ED
115-120 F6.3 [10-7W] logEL [31.58/35.88]? log of white-band energy
122-126 F5.3 [10-7W] e_logEL [0.012/0.3]? Uncertainty in logEL
128-133 F6.3 [10-7W] logEbol [32.12/36.42]? log of bolometric energy
135-139 F5.3 [10-7W] e_logEbol [0.012/0.3]? Uncertainty in logEbol
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Global notes:
Note (G1): * means the stars have unreliable Gaia cross-matched sources.
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Acknowledgements:
Qichun Liu, lqc22(at)mails.tsinghua.edu.cn
References:
Lin et al., Paper I 2022MNRAS.509.2362L 2022MNRAS.509.2362L
Lin et al., Paper II 2023MNRAS.523.2172L 2023MNRAS.523.2172L, Cat. J/MNRAS/523/2172
(End) Patricia Vannier [CDS] 16-Feb-2023