J/A+A/649/A90 KMT-2018-BLG-1025Lb I light curve (Han+, 2021)
KMT-2018-BLG-1025Lb: microlensing super-Earth planet orbiting a low-mass star.
Han C., Udalski A., Lee C.-U., Albrow M.D., Chung S.-J., Gould A.,
Hwang K.-H., Jung Y.K., Kim D., Kim H.-W., Ryu Y.-H., Shin I.-G.,
Shvartzvald Y., Yee J.C., Zang W., Cha S.-M., Kim D.-J., Kim S.-L.,
Lee D.-J., Lee Y., Park B.-G., Pogge R.W., Kim C.-H., Kim W.-T., Mroz P.,
Szymanski M.K., Skowron J., Poleski R., Soszynski I., Pietrukowicz P.,
Kozlowski S., Ulaczyk K., Rybicki K.A., Iwanek P., Wrona M.
(The KMTNet Collaboration and The OGLE Collaboration)
<Astron. Astrophys. 649, A90 (2021)>
=2021A&A...649A..90H 2021A&A...649A..90H (SIMBAD/NED BibCode)
ADC_Keywords: Stars, double and multiple ; Exoplanets ; Gravitational lensing ;
Photometry ; Optical
Keywords: gravitational microlensing: micro - planets and satellites: general
Abstract:
We aim to find missing microlensing planets hidden in the unanalyzed
lensing events of previous survey data.
For this purpose, we conduct a systematic inspection of
high-magnification microlensing events, with peak magnifications
Apeak≳30, in the data collected from high-cadence surveys in and
before the 2018 season. From this investigation, we identify an
anomaly in the lensing light curve of the event KMT-2018-BLG-1025. The
analysis of the light curve indicates that the anomaly is caused by a
very low mass-ratio companion to the lens.
We identify three degenerate solutions, in which the ambiguity between
a pair of solutions (solutions B) is caused by the previously known
close-wide degeneracy, and the degeneracy between these and the
other solution (solution A) is a new type that has not been reported
before. The estimated mass ratio between the planet and host is
q∼0.8x10-4 for the solution A and q∼1.6x10-4 for the solutions B.
From the Bayesian analysis conducted with measured observables, we
estimate that the masses of the planet and host and the distance to
the lens are (Mp, Mh, DL)~(6.1M☉, 0.22MEarth, 6.7kpc) for the
solution A and ~(4.4M☉, 0.08MEarth, 7.5kpc) for the solutions
B. The planet mass is in the category of a super-Earth regardless of
the solutions, making the planet the eleventh super-Earth planet, with
masses lying between those of Earth and the Solar system's ice
giants, discovered by microlensing.
Description:
The planet was found from the analysis of the microlensing event
KMT-2018-BLG-1075. The source star of the event lies in the Galactic
bulge field with the equatorial coordinates of (RA, DE)=(17:59:27.94,
-27:52:41.02), which correspond to the Galactic coordinates of
(l, b) = (2.461°, -2.082°). The flux from the source, which had
been constant before the lensing-induced magnification with an
apparent baseline brightness of I∼19.65, was highly magnified for
about 10 days centered at HJD'=HJD-2450000∼8274.85. The event was
found from the post-season inspection of the 2018 season data using
the KMTNet Event Finder System (Kim et al., 2018AJ....155...76K 2018AJ....155...76K). At
the time of finding, the event drew little attention due to the
similarity of the lensing light curve to that of a regular
single-source single-lens (1L1S) event.
Objects:
-----------------------------------------------
RA (2000) DE Designation(s)
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17 59 27.94 -27 52 41.02 KMT-2018-BLG-1075
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ioglei.dat 26 1457 OGLE observed I-band light curve
ikmta1i.dat 26 1423 KMTA1 model I-band light curve
ikmta2i.dat 26 1246 KMTA2 model I-band light curve
ikmtc1i.dat 26 1563 KMTC1 model I-band light curve
ikmtc2i.dat 26 1790 KMTC2 model I-band light curve
ikmts1i.dat 26 1357 KMTS1 model I-band light curve
ikmts2i.dat 26 1249 KMTS2 model I-band light curve
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Byte-by-byte Description of file: *.dat
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Bytes Format Units Label Explanations
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1- 10 F10.5 d Date Helicoentric Julian date (HJD-2450000)
13- 18 F6.3 mag Imag I magnitude
22- 26 F5.3 mag e_Imag rms uncertainty in Imag
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Acknowledgements:
Cheongho Han, cheongho(at)astroph.chungbuk.ac.kr
(End) Patricia Vannier [CDS] 19-Mar-2021