J/AJ/169/288 Light curves of microlensing events revealing planets (Han+, 2025)
Four planets found through microlensing events involving faint source stars.
Han C., Albrow M.D., Lee C.-U., Chung S.-J., Gould A., Hwang K.-H.,
Jung Y.K., Ryu Y.-H., Shvartzvald Y., Shin I.-G., Yee J.C., Yang H.,
Zang W., Cha S.-M., Kim D., Kim D.-J., Kim S.-L., Lee D.-J., Lee Y.,
Park B.-G., Pogge R.W.
<Astron. J., 169, 288 (2025)>
=2025AJ....169..288H 2025AJ....169..288H
ADC_Keywords: Exoplanets; Photometry; Optical; Gravitational lensing
Keywords: Gravitational microlensing exoplanet detection ;
Gravitational microlensing
Abstract:
To conduct a comprehensive demographic study of microlensing planets,
it is essential to detect all planetary signals that exceed a
predefined threshold through a detailed analysis of survey data. We
reanalyzed previous data from the Korea Microlensing Telescope Network
survey to search for weak planetary signals in lensing events
involving faint source stars. For events with potential short-term
anomalies identified in the initial search, we validated the signals
using rereduced data and conducted detailed modeling of the anomalous
events. This process led to the discovery of four planetary events:
KMT-2017-BLG-2197, KMT-2022-BLG-1790, KMT-2022-BLG-2076, and
KMT-2023-BLG-2209. For all these events, the modeling resulted in two
solutions due to the well-known inner-outer degeneracy. The estimated
masses of the planets and their hosts are approximately
(Mp/MJ,Mh/M☉)~(0.36,7.9) for KMT-2017-BLG-2197L,
~(0.6,1.7) for KMT-2022-BLG-1790L, ~(0.67,0.9) for KMT-2022-BLG-2076L,
and ~(0.73,0.8) for KMT-2023-BLG-2209L. The planetary systems
KMT-2017-BLG-2197L and KMT-2022-BLG-1790L are likely located in the
Galactic bulge, while KMT-2022-BLG-2076L and KMT-2023-BLG-2209L are
more likely situated in the disk.
Description:
All the planets reported in this work were discovered through the
analysis of events exclusively detected by the KMTNet survey. The
KMTNet survey operates using three telescopes located at Siding Spring
Observatory in Australia (KMTA), Cerro Tololo Inter-American
Observatory in Chile (KMTC), and South African Astronomical
Observatory in South Africa (KMTS). These identical telescopes each
feature a 1.6m aperture and are equipped with a camera offering a
4deg2 field of view. The events were identified using the KMT
EventFinder system (Kim+, 2018AJ....155...76K 2018AJ....155...76K) applied to the data.
For the events KMT-2022-BLG-1790 and KMT-2023-BLG-2209, the source is
located in the overlapping region of two primary fields, toward which
observations were conducted with a 0.5hr cadence for each field,
resulting in a combined cadence of 0.25hr.
Observations of the events were primarily carried out in the I band of
the Johnson-Cousins BVRI filter system. To determine the source
color of the events, approximately one-tenth of the images were taken
in the V band. The observational cadence varied from 0.25 to 2.5hr,
depending on the event. For the data used in the analysis, we adjusted
the errors to ensure that they aligned with the scatter of the data
and that the χ2 value for the best-fit model equaled unity for
each data set.
Objects:
-----------------------------------------------------------------
RA (2000) DE Designation(s)
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17 30 26.71 -30 09 33.5 KMT-2017-BLG-2197 = KMT-2017-BLG-2197
18 04 13.50 -27 02 05.1 KMT-2022-BLG-1790 = KMT-2022-BLG-1790
17 52 12.27 -29 01 40.5 KMT-2022-BLG-2076 = KMT-2022-BLG-2076
17 55 58.60 -29 18 20.4 KMT-2023-BLG-2209 = KMT-2023-BLG-2209
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 92 4 Source coordinates, I-band extinction, observation
field, and cadence
dbf1/* . 4 Light curve of the lensing event KMT-2017-BLG-2197
(Data behind Figure 1)
dbf3/* . 7 Lensing light curve of KMT-2022-BLG-1790
(Data behind Figure 3)
dbf5/* . 4 Light curve of the lensing event KMT-2022-BLG-2076
(Data behind Figure 5)
dbf7/* . 7 Lensing light curve of KMT-2023-BLG-2209
(Data behind Figure 7)
lc/* . 18 Interactive light curves files (added by CDS)
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See also:
J/A+A/549/A147 : Abund. of microlensed bulge dwarf stars. V. (Bensby+, 2013)
J/AJ/161/293 : LCs of OGLE-2018-BLG-0567 and OGLE-2018-BLG-0962 (Jung+, 2021)
J/AJ/162/163 : Systematic KMTNet Planetary Anomaly Search. I. (Zang+, 2021)
J/AJ/163/43 : Systematic KMTNet Planetary Anomaly Search. II. (Hwang+, 2022)
J/AJ/165/103 : Systematic KMTNet Planetary Anomaly Search. VII. (Zang+, 2023)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 17 A17 --- Event Event identifier
19- 20 I2 h RAh Hour of right ascension (J2000)
22- 23 I2 min RAm Minute of right ascension (J2000)
25- 29 F5.2 s RAs Second of right ascension (J2000)
31 A1 --- DE- Sign of declination (J2000)
32- 33 I2 deg DEd Degree of declination (J2000)
35- 36 I2 arcmin DEm Arcminute of declination (J2000)
38- 42 F5.2 arcsec DEs Arcsecond of declination (J2000)
44- 50 F7.4 deg l [-2.8/3.8] Galactic longitude
52- 58 F7.4 deg b [-2.6/2.2] Galactic latitude
60- 64 F5.2 mag Imag [19/20.6] I band baseline magnitude
66- 69 F4.2 mag AI [1.24/2.91] Extinction toward the field
71- 82 A12 --- Field KMTNet field name
84- 87 F4.2 h Cad [0.25/2.5] Observational cadence
89- 92 A4 --- Files Link to the light curve files in MRT format
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 19-Feb-2026