J/AJ/159/116 I-band light curves of OGLE-2015-BLG-1771Lb (Zhang+, 2020)
OGLE-2015-BLG-1771Lb: a microlens planet orbiting an ultracool dwarf?
Zhang X., Zang W., Udalski A., Gould A., Ryu Y.-H., Wang T., Yang H.,
Mao S., Mroz P., Skowron J., Poleski R., Szymanski M.K., Soszynski I.,
Pietrukowicz P., KozloGwski S., Ulaczyk K., Albrow M.D., Chung S.-J.,
Han C., Hwang K.-H., Jung Y.K., Shin I.-G., Shvartzvald Y., Yee J.C.,
Zhu W., Cha S.-M., Kim D.-J., Kim H.-W., Kim S.-L., Lee C.-U., Lee D.-J.,
Lee Y., Park B.-G., Pogge R.W.
<Astron. J., 159, 116 (2020)>
=2020AJ....159..116Z 2020AJ....159..116Z
ADC_Keywords: Gravitational lensing; Exoplanets; Photometry, RI
Keywords: Gravitational microlensing exoplanet detection
Abstract:
We report the discovery and the analysis of the short (tE<5days)
planetary microlensing event, OGLE-2015-BLG-1771. The event was
discovered by the Optical Gravitational Lensing Experiment, and the
planetary anomaly (at I∼19) was captured by The Korea Microlensing
Telescope Network. The event has three surviving planetary models that
explain the observed light curves, with planet-host mass ratio
q∼5.4x10-3, 4.5x10-3 and 4.5x10-2, respectively. The first model
is the best-fit model, while the second model is disfavored by
Δχ2^_∼3. The last model is strongly disfavored by
Δχ2^_∼15 but not ruled out. A Bayesian analysis using a
Galactic model indicates that the first two models are probably
composed of a Saturn-mass planet orbiting a late M dwarf, while the
third one could consist of a super-Jovian planet and a mid-mass brown
dwarf. The source-lens relative proper motion is µrel∼9mas/yr, so
the source and lens could be resolved by current adaptive-optics
instruments in 2020 if the lens is luminous.
Description:
OGLE-2015-BLG-1771 was discovered by the Optical Gravitational Lensing
Experiment (OGLE, 2015AcA....65....1U 2015AcA....65....1U) using its 1.3m Warsaw Telescope
at the Las Campanas Observatory in Chile and alerted by the OGLE Early
Warning System at UT 00:46 on 2015 August 2. The event was located at
equatorial coordinates (RAJ2000=17:55:11.76,DEJ2000=-28:51:45.9). It
therefore lies in OGLE field BLG505, monitored by OGLE with a cadence
of Γ=3/hr.
The event was also observed by the Korea Microlensing Telescope
Network (KMTNet). KMTNet consists of three 1.6m telescopes, equipped
with 4deg2 field-of-view cameras at the Cerro Tololo Interamerican
Observatory (CTIO) in Chile (KMTC), the South African Astronomical
Observatory (SAAO) in South Africa (KMTS), and the Siding Spring
Observatory (SSO) in Australia (KMTA). The event was located in the
KMTNet BLG02 field, which was observed in 2015 with a cadence of
Γ=6/hr.
The majority of observations by OGLE and KMTNet were taken in the
I-band, with some V-band images taken for the color measurement of
microlens sources.
Objects:
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RA (ICRS) DE Designation(s)
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17 55 11.76 -28 51 45.9 OGLE-2015-BLG-1771Lb = NAME EWS 2015-BLG-1771b
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
kmta.dat 52 2032 KMTA (Siding Spring Observatory, Australia)
I band light curve
kmtc.dat 52 4343 KMTC (Cerro Tololo Interamerican Observatory, Chile)
I band light curve
kmts.dat 52 2683 KMTS (South African Astronomical Observatory)
I band light curve
ogle.dat 26 15700 OGLE (Las Campanas Observatory, Chile)
I band light curve
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See also:
J/AcA/50/421 : OGLE-II DIA BUL_SC1 field (Wozniak, 2000)
J/other/Nat/481.167 : 2002-2007 PLANET microlensing events (Assan+, 2012)
J/A+A/549/A147 : Abundances microlensed bulge dwarf stars.V. (Bensby+,2013)
J/MNRAS/457/4089 : Frequency of snowline-region planets (Shvartzvald+, 2016)
J/AJ/154/210 : 2015 high-cadence Spitzer microlensing events (Zhu+, 2017)
J/A+A/617/A135 : 20 years of photometric microlensing (Mustill+, 2018)
J/A+A/618/A44 : Predicted microlensing events from Gaia DR2 (Bramich, 2018)
J/AcA/68/183 : Microlensing Events for 21st Century (Bramich+, 2018)
J/A+A/627/A49 : Teegarden's Star RV and Hα curves (Zechmeister+,2019)
J/ApJS/244/29 : Microlensing events toward the Galactic bulge (Mroz+, 2019)
J/A+A/633/A98 : Gaia16aye microlensing event photometry (Wyrzykowski+,2020)
Byte-by-byte Description of file: kmt*.dat
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Bytes Format Units Label Explanations
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1- 10 F10.5 d HJD [7056.8/7316] Heliocentric Julian Date;
HJD-2450000
12- 24 F13.4 --- delta [-1799193/253464] Delta flux
26- 35 F10.4 --- e_delta [124/60676] Uncertainty in delta
37- 41 F5.2 arcsec FWHM [-1/14.4] Seeing full width at half maximum
43- 47 I5 ct/s Sky [194/40595] Sky brightness
49- 52 F4.2 --- Airmass [1/1.95] Airmass (secz)
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Byte-by-byte Description of file: ogle.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d HJD [2455260/2458426] Heliocentric Julian Date
15- 20 F6.3 mag Imag [19.12/22.07] OGLE I band magnitude (1)
22- 26 F5.3 mag e_Imag [0.04/1.89] Uncertainty in Imag
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Note (1): The I band magnitude is the instrumental magnitude but the difference
to the standard I-band magnitude is within 0.2mag
(Udalski+, 2015AcA....65....1U 2015AcA....65....1U).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 29-Apr-2020