/ftp/cats/J_other/PASP/131/H4201



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J/PASP/131/H4201    Variable stars in Southern polar region  (Ratzloff+, 2019)
The following files can be converted to FITS (extension .fit or fit.gz)
	table10.dat table11.dat
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Query from: http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=J/PASP/131/H4201
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drwxr-xr-x 6 cats archive 134 Sep 12 2019 [Up] drwxr-xr-x 3 cats archive 297 May 26 2021 [TAR file] -rw-r--r-- 1 cats archive 480 Sep 12 2019 .message -r--r--r-- 1 cats archive 5108 Sep 12 2019 ReadMe -rw-r--r-- 1 cats archive 350 Sep 12 2019 +footg5.gif -rw-r--r-- 1 cats archive 2630 Sep 12 2019 +footg8.gif -r--r--r-- 1 cats archive 12960 Aug 14 2019 table10.dat [txt] [txt.gz] [fits] [fits.gz] [html] -r--r--r-- 1 cats archive 15264 Aug 14 2019 table11.dat [txt] [txt.gz] [fits] [fits.gz] [html]
Beginning of ReadMe : J/PASP/131/H4201 Variable stars in Southern polar region (Ratzloff+, 2019) ================================================================================ Variables in the Southern polar region Evryscope 2016 data set. Ratzloff J.K., Corbett H.T., Law N.M., Barlow B.N., Glazier A., Howard W.S., Fors O., Del Ser D., Trifonov T. <Publ. Astron. Soc. Pac., 131, h4201 (2019)> =2019PASP..131h4201R (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Stars, variable ; Binaries, eclipsing Abstract: The regions around the celestial poles offer the ability to find and characterize long-term variables from ground-based observatories. We used multi-year Evryscope data to search for high-amplitude ( =5% or greater) variable objects among 160000 bright stars (m_v_<14.5) near the South Celestial Pole. We developed a machine-learning-based spectral classifier to identify eclipse and transit candidates with M-dwarf or K-dwarf host stars, and potential low-mass secondary stars or gas-giant planets. The large amplitude transit signals from low-mass companions of smaller dwarf host stars lessens the photometric precision and systematics removal requirements necessary for detection, and increases the discoveries from long-term observations with modest light-curve precision among the faintest stars in the survey. The Evryscope is a robotic telescope array that observes the Southern sky continuously at 2-minute cadence, searching for stellar variability, transients, transits around exotic stars and other observationally challenging astrophysical variables. The multi-year photometric stability is better than 1% for bright stars in uncrowded regions, with a 3sigma limiting magnitude of g=16 in dark time. In this study, covering all stars 9<m_v_<14.5, in declinations -75deg to -90deg, and searching for high-amplitude variability, we recover 346 known variables and discover 303 new variables, including 168 eclipsing binaries. We characterize the discoveries and provide the amplitudes, periods, and variability type. A 1.7R_J_ planet candidate with a late K-dwarf primary was found and the transit signal was verified with the PROMPT telescope network. Further follow-up revealed this object to be a likely grazing eclipsing binary system with nearly identical primary and secondary K5 stars. Radial-velocity measurements from the Goodman Spectrograph on the 4.1 meter SOAR telescope of the likely lowest-mass targets reveal that six of the eclipsing binary discoveries are low-mass (0.06-0.37M_sun_) secondaries with K-dwarf primaries, strong candidates for precision mass-radius measurements. Description: All eclipsing binary and variable discoveries were detected in a transit search of the polar region (declinations -75 to -90deg). The observations were taken from Au- gust 9, 2016 to April 4, 2017. The exposure time was 120s through a Sloan-g filter and each source typically had 16000 epochs.

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