We present a catalog of 1143 periodic variables, compiled from our image-subtracted photometric analysis of the K2 Campaign-0 super stamp. This super stamp is centered on the open clusters M35 and ...NGC 2158. Approximately 46% of our periodic variables were previously unreported. Of the catalog variables, we find that 331 are members of M35 and 56 are members of NGC 2158 ( ). Our catalog contains two new transiting exoplanet candidates, both of which orbit field stars. The smaller planet candidate has a radius of 0.35 0.04 and orbits a K dwarf ( = 15.4 mag) with a transit depth of 2.9 millimag. The larger planet candidate has a radius of 0.72 0.02 and orbits a late G-type star ( = 15.7 mag) with a transit depth of 2.2 millimag. The larger planet candidate may be an unresolved binary or a false alarm. Our catalog includes 44 eclipsing binaries (EBs), including ten new detections. Of the EBs, one is an M35 member and five are NGC 2158 members. Our catalog contains a total of 1097 nontransiting variable stars, including a field δ Cepheid exhibiting double mode pulsations, 561 rotational variables, and 251 pulsating variables (primarily γ Doradus and δ Scuti types). The periods of our catalog sources range between 43 minutes to 24 days. The known ages of our reported cluster variables will facilitate investigations of a variety of stellar evolutionary processes.
Renewable energy sources and especially solar energy may be the answer to the increasing demand for energy, leading to the reduction of fossil fuel consumption and its associated negative ...environmental impact. An attractive solution to this problem could be the combination of renewable and conventional energy sources technologies such as the integrated solar combined cycle power plants (ISCCP). In this paper the operation of a 50 MW ISCCP with natural gas and parabolic trough solar collectors was simulated using TRNSYS software. The proposed power plant performance, fuel consumption and solar contribution were analyzed through six different simulation scenarios for different collector area. Two different modes of operation, namely power boost and fuel saving, were considered. Also, an economic analysis shows the optimal contribution rate of solar field taking into consideration the results of various simulation scenarios.
•Development of new technique for integration of solar thermal technologies in conventional power plants.•Development of easy use TRNSYS software for integration of solar energy to power plant.•Analysis of six different simulation scenarios and two different modes of operation.
We observed the open clusters M35 and NGC 2158 during the initial K2 campaign (C0). Reducing these data to high-precision photometric timeseries is challenging due to the wide point-spread function ...(PSF) and the blending of stellar light in such dense regions. We developed an image-subtraction-based K2 reduction pipeline that is applicable to both crowded and sparse stellar fields. We applied our pipeline to the data-rich C0 K2 super stamp, containing the two open clusters, as well as to the neighboring postage stamps. In this paper, we present our image subtraction reduction pipeline and demonstrate that this technique achieves ultra-high photometric precision for sources in the C0 super stamp. We extract the raw light curves of 3960 stars taken from the UCAC4 and EPIC catalogs and de-trend them for systematic effects. We compare our photometric results with the prior reductions published in the literature. For de-trended TFA-corrected sources in the 12-12.25 K p magnitude range, we achieve a best 6.5-hour window running rms of 35 ppm, falling to 100 ppm for fainter stars in the 14-14.25 K p magnitude range. For stars with K p > 14 , our de-trended and 6.5-hour binned light curves achieve the highest photometric precision. Moreover, all our TFA-corrected sources have higher precision on all timescales investigated. This work represents the first published image subtraction analysis of a K2 super stamp. This method will be particularly useful for analyzing the Galactic bulge observations carried out during K2 campaign 9. The raw light curves and the final results of our de-trending processes are publicly available at http://k2.hatsurveys.org/archive/.
We report the discovery of four transiting F-M binary systems with companions between 0.1 and 0.2 M in mass by the HATSouth survey. These systems have been characterized via a global analysis of the ...HATSouth discovery data, combined with high-resolution radial velocities and accurate transit photometry observations. We determined the masses and radii of the component stars using a combination of two methods: isochrone fitting of spectroscopic primary star parameters and equating spectroscopic primary star rotation velocity with spin-orbit synchronization. These new very low mass companions are HATS550-016B (
,
), HATS551-019B (
,
), HATS551-021B (
,
) and HATS553-001B (
,
). We examine our sample in the context of the radius anomaly for fully convective low-mass stars. Combining our sample with the 13 other well-studied very low mass stars, we find a tentative 5 per cent systematic deviation between the measured radii and theoretical isochrone models.
We have performed an extensive search for planet candidates in the publicly available Kepler long cadence data from quarters Q1 through Q6. The search method consists of initial de-trending of the ...data, applying the trend filtering algorithm, searching for transit signals with the Box Least Squares fitting method in three frequency domains, visual inspection of the potential transit candidates and an in-depth analysis of the shortlisted candidates. In this paper we present 150 new periodic planet candidates and seven single transit events, 72 of which are in multiple systems. The periods of these planet candidates vary from ∼0.17 to ∼440 d. 124 of the planet candidates have radii smaller than 3 R
⊕. We recover 82.5 per cent of the Batalha et al. Kepler Objects of Interest (KOI) catalogue. We also report 40 newly identified false positives - systems that look like transiting planets, but are probably due to blended eclipsing binaries. Our search improves the statistics in the short-period and small-planet radii parameter ranges.
Abstract
We report the discovery of two transiting Neptunes by the HATSouth survey. The planet HATS-37Ab has a mass of
(31.5 ± 13.4
M
⊕
) and a radius of
, and is on a
day orbit around a
mag,
star ...with a radius of
. We also present evidence that the star HATS-37A has an unresolved stellar companion HATS-37B, with a photometrically estimated mass of
. The planet HATS-38b has a mass of
(23.5 ± 3.5
M
⊕
) and a radius of
, and is on a
day orbit around a
mag,
star with a radius of
. Both systems appear to be old, with isochrone-based ages of
Gyr, and
Gyr, respectively. Both HATS-37Ab and HATS-38b lie in the Neptune desert and are thus examples of a population with a low occurrence rate. They are also among the lowest-mass planets found from ground-based wide-field surveys to date.
Abstract
We report the discovery of 10 transiting extrasolar planets by the HATSouth survey. The planets range in mass from the super-Neptune HATS-62b, with
, to the super-Jupiter HATS-66b, with
, ...and in size from the Saturn HATS-69b, with
, to the inflated Jupiter HATS-67b, with
. The planets have orbital periods between
days (HATS-67b) and
days (HATS-61b). The hosts are dwarf stars with masses ranging from
(HATS-69) to
(HATS-64) and have apparent magnitudes between
mag (HATS-68) and
mag (HATS-66). The super-Neptune HATS-62b is the least massive planet discovered to date with a radius larger than Jupiter. Based largely on the
Gaia
DR2 distances and broadband photometry, we identify three systems (HATS-62, HATS-64, and HATS-65) as having possible unresolved binary star companions. We discuss in detail our methods for incorporating the
Gaia
DR2 observations into our modeling of the system parameters and into our blend analysis procedures.
We report the discovery of two transiting extrasolar planets by the HATSouth survey. HATS-9b orbits an old (10.8 + or - 1.5 Gyr) V = 13.3 G dwarf star with a period P approximately 1.9153 days. The ...host star has a mass of 1.03 M sub(odot), radius of 1.503 Rodot, and effective temperature 5366 + or - 70 K. The planetary companion has a mass of 0.837 M sub(J) and radius of 1.065 R sub(J), yielding a mean density of 0.85 g cm super(-3). HATS-10b orbits a V = 13.1 G dwarf star with a period P approximately 3.3128 days. The host star has a mass of 1.1 M sub(odot), radius of 1.11 R sub(odot), and effective temperature 5880 + or - 120 K. The planetary companion has a mass of 0.53 M sub(J) and radius of 0.97 R sub(J), yielding a mean density of 0.7 g cm super(-3). Both planets are compact in comparison with planets receiving similar irradiation from their host stars and lie in the nominal coordinates of Field 7 of K2, but only HATS-9b falls on working silicon. Future characterization of HATS-9b with the exquisite photometric precision of the Kepler telescope may provide measurements of its reflected light signature.
We report the discovery of HATS-17b, the first transiting warm Jupiter of the HATSouth network. HATS-17b transits its bright (V= 12.4) G-type (Mlow * = 1.131 + or - 0.030 M sub(middot in circle), ...Rlow * = (ProQuest: Formulae and/or non-USASCII text omitted) R sub(middot in circle)) metal-rich (Fe/H = +0.3 dex) host star in a circular orbit with a period of P= 16.2546 days. HATS-17b has a very compact radius of 0.777 + or - 0.056 R sub(J) given its Jupiter-like mass of 1.338 + or - 0.065 M sub(J). Up to 50% of the mass of HATS-17b may be composed of heavy elements in order to explain its high density with current models of planetary structure. HATS-17b is the longest period transiting planet discovered to date by a ground-based photometric survey, and is one of the brightest transiting warm Jupiter systems known. The brightness of HATS-17 will allow detailed follow-up observations to characterize the orbital geometry of the system and the atmosphere of the planet.
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