The multiplicity of massive stars in the Orion Nebula cluster as seen with long-baseline interferometry

The characterization of multiple stellar systems is an important ingredient for testing current star formation models. Stars are more often found in multiple systems, the more massive they are. A complete knowledge of the multiplicity of high-mass stars over the full range of orbit separations is thus essential to understand their still debated formation process. Observations of the Orion Nebula Cluster can help to answer the question about the origin and evolution of multiple stars. Earlier studies provide a good knowledge about the multiplicity of the stars at very small (spectroscopic) and large separations (AO, speckle) and thus make the ONC a good target for such a project. We used the NIR interferometric instrument AMBER at VLTI to observe a sample of bright stars in the ONC. We complement our data set by archival NACO observations of \theta 1 Ori A to obtain more information about the orbit of the close visual companion. Our observations resolve the known multiple systems \theta 1 Ori C and \theta 1 Ori A and provide new orbit points, which confirm the predicted orbit and the determined stellar parameters for \theta 1 Ori C. Combining AMBER and NACO data for \theta 1 Ori A we were able to follow the motion of the companion from 2003 to 2011. We furthermore find hints for a companion around \theta 1 Ori D and a previously unknown companion to NU Ori. With a probability of ~90% we can exclude further companions with masses of > 3 Msun around our sample stars for separations between ~2 mas and ~110 mas. We conclude that the companion around \theta 1 Ori A is most likely physically related to the primary star. The newly discovered possible companions further increase the multiplicity in the ONC. For our sample of two O and three B-type stars we find on average 2.5 known companions per primary, which is around five times more than for low-mass stars.Comment: accepted by A&

Planetary Candidates Observed by Kepler V: Planet Sample from Q1-Q12 (36 Months)

The Kepler mission discovered 2842 exoplanet candidates with 2 years of data. We provide updates to the Kepler planet candidate sample based upon 3 years (Q1-Q12) of data. Through a series of tests to exclude false-positives, primarily caused by eclipsing binary stars and instrumental systematics, 855 additional planetary candidates have been discovered, bringing the total number known to 3697. We provide revised transit parameters and accompanying posterior distributions based on a Markov Chain Monte Carlo algorithm for the cumulative catalogue of Kepler Objects of Interest. There are now 130 candidates in the cumulative catalogue that receive less than twice the flux the Earth receives and more than 1100 have a radius less than 1.5 Rearth. There are now a dozen candidates meeting both criteria, roughly doubling the number of candidate Earth analogs. A majority of planetary candidates have a high probability of being bonafide planets, however, there are populations of likely false-positives. We discuss and suggest additional cuts that can be easily applied to the catalogue to produce a set of planetary candidates with good fidelity. The full catalogue is publicly available at the NASA Exoplanet Archive.Comment: Accepted for publication, ApJ

First Data Release of the Hyper Suprime-Cam Subaru Strategic Program

The Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) is a three-layered imaging survey aimed at addressing some of the most outstanding questions in astronomy today, including the nature of dark matter and dark energy. The survey has been awarded 300 nights of observing time at the Subaru Telescope and it started in March 2014. This paper presents the first public data release of HSC-SSP. This release includes data taken in the first 1.7 years of observations (61.5 nights) and each of the Wide, Deep, and UltraDeep layers covers about 108, 26, and 4 square degrees down to depths of i~26.4, ~26.5, and ~27.0 mag, respectively (5sigma for point sources). All the layers are observed in five broad bands (grizy), and the Deep and UltraDeep layers are observed in narrow bands as well. We achieve an impressive image quality of 0.6 arcsec in the i-band in the Wide layer. We show that we achieve 1-2 per cent PSF photometry (rms) both internally and externally (against Pan-STARRS1), and ~10 mas and 40 mas internal and external astrometric accuracy, respectively. Both the calibrated images and catalogs are made available to the community through dedicated user interfaces and database servers. In addition to the pipeline products, we also provide value-added products such as photometric redshifts and a collection of public spectroscopic redshifts. Detailed descriptions of all the data can be found online. The data release website is https://hsc-release.mtk.nao.ac.jp/.Comment: 34 pages, 20 figures, 7 tables, moderate revision, accepted for publication in PAS

High-Contrast Imaging of Intermediate-Mass Giants with Long-Term Radial Velocity Trends

A radial velocity (RV) survey for intermediate-mass giants has been operated for over a decade at Okayama Astrophysical Observatory (OAO). The OAO survey has revealed that some giants show long-term linear RV accelerations (RV trends), indicating the presence of outer companions. Direct imaging observations can help clarify what objects generate these RV trends. We present the results of high-contrast imaging observations of six intermediate-mass giants with long-term RV trends using the Subaru Telescope and HiCIAO camera. We detected co-moving companions to gamma Hya B (0.61+0.12 0.14 Stellar Mass), HD 5608 B (0.10 +/- 0.01 Stellar Mass), and HD 109272 B (0.28 +/- 0.06 Stellar Mass). For the remaining targets( Dra, 18 Del, and HD 14067) we exclude companions more massive than 30-60 M(sub Jup) at projected separations of 1-7. We examine whether these directly imaged companions or unidentified long-period companions can account for the RV trends observed around the six giants. We find that the Kozai mechanism can explain the high eccentricity of the inner planets Dra b, HD 5608 b, and HD 14067 b

VaTEST II: Statistical Validation of 11 TESS-Detected Exoplanets Orbiting K-type Stars

NASA's Transiting Exoplanet Survey Satellite (TESS) is an all-sky survey mission designed to find transiting exoplanets orbiting nearby bright stars. It has identified more than 329 transiting exoplanets, and almost 6,000 candidates remain unvalidated. In this manuscript, we discuss the findings from the ongoing VaTEST (Validation of Transiting Exoplanets using Statistical Tools) project, which aims to validate new exoplanets for further characterization. We validated 11 new exoplanets by examining the light curves of 24 candidates using the LATTE and TESS-Plot tools and computing the False Positive Probabilities using the statistical validation tool TRICERATOPS. These include planets suitable for atmospheric characterization using transmission spectroscopy (TOI-2194b), emission spectroscopy (TOI-3082b and TOI-5704b) and for both transmission and emission spectroscopy (TOI-672b, TOI- 1694b, and TOI-2443b); One super-Earth (TOI-2194b) orbiting a bright (V = 8.42 mag), metal-poor ([Fe/H] = -0.3720 $\pm$ 0.1) star; one short-period Neptune-like planet (TOI-5704) in the Hot Neptune Desert. In total, we validated 1 super-Earth, 7 sub-Neptunes, 1 Neptune-like, and 2 sub-Saturn or super-Neptune-like exoplanets. Additionally, we identify five likely planet candidates (TOI-323, TOI- 1180, TOI-2200, TOI-2408 and TOI-3913) which can be further studied to establish their planetary nature.Comment: Accepted for Publication in Astronomical Journal, 28 Pages, 7 Figure

The Fundamental Stellar Parameters of FGK Stars in the SEEDS Survey Norman, OK 73071, USA

Large exoplanet surveys have successfully detected thousands of exoplanets to-date. Utilizing these detections and non-detections to constrain our understanding of the formation and evolution of planetary systems also requires a detailed understanding of the basic properties of their host stars. We have determined the basic stellar properties of F, K and G stars in the Strategic Exploration of Exoplanets and Disks with Subaru (SEEDS) survey from Echelle spectra taken at the Apache Point Observatory's 3.5m telescope. Using ROBOSPECT to extract line equivalent widths and Temperature Gravity microtrubulent Velocity ITerations to calculate the fundamental parameters, we have computed T(sub eff), log(g), v(sub t), [Fe/H], chromospheric activity and the age for our sample. Our methodology was calibrated against previously published results for a portion of our sample. The distribution of [Fe/H] in our sample is consistent with that typical of the Solar neighbourhood. Additionally, we find the ages of most of our sample are less than 500 Myr, but note that we cannot determine robust ages from significantly older stars via chromospheric activity age indicators. The future meta-analysis of the frequency of wide stellar and sub-stellar companions imaged via the SEEDS survey will utilize our results to constrain the occurrence of detected comoving companions with the properties of their host stars