KELT-7b: A hot Jupiter transiting a bright V=8.54 rapidly rotating F-star

We report the discovery of KELT-7b, a transiting hot Jupiter with a mass of $1.28 \pm 0.18$ MJ, radius of $1.53_{-0.047}^{+0.046}$ RJ, and an orbital period of $2.7347749 \pm 0.0000039$ days. The bright host star (HD33643; KELT-7) is an F-star with $V=8.54$, Teff $=6789_{-49}^{+50}$ K, [Fe/H] $=0.139_{-0.081}^{+0.075}$, and $\log{g}=4.149 \pm 0.019$. It has a mass of $1.535_{-0.054}^{+0.066}$ Msun, a radius of $1.732_{-0.045}^{+0.043}$ Rsun, and is the fifth most massive, fifth hottest, and the ninth brightest star known to host a transiting planet. It is also the brightest star around which KELT has discovered a transiting planet. Thus, KELT-7b is an ideal target for detailed characterization given its relatively low surface gravity, high equilibrium temperature, and bright host star. The rapid rotation of the star ($73 \pm 0.5$ km/s) results in a Rossiter-McLaughlin effect with an unusually large amplitude of several hundred m/s. We find that the orbit normal of the planet is likely to be well-aligned with the stellar spin axis, with a projected spin-orbit alignment of $\lambda=9.7 \pm 5.2$ degrees. This is currently the second most rapidly rotating star to have a reflex signal (and thus mass determination) due to a planetary companion measured.Comment: Accepted to The Astronomical Journa

KELT-6b: A P~7.9 d Hot Saturn Transiting a Metal-Poor Star with a Long-Period Companion

We report the discovery of KELT-6b, a mildly-inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V=10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T_eff=6102 \pm 43 K, log(g_*)=4.07_{-0.07}^{+0.04} and [Fe/H]=-0.28 \pm 0.04, with an inferred mass M_*=1.09 \pm 0.04 M_sun and radius R_star=1.58_{-0.09}^{+0.16} R_sun. The planetary companion has mass M_P=0.43 \pm 0.05 M_J, radius R_P=1.19_{-0.08}^{+0.13} R_J, surface gravity log(g_P)=2.86_{-0.08}^{+0.06}, and density rho_P=0.31_{-0.08}^{+0.07} g~cm^{-3}. The planet is on an orbit with semimajor axis a=0.079 \pm 0.001 AU and eccentricity e=0.22_{-0.10}^{+0.12}, which is roughly consistent with circular, and has ephemeris of T_c(BJD_TDB)=2456347.79679 \pm 0.00036 and P=7.845631 \pm 0.000046 d. Equally plausible fits that employ empirical constraints on the host star parameters rather than isochrones yield a larger planet mass and radius by ~4-7%. KELT-6b has surface gravity and incident flux similar to HD209458b, but orbits a host that is more metal poor than HD209458 by ~0.3 dex. Thus, the KELT-6 system offers an opportunity to perform a comparative measurement of two similar planets in similar environments around stars of very different metallicities. The precise radial velocity data also reveal an acceleration indicative of a longer-period third body in the system, although the companion is not detected in Keck adaptive optics images.Comment: Published in AJ, 17 pages, 15 figures, 6 table

Discovery of δ Scuti Pulsations in the Young Hybrid Debris Disk Star HD 156623

The bRing robotic observatory network was built to search for circumplanetary material within the transiting Hill sphere of the exoplanet β Pic b across its bright host star β Pic. During the bRing survey of β Pic, it simultaneously monitored the brightnesses of thousands of bright stars in the southern sky (V ; 4–8, δ −30°). In this work, we announce the discovery of δ Scuti pulsations in the A-type star HD 156623 using bRing data. HD 156623 is notable as it is a well-studied young star with a dusty and gas-rich debris disk, previously detected using ALMA. We present the observational results on the pulsation periods and amplitudes for HD 156623, discuss its evolutionary status, and provide further constraints on its nature and age. We find strong evidence of frequency regularity and grouping. We do not find evidence of frequency, amplitude, or phase modulation for any of the frequencies over the course of the observations. We show that HD 156623 is consistent with other hot and highfrequency pre-main sequence and early zero-age main sequence (ZAMS) δ Scutis as predicted by theoretical models and corresponding evolutionary tracks, although we observe that HD 156623 lies hotter than the theoretical blue edge of the classical instability strip. This, coupled with our characterization and Sco–Cen membership analyses, suggests that the star is most likely an outlying ZAMS member of the ∼16 Myr Upper Centaurus-Lupus subgroup of the Sco–Cen associatio

Kelt-4Ab: An inflated hot jupiter transiting the bright (V ∼ 10) component of a hierarchical triple

We report the discovery of KELT-4Ab, an inflated, transiting Hot Jupiter orbiting the brightest component of ahierarchical triple stellar system. The host star is an F star with Teff =6206 ± 75 K, log g =4.108 ± 0.014, [Fe/H]= -0.116+0.069+0.065, M∗ = 1.201-0.061+0.067 M⊙, and R∗ = 1.603-0.038+0.039 R⊙. The best-fit linear ephemeris is BJDTDB =2456193.29157±0.00021 + E(2.9895936±0.0000048). With a magnitude of V∼10, a planetary radius of 1.699-0.045+0.046 RJ, and a mass of 0.902-0.059+0.060 MJ, it is the brightest host among the population of inflated Hot Jupiters (RP \u3e 1.5RJ), making it a valuable discovery for probing the nature of inflated planets. In addition, its existence within a hierarchical triple and its proximity to Earth (210 pc) provide a unique opportunity for dynamical studies with continued monitoring with high resolution imaging and precision radial velocities. The projected separation between KELT-4A and KELT-4BC is 328±16 AU and the projected separation between KELT-4B and KELT-4C is 10.30±0.74 AU. Assuming face-on, circular orbits, their respective periods would be 3780±290 and 29.4±3.6 years and the astrometric motions relative to the epoch in this work of both the binary stars around each other and of the binary around the primary star would be detectable now and may provide meaningful constraints on the dynamics of the system

KELT-6b: A P ~ 7.9 Day Hot Saturn Transiting a Metal-poor Star with a Long-period Companion

We report the discovery of KELT-6b, a mildly inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V = 10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T eff = 6102 ± 43 K, , and [Fe/H] = –0.28 ± 0.04, with an inferred mass M = 1.09 ± 0.04 M ☉ and radius . The planetary companion has mass MP = 0.43 ± 0.05 M Jup, radius , surface gravity , and density . The planet is on an orbit with semimajor axis a = 0.079 ± 0.001 AU and eccentricity , which is roughly consistent with circular, and has ephemeris of T c(BJDTDB) = 2456347.79679 ± 0.00036 and P = 7.845631 ± 0.000046 days. Equally plausible fits that employ empirical constraints on the host-star parameters rather than isochrones yield a larger planet mass and radius by ~4}-7}. KELT-6b has surface gravity and incident flux similar to HD 209458b, but orbits a host that is more metal poor than HD 209458 by ~0.3 dex. Thus, the KELT-6 system offers an opportunity to perform a comparative measurement of two similar planets in similar environments around stars of very different metallicities. The precise radial velocity data also reveal an acceleration indicative of a longer-period third body in the system, although the companion is not detected in Keck adaptive optics images

Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty

This study explores how researchers’ analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers’ expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each team’s workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers’ results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings

bRing: An observatory dedicated to monitoring the β Pictoris b Hill sphere transit

Aims. We describe the design and first light observations from the β Pictoris b Ring ("bRing") project. The primary goal is to detect photometric variability from the young star β Pictoris due to circumplanetary material surrounding the directly imaged young extrasolar gas giant planet β Pictoris b. Methods. Over a nine month period centred on September 2017, the Hill sphere of the planet will cross in front of the star, providing a unique opportunity to directly probe the circumplanetary environment of a directly imaged planet through photometric and spectroscopic variations. We have built and installed the first of two bRing monitoring stations (one in South Africa and the other in Australia) that will measure the flux of β Pictoris, with a photometric precision of 0.5% over 5 min. Each station uses two wide field cameras to cover the declination of the star at all elevations. Detection of photometric fluctuations will trigger spectroscopic observations with large aperture telescopes in order to determine the gas and dust composition in a system at the end of the planet-forming era. Results. The first three months of operation demonstrate that bRing can obtain better than 0.5% photometry on β Pictoris in five minutes and is sensitive to nightly trends enabling the detection of any transiting material within the Hill sphere of the exoplanet.M.A.K., R.S., P.D. gratefully acknowledge funding from NOVA and Leiden Observatory. We thank the NWO/NRF for travel funding for this project. S.M.C., and B.B.D.L. thank NRF PDP. This work is based on the research supported by the National Research Foundation. This research made use of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration et al. 2013). We thank the SAAO operations/technical staff for their logistical support in the commissioning of bRing in Sutherland.E.E.M. and S.N.M. acknowledge support from the NASA NExSS program. Construction of the bRing observatory to be sited at Siding Springs, Australia would not be possible without a University of Rochester University Research Award, help from Mike Culver and Rich Sarkis (UR), and generous donations of time, services, and materials from Joe and Debbie Bonvissuto of Freight Expediters, Michael Akkaoui and his team at Tanury Industries, Robert Harris and Michael Fay at BCI, Koch Division, Mark Paup, Dave Mellon, and Ray Miller and the Zippo Tool Room. E.E.M.’s contribution to this study was started at the University of Rochester, sponsored by a University Research Award, and was completed at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement by the United States Government or the Jet Propulsion Laboratory, California Institute of Technology. This document is approved for unlimited release (CL#17-4355). We thank our anonymous referee for comments that improved this manuscrip