373 research outputs found
A Monitoring Campaign for Luhman 16AB. I. Detection of Resolved Near-Infrared Spectroscopic Variability
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The EBLM Project I-Physical and orbital parameters, including spin-orbit angles, of two low-mass eclipsing binaries on opposite sides of the Brown Dwarf limit
Full text linkpeer reviewedThis paper introduces a series of papers aiming to study the dozens of low mass eclipsing binaries (EBLM), with F, G, K primaries, that have been discovered in the course of the WASP survey. Our objects are mostly single-line binaries whose eclipses have been detected by WASP and were initially followed up as potential planetary transit candidates. These have bright primaries, which facilitates spectroscopic observations during transit and allows the study of the spin-orbit distribution of F, G, K+M eclipsing binaries through the Rossiter-McLaughlin effect. Here we report on the spin-orbit angle of WASP-30b, a transiting brown dwarf, and improve its orbital parameters. We also present the mass, radius, spin-orbit angle and orbital parameters of a new eclipsing binary, J1219-39b (1SWAPJ121921.03-395125.6, TYC 7760-484-1), which, with a mass of 95 +/- 2 Mjup, is close to the limit between brown dwarfs and stars. We find that both objects orbit in planes that appear aligned with their primaries' equatorial planes. Neither primaries are synchronous. J1219-39b has a modestly eccentric orbit and is in agreement with the theoretical mass--radius relationship, whereas WASP-30b lies above it
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A GROUND-BASED OPTICAL TRANSMISSION SPECTRUM OF WASP-6b
No full textWe present a ground-based optical transmission spectrum of the inflated sub-Jupiter-mass planet WASP-6b. The spectrum was measured in 20 spectral channels from 480 nm to 860 nm using a series of 91 spectra over a complete transit event. The observations were carried out using multi-object differential spectrophotometry with the Inamori-Magellan Areal Camera and Spectrograph on the Baade Telescope at Las Campanas Observatory. We model systematic effects on the observed light curves using principal component analysis on the comparison stars and allow for the presence of short and long memory correlation structure in our Monte Carlo Markov Chain analysis of the transit light curves for WASP-6. The measured transmission spectrum presents a general trend of decreasing apparent planetary size with wavelength and lacks evidence for broad spectral features of Na and K predicted by clear atmosphere models. The spectrum is consistent with that expected for scattering that is more efficient in the blue, as could be caused by hazes or condensates in the atmosphere of WASP-6b. WASP-6b therefore appears to be yet another massive exoplanet with evidence for a mostly featureless transmission spectrum, underscoring the importance that hazes and condensates can have in determining the transmission spectra of exoplanets.Fondo Nacional de Desarrollo Científico y Tecnológico (Chile) (FONDECYT project 1130857)Comisión Nacional de Investigación Ciencia y Tecnología (Chile) (BASAL CATA PFB-06)World Bank (Millennium Science Initiative)Chile. Ministry of Economy (Nucleus P10-022-F)Pontifical Catholic University of Chile (proyecto investigacion interdisciplinaria 25/2011)Comisión Nacional de Investigación Ciencia y Tecnología (Chile) (CONICYT-PCHA/Doctorado Nacional)Fondo Nacional de Desarrollo Científico y Tecnológico (Chile) (FONDECYT postdoctoral fellowship 3120097)Science and Technology Facilities Council (Great Britain) (STFC consolidated grant ST/J0016/1)United States. National Aeronautics and Space Administration (Sagan Exoplanet Fellowship administered by the NASA Exoplanet Science Institute (NExScI))Swiss National Science Foundation (Fellow, grant number PBGEP2-145594
Exoplanets: Migration of giants
No full textThe origin of hot Jupiters, large gaseous planets in close orbits around stars, is unknown. Observations suggest that such planets are abundant in stellar clusters, and can result from encounters with other celestial bodies
VaTEST. II. Statistical Validation of 11 TESS-detected Exoplanets Orbiting K-type Stars
No full textMistry, Priyashkumar et al.--Full list of authors: Mistry, Priyashkumar; Pathak, Kamlesh; Prasad, Aniket; Lekkas, Georgios; Bhattarai, Surendra; Gharat, Sarvesh; Maity, Mousam; Kumar, Dhruv; Collins, Karen A.; Schwarz, Richard P.; Mann, Christopher R.; Furlan, Elise; Howell, Steve B.; Ciardi, David; Bieryla, Allyson; Matthews, Elisabeth C.; Gonzales, Erica; Ziegler, Carl; Crossfield, Ian; Giacalone, Steven; Tan, Thiam-Guan; Evans, Phil; Helminiak, Krzysztof G.; Collins, Kevin I.; Narita, Norio; Fukui, Akihiko; Pozuelos, Francisco J.; Dressing, Courtney; Soubkiou, Abderahmane; Benkhaldoun, Zouhair; Schlieder, Joshua E.; Suarez, Olga; Barkaoui, Khalid; Palle, Enric; Murgas, Felipe; Srdoc, Gregor; Goliguzova, Maria V.; Strakhov, Ivan A.; Gnilka, Crystal; Lester, Kathryn; Littlefield, Colin; Scott, Nic; Matson, Rachel; Gillon, Michael; Jehin, Emmanuel; Timmermans, Mathilde; Ghachoui, Mourad; Abe, Lyu; Bendjoya, Philippe; Guillot, Tristan; Triaud, Amaury H. M. J.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 6000 candidates remain unvalidated. In this manuscript, we discuss the findings from the ongoing Validation of Transiting Exoplanets using Statistical Tools (VaTEST) 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). Our validated planets have one super-Earth (TOI-2194b) orbiting a bright (V = 8.42 mag), metal-poor ([Fe/H] = −0.3720 ± 0.1) star, and one short-period Neptune-like planet (TOI-5704) in the hot-Neptune desert. In total, we validated one super-Earth, seven sub-Neptunes, one Neptune-like, and two 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. © 2023. The Author(s). Published by the American Astronomical Society.M.V.G. and I.A.S. acknowledge the support of Ministry of Science and Higher Education of the Russian Federation under the grant 075-15-2020-780 (N13.1902.21.0039). Funding for the TESS mission is provided by NASA's Science Mission Directorate. KAC acknowledges support from the TESS mission via subaward s3449 from MIT. Some of the observations in this paper made use of the High-Resolution Imaging instruments 'Alopeke and Zorro and were obtained under Gemini LLP Proposal Number: GN/S-2021A-LP-105. 'Alopeke and Zorro were funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. 'Alopeke was mounted on the Gemini North telescope of the international Gemini Observatory, a program of NSF's OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. On behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigación y Desarrollo (Chile), Ministerio de Ciencia, Tecnología e Innovación (Argentina), Ministério da Ciência, Tecnologia, Inovações e Comunicações (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This work makes use of observations from the LCOGT network. Part of the LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF. This paper makes use of observations made with the MuSCAT2 instrument, developed by the Astrobiology Center, at TCS operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This paper is based on observations made with the MuSCAT3 instrument, developed by the Astrobiology Center and under financial supports by JSPS KAKENHI (JP18H05439) and JST PRESTO (JPMJPR1775), at Faulkes Telescope North on Maui, HI, operated by the Las Cumbres Observatory. This research has made use of the Exoplanet Follow-up Observation Program (ExoFOP; DOI:10.26134/ExoFOP5) website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This publication makes use of data products collected by the TESS mission and obtained from the MAST data archive at the Space Telescope Science Institute (STScI). The light curve and target pixel file data used in this paper can be found in 10.17909/t9-nmc8-f686. C.M. would like to gratefully acknowledge the entire Dragonfly Telephoto Array team, and Bob Abraham in particular, for allowing their telescope bright time to be put to use observing exoplanets. TRAPPIST-South is funded by the Belgian National Fund for Scientific Research (F.R.S.-FNRS) under grant PDR T.0120.21, with the participation of the Swiss National Science Fundation (SNF). M.G. is F.R.S-FNRS Research Director. E.J. is F.R.S-FNRS Senior Research Associate. The postdoctoral fellowship of KB is funded by F.R.S.-FNRS grant T.0109.20 and by the Francqui Foundation. This publication benefits from the support of the French Community of Belgium in the context of the FRIA Doctoral Grant awarded to MT. F.J.P. acknowledges financial support from the grant CEX2021-001131-S funded by MCIN/AEI/ 10.13039/501100011033. This research received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement n° 803193/BEBOP), and from the Science and Technology Facilities Council (STFC; grant n° ST/S00193X/1). This work makes use of observations from the ASTEP telescope. ASTEP benefited from the support of the French and Italian polar agencies IPEV and PNRA in the framework of the Concordia station program, from INSU, ESA, the University of Birmingham, and STFC.With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2021-001131-S).Peer reviewe
Confirming & detecting circumbinary planets using radial-velocities.
Full text linkThanks to its long photometric stares, PLATO will likely identify multiple transiting circumbinary planets. However the duration of its long stares are insufficient to measure circumbinary planet masses accurately using eclipse timing variations of the central binary. In this talk I show our efforts on HARPS and SOPHIE to detect circumbinary planets orbiting single-lined eclipse binaries. I will show the first ground-based detections of circumbinary planets made by SOPHIE, HARPS in radial-velocities, and the
first circumbinary planet transit obtained from ground, using ASTEP in Antarctica. The methods we are developing are key to prepare for the confirmation of PLATO's circumbinary planets
Hubble Space Telescope search for the transit of the Earth-mass exoplanet α Centauri B b
Full text linkpeer reviewedResults from exoplanet surveys indicate that small planets (super-Earth size and below) are abundant in our Galaxy. However, little is known about their interiors and atmospheres. There is therefore a need to find small planets transiting bright stars, which would enable a detailed characterization of this population of objects. We present the results of a search for the transit of the Earth-mass exoplanet α Centauri B b with the Hubble Space Telescope (HST). We observed α Centauri B twice in 2013 and 2014 for a total of 40 h. We achieve a precision of 115 ppm per 6-s exposure time in a highly saturated regime, which is found to be consistent across HST orbits. We rule out the transiting nature of α Centauri B b with the orbital parameters published in the literature at 96.6 per cent confidence. We find in our data a single transit-like event that could be associated with another Earth-sized planet in the system, on a longer period orbit. Our programme demonstrates the ability of HST to obtain consistent, high-precision photometry of saturated stars over 26 h of continuous observations
The BANANA Project. V. Misaligned and Precessing Stellar Rotation Axes in CV Velorum
Full text linkpeer reviewedAs part of the Binaries Are Not Always Neatly Aligned project (BANANA), we have found that the eclipsing binary CV Velorum has misaligned rotation axes. Based on our analysis of the Rossiter-McLaughlin effect, we find sky-projected spin-orbit angles of β[SUB]p[/SUB] = -52° ± 6° and β[SUB]s[/SUB] = 3° ± 7° for the primary and secondary stars (B2.5V + B2.5V, P = 6.9 days). We combine this information with several measurements of changing projected stellar rotation speeds (vsin i [SUB]sstarf[/SUB]) over the last 30 yr, leading to a model in which the primary star's obliquity is ≈65°, and its spin axis precesses around the total angular momentum vector with a period of about 140 yr. The geometry of the secondary star is less clear, although a significant obliquity is also implicated by the observed time variations in the vsin i [SUB]sstarf[/SUB]. By integrating the secular tidal evolution equations backward in time, we find that the system could have evolved from a state of even stronger misalignment similar to DI Herculis, a younger but otherwise comparable binary. Based on observations made with ESOs 2.2 m Telescopes at the La Silla Paranal Observatory under programme ID 084.C-1008 and under MPIA guaranteed time
The Rossiter–McLaughlin Effect in Exoplanet Research
No full textThe Rossiter-McLaughlin effect occurs during a planet's transit. It provides the main means of measuring the sky-projected spin-orbit angle between a planet's orbital plane and its host star's equatorial plane. Observing the Rossiter-McLaughlin effect is now a near routine procedure. It is an important element in the orbital characterization of transiting exoplanets. Measurements of the spin-orbit angle have revealed a surprising diversity, far from the placid, Kantian, and Laplacian ideals, whereby planets form, and remain, on orbital planes coincident with their star's equator. This chapter will review a short history of the Rossiter-McLaughlin effect, how it is modeled, and will summarize the current state of the field before describing other uses for a spectroscopic transit and alternative methods of measuring the spin-orbit angle.</p
Small Star Opportunities
No full textThe small star opportunity usually refers to considering low-mass stars of M dwarf spectral type in order to improve the prospects of detecting low-mass exoplanets using Doppler and transit surveys. Besides exoplanet detection and atmospheric characterization, small stars also offer multiple opportunities to investigate other questions, including key aspects of planet formation. This chapter discusses the important questions, opportunities and challenges in this direction
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