scholarly journals The Rossiter-McLaughlin effect for exoplanets

2010 ◽  
Vol 6 (S276) ◽  
pp. 230-237
Author(s):  
Joshua N. Winn
Keyword(s):  
Measurement Technique ◽  
Planet Formation ◽  
Hot Jupiters ◽  
Transiting Planets ◽  
History Of ◽  
And Migration

AbstractThere are now more than 35 stars with transiting planets for which the stellar obliquity—or more precisely its sky projection—has been measured, via the eponymous effect of Rossiter and McLaughlin. The history of these measurements is intriguing. For 8 years a case was gradually building that the orbits of hot Jupiters are always well-aligned with the rotation of their parent stars. Then in a sudden reversal, many misaligned systems were found, and it now seems that even retrograde systems are not uncommon. I review the measurement technique underlying these discoveries, the patterns that have emerged from the data, and the implications for theories of planet formation and migration.

scholarly journals A New Window into Planet Formation and Migration: Refractory-to-Volatile Elemental Ratios in Ultra-hot Jupiters

2021 ◽  
Vol 914 (1) ◽  
pp. 12
Author(s):  
Joshua D. Lothringer ◽  
Zafar Rustamkulov ◽  
David K. Sing ◽  
Neale P. Gibson ◽  
Jamie Wilson ◽  
...  
Keyword(s):  
Planet Formation ◽  
Elemental Ratios ◽  
Hot Jupiters ◽  
And Migration

scholarly journals Constraining the orbit of the planet-hosting binary τ Boötis

2019 ◽  
Vol 625 ◽  
pp. A59 ◽  
Author(s):  
A. B. Justesen ◽  
S. Albrecht
Keyword(s):  
High Eccentricity ◽  
Primary Star ◽  
Orbital Inclination ◽  
Hot Jupiters ◽  
Migration History ◽  
History Of ◽  
And Migration ◽  
Planetary Migration ◽  
Astrometric Data ◽  
Hot Jupiter

Context. The formation of planets in compact or highly eccentric binaries and the migration of hot Jupiters are two outstanding problems in planet formation. Detailed characterisation of known systems is important for informing and testing models. The hot Jupiter τ Boo Ab orbits the primary star in the long-period (P ≳ 1000 yr), highly eccentric (e ~ 0.9) double star system τ Boötis. Due to the long orbital period, the orbit of the stellar binary is poorly constrained. Aims. Here we aim to constrain the orbit of the stellar binary τ Boo AB in order to investigate the formation and migration history of the system. The mutual orbital inclination of the stellar companion and the hot Jupiter has important implications for planet migration. The binary eccentricity and periastron distance are important for understanding the conditions under which τ Boo Ab formed. Methods. We combine more than 150 yr of astrometric data with twenty-five years of high-precision radial velocities. The combination of sky-projected and line-of-sight measurements places tight constraints on the orbital inclination, eccentricity, and periastron distance of τ Boo AB. Results. We determine the orbit of τ Boo B and find an orbital inclination of 47.2−3.7+2.7°, a periastron distance of 28.3−3.0+2.3 au, and an eccentricity of 0.87−0.03+0.04. We find that the orbital inclinations of τ Boo Ab and τ Boo B, as well as the stellar spin-axis of τ Boo A coincide at ~45°, a result consistent with the assumption of a well-aligned, coplanar system. Conclusions. The likely aligned, coplanar configuration suggests planetary migration within a well-aligned protoplanetary disc. Due to the high eccentricity and small periastron distance of τ Boo B, the protoplanetary disc was tidally truncated at ≈6 au. We suggest that τ Boo Ab formed near the edge of the truncated disc and migrated inwards with high eccentricity due to spiral waves generated by the stellar companion.

scholarly journals Chemical fingerprints of hot Jupiter planet formation

2018 ◽  
Vol 612 ◽  
pp. A93 ◽  
Author(s):  
J. Maldonado ◽  
E. Villaver ◽  
C. Eiroa
Keyword(s):  
Planet Formation ◽  
Statistical Tests ◽  
Giant Planets ◽  
Volatile Elements ◽  
Hot Jupiters ◽  
Chemical Fingerprints ◽  
Gas Giant ◽  
Orbital Periods ◽  
And Migration

Context. The current paradigm to explain the presence of Jupiter-like planets with small orbital periods (P < 10 days; hot Jupiters), which involves their formation beyond the snow line following inward migration, has been challenged by recent works that explore the possibility of in situ formation. Aims. We aim to test whether stars harbouring hot Jupiters and stars with more distant gas-giant planets show any chemical peculiarity that could be related to different formation processes. Methods. Our methodology is based on the analysis of high-resolution échelle spectra. Stellar parameters and abundances of C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, and Zn for a sample of 88 planet hosts are derived. The sample is divided into stars hosting hot (a < 0.1 au) and cool (a > 0.1 au) Jupiter-like planets. The metallicity and abundance trends of the two sub-samples are compared and set in the context of current models of planet formation and migration. Results. Our results show that stars with hot Jupiters have higher metallicities than stars with cool distant gas-giant planets in the metallicity range +0.00/+0.20 dex. The data also shows a tendency of stars with cool Jupiters to show larger abundances of α elements. No abundance differences between stars with cool and hot Jupiters are found when considering iron peak, volatile elements or the C/O, and Mg/Si ratios. The corresponding p-values from the statistical tests comparing the cumulative distributions of cool and hot planet hosts are 0.20, <0.01, 0.81, and 0.16 for metallicity, α, iron-peak, and volatile elements, respectively. We confirm previous works suggesting that more distant planets show higher planetary masses as well as larger eccentricities. We note differences in age and spectral type between the hot and cool planet host samples that might affect the abundance comparison. Conclusions. The differences in the distribution of planetary mass, period, eccentricity, and stellar host metallicity suggest a different formation mechanism for hot and cool Jupiters. The slightly larger α abundances found in stars harbouring cool Jupiters might compensate their lower metallicities allowing the formation of gas-giant planets.

scholarly journals Connecting planet formation and astrochemistry

2019 ◽  
Vol 627 ◽  
pp. A127 ◽  
Author(s):  
Alexander J. Cridland ◽  
Christian Eistrup ◽  
Ewine F. van Dishoeck
Keyword(s):  
Solar System ◽  
Planet Formation ◽  
Chemical Kinetic ◽  
Total Carbon ◽  
Dust Grains ◽  
Excess Carbon ◽  
Hot Jupiters ◽  
And Migration ◽  
Grain Surface ◽  
Carbon Excess

Combining a time-dependent astrochemical model with a model of planet formation and migration, we compute the carbon-to-oxygen ratio (C/O) of a range of planetary embryos starting their formation in the inner solar system (1–3 AU). Most of the embryos result in hot Jupiters (M ≥ MJ, orbital radius <0.1 AU) while the others result in super-Earths at wider orbital radii. The volatile and ice abundance of relevant carbon and oxygen bearing molecular species are determined through a complex chemical kinetic code that includes both gas and grain surface chemistry. This is combined with a model for the abundance of the refractory dust grains to compute the total carbon and oxygen abundance in the protoplanetary disk available for incorporation into a planetary atmosphere. We include the effects of the refractory carbon depletion that has been observed in our solar system, and posit two models that would put this missing carbon back into the gas phase. This excess gaseous carbon then becomes important in determining the final planetary C/O because the gas disk now becomes more carbon rich relative to oxygen (high gaseous C/O). One model, where the carbon excess is maintained throughout the lifetime of the disk results in hot Jupiters that have super-stellar C/O. The other model deposits the excess carbon early in the disk life and allows it to advect with the bulk gas. In this model the excess carbon disappears into the host star within 0.8 Myr, returning the gas disk to its original (substellar) C/O, so the hot Jupiters all exclusively have substellar C/O. This shows that while the solids tend to be oxygen rich, hot Jupiters can have super-stellar C/O if a carbon excess can be maintained by some chemical processing of the dust grains. The atmospheric C/O of the super-Earths at larger radii are determined by the chemical interactions between the gas and ice phases of volatile species rather than the refractory carbon model. Whether the carbon and oxygen content of the atmosphere was accreted primarily by gas or solid accretion is heavily dependent on the mass of the atmosphere and where in the disk the growing planet accreted.

scholarly journals Spin-orbit alignment of exoplanet systems: analysis of an ensemble of asteroseismic observations

2015 ◽  
Vol 11 (A29B) ◽  
pp. 636-641
Author(s):  
Tiago L. Campante
Keyword(s):  
Signal To Noise Ratio ◽  
Spin Orbit ◽  
Planetary Formation ◽  
Hot Jupiters ◽  
Transiting Planets ◽  
Oscillation Modes ◽  
Solar Type ◽  
And Migration ◽  
Exoplanet Systems ◽  
Host Stars

AbstractMeasuring the obliquities of exoplanet-host stars provides invaluable diagnostic information for theories of planetary formation and migration. Most of these results have so far been obtained by measuring the Rossiter–McLaughlin effect, clearly favoring systems that harbor hot Jupiters. While it would be extremely helpful to extend these measurements to long-period and multiple-planet systems, it is also true that the latter systems tend to involve smaller planets, making it ever so difficult to apply such techniques. Asteroseismology provides a powerful method of determining the inclination of the stellar spin axis — from an analysis of the rotationally-induced splittings of the oscillation modes — whose applicability is ultimately determined by the stellar parameters and not by the signal-to-noise ratio of the transit data. Here we present the first statistical analysis of an ensemble of asteroseismic obliquity measurements obtained for solar-type stars with transiting planets. The sample consists of 25 Kepler planet-candidate host stars, 14 of which are multi-transiting systems. We seek empirical constraints on the spin-orbit alignment of exoplanet systems and discuss the implications for theories of planetary formation and migration.

Intraocular tuberculosis, a challenge in diagnosis and treatment

2020 ◽  
Vol 3 ◽  
pp. 4
Author(s):  
Martina Larroude ◽  
Gustavo Ariel Budmann
Keyword(s):  
Developing Countries ◽  
Clinical Signs ◽  
Steady Increase ◽  
Ocular Tuberculosis ◽  
Industrial Countries ◽  
Choroidal Granuloma ◽  
History Of ◽  
And Migration ◽  
Ocular Tb

Ocular tuberculosis (TB) is an extrapulmonary tuberculous condition and has variable manifestations. The incidence of TB is still high in developing countries, and a steady increase in new cases has been observed in industrial countries as a result of the growing number of immunodeficient patients and migration from developing countries. Choroidal granuloma is a rare and atypical location of TB. We present a case of a presumptive choroidal granuloma. This case exposes that diagnosis can be remarkably challenging when there is no history of pulmonary TB. The recognition of clinical signs of ocular TB is extremely important since it provides a clinical pathway toward tailored investigations and decision making for initiating anti-TB therapy and to ensure a close follow-up to detect the development of any complication.

Searching for 3D effects in the optical, high spectral resolution emission spectrum of KELT-9b

2021 ◽  
Author(s):  
Lorenzo Pino ◽  
Matteo Brogi ◽  
Jean-Michel Désert ◽  
Emily Rauscher
Keyword(s):  
Emission Spectrum ◽  
Spectral Resolution ◽  
Planet Formation ◽  
Emission Spectra ◽  
Optical Emission ◽  
High Spectral Resolution ◽  
Optical Emission Spectrum ◽  
Hot Jupiters ◽  
Atmospheric Structure ◽  
3D Effects

&lt;p&gt;Ultra-hot Jupiters (UHJs; T&lt;sub&gt;eq&lt;/sub&gt; &amp;#8805; 2500 K) are the hottest gaseous giants known. They emerged as ideal laboratories to test theories of atmospheric structure and its link to planet formation. Indeed, because of their high temperatures, (1) they likely host atmospheres in chemical equilibrium and (2) clouds do not form in their day-side. Their continuum, which can be measured with space-facilities, can be mostly attributed to H- opacity, an indicator of metallicity. From the ground, the high spectral resolution emission spectra of UHJs contains thousands of lines of refractory (Fe, Ti, TiO, &amp;#8230;) and volatile species (OH, CO, &amp;#8230;), whose combined atmospheric abundances could track planet formation history in a unique way. In this talk, we take a deeper look to the optical emission spectrum of KELT-9b covering planetary phases 0.25 - 0.75 (i.e. between secondary eclipse and quadrature), and search for the effect of atmospheric dynamics and three-dimensionality of the planet atmosphere on the resolved line profiles, in the context of a consolidated statistical framework. We discuss the suitability of the traditionally adopted 1D models to interprete phase-resolved observations of ultra-hot Jupiters, and the potential of this kind of observations to probe their 3D atmospheric structure and dynamics. Ultimately, understanding which factors affect the line-shape in UHJs will also lead to more accurate and more precise abundance measurements, opening a new window on exoplanet formation and evolution.&lt;/p&gt;

scholarly journals ECCLESIASTIC TYPIKON FROM THE SCIENTIFIC LIBRARY OF KYIV UNIVERSITY: ATTRIBUTION OF MANUSCRIPT

2018 ◽  
pp. 24-29
Author(s):  
S. Voloshchenko
Keyword(s):  
Key Words ◽  
Construction Materials ◽  
The State ◽  
Slavonic Language ◽  
National University ◽  
History Of ◽  
Rare Books ◽  
And Migration

The principles of scientific attribution of liturgical cyrillic manuscripts, which has been worked out by author, are examined. The thorough study of Jerusalem Ecclesiastic Typikon from the rare books and manuscripts department’s collection of Maksymovych Scientific Library of Taras Shevchenko National University of Kyiv is conducted. The stages of manuscript attribution are analyzed, including the date identification and localization of its origins and use. The type and the title of the codex have been identificated by the analysis of book’s texts. The linguistic variant of Church Slavonic language, used for re-writing the copy, is revealed, which has helped to localize the place of creation. Detailed watermark analysis of paper, which the copy had been made of, has allowed to estimate date range of its production. The problematic ascertainment of the date of creation has been also supported by the analysis of the textual sources, studying of palaeographic peculiarities of cyrillic script book, the inner book’s decorative features. The problem of binding production date, its construction, materials and design, is formulated. The state of preservation of manuscript is analysed, which led the author to understanding the extent of book’s relevance for its readers. The history of manuscript restoration and its stages have been studied. The places of use and migration of the copy are revealed on the basis of provenance examination up till its arrival to Maksymovych Scientific Library’s rare books collection. Key words: Jerusalem Ecclesiastic Typikon, manuscript, Cyrillic manuscript, attribution, codicology, Maksymovych Scientific Library of Taras Shevchenko National University of Kyiv.

scholarly journals Franjo Tuđman and Demographic Revitalization/Sustainability of Croatia

2021 ◽  
Vol 17 (1) ◽  
pp. 129-147
Author(s):  
Dražen Živić
Keyword(s):  
Age Groups ◽  
Reproductive Potential ◽  
Demographic Development ◽  
Significant Discrepancy ◽  
Population Policies ◽  
Demographic Challenges ◽  
Demographic Aging ◽  
History Of ◽  
The Republic ◽  
And Migration

According to a number of relevant demographic and statistical indicators, Croatia is in a deep demographic crisis in all aspects of demographic dynamics and structural-demographic development. Total depopulation, natural decline, negative migration balance, demographic aging, and spatial polarization of the population – are fundamental long-term and current demographic trends and processes that, thanks to available data from census, vital and migration statistics can be monitored almost continuously from the middle of last century until today. The current demographic picture of Croatia is marked by natural and mechanical population losses, which means more deaths from birth and more emigration than immigration, with significantly disturbed relations between large (functional) age groups that threaten further collapse of bio reproductive potential and economic activity of the population. Croatian demographers warned of this circumstance during socialist Yugoslavia, especially after reaching independence in 1991. In their research, they were especially committed to the design and implementation of active and stimulating population policies, which had a certain impact in the formation of some decisions and documents of Croatian state policy during the 1990s. In this sense, it is scientifically relevant to valorize Dr. Tuđman’s attitude towards Croatian demographic issues, because demographic challenges have been and still are in significant discrepancy with socially desirable demographic pro-cesses and trends as key factors in the development and progress of the Croatian state and society, especially from 1991 and onwards. Therefore, in the context of Tuđman’s work as a politician (president of the Croatian Democratic Union from 1989 to 1999) and statesman (president of the Republic of Croatia from 1990 to 1999), but also as a scientist and public figure (director of the Institute for the History of the Labor Movement from 1961 to 1967) it is useful to investigate whether and to what extent there is a consistent attitude towards the demographic situation and problems of Croatia and, accordingly, whether we find the issue of Croatian demography at the center or on the margins of interest in his public work.

scholarly journals Historical tools and current societal challenges: reflections on a collection of environmental migration cases

2020 ◽  
Vol 198 (1-2) ◽  
pp. 151-162
Author(s):  
Roberta Biasillo
Keyword(s):  
Political Ecology ◽  
Environmental History ◽  
Sources Of Information ◽  
Horizon 2020 ◽  
Historical Perspectives ◽  
Environmental Migration ◽  
Societal Challenges ◽  
History Of ◽  
Migration Flows ◽  
And Migration

Through considering a "Geo Archive" as a tool of history, this paper explores several conundrums concerning environmental migration in social sciences. It demonstrates how historical perspectives can problematize and unsettle various automatisms that are widely present in journalistic, public, and policy discourses. Through examples from the Geo Archive, the article illustrates how unavoidable historical dimensions can enrich our understandings on the interaction between environmental issues and migration flows. This paper engages with an open access "archive in-the-making". This Geo Archive includes case studies of migration flows and puts those flows in conversation with environmental transformations and climatic changes. The analysed collection presents high-profile stories which are representative samples of different approaches, temporalities, geographies, sources of information, narratives, and scales. This endeavour encompasses different disciplines and fields of expertise: environmental humanities, IT and communication experts, and political ecology. The archive places itself within the realms of public history, environmental history, and history of the present and aims to reach out to wider audiences. This digital humanities project stemmed from a support action funded by the EU initiative Horizon 2020 titled CLISEL whose overarching goal was to analyse and better inform institutional responses and policies addressing climate refugees and migrants.

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