A homogeneous spectroscopic analysis of host stars  of transiting planets

AbstractWe report on preliminary results of spectroscopic determination of the atmospheric parameters and chemical abundances of the parent stars of the recently discovered transiting planets CoRoT-2b and CoRoT-4b. We found a flat distribution of the relative abundances as a function of their condensation temperatures. Also, we introduce a new methodology to investigate a relation between the abundances of these stars and the internal migration of their planets.

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Radio eclipses of exoplanets by the winds of their host stars

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa422 ◽

2020 ◽

Vol 493 (1) ◽

pp. 1492-1497 ◽

Cited By ~ 1

Author(s):

R D Kavanagh ◽

A A Vidotto

Keyword(s):

Radio Emission ◽

Stellar Wind ◽

Loss Rate ◽

Planetary System ◽

Mass Loss Rate ◽

Large Fraction ◽

Orbital Parameters ◽

Transiting Planets ◽

Specific Frequency ◽

Host Stars

ABSTRACT The search for exoplanetary radio emission has resulted in zero conclusive detections to date. Various explanations for this have been proposed, from the observed frequency range, telescope sensitivity, to beaming of the emission. In a recent paper, we illustrated that exoplanets can orbit through the radio photosphere of the wind of the host star, a region that is optically thick at a specific frequency, for a large fraction of their orbits. As a result, radio emission originating from the planet could be absorbed or ‘eclipsed’ by the wind of the host star. Here, we investigate how the properties of the stellar wind and orbital parameters affect the fraction of the orbit where the planet is eclipsed by the stellar wind. We show that planets orbiting stars with low-density winds are more favourable for detection in the radio. In terms of the orbital parameters, emission from transiting planets can escape the stellar wind easiest. We apply our model to the τ Boo planetary system, and show that observing the fraction of the planet’s orbit where it is eclipsed by the wind of the host star could be used to constrain the properties of the stellar wind. However, our model developed would need to be used in conjunction with a separate method to disentangle the mass-loss rate and temperature of the stellar wind.

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Planetary Transits and Tidal Evolution

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308026434 ◽

2008 ◽

Vol 4 (S253) ◽

pp. 217-229

Author(s):

Brian Jackson ◽

Rory Barne ◽

Richard Greenberg

Keyword(s):

Physical Properties ◽

Thermal Evolution ◽

Orbital Evolution ◽

Tidal Evolution ◽

Transiting Planets ◽

Tidal Heating ◽

The Masses ◽

In Transit ◽

Host Stars ◽

Transit Probability

AbstractTransiting planets are generally close enough to their host stars that tides may govern their orbital and thermal evolution. We present calculations of the tidal evolution of recently discovered transiting planets and discuss their implications. The tidal heating that accompanies this orbital evolution can be so great that it controls the planet's physical properties and may explain the large radii observed in several cases, including, for example, TrES-4. Also, since a planet's transit probability depends on its orbit, it evolves due to tides. Current values depend sensitively on the physical properties of the star and planet, as well as on the system's age. As a result, tidal effects may introduce observational biases in transit surveys, which may already be evident in current observations. Transiting planets tend to be younger than non-transiting planets, an indication that tidal evolution may have destroyed many close-in planets. Also the distribution of the masses of transiting planets may constrain the orbital inclinations of non-transiting planets.

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TTVs study in southern stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312005236 ◽

2011 ◽

Vol 7 (S286) ◽

pp. 441-444

Author(s):

Romina Petrucci ◽

Emiliano Jofré ◽

Martín Schwartz ◽

Andrea Buccino ◽

Pablo Mauas

Keyword(s):

Monitoring Program ◽

San Juan ◽

Transiting Planets ◽

Planetary Mass ◽

Photometric Monitoring ◽

Host Stars ◽

Good Agreement ◽

Planetary Transits

AbstractIn this contribution we present 4 complete planetary transits observed with the 40-cm telescope “Horacio Ghielmetti” located in San Juan(Argentina). These objects correspond to a continuous photometric monitoring program of Southern planet host-stars that we are carrying out since mid-2011. The goal of this project is to detect additional planetary mass objects around stars with known transiting-planets through Transit Timing Variations (TTVs). For all 4 transits the depth and duration are in good agreement with the values published in the discovery papers.

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Dynamical masses of two infant giant planets

10.21203/rs.3.rs-484057/v1 ◽

2021 ◽

Author(s):

Alejandro Suárez Mascareño ◽

Mario Damasso ◽

Nicolas Lodieu ◽

Alessandro Sozzetti ◽

Víctor Béjar ◽

...

Keyword(s):

Solar System ◽

Orbital Period ◽

Giant Planets ◽

Final Size ◽

Stellar Activity ◽

Planetary Evolution ◽

Transiting Planets ◽

Solar Type ◽

Host Stars ◽

Dynamical Masses

Abstract Current theories of planetary evolution predict that infant giant planets have large radii and very low densities before they slowly contract to reach their final size after about several hundred million years 1, 2. These theoretical expectations remain untested to date, despite the increasing number of exoplanetary discoveries, as the detection and characterisation of very young planets is extremely challenging due to the intense stellar activity of their host stars 3, 4. However, the recent discoveries of young planetary transiting systems allow to place initial constraints on evolutionary models5–9. With an estimated age of 20 million years, V1298 Tau is one of the youngest solar-type stars known to host transiting planets: it harbours a multiple system composed of two Neptune-sized, one Saturn-sized, and one Jupiter-sized planets 10, 11. Here we report the dynamical masses of two of the four planets. We find that planet b, with an orbital period of 24 days, has a mass of 0.60 Jupiter masses and a density similar to the giant planets of the Solar System and other known giant exoplanets with significantly older ages 12, 13. Planet e, with an orbital period of 40 days, has a mass of 1.21 Jupiter masses and a density larger than most giant exoplanets. This is unexpected for planets at such a young age and suggests that some giant planets might evolve and contract faster than anticipated, thus challenging current models of planetary evolution.

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

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316006232 ◽

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.

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HATS-34b and HATS-46b: Re-characterisation Using TESS and Gaia

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3995 ◽

2020 ◽

Author(s):

Emma M Louden ◽

Joel D Hartman

Keyword(s):

Observational Data ◽

High Precision ◽

Light Curves ◽

Star Mass ◽

Transiting Planets ◽

Precision And Accuracy ◽

Host Stars

Abstract We present a revised characterisation of the previously discovered transiting planet systems HATS-34 and HATS-46. We make use of the newly available space-based light curves from the NASA TESS mission and high-precision parallax and absolute photometry measurements from the ESA Gaia mission to determine the mass and radius of the planets and host stars with dramatically increased precision and accuracy compared to published values, with the uncertainties in some parameters reduced by as much as a factor of seven. Using an isochrone-based fit, for HATS-34 we measure a revised host star mass and radius of $0.952^{+0.040}_{-0.020}\, M_\odot$ and of 0.9381 ± 0.0080 R⊙, respectively, and a revised mass and radius for the transiting planet of 0.951 ± 0.050 MJ, and 1.282 ± 0.064 RJ, respectively. Similarly, for HATS-46 we measure a revised mass and radius for the host star of 0.869 ± 0.023 M⊙, and 0.894 ± 0.010 R⊙, respectively, and a revised mass and radius for the planet of 0.158 ± 0.042 MJ, and 0.951 ± 0.029 RJ, respectively. The uncertainties that we determine on the stellar and planetary masses and radii are also substantially lower than re-determinations that incorporate the Gaia results without performing a full re-analysis of the light curves and other observational data. We argue that, in light of Gaia and TESS, a full re-analysis of previously discovered transiting planets is warranted.

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Characterization of Chemical Impurities in Glutaraldehyde

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100116723 ◽

1975 ◽

Vol 33 ◽

pp. 620-621

Author(s):

B. J. Grenon ◽

A. J. Tousimis

Keyword(s):

Glutaric Acid ◽

Spectroscopic Analysis ◽

Aldol Condensation ◽

Condensation Product ◽

Amorphous Solid ◽

Water Soluble ◽

Impurity Component ◽

Chemical Impurities ◽

Soluble Liquid

Ever since the introduction of glutaraldehyde as a fixative in electron microscopy of biological specimens, the identification of impurities and consequently their effects on biologic ultrastructure have been under investigation. Several reports postulate that the impurities of glutaraldehyde, used as a fixative, are glutaric acid, glutaraldehyde polymer, acrolein and glutaraldoxime.Analysis of commercially available biological or technical grade glutaraldehyde revealed two major impurity components, none of which has been reported. The first compound is a colorless, water-soluble liquid with a boiling point of 42°C at 16 mm. Utilizing Nuclear Magnetic Resonance (NMR) spectroscopic analysis, this compound has been identified to be — dihydro-2-ethoxy 2H-pyran. This impurity component of the glutaraldehyde biological or technical grades has an UV absorption peak at 235nm. The second compound is a white amorphous solid which is insoluble in water and has a melting point of 80-82°C. Initial chemical analysis indicates that this compound is an aldol condensation product(s) of glutaraldehyde.

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Elemental analysis of human erythrocytes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010015318x ◽

1989 ◽

Vol 47 ◽

pp. 242-243

Author(s):

S. A. Livesey ◽

A. A. del Campo ◽

E. S. Griffey ◽

D. Ohlmer ◽

T. Schifani ◽

...

Keyword(s):

Sample Preparation ◽

Elemental Analysis ◽

Human Erythrocyte ◽

Spectroscopic Analysis ◽

Model System ◽

Human Erythrocytes ◽

List Type ◽

Chemical Fixation ◽

Ethanol Dehydration ◽

Lowicryl K4m

The aim of this study is to compare methods of sample preparation for elemental analysis. The model system which is used is the human erythrocyte. Energy dispersive spectroscopic analysis has been previously reported for cryofixed and cryosectioned erythrocytes. Such work represents the reference point for this study. The use of plastic embedded samples for elemental analysis has also been documented. The work which is presented here is based on human erythrocytes which have been either chemically fixed and embedded or cryofixed and subsequently processed by a variety of techniques which culminated in plastic embedded samples.Heparinized and washed erythrocytes were prepared by the following methods for this study :(1). Chemical fixation in 4% paraformaldehyde/0.25% glutaraldehyde/0.2 M sucrose in 0.1 M Na cacodylate, pH 7.3 for 30 min, followed by ethanol dehydration, infiltration and embedding in Lowicryl K4M at -20° C.

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