scholarly journals The PLATO space mission: studying planetary transits and stellar oscillations simultaneously

2008 ◽  
Vol 4 (S253) ◽  
pp. 564-566
Author(s):  
Malcolm Fridlund
Keyword(s):  
Thermal Environment ◽  
Space Mission ◽  
High Time Resolution ◽  
Stellar Oscillations ◽  
Cosmic Vision ◽  
Exoplanetary Systems ◽  
Seismic Oscillations ◽  
Host Stars ◽  
Very High ◽  
Planetary Transits

AbstractPLATO (PLAnetary Transits and Oscilliations of stars) is a proposed mission of the European Space Agency's Science programme Cosmic Vision 2015–2025, currently under industrial study, and with a planned launch by the end of 2017. Its task is to better understand the properties of exoplanetary systems. As such it will detect and characterise exoplanets using their transit signature in front of a large sample of bright stars and simultaneously measuring the seismic oscillations of the parent star of these exoplanets. The mission will be orbiting the Sun-Earth L2 point, which provides a stable thermal environment and maximum uninterrupted observing efficiency. The payload consists of a number (> 28) of individual catadioptric telescopes, covering > 550 sq. degrees. Since the goal is to search for terrestrial exoplanets within the habitable zone of their host stars, and carry out asteroseismological observations of the host stars, very high photometric precision, high time resolution, and high duty-cycle visible photometry is required. Ground-based observations are needed to complement the observations made by PLATO to allow for further exoplanetary characterization. This paper consists of a summary of the preliminary results achieved by the ESA internal pre-assessment study.

scholarly journals The PLATO mission

2010 ◽  
Vol 6 (S276) ◽  
pp. 354-358 ◽  
Author(s):  
Heike Rauer ◽  
Claude Catala ◽  
Keyword(s):  
Detailed Analysis ◽  
Terrestrial Planets ◽  
Study Phase ◽  
Habitable Zone ◽  
Cosmic Vision ◽  
Exoplanetary Systems ◽  
Basic Parameters ◽  
Definition Study ◽  
Planetary Transits

AbstractThe PLAnetary Transits and Oscillations of stars (PLATO) mission is in its definition study phase in the context of ESA's Cosmic Vision 2015-2025 program. PLATO is applying for a launch in 2017/18. Its goal is to detect transiting exoplanets, including terrestrial planets in the habitable zone, and to determine their basic parameters with unprecedented accuracy. In combination with the detailed analysis of the stellar parameters by astroseismology and with ground-based follow-up observations, this will allow characterizing the main properties of exoplanetary systems to a level not achieved before.

scholarly journals On the alignment of debris discs and their host stars’ rotation axis - implications for spin-orbit misalignment in exoplanetary systems

2011 ◽  
Vol 413 (1) ◽  
pp. L71-L75 ◽  
Author(s):  
C. A. Watson ◽  
S. P. Littlefair ◽  
C. Diamond ◽  
A. Collier Cameron ◽  
A. Fitzsimmons ◽  
...  
Keyword(s):  
Rotation Axis ◽  
Spin Orbit ◽  
Exoplanetary Systems ◽  
Host Stars

scholarly journals The Three-Dimensional Locating of VHF Broadband Lightning Interferometers

Atmosphere ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 317 ◽  
Author(s):  
Hengyi Liu ◽  
Shi Qiu ◽  
Wansheng Dong
Keyword(s):  
Time Resolution ◽  
High Frequency ◽  
Three Dimensional ◽  
High Time Resolution ◽  
Very High Frequency ◽  
Time Difference Of Arrival ◽  
Lightning Discharges ◽  
Total Lightning ◽  
Locating Information ◽  
Very High

VHF (Very High Frequency) lightning interferometers can locate and observe lightning discharges with a high time resolution. Especially the appearance of continuous interferometers makes the 2-D location of interferometers further improve in time resolution and completeness. However, there is uncertainty in the conclusion obtained by simply analyzing the 2-D locating information. Without the support of other 3-D total lightning locating networks, the 2-station interferometer becomes an option to obtain 3-D information. This paper introduces a 3-D lightning location method of a 2-station broadband interferometer, which uses the theodolite wind measurement method for reference, and gives the simulation results of the location accuracy. Finally, using the multi-baseline continuous 2-D locating method and the 3-D locating method, the locating results of one intra-cloud flash and the statistical results of the initiation heights of 61 cloud-to-ground flashes and 80 intra-cloud flashes are given. The results show that the two-station interferometer has high observation accuracy on both sides of the connection between the two sites. The locating accuracy will deteriorate as the distance between the radiation source and the two stations increases or the height decreases. The actual locating results are similar to those of the existing VHF TDOA (Time Difference of Arrival) lightning locating network.

scholarly journals Host-star and exoplanet compositions: a pilot study using a wide binary with a polluted white dwarf

2021 ◽  
Vol 503 (2) ◽  
pp. 1877-1883
Author(s):  
Amy Bonsor ◽  
Paula Jofré ◽  
Oliver Shorttle ◽  
Laura K Rogers ◽  
Siyi Xu(许偲艺) ◽  
...  
Keyword(s):  
White Dwarf ◽  
Planetary System ◽  
Kuiper Belt ◽  
Wide Binary ◽  
Elemental Abundances ◽  
Exoplanetary Systems ◽  
Planetary Bodies ◽  
Refractory Composition ◽  
Observational Errors ◽  
Host Stars

ABSTRACT Planets and stars ultimately form out of the collapse of the same cloud of gas. Whilst planets, and planetary bodies, readily loose volatiles, a common hypothesis is that they retain the same refractory composition as their host star. This is true within the Solar system. The refractory composition of chondritic meteorites, Earth, and other rocky planetary bodies are consistent with solar, within the observational errors. This work aims to investigate whether this hypothesis holds for exoplanetary systems. If true, the internal structure of observed rocky exoplanets can be better constrained using their host star abundances. In this paper, we analyse the abundances of the K-dwarf, G200-40, and compare them to its polluted white dwarf companion, WD 1425+540. The white dwarf has accreted planetary material, most probably a Kuiper belt-like object, from an outer planetary system surviving the star’s evolution to the white dwarf phase. Given that binary pairs are chemically homogeneous, we use the binary companion, G200-40, as a proxy for the composition of the progenitor to WD 1425+540. We show that the elemental abundances of the companion star and the planetary material accreted by WD 1425+540 are consistent with the hypothesis that planet and host-stars have the same true abundances, taking into account the observational errors.

scholarly journals Different types of star-planet interactions

2019 ◽  
Vol 15 (S354) ◽  
pp. 259-267
Author(s):  
A. A. Vidotto
Keyword(s):  
Physical Characteristics ◽  
Electromagnetic Spectrum ◽  
Exoplanetary Systems ◽  
Different Types ◽  
Host Stars

AbstractStars and their exoplanets evolve together. Depending on the physical characteristics of these systems, such as age, orbital distance and activity of the host stars, certain types of star-exoplanet interactions can dominate during given phases of the evolution. Identifying observable signatures of such interactions can provide additional avenues for characterising exoplanetary systems. Here, I review some recent works on star-planet interactions and discuss their observability at different wavelengths across the electromagnetic spectrum.

A Pulse-Based 60GHz Ranging System

2014 ◽  
Vol 1049-1050 ◽  
pp. 2092-2095
Author(s):  
Min Wang ◽  
Hao Zhang ◽  
Ting Ting Lu
Keyword(s):  
Wireless Communication ◽  
Theoretical Analysis ◽  
Time Resolution ◽  
Communication System ◽  
Robot Navigation ◽  
High Accuracy ◽  
High Time Resolution ◽  
Hazardous Area ◽  
Area Monitoring ◽  
Very High

60GHz signal has very high time resolution and multipath resolution, thus having the potential of achieving high accuracy ranging and positioning at centimeter level or even millimeter level. This technology has great application value in fields like indoor robot navigation, hazardous area monitoring and accurate positioning. In this paper, after designing the pulse-based 60GHz wireless communication system, we proposed a pulse-based 60GHz ranging system. Theoretical analysis and simulations demonstrate that the proposed system can achieve good ranging performance.

Twinkle: a low-Earth orbit, visible and infrared observatory for exoplanet and solar system spectroscopy

2020 ◽  
Author(s):  
Billy Edwards ◽  
Marcell Tessenyi ◽  
Giovanna Tinetti ◽  
Giorgio Savini ◽  
Ian Stotesbury ◽  
...  
Keyword(s):  
Solar System ◽  
Thermal Environment ◽  
Space Mission ◽  
Low Earth Orbit ◽  
Atmospheric Composition ◽  
Orbital Parameters ◽  
Short Period ◽  
Wide Range ◽  
Solar System Objects ◽  
Scientific Potential

<p>The Twinkle Space Mission is a space-based observatory that has been conceived to measure the atmospheric composition of exoplanets, stars and solar system objects. The satellite is based on a high-heritage platform and will carry a 0.45 m telescope with a visible and infrared spectrograph providing simultaneous wavelength coverage from 0.5 - 4.5 μm. The spacecraft will be launched into a Sun-synchronous low-Earth polar orbit and will operate in this highly stable thermal environment for a baseline lifetime of seven years.</p> <p>Twinkle will have the capability to provide high-quality infrared spectroscopic characterisation of the atmospheres of hundreds of bright exoplanets, covering a wide range of planetary types. It will also be capable of providing phase curves for hot, short-period planets around bright stars targets and of providing ultra-precise photometric light curves to accurately constrain orbital parameters, including ephemerides and TTVs/TDVs present in multi-planet systems.</p> <p>Twinkle is available for researchers around the globe in two ways:</p> <p>1) joining its collaborative multi-year survey programme, which will observe hundreds of exoplanets and solar system objects; and</p> <p>2) accessing dedicated telescope time on the spacecraft, which they can schedule for any combination of science cases.</p> <p>I will present an overview of Twinkle’s capabilities and discuss some example exoplanet surveys to highlight the broad range of targets the mission could observe, demonstrating the huge scientific potential of the spacecraft.</p>

Twinkle: a low-Earth orbit, visible and infrared observatory for exoplanet and solar system spectroscopy

2020 ◽  
Author(s):  
Billy Edwards ◽  
Marcell Tessenyi ◽  
Giorgio Savini ◽  
Giovanna Tinetti ◽  
Ian Stotesbury ◽  
...  
Keyword(s):  
Solar System ◽  
Near Infrared ◽  
Surface Composition ◽  
Thermal Environment ◽  
Space Mission ◽  
Low Earth Orbit ◽  
Atmospheric Composition ◽  
Solar System Objects ◽  
Scientific Potential ◽  
Asteroids And Comets

<p>The Twinkle Space Mission is a space-based observatory that has been conceived to measure the atmospheric composition of exoplanets, stars and solar system objects. The satellite is based on a high-heritage platform and will carry a 0.45 m telescope with a visible and infrared spectrograph providing simultaneous wavelength coverage from 0.5 - 4.5 μm. The spacecraft will be launched into a Sun-synchronous low-Earth polar orbit and will operate in this highly stable thermal environment for a baseline lifetime of seven years.</p> <p>Twinkle’s rapid pointing and non-sidereal tracking capabilities will enable the observation of a diverse array of Solar System objects, including asteroids and comets. Twinkle aims to provide a visible and near-infrared spectroscopic population study of asteroids and comets to study their surface composition and monitor activity. Its wavelength coverage and position above the atmosphere will make it particularly well-suited for studying hydration features that are obscured by telluric lines from the ground as well as searching for other spectral signatures such as organics, silicates and CO<sub>2</sub>.</p> <p>Twinkle is available for researchers around the globe in two ways:</p> <p>1) joining its collaborative multi-year survey programme, which will observe hundreds of exoplanets and solar system objects; and</p> <p>2) accessing dedicated telescope time on the spacecraft, which they can schedule for any combination of science cases.</p> <p>I will present an overview of Twinkle’s capabilities and discuss the broad range of targets the mission could observe, demonstrating the huge scientific potential of the spacecraft.</p>

Hypersonic Propulsion-breaking the Thermal Barrier

1993 ◽  
Vol 207 (1) ◽  
pp. 47-59 ◽  
Author(s):  
J P Weidner
Keyword(s):  
Large Volume ◽  
Thermal Environment ◽  
Hypersonic Vehicle ◽  
Propulsion System ◽  
Thermal Barrier ◽  
Hypersonic Propulsion ◽  
Very High

The challenges of hypersonic propulsion impose unique features on the hypersonic vehicle—from large volume requirements to contain cryogenic fuel to airframe-integrated propulsion required to process sufficient quantities of air. Additional challenges exist in the design of the propulsion module that must be capable of efficiently processing air at very high enthalpies, adding and mixing fuel at supersonic speeds and expanding the exhaust products to generate thrust greater than drag. The paper explores the unique challenges of the integrated hypersonic propulsion system, addresses propulsion cycle selection to cope with the severe thermal environment and reviews the direction of propulsion research at hypervelocity speeds.

scholarly journals The effects of stellar winds and magnetic fields on exoplanets

2013 ◽  
Vol 9 (S302) ◽  
pp. 228-236 ◽  
Author(s):  
A. A. Vidotto
Keyword(s):  
Solar System ◽  
Interplanetary Medium ◽  
Great Majority ◽  
Stellar Winds ◽  
Stellar Rotation ◽  
Low Mass Stars ◽  
Exoplanetary Systems ◽  
Cool Stars ◽  
Low Mass ◽  
Host Stars

AbstractThe great majority of exoplanets discovered so far are orbiting cool, low-mass stars whose properties are relatively similar to the Sun. However, the stellar magnetism of these stars can be significantly different from the solar one, both in topology and intensity. In addition, due to the present-day technology used in exoplanetary searches, most of the currently known exoplanets are found orbiting at extremely close distances to their host stars (< 0.1 au). The dramatic differences in stellar magnetism and orbital radius can make the interplanetary medium of exoplanetary systems remarkably distinct from that of the Solar System. To constrain interactions between exoplanets and their host-star's magnetised winds and to characterise the interplanetary medium that surrounds exoplanets, more realistic stellar wind models, which account for factors such as stellar rotation and the complex stellar magnetic field configurations of cool stars, must be employed. Here, I briefly review the latest progress made in data-driven modelling of magnetised stellar winds. I also show that the interaction of the stellar winds with exoplanets can lead to several observable signatures, some of which that are absent in our own Solar System.

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