scholarly journals On the Origins of Eccentric Close-in Planets

2008 ◽  
Vol 4 (S253) ◽  
pp. 189-195 ◽  
Author(s):  
Soko Matsumura ◽  
Genya Takeda ◽  
Fred A. Rasio
Keyword(s):  
Solar System ◽  
Quality Factor ◽  
Extrasolar Planets ◽  
External Perturbation ◽  
Central Star ◽  
Circular Orbits ◽  
Secular Perturbation ◽  
New Class ◽  
Stellar Ages ◽  
Host Stars

AbstractStrong tidal interaction with the central star can circularize the orbits of close-in planets. With the standard tidal quality factorQof our solar system, estimated circularization timescales for close-in extrasolar planets are typically shorter than the age of the host stars. While most extrasolar planets with orbital radiia≲ 0.1 AU indeed have circular orbits, some close-in planets with substantial orbital eccentricities have recently been discovered. This new class of eccentric close-in planets implies that either their tidalQfactor is considerably higher, or circularization is prevented by an external perturbation. Here we constrain the tidalQfactor for transiting extrasolar planets by comparing their circularization times with accurately determined stellar ages. Using estimated secular perturbation timescales, we also provide constraints on the properties of hypothetical second planets exterior to the known eccentric close-in planets.

scholarly journals Extrasolar Planets and Prospects for Terrestrial Planets

2004 ◽  
Vol 213 ◽  
pp. 11-24 ◽  
Author(s):  
Geoffrey W. Marcy ◽  
R. Paul Butler ◽  
Steven S. Vogt ◽  
Debra A. Fischer
Keyword(s):  
Solar System ◽  
Milky Way ◽  
Extrasolar Planets ◽  
Terrestrial Planets ◽  
Habitable Zone ◽  
Milky Way Galaxy ◽  
System Architectures ◽  
Rocky Planets ◽  
Host Stars ◽  
Eccentricity Orbit

Examination of ∼2000 sun–like stars has revealed 97 planets (as of 2002 Nov), all residing within our Milky Way Galaxy and within ∼200 light years of our Solar System. They have masses between 0.1 and 10 times that of Jupiter, and orbital sizes of 0.05–5 AU. Thus planets occupy the entire detectable domain of mass and orbits. News & summaries about extrasolar planets are provided at: http://exoplanets.org. These planets were all discovered by the wobble of the host stars, induced gravitationally by the planets, causing a periodicity in the measured Doppler effect of the starlight. Earth–mass planets remain undetectable, but space–based missions such as Kepler, COROT and SIM may provide detections of terrestrial planets within the next decade.The number of planets increases with decreasing planet mass, indicating that nature makes more small planets than jupiter–mass planets. Extrapolation, though speculative, bodes well for an even larger number of earth–mass planets. These observations and the theory of planet formation suggests that single sun–like stars commonly harbor earth–sized rocky planets, as yet undetectable. The number of planets increases with increasing orbital distance from the host star, and most known planets reside in non–circular orbits. Many known planets reside in the habitable zone (albeit being gas giants) and most newly discovered planets orbit beyond 1 AU from their star. A population of Jupiter–like planets may reside at 5–10 AU from stars, not easily detectable at present. The sunlike star 55 Cancri harbors a planet of 4–10 Jupiter masses orbiting at 5.5 AU in a low eccentricity orbit, the first analog of our Jupiter, albeit with two large planets orbiting inward.To date, 10 multiple–planet systems have been discovered, with four revealing gravitational interactions between the planets in the form of resonances. GJ 876 has two planets with periods of 1 and 2 months. Other planetary systems are “hierarchical”, consisting of widely separated orbits. These two system architectures probably result from gravitational interactions among the planets and between the planets and the proto-planetary disk out of which they formed.

The Lick Observatory Planet Search

1997 ◽  
Vol 161 ◽  
pp. 331-342 ◽  
Author(s):  
R. Paul Butler ◽  
Geoffrey W. Marcy
Keyword(s):  
Solar System ◽  
Extrasolar Planets ◽  
Brown Dwarfs ◽  
The Other ◽  
Absorption Cell ◽  
Circular Orbits ◽  
Doppler Shifts ◽  
Keplerian Orbits ◽  
Ccd Detector ◽  
Wavelength Scale

AbstractWe have constructed a precision Doppler technique with which we have detected 6 extrasolar planets to date. Doppler precision is achieved by inserting an iodine absorption cell in the telescope, providing a fiducial wavelength scale against which to measure Doppler shifts. Our current precision is 3 m s−1, which corresponds to one part in one hundred million in wavelength, or 1/1000 th of a pixel on the CCD detector. As of 1996 August, our survey of 120 stars has revealed six stars that show velocity variations consistent with Jupiter-mass companions in Keplerian orbits. These objects span a greater range of orbital radii and eccentricity than the planets in our own solar system. Three of these objects are «51 Peg-type» planets with circular orbits having radii 0.15 AU or less. The other three objects have masses between 1.7 and 6.5 MJUP, eccentricities between 0.01 and 0.6, and semi-major axes between 0.4 and 2.1 AU. We have not found any objects having masses between 10 and 80 MJUP, the domain usually associated with brown dwarfs. These six new companions represent a new population of objects having extremely low masses, similar to that of Jupiter. We have begun a survey of an additional 400 stars using the Keck 10-m telescope, which will allow the detection of Neptune-mass planets.

scholarly journals Origins of water in the Solar System leading to habitable worlds

2015 ◽  
Vol 11 (A29B) ◽  
pp. 400-400
Author(s):  
Karen Meech
Keyword(s):  
Solar System ◽  
Extrasolar Planets ◽  
Protoplanetary Disk ◽  
Water Ice ◽  
Snow Line ◽  
Habitable Zones ◽  
Geochemical Markers ◽  
New Research ◽  
Life On Earth ◽  
Host Stars

AbstractLife on Earth depends on an aqueous biochemistry, and water is a key component of habitability on Earth and for likely other habitable environments in the solar system. While water is ubiquitous in the interstellar medium, and plays a key role in protoplanetary disk chemistry, the inner solar system is relatively dry. We now have evidence for potentially thousands of extrasolar planets, dozens of which may be located in their host stars habitable zones. Understanding how planets in the habitable zone accrete their water, is key to understanding the likelihood for habitability. Given that many disk models show that Earth formed inside the water-ice snow line of our solar system, understanding how the inner solar system received its water is important for understanding the potential for other planetary systems to host habitable worlds. Boundaries for the timing of the water delivery are constrained by cosmochemistry and geochemistry. Possible scenarios for the delivery of water to the inner solar system include adsorption on dust from protoplanetary disk gas, chemical reactions on the early earth, and delivery from planetesimals forming outside the water-ice snow line. This talk will set the stage for understanding the isotopic and geochemical markers along with the dynamical delivery mechanisms that will help uncover the origins of Earths water. This introduction will provide an overview for understanding the distribution of water in the solar system, in particular for the inner solar system and terrestrial planets Xand the details will be developed in the subsequent talks. Additionally information will be presented regarding new inner solar system reservoirs of water that can shed light on origins (the main belt comets), and new research about water in the Earth.

From Dust to Life

2017 ◽  
Author(s):  
John Chambers ◽  
Jacqueline Mitton
Keyword(s):  
Solar System ◽  
Extrasolar Planets ◽  
Planetary Systems ◽  
History Of Astronomy ◽  
Human Origins ◽  
History Of ◽  
The Subject ◽  
Emergence Of Life

The birth and evolution of our solar system is a tantalizing mystery that may one day provide answers to the question of human origins. This book tells the remarkable story of how the celestial objects that make up the solar system arose from common beginnings billions of years ago, and how scientists and philosophers have sought to unravel this mystery down through the centuries, piecing together the clues that enabled them to deduce the solar system's layout, its age, and the most likely way it formed. Drawing on the history of astronomy and the latest findings in astrophysics and the planetary sciences, the book offers the most up-to-date and authoritative treatment of the subject available. It examines how the evolving universe set the stage for the appearance of our Sun, and how the nebulous cloud of gas and dust that accompanied the young Sun eventually became the planets, comets, moons, and asteroids that exist today. It explores how each of the planets acquired its unique characteristics, why some are rocky and others gaseous, and why one planet in particular—our Earth—provided an almost perfect haven for the emergence of life. The book takes readers to the very frontiers of modern research, engaging with the latest controversies and debates. It reveals how ongoing discoveries of far-distant extrasolar planets and planetary systems are transforming our understanding of our own solar system's astonishing history and its possible fate.

Atmospheric dynamics of tidally synchronized extrasolar planets

2008 ◽  
Vol 366 (1884) ◽  
pp. 4477-4488 ◽  
Author(s):  
James Y.-K Cho
Keyword(s):  
Temperature Distribution ◽  
Solar System ◽  
Flow Pattern ◽  
Extrasolar Planets ◽  
Atmospheric Dynamics ◽  
Reliable Interpretation ◽  
Near Future ◽  
Theoretical Issues

Tidally synchronized planets present a new opportunity for enriching our understanding of atmospheric dynamics on planets. Subject to an unusual forcing arrangement (steady irradiation on the same side of the planet throughout its orbit), the dynamics on these planets may be unlike that on any of the Solar System planets. Characterizing the flow pattern and temperature distribution on the extrasolar planets is necessary for reliable interpretation of data currently being collected, as well as for guiding future observations. In this paper, several fundamental concepts from atmospheric dynamics, likely to be central for characterization, are discussed. Theoretical issues that need to be addressed in the near future are also highlighted.

scholarly journals Retrograde resonances in compact multi-planetary systems: a feasible stabilizing mechanism

2007 ◽  
Vol 3 (S249) ◽  
pp. 511-516 ◽  
Author(s):  
Julie Gayon ◽  
Eric Bois
Keyword(s):  
Body Problem ◽  
Extrasolar Planets ◽  
Planetary Systems ◽  
Central Star ◽  
Point Of View ◽  
Outer Planet ◽  
Mean Motion Resonances ◽  
Hot Jupiters ◽  
The Stability ◽  
Orbital Data

AbstractMulti-planet systems detected until now are in most cases characterized by hot-Jupiters close to their central star as well as high eccentricities. As a consequence, from a dynamical point of view, compact multi-planetary systems form a variety of the general N-body problem (with N ≥ 3), whose solutions are not necessarily known. Extrasolar planets are up to now found in prograde (i.e. direct) orbital motions about their host star and often in mean-motion resonances (MMR). In the present paper, we investigate a theoretical alternative suitable for the stability of compact multi-planetary systems. When the outer planet moves on a retrograde orbit in MMR with respect to the inner planet, we find that the so-called retrograde resonances present fine and characteristic structures particularly relevant for dynamical stability. We show that retrograde resonances and their resources open a family of stabilizing mechanisms involving specific behaviors of apsidal precessions. We also point up that for particular orbital data, retrograde MMRs may provide more robust stability compared to the corresponding prograde MMRs.

scholarly journals Can we detect aurora in exoplanets orbiting M dwarfs?

2019 ◽  
Vol 488 (1) ◽  
pp. 633-644 ◽  
Author(s):  
A A Vidotto ◽  
N Feeney ◽  
J H Groh
Keyword(s):  
Solar System ◽  
Radio Emission ◽  
Stellar Wind ◽  
Engineering Calculation ◽  
M Dwarfs ◽  
Radio Detection ◽  
Dwarf Planets ◽  
M Dwarf ◽  
Host Stars ◽  
New Instruments

ABSTRACT New instruments and telescopes, such as SPIRou, CARMENES, and Transiting Exoplanet Survey Satellite (TESS), will increase manyfold the number of known planets orbiting M dwarfs. To guide future radio observations, we estimate radio emission from known M dwarf planets using the empirical radiometric prescription derived in the Solar system, in which radio emission is powered by the wind of the host star. Using solar-like wind models, we find that the most promising exoplanets for radio detections are GJ 674 b and Proxima b, followed by YZ Cet b, GJ 1214 b, GJ 436 b. These are the systems that are the closest to us (<10 pc). However, we also show that our radio fluxes are very sensitive to the unknown properties of winds of M dwarfs. So, which types of winds would generate detectable radio emission? In a ‘reverse engineering’ calculation, we show that winds with mass-loss rates $\dot{M} \gtrsim \kappa _{\rm sw} /u_{\rm sw}^3$ would drive planetary radio emission detectable with present-day instruments, where usw is the local stellar wind velocity and κsw is a constant that depends on the size of the planet, distance, and orbital radius. Using observationally constrained properties of the quiescent winds of GJ 436 and Proxima Cen, we conclude that it is unlikely that GJ 436 b and Proxima b would be detectable with present-day radio instruments, unless the host stars generate episodic coronal mass ejections. GJ 674 b, GJ 876 b, and YZ Cet b could present good prospects for radio detection, provided that their host stars’ winds have $\dot{M} u_{\rm sw}^{3} \gtrsim 1.8\times 10^{-4} \, {\rm M}_\odot \,{\rm yr}^{-1}\, ({\rm km\,s^{-1}})^{3}$.

scholarly journals The Potential for Archaeology Within and Beyond the Habitable Zones (HZ) of the Milky Way

2004 ◽  
Vol 213 ◽  
pp. 505-510
Author(s):  
John B. Campbell
Keyword(s):  
Remote Sensing ◽  
Solar System ◽  
Milky Way ◽  
Extrasolar Planets ◽  
Habitable Zone ◽  
The Moon ◽  
Habitable Zones ◽  
Remote Sensing Techniques ◽  
Main Region

As archaeology is established on Earth and we are actively exploring the Solar System and beyond, there is the potential to develop a number of forms of exo-archaeology. The archaeology of the things intelligent species do in theory could be practised anywhere, provided one can detect the evidence. Sites are being created by us elsewhere within our star's habitable zone (HZ), namely on the Moon and Mars, and at least molecular traces of human-created probes are being left beyond the HZ (Venus, Jupiter etc.). The successful detection of extrasolar planets and the possible identification of HZs round other stars raise the possibility for the development of extrasolar archaeology, at least initially by remote sensing techniques. Within the Milky Way the main region to investigate is the galactic habitable zone (GHZ), though there could be archaeological traces of technological behaviours beyond it.

scholarly journals PlanetCARMA: A New Framework for Studying the Microphysics of Planetary Atmospheres

Atmosphere ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1064
Author(s):  
Erika Barth
Keyword(s):  
Solar System ◽  
Extrasolar Planets ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Planetary Body ◽  
Solar System Bodies ◽  
Fortran 90 ◽  
Primary Advantage ◽  
New Framework ◽  
Modular Format

The Community Aerosol and Radiation Model for Atmospheres (CARMA) has been updated to apply to atmospheres of the Solar System outside of Earth. CARMA, as its name suggests, is a coupled aerosol microphysics and radiative transfer model and includes the processes of nucleation, condensation, evaporation, coagulation, and vertical transport. Previous model versions have been applied separately to the atmospheres of Solar System bodies and extrasolar planets. The primary advantage to PlanetCARMA is that the core physics routines each reside in their own self-contained modules and can be turned on/off as desired while a separate planet module supplies all the necessary parameters to apply the model run to a particular planet (or planetary body). So a single codebase is used for all planetary studies. PlanetCARMA has also been updated to Fortran 90 modular format. Examples of outer solar system atmosphere applications are shown.

scholarly journals Solar system tests of a new class of f(z) theory

2020 ◽  
Vol 29 (08) ◽  
pp. 2050060
Author(s):  
Ji-Yao Wang ◽  
Chao-Jun Feng ◽  
Xiang-Hua Zhai ◽  
Xin-Zhou Li
Keyword(s):  
Solar System ◽  
Observational Data ◽  
Ricci Scalar ◽  
Parametric Models ◽  
Alternative Models ◽  
New Class ◽  
Cosmological Data ◽  
Ppn Parameters ◽  
Models Of Gravity

Recently, a new kind of [Formula: see text] theory is proposed to provide a different perspective for the development of reliable alternative models of gravity in which the [Formula: see text] Lagrangian terms are reformulated as polynomial parametrizations [Formula: see text]. In the previous study, the parameters in the [Formula: see text] models have been constrained by using cosmological data. In this paper, these models will be tested by the observations in the solar system. After solving the Ricci scalar as a function of the redshift, one could obtain [Formula: see text] that could be used to calculate the standard Parametrized-Post-Newtonian (PPN) parameters. First, we fit the parametric models with the latest cosmological observational data. Then, the tests are performed by solar system observations. And last we combine the constraints of solar system and cosmology together and reconstruct the [Formula: see text] actions of the [Formula: see text] parametric models.

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