scholarly journals Formation and detectability of Earth-like planets around Alpha-Centauri B

2007 ◽  
Vol 3 (S249) ◽  
pp. 313-318
Author(s):  
Erica Davis
Keyword(s):  
Radial Velocity ◽  
Planet Formation ◽  
Planetary Systems ◽  
Terrestrial Planet ◽  
Mass Range ◽  
Noise Spectrum ◽  
Habitable Zone ◽  
Earth Like Planets ◽  
Late Stages ◽  
High Cadence

AbstractWe simulate the late stages of planet formation around Alpha Centauri B and analyze the detectability of the resulting terrestrial planet systems. The N-body accretionary evolution of a Σ ∝ r−-1 disk populated with 400–900 lunar-mass oligarchs is followed for 200 Myr for each simulation. All of eight runs result in the formation of multiple-planet systems with at least one planet in the 1–2 M⊕ mass range at 0.5–1.5 AU. We examine the detectability of our simulated planetary systems by generating synthetic radial velocity observations including noise based on the radial velocity residuals to the recently published three planet fit to the nearby K0V star HD 69830. Using these synthetic observations, we find that we can reliably detect a 1.8 M⊕ planet in the habitable zone of α Centauri B after only three years of high cadence observations. We also find that the planet is detectable even if the radial velocity precision is 3 ms−1, as long as the noise spectrum is white.

scholarly journals Earth-size planet formation in the habitable zone of circumbinary stars

2020 ◽  
Vol 494 (1) ◽  
pp. 1045-1057 ◽  
Author(s):  
G O Barbosa ◽  
O C Winter ◽  
A Amarante ◽  
A Izidoro ◽  
R C Domingos ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Planet Formation ◽  
Terrestrial Planet ◽  
Close Binary ◽  
Habitable Zone ◽  
Density Profiles ◽  
Habitable Planets ◽  
Habitable Zones ◽  
Test Particles ◽  
The Stability

ABSTRACT This work investigates the possibility of close binary (CB) star systems having Earth-size planets within their habitable zones (HZs). First, we selected all known CB systems with confirmed planets (totaling 22 systems) to calculate the boundaries of their respective HZs. However, only eight systems had all the data necessary for the computation of HZ. Then, we numerically explored the stability within HZs for each one of the eight systems using test particles. From the results, we selected five systems that have stable regions inside HZs, namely Kepler-34,35,38,413, and 453. For these five cases of systems with stable regions in HZ, we perform a series of numerical simulations for planet formation considering discs composed of planetary embryos and planetesimals, with two distinct density profiles, in addition to the stars and host planets of each system. We found that in the case of the Kepler-34 and 453 systems, no Earth-size planet is formed within HZs. Although planets with Earth-like masses were formed in Kepler-453, they were outside HZ. In contrast, for the Kepler-35 and 38 systems, the results showed that potentially habitable planets are formed in all simulations. In the case of the Kepler-413system, in just one simulation, a terrestrial planet was formed within HZ.

scholarly journals Resilient habitability of nearby exoplanet systems

2019 ◽  
Vol 492 (1) ◽  
pp. 352-368 ◽  
Author(s):  
Giorgi Kokaia ◽  
Melvyn B Davies ◽  
Alexander J Mustill
Keyword(s):  
Giant Planet ◽  
Planetary Systems ◽  
Observational Constraints ◽  
Habitable Zone ◽  
Habitable Zones ◽  
Test Particles ◽  
Planetary Orbits ◽  
Two Systems ◽  
Earth Like Planets ◽  
Exoplanet Systems

ABSTRACT We investigate the possibility of finding Earth-like planets in the habitable zone of 34 nearby FGK-dwarfs, each known to host one giant planet exterior to their habitable zone detected by RV. First we simulate the dynamics of the planetary systems in their present day configurations and determine the fraction of stable planetary orbits within their habitable zones. Then, we postulate that the eccentricity of the giant planet is a result of an instability in their past during which one or more other planets were ejected from the system. We simulate these scenarios and investigate whether planets orbiting in the habitable zone survive the instability. Explicitly we determine the fraction of test particles, originally found in the habitable zone, which remain in the habitable zone today. We label this fraction the resilient habitability of a system. We find that for most systems the probability of planets existing [or surviving] on stable orbits in the habitable zone becomes significantly smaller when we include a phase of instability in their history. We present a list of candidate systems with high resilient habitability for future observations. These are: HD 95872, HD 154345, HD 102843, HD 25015, GJ 328, HD 6718, and HD 150706. The known planets in the last two systems have large observational uncertainties on their eccentricities, which propagate into large uncertainties on their resilient habitability. Further observational constraints of these two eccentricities will allow us to better constrain the survivability of Earth-like planets in these systems.

scholarly journals N-body Simulations of Planet Formation

2003 ◽  
Vol 208 ◽  
pp. 25-35 ◽  
Author(s):  
Shigeru Ida ◽  
Eiichiro Kokubo ◽  
Junko Kominami
Keyword(s):  
Final Stage ◽  
Planet Formation ◽  
Planetary Systems ◽  
Terrestrial Planet ◽  
The Other ◽  
Other Hand ◽  
Giant Impacts ◽  
Gas Accretion

Accretion from many small planetesimals to planets is reviewed. Solid protoplanets accrete through runaway and oligarchic growth until they become isolated. The isolation mass of protoplanets in terrestrial planet region is about 0.1-0.2 Earth mass, which suggests giant impacts among the protoplanets in the final stage of terrestrial planet formation. On the other hand, the isolation mass in Jupiter's and Saturn's orbits is about a few to 5 Earth masses, which may be massive enough to trigger gas accretion onto the cores. The isolation mass in Uranus and Neptune's orbits is as large as their present cores. Extending the above arguments to extrasolar planetary systems that are formed from disks with various initial masses, we also discuss diversity of extrasolar planetary systems.

scholarly journals Polarimetry as a tool to find and characterise habitable planets orbiting white dwarfs

2014 ◽  
Vol 10 (S305) ◽  
pp. 325-332 ◽  
Author(s):  
Luca Fossati ◽  
Stefano Bagnulo ◽  
Carole A. Haswell ◽  
Manish R. Patel ◽  
Richard Busuttil ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Uv Radiation ◽  
Uv Irradiation ◽  
White Dwarf ◽  
White Dwarfs ◽  
Terrestrial Planet ◽  
Habitable Zone ◽  
Habitable Planets ◽  
Earth Like Planets ◽  
M Dwarf

AbstractThere are several ways planets can survive the giant phase of the host star, hence one can consider the case of Earth-like planets orbiting white dwarfs. As a white dwarf cools from 6000 K to 4000 K, a planet orbiting at 0.01 AU from the star would remain in the continuous habitable zone (CHZ) for about 8 Gyr. Polarisation due to a terrestrial planet in the CHZ of a cool white dwarf (CWD) is 102 (104) times larger than it would be in the habitable zone of a typical M-dwarf (Sun-like star). Polarimetry is thus a powerful tool to detect close-in planets around white dwarfs. Multi-band polarimetry would also allow one to reveal the presence of a planet atmosphere, even providing a first characterisation. With current facilities a super-Earth-sized atmosphereless planet is detectable with polarimetry around the brightest known CWD. Planned future facilities render smaller planets detectable, in particular by increasing the instrumental sensitivity in the blue. Preliminary habitability study show also that photosynthetic processes can be sustained on Earth-like planets orbiting CWDs and that the DNA-weighted UV radiation dose for an Earth-like planet in the CHZ is less than the maxima encountered on Earth, hence white dwarfs are compatible with the persistence of complex life from the perspective of UV irradiation.

scholarly journals Terrestrial planet formation in low-mass disks: dependence with initial conditions

2014 ◽  
Vol 9 (S310) ◽  
pp. 218-219
Author(s):  
M. P. Ronco ◽  
G. C. de Elía ◽  
O. M. Guilera
Keyword(s):  
Gas Phase ◽  
Analytical Model ◽  
Ad Hoc ◽  
Planet Formation ◽  
Initial Conditions ◽  
Planetary Systems ◽  
Terrestrial Planet ◽  
Initial Distribution ◽  
Protoplanetary Disk ◽  
Low Mass

AbstractIn general, most of the studies of terrestrial-type planet formation typically use ad hoc initial conditions. In this work we improved the initial conditions described in Ronco & de Elía (2014) starting with a semi-analytical model wich simulates the evolution of the protoplanetary disk during the gas phase. The results of the semi-analytical model are then used as initial conditions for the N-body simulations. We show that the planetary systems considered are not sensitive to the particular initial distribution of embryos and planetesimals and thus, the results are globally similar to those found in the previous work.

scholarly journals Terrestrial Planet Formation: The Solar System and Other Systems

2004 ◽  
Vol 202 ◽  
pp. 159-166
Author(s):  
Shigeru Ida ◽  
Eiichiro Kokubo
Keyword(s):  
Solar System ◽  
Final Stage ◽  
Extrasolar Planets ◽  
Planet Formation ◽  
Terrestrial Planet ◽  
The Other ◽  
Terrestrial Planets ◽  
Giant Impacts ◽  
Earth Like Planets ◽  
Jovian Planet

Accretion of terrestrial planets and solid cores of jovian planets is discussed, based on the results of our N-body simulations. Protoplanets accrete from planetesimals through runaway and oligarchic growth until they become isolated. The isolation mass of protoplanets in terrestrial planet region is about 0.2 Earth mass, which suggests that in the final stage of terrestrial planet formation giant impacts between the protoplanets occur. On the other hand, the isolation mass in jovian planet region is about a few to 10 Earth masses, which may be massive enough to form a gas giant. Extending the above arguments to disks with various initial masses, we discuss diversity of planetary systems. We predict that the extrasolar planets so far discovered may correspond to the systems formed from disks with large initial masses and that the other disks with smaller masses, which are the majority of the disks, may form Earth-like planets.

scholarly journals The Diversity of Extrasolar Terrestrial Planets

2009 ◽  
Vol 5 (S265) ◽  
pp. 399-402
Author(s):  
Jade C. Bond ◽  
Dante S. Lauretta ◽  
David P. O'Brien
Keyword(s):  
Chemical Equilibrium ◽  
Planet Formation ◽  
Planetary Systems ◽  
Solid Material ◽  
Terrestrial Planet ◽  
Building Blocks ◽  
Terrestrial Planets ◽  
Dynamical Models ◽  
Diverse Range ◽  
Host Stars

AbstractExtrasolar planetary host stars are enriched in key planet-building elements. These enrichments have the potential to drastically alter the building blocks available for terrestrial planet formation. Here we report on the combination of dynamical models of late-stage terrestrial planet formation within known extrasolar planetary systems with chemical equilibrium models of the composition of solid material within the disk. This allows us to constrain the bulk elemental composition of extrasolar terrestrial planets. A wide variety of resulting planetary compositions exist, ranging from those that are essentially “Earth-like”, containing metallic Fe and Mg-silicates, to those that are dominated by graphite and SiC. This implies that a diverse range of terrestrial planets are likely to exist within extrasolar planetary systems.

scholarly journals Astrometric planet searches with SIM PlanetQuest

2007 ◽  
Vol 3 (S248) ◽  
pp. 238-243
Author(s):  
C. A. Beichman ◽  
S. C. Unwin ◽  
M. Shao ◽  
A. M. Tanner ◽  
J. H. Catanzarite ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Direct Detection ◽  
Terrestrial Planet ◽  
Young Stars ◽  
Terrestrial Planets ◽  
Habitable Zones ◽  
Terrestrial Planet Finder ◽  
Candidate Target ◽  
Deep Survey ◽  
Earth Like Planets

AbstractSIM will search for planets with masses as small as the Earth's orbiting in the ‘habitable zones’ around more than 100 of the nearest stars and could discover many dozen if Earth-like planets are common. With a planned “Deep Survey” of 100–450 stars (depending on desired mass sensitivity) SIM will search for terrestrial planets around all of the candidate target stars for future direct detection missions such as Terrestrial Planet Finder and Darwin. SIM's “Broad Survey” of 2100 stars will characterize single and multiple-planet systems around a wide variety of stellar types, including many now inaccessible with the radial velocity technique. In particular, SIM will search for planets around young stars providing insights into how planetary systems are born and evolve with time.

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