Case studies of habitable Trojan planets in the system of HD 23079

AbstractWe investigate the possibility of habitable Trojan planets in the HD 23079 star–planet system. This system consists of a solar-type star and a Jupiter-type planet, which orbits the star near the outer edge of the stellar habitable zone in an orbit of low eccentricity. We find that in agreement with previous studies Earth-mass habitable Trojan planets are possible in this system, although the success of staying within the zone of habitability is significantly affected by the orbital parameters of the giant planet and by the initial condition of the theoretical Earth-mass planet. In one of our simulations, the Earth-mass planet is captured by the giant planet and thus becomes a habitable moon.

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A Step Toward Eta-sub-Earth

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313012593 ◽

2012 ◽

Vol 8 (S293) ◽

pp. 84-87

Author(s):

Wesley A. Traub

Keyword(s):

Type Star ◽

Terrestrial Planets ◽

Habitable Zone ◽

Reaction Wheel ◽

Expected Number ◽

Initial Examination ◽

True Value ◽

Kepler Mission ◽

Solar Type ◽

Solar Type Star

AbstractThe Kepler mission observed exoplanet transits for 4 full years (greater than its expected lifetime of 3.5 years) until it became inoperable for its original purpose, as a result of a reaction wheel failure. Kepler was spectacularly successful in its goal of observing exoplanet transits of host star disks for the purpose of measuring the statistics of such transits in its target star sample. The Kepler data, when fully analyzed, will determine the statistics of planets in the underlying population, and in particular the expected number of terrestrial planets in habitable zone orbits per solar-type star, the quantity known as eta-sub-Earth. This report is an initial examination of Kepler's third catalog (Feb. 2012) of planets and candidate planets. I find that the apparent projected value of eta-sub-Earth is several times smaller than I had found from the second catalog, but that the data are now approaching the point where intrinsic biases can be uncovered. When all bias factors are eventually found, it is likely that the true value of eta-sub-Earth will be substantially greater than its current apparent value.

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The Galactic cosmic ray intensity at the evolving Earth and young exoplanets

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2737 ◽

2020 ◽

Vol 499 (2) ◽

pp. 2124-2137

Author(s):

D Rodgers-Lee ◽

A A Vidotto ◽

A M Taylor ◽

P B Rimmer ◽

T P Downes

Keyword(s):

Cosmic Rays ◽

Transport Model ◽

Solar Rotation ◽

Cosmic Ray ◽

Galactic Cosmic Rays ◽

Type Star ◽

The Earth ◽

Solar Type ◽

Galactic Cosmic Ray ◽

Solar Type Star

ABSTRACT Cosmic rays may have contributed to the start of life on the Earth. Here, we investigate the evolution of the Galactic cosmic ray spectrum at the Earth from ages t = 0.6−6.0 Gyr. We use a 1D cosmic ray transport model and a 1.5D stellar wind model to derive the evolving wind properties of a solar-type star. At $t=1\,$ Gyr, approximately when life is thought to have begun on the Earth, we find that the intensity of ∼GeV Galactic cosmic rays would have been ∼10 times smaller than the present-day value. At lower kinetic energies, Galactic cosmic ray modulation would have been even more severe. More generally, we find that the differential intensity of low-energy Galactic cosmic rays decreases at younger ages and is well described by a broken power law in solar rotation rate. We provide an analytic formula of our Galactic cosmic ray spectra at the Earth’s orbit for different ages. Our model is also applicable to other solar-type stars with exoplanets orbiting at different radii. Specifically, we use our Galactic cosmic ray spectrum at 20 au for $t=600\,$ Myr to estimate the penetration of cosmic rays in the atmosphere of HR 2562b, a directly imaged exoplanet orbiting a young solar-type star. We find that the majority of particles <0.1 GeV are attenuated at pressures ≳10−5 bar and thus do not reach altitudes below ∼100 km. Observationally constraining the Galactic cosmic ray spectrum in the atmosphere of a warm Jupiter would in turn help constrain the flux of cosmic rays reaching young Earth-like exoplanets.

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Surface differential rotation and photospheric magnetic field of the young solar-type star HD 171488 (V889 Her)

Monthly Notices of the Royal Astronomical Society ◽

10.1111/j.1365-2966.2006.10503.x ◽

2006 ◽

Vol 370 (1) ◽

pp. 468-476 ◽

Cited By ~ 64

Author(s):

S. C. Marsden ◽

J.-F. Donati ◽

M. Semel ◽

P. Petit ◽

B. D. Carter

Keyword(s):

Magnetic Field ◽

Differential Rotation ◽

Photospheric Magnetic Field ◽

Type Star ◽

Solar Type ◽

Solar Type Star

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COMMISSION 53: EXTRASOLAR PLANETS

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308025465 ◽

2008 ◽

Vol 4 (T27A) ◽

pp. 181-182

Author(s):

Michel Mayor ◽

Alan P. Boss ◽

Paul R. Butler ◽

William B. Hubbard ◽

Philip A. Ianna ◽

...

Keyword(s):

Working Group ◽

Extrasolar Planets ◽

Theoretical Work ◽

Vice President ◽

The Other ◽

Type Star ◽

Extrasolar Planet ◽

General Assembly ◽

Solar Type ◽

Solar Type Star

Commission 53 on Extrasolar Planets was created at the 2006 Prague General Assembly of the IAU, in recognition of the outburst of astronomical progress in the field of extrasolar planet discovery, characterization, and theoretical work that has occurred since the discovery of the pulsar planets in 1992 and the discovery of the first planet in orbit around a solar-type star in 1995. Commission 53 is the logical successor to the IAU Working Group on Extrasolar Planets WG-ESP, which ended its six years of existence in August 2006. The founding president of Commission 53 is Michael Mayor, in honor of his seminal contributions to this new field of astronomy. The vice-president is Alan Boss, the former chair of the WG-ESP, and the members of the Commission 53 Organizing Committee are the other former members of the WG-ESP.

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