scholarly journals Mapping the Distributions of Exoplanet Populations with NICI and GPI

2015 ◽  
Vol 10 (S314) ◽  
pp. 220-225
Author(s):  
Eric L. Nielsen ◽  
Michael C. Liu ◽  
Zahed Wahhaj ◽  
Beth A. Biller ◽  
Thomas L. Hayward ◽  
...  
Keyword(s):  
Low Frequency ◽  
Major Axis ◽  
Giant Planets ◽  
Direct Imaging ◽  
Semi Major Axis ◽  
Solar Systems ◽  
Test Models ◽  
Nearby Stars ◽  
Formation And Evolution ◽  
Band Contrast

AbstractWhile more and more long-period giant planets are discovered by direct imaging, the distribution of planets at these separations (≳5 AU) has remained largely uncertain, especially compared to planets in the inner regions of solar systems probed by RV and transit techniques. The low frequency, the detection challenges, and heterogeneous samples make determining the mass and orbit distributions of directly imaged planets at the end of a survey difficult. By utilizing Monte Carlo methods that incorporate the age, distance, and spectral type of each target, we can use all stars in the survey, not just those with detected planets, to learn about the underlying population. We have produced upper limits and direct measurements of the frequency of these planets with the most recent generation of direct imaging surveys. The Gemini NICI Planet-Finding Campaign observed 220 young, nearby stars at a median H-band contrast of 14.5 magnitudes at 1”, representing the largest, deepest search for exoplanets by the completion of the survey. The Gemini Planet Imager Exoplanet Survey is in the process of surveying 600 stars, pushing these contrasts to a few tenths of an arcsecond from the star. With the advent of large surveys (many hundreds of stars) using advanced planet-imagers we gain the ability to move beyond measuring the frequency of wide-separation giant planets and to simultaneously determine the distribution as a function of planet mass, semi-major axis, and stellar mass, and so directly test models of planet formation and evolution.

scholarly journals How planet–planet scattering can create high-inclination as well as long-period orbits

2010 ◽  
Vol 6 (S276) ◽  
pp. 225-229 ◽  
Author(s):  
Sourav Chatterjee ◽  
Eric B. Ford ◽  
Frederic A. Rasio
Keyword(s):  
Major Axis ◽  
Theoretical Models ◽  
Giant Planets ◽  
Direct Imaging ◽  
Semi Major Axis ◽  
Hot Jupiters ◽  
Long Period ◽  
Outer Disk ◽  
Planetary Orbits ◽  
Core Accretion

AbstractRecent observations have revealed two new classes of planetary orbits. Rossiter-Mclaughlin (RM) measurements have revealed hot Jupiters in high-obliquity orbits. In addition, direct-imaging has discovered giant planets at large (~ 100 AU) separations via direct-imaging technique. Simple-minded disk-migration scenarios are inconsistent with the high-inclination (and even retrograde) orbits as seen in recent RM measurements. Furthermore, forming giant planets at large semi-major axis (a) may be challenging in the core-accretion paradigm. We perform many N-body simulations to explore the two above-mentioned orbital architectures. Planet–planet scattering in a multi-planet system can naturally excite orbital inclinations. Planets can also get scattered to large distances. Large-a planetary orbits created from planet–planet scattering are expected to have high eccentricities (e). Theoretical models predict that the observed long-period planets, such as Fomalhaut-b have moderate e ≈ 0.3. Interestingly, these are also in systems with disks. We find that if a massive-enough outer disk is present, a scattered planet may be circularized at large a via dynamical friction from the disk and repeated scattering of the disk particles.

scholarly journals SOPHIE velocimetry of Kepler transit candidates

2018 ◽  
Vol 615 ◽  
pp. A90 ◽  
Author(s):  
J. M. Almenara ◽  
R. F. Díaz ◽  
G. Hébrard ◽  
R. Mardling ◽  
C. Damiani ◽  
...  
Keyword(s):  
Planetary System ◽  
Major Axis ◽  
Giant Planets ◽  
Eccentric Orbit ◽  
Semi Major Axis ◽  
Hot Jupiters ◽  
Timing Data ◽  
Single Host ◽  
Velocity Information ◽  
The Masses

Kepler-419 is a planetary system discovered by the Kepler photometry which is known to harbour two massive giant planets: an inner 3 MJ transiting planet with a 69.8-day period, highly eccentric orbit, and an outer 7.5 MJ non-transiting planet predicted from the transit-timing variations (TTVs) of the inner planet b to have a 675-day period, moderately eccentric orbit. Here we present new radial velocity (RV) measurements secured over more than two years with the SOPHIE spectrograph, where both planets are clearly detected. The RV data is modelled together with the Kepler photometry using a photodynamical model. The inclusion of velocity information breaks the MR−3 degeneracy inherent in timing data alone, allowing us to measure the absolute stellar and planetary radii and masses. With uncertainties of 12 and 13% for the stellar and inner planet radii, and 35, 24, and 35% for the masses of the star, planet b, and planet c, respectively, these measurements are the most precise to date for a single host star system using this technique. The transiting planet mass is determined at better precision than the star mass. This shows that modelling the radial velocities and the light curve together in systems of dynamically interacting planets provides a way of characterising both the star and the planets without being limited by knowledge of the star. On the other hand, the period ratio and eccentricities place the Kepler-419 system in a sweet spot; had around twice as many transits been observed, the mass of the transiting planet could have been measured using its own TTVs. Finally, the origin of the Kepler-419 system is discussed. We show that the system is near a coplanar high-eccentricity secular fixed point, related to the alignment of the orbits, which has prevented the inner orbit from circularising. For most other relative apsidal orientations, planet b’s orbit would be circular with a semi-major axis of 0.03 au. This suggests a mechanism for forming hot Jupiters in multiplanetary systems without the need of high mutual inclinations.

scholarly journals Orbital effects of a monochromatic plane gravitational wave with ultra-low frequency incident on a gravitationally bound two-body system

2014 ◽  
Author(s):  
Lorenzo Iorio
Keyword(s):  
Gravitational Wave ◽  
Extrasolar Planets ◽  
A Priori ◽  
Low Frequency ◽  
Major Axis ◽  
Characteristic Size ◽  
Body System ◽  
Semi Major Axis ◽  
Plane Gravitational Wave

We analytically compute the long-term orbital variations of a test particle orbiting a central body acted upon by an incident monochromatic plane gravitational wave. We assume that the characteristic size of the perturbed two-body system is much smaller than the wavelength of the wave. Moreover, we also suppose that the wave's frequency νg is much smaller than the particle's orbital one nb. We make neither a priori assumptions about the direction of the wavevector k nor on the orbital configuration of the particle. While the semi-major axis a is left unaffected, the eccentricity e, the inclination I, the longitude of the ascending node Ω, the longitude of pericenter ϖ and the mean anomaly ℳ undergo non-vanishing long-term changes of the form dΨ/dt=F(Kij;e,I,Ω,ω),Ψ=e,I,Ω,ϖ,M, where Kij, i,j=1,2,3 are the coefficients of the tidal matrix K. Thus, in addition to the variations of its orientation in space, the shape of the orbit would be altered as well. Strictly speaking, such effects are not secular trends because of the slow modulation introduced by K and by the orbital elements themselves: they exhibit peculiar long-term temporal patterns which would be potentially of help for their detection in multidecadal analyses of extended data records of planetary observations of various kinds. In particular, they could be useful in performing independent tests of the inflation-driven ultra-low gravitational waves whose imprint may have been indirectly detected in the Cosmic Microwave Background by the Earth-based experiment BICEP2. Our calculation holds, in general, for any gravitationally bound two-body system whose orbital frequency nb is much larger than the frequency νg of the external wave, like, e.g., extrasolar planets and the stars orbiting the Galactic black hole. It is also valid for a generic perturbation of tidal type with constant coefficients over timescales of the order of the orbital period of the perturbed particle.

scholarly journals Orbital effects of a monochromatic plane gravitational wave with ultra-low frequency incident on a gravitationally bound two-body system

2014 ◽  
Author(s):  
Lorenzo Iorio
Keyword(s):  
Gravitational Wave ◽  
Extrasolar Planets ◽  
A Priori ◽  
Low Frequency ◽  
Major Axis ◽  
Characteristic Size ◽  
Body System ◽  
Semi Major Axis ◽  
Plane Gravitational Wave

We analytically compute the long-term orbital variations of a test particle orbiting a central body acted upon by an incident monochromatic plane gravitational wave. We assume that the characteristic size of the perturbed two-body system is much smaller than the wavelength of the wave. Moreover, we also suppose that the wave's frequency νg is much smaller than the particle's orbital one nb. We make neither a priori assumptions about the direction of the wavevector k nor on the orbital configuration of the particle. While the semi-major axis a is left unaffected, the eccentricity e, the inclination I, the longitude of the ascending node Ω, the longitude of pericenter ϖ and the mean anomaly ℳ undergo non-vanishing long-term changes of the form dΨ/dt=F(Kij;e,I,Ω,ω),Ψ=e,I,Ω,ϖ,M, where Kij, i,j=1,2,3 are the coefficients of the tidal matrix K. Thus, in addition to the variations of its orientation in space, the shape of the orbit would be altered as well. Strictly speaking, such effects are not secular trends because of the slow modulation introduced by K and by the orbital elements themselves: they exhibit peculiar long-term temporal patterns which would be potentially of help for their detection in multidecadal analyses of extended data records of planetary observations of various kinds. In particular, they could be useful in performing independent tests of the inflation-driven ultra-low gravitational waves whose imprint may have been indirectly detected in the Cosmic Microwave Background by the Earth-based experiment BICEP2. Our calculation holds, in general, for any gravitationally bound two-body system whose orbital frequency nb is much larger than the frequency νg of the external wave, like, e.g., extrasolar planets and the stars orbiting the Galactic black hole. It is also valid for a generic perturbation of tidal type with constant coefficients over timescales of the order of the orbital period of the perturbed particle.

scholarly journals The Formation and Evolution of the Perseid Meteoroid Stream

1996 ◽  
Vol 150 ◽  
pp. 101-104
Author(s):  
Nathan W. Harris
Keyword(s):  
Orbital Stability ◽  
Direct Consequence ◽  
Major Axis ◽  
Orbital Evolution ◽  
Meteoroid Stream ◽  
Semi Major Axis ◽  
Meteoroid Streams ◽  
Integration Techniques ◽  
Formation And Evolution ◽  
Direct Numerical Integration

AbstractThe orbital evolution of two modelled ‘Perseid’ meteoroid streams is investigated using direct numerical integration techniques. We conclude that, in the absence of significant meteoroid velocity determination errors, the observed meteoroid orbital semi-major axis distribution is a direct consequence of the cometary ejection process and not due to subsequent orbital evolution. A high ejection-velocity (~ 0.6 km s-1) model stream succeeds in reproducing the observations. Conclusions are made concerning how the orbital stability of Earth-orbit-intersecting Perseid metecroids varies with initial orbital semi-major axis.

scholarly journals PLANETARY MIGRATION IN EVOLVING PLANETESIMAL DISKS

2003 ◽  
Vol 12 (08) ◽  
pp. 1399-1414 ◽  
Author(s):  
İ. SAFFET YEŞİLYURT ◽  
E. NİHAL ERCAN ◽  
A. DEL POPOLO
Keyword(s):  
Accretion Disks ◽  
Migration Rate ◽  
Major Axis ◽  
Solid Particles ◽  
Giant Planets ◽  
Semi Major Axis ◽  
Density Profiles ◽  
Disk Model ◽  
Characteristic Radius ◽  
Planetary Migration

In the current paper, we further improved the model for the migration of planets introduced and extended to time-dependent planetesimal accretion disks by Del Popolo. In the current study, the assumption of Del Popolo, that the surface density in planetesimals is proportional to that of gas, is relaxed. In order to obtain the evolution of planetesimal density, we use a method developed by Stepinski and Valageas which is able to simultaneously follow the evolution of gas and solid particles for up to 107 years. Then, the disk model is coupled to migration model introduced by Del Popolo in order to obtain the migration rate of the planet in the planetesimal. We find that the properties of solids known to exist in protoplanetary systems, together with reasonable density profiles for the disk, lead to a characteristic radius in the range 0.03–0.2 AU for the final semi-major axis of the giant planet.Hence our model can explain the properties of discovered extrasolar giant planets.

scholarly journals Planetary migration in gaseous protoplanetary disks

2007 ◽  
Vol 3 (S249) ◽  
pp. 331-346
Author(s):  
Frédéric S. Masset
Keyword(s):  
Major Axis ◽  
Giant Planets ◽  
Type I ◽  
Type Ii ◽  
Orbital Elements ◽  
Intermediate Mass ◽  
Semi Major Axis ◽  
Low Mass ◽  
Planetary Migration ◽  
Different Parts

AbstractTides come from the fact that different parts of a system do not fall in exactly the same way in a non-uniform gravity field. In the case of a protoplanetary disk perturbed by an orbiting, prograde protoplanet, the protoplanet tides raise a wake in the disk which causes the orbital elements of the planet to change over time. The most spectacular result of this process is a change in the protoplanet's semi-major axis, which can decrease by orders of magnitude on timescales shorter than the disk lifetime. This drift in the semi-major axis is called planetary migration. In a first part, we describe how the planet and disk exchange angular momentum and energy at the Lindblad and corotation resonances. Next we review the various types of planetary migration that have so far been contemplated: type I migration, which corresponds to low-mass planets (less than a few Earth masses) triggering a linear disk response; type II migration, which corresponds to massive planets (typically at least one Jupiter mass) that open up a gap in the disk; “runaway” or type III migration, which corresponds to sub-giant planets that orbit in massive disks; and stochastic or diffusive migration, which is the migration mode of low- or intermediate-mass planets embedded in turbulent disks. Lastly, we present some recent results in the field of planetary migration.

scholarly journals The Impact of Transiting Planet Science on the Next Generation of Direct-Imaging Planet Searches

2008 ◽  
Vol 4 (S253) ◽  
pp. 556-559
Author(s):  
Joseph C. Carson
Keyword(s):  
A Priori ◽  
Major Axis ◽  
Next Generation ◽  
A Priori Information ◽  
Direct Imaging ◽  
Semi Major Axis ◽  
Absorption Bands ◽  
Imaging Results ◽  
Priori Information ◽  
The Impact

AbstractWithin the next five years, a number of direct-imaging planet search instruments, like the VLT SPHERE instrument, will be coming online. To successfully carry out their programs, these instruments will rely heavily on a-priori information on planet composition, atmosphere, and evolution. Transiting planet surveys, while covering a different semi-major axis regime, have the potential to provide critical foundations for these next-generation surveys. For example, improved information on planetary evolutionary tracks may significantly impact the insights that can be drawn from direct-imaging statistical data. Other high-impact results from transiting planet science include information on mass-to-radius relationships as well as atmospheric absorption bands. The marriage of transiting planet and direct-imaging results may eventually give us the first complete picture of planet migration, multiplicity, and general evolution.

scholarly journals LIStEN: L′ band Imaging Survey for Exoplanets in the North

2021 ◽  
Vol 645 ◽  
pp. A88
Author(s):  
Arianna Musso Barcucci ◽  
Ralf Launhardt ◽  
André Müller ◽  
Grant M. Kennedy ◽  
Roy van Boekel ◽  
...  
Keyword(s):  
Proper Motion ◽  
Major Axis ◽  
Mass Detection ◽  
Semi Major Axis ◽  
Simultaneous Imaging ◽  
The North ◽  
Nearby Stars ◽  
Low Mass ◽  
Differential Imaging ◽  
By Products

Context. Planetary systems and debris discs are natural by-products of the star formation process, and they affect each other. The direct imaging technique allows simultaneous imaging of both a companion and the circumstellar disc it resides in, and is thus a valuable tool to study companion-disc interactions. However, the number of systems in which a companion and a disc have been detected at the same time remains low. Aims. Our aim is to increase this sample, and to continue detecting and studying the population of giant planets in wide orbits. Methods. We carry out the L′ band Imaging Survey for Exoplanets in the North (LIStEN), which targeted 28 nearby stars: 24 are known to harbour a debris disc (DD) and the remaining 4 are protoplanetary disc-hosting stars. We aim to detect possible new companions, and study the interactions between the companion and their discs. Angular differential imaging observations were carried out in the L′ band at 3.8 μm using the LMIRCam instrument at the LBT, between October 2017 and April 2019. Results. No new companions were detected. We combined the derived mass detection limits with information on the disc, and on the proper motion of the host star, to constrain the presence of unseen planetary and low-mass stellar companion around the 24 disc-hosting stars in our survey. We find that 2 have an uncertain DD status and the remaining 22 have disc sizes compatible with self-stirring. Three targets show a proper motion anomaly (PMa) compatible with the presence of an unseen companion. Conclusions. Our achieved mass limits combined with the PMa analysis for HD 113337 support the presence of a second companion around the star, as suggested in previous RV studies. Our mass limits also help to tighten the constraints on the mass and semi-major axis of the unseen companions around HD 161868 and HD 8907.

scholarly journals HD 83443: a system with two Saturns

2004 ◽  
Vol 202 ◽  
pp. 84-86 ◽  
Author(s):  
M. Mayor ◽  
D. Naef ◽  
F. Pepe ◽  
D. Queloz ◽  
N. C. Santos ◽  
...  
Keyword(s):  
Planetary System ◽  
Major Axis ◽  
Giant Planets ◽  
Outer Planet ◽  
Semi Major Axis ◽  
Dynamical Study ◽  
Low Mass ◽  
The Stability ◽  
Extrasolar Planetary System

We report the discovery of an extrasolar planetary system with two Saturnian planets around the star HD 83443. The new planetary system is unusual by more than one aspect, as it contains two very low–mass gaseous giant planets, both on very tight orbits. Among the planets detected so far, the inner planet has the smallest semi–major axis (0.038 AU) and period (2.985 days) whereas the outer planet is the lightest one with m2 sin i = 0.53 MSat. A preliminary dynamical study confirms the stability of the system.

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