scholarly journals Characterizing the Eccentricities of Transiting Extrasolar Planets with Kepler and CoRoT

2008 ◽  
Vol 4 (S253) ◽  
pp. 111-119
Author(s):  
Eric B. Ford ◽  
Knicole D. Colón
Keyword(s):  
Radial Velocity ◽  
Extrasolar Planets ◽  
Giant Planets ◽  
Physical Parameters ◽  
Tidal Dissipation ◽  
Transiting Planets ◽  
Photometric Observations ◽  
Short Period ◽  
Photometric Measurements ◽  
Rocky Planets

AbstractRadial velocity planet searches have revealed that many giant planets have large eccentricities, in striking contrast with the giant planets in the solar system and prior theories of planet formation. The realization that many giant planets have large eccentricities raises a fundamental question: Do terrestrial-size planets of other stars typically have significantly eccentric orbits or nearly circular orbits like the Earth? While space-based missions such as CoRoT and Kepler will be capable of detecting nearly Earth-sized planets, it will be extremely challenging to measure their eccentricities using radial velocity observations. We review several ways that photometric measurements of transit light curves can constrain the eccentricity of transiting planets. In particular, photometric observations of transit durations can be used to characterize the distribution of orbital eccentricities for various populations of transiting planets (e.g., nearly Earth-sized planets in the habitable zone) without relying on radial velocity measurements. Applying this technique to rocky planets to be found by CoRoT and Kepler will enable constraints on theories for the excitation of eccentricities and tidal dissipation. We also remind observers that several short-period transiting planets are known to have significant eccentricities and caution that assuming they are on a circular orbit can reduce the probability of detecting transits, impact planning for follow-up observations, and adversely affect measurements of the physical parameters of the star and planet.

Longevity of moons around habitable planets

2014 ◽  
Vol 13 (4) ◽  
pp. 324-336 ◽  
Author(s):  
Takashi Sasaki ◽  
Jason W. Barnes
Keyword(s):  
Orbital Period ◽  
Extrasolar Planets ◽  
The Sun ◽  
Habitable Zone ◽  
Evolution Theory ◽  
Earth System ◽  
The Moon ◽  
Tidal Dissipation ◽  
Habitable Planets ◽  
Rocky Planets

AbstractWe consider tidal decay lifetimes for moons orbiting habitable extrasolar planets using the constant Q approach for tidal evolution theory. Large moons stabilize planetary obliquity in some cases, and it has been suggested that large moons are necessary for the evolution of complex life. We find that the Moon in the Sun–Earth system must have had an initial orbital period of not slower than 20 h rev−1 for the moon's lifetime to exceed a 5 Gyr lifetime. We assume that 5 Gyr is long enough for life on planets to evolve complex life. We show that moons of habitable planets cannot survive for more than 5 Gyr if the stellar mass is less than 0.55 and 0.42 M⊙ for Qp=10 and 100, respectively, where Qp is the planetary tidal dissipation quality factor. Kepler-62e and f are of particular interest because they are two actually known rocky planets in the habitable zone. Kepler-62e would need to be made of iron and have Qp=100 for its hypothetical moon to live for longer than 5 Gyr. A hypothetical moon of Kepler-62f, by contrast, may have a lifetime greater than 5 Gyr under several scenarios, and particularly for Qp=100.

scholarly journals Transit & RV Observations of Exoplanets by the 1-m Telescope at Weihai

2012 ◽  
Vol 8 (S293) ◽  
pp. 33-35
Author(s):  
Chen Cao ◽  
Dayong Ren ◽  
Dongyang Gao ◽  
Jicheng Zhang ◽  
Nan Song ◽  
...  
Keyword(s):  
High Resolution ◽  
Radial Velocity ◽  
Extrasolar Planets ◽  
Physical Parameters ◽  
Velocity Measurements ◽  
Preliminary Results

AbstractBy using the 1-m reflecting telescope at Weihai Observatory of Shandong University, the transit observations of seven stars are carried out to accurately estimate the physical parameters of extrasolar planets. Besides, a new high-resolution spectrograph (WES) was installed on this telescope for radial velocity measurements on exoplanets, we will show some preliminary results.

scholarly journals Towards a fully automated eclipsing binary solver for Gaia

2008 ◽  
Vol 4 (S253) ◽  
pp. 402-403
Author(s):  
Brandon Tingley ◽  
Gilles Sadowski ◽  
Christos Siopis
Keyword(s):  
Radial Velocity ◽  
High Precision ◽  
Eclipsing Binaries ◽  
Physical Parameters ◽  
Graphical Interface ◽  
Velocity Measurements ◽  
New Approach ◽  
Eclipsing Binary ◽  
Photometric Observations

AbstractGaia, an ESA cornerstone mission, will obtain of the order of 100 high-precision photometric observations and lower precision radial velocity measurements over five years for around a billion stars – several hundred thousand of which will be eclipsing binaries. In order to extract the characteristics of these systems, a fully automated code must be available. During the process of this development, two tools that may be of use to the transit community have emerged: a very fast, simple, detached eclipsing binary simulator/solver based on a new approach and an interacting eclipsing binary simulator with most of the features of the Wilson-Devinney and Nightfall codes, but fully documented and written in easy-to-follow and highly portable Java. Currently undergoing development and testing, this code includes an intuitive graphical interface and an optimizer for the estimation of the physical parameters of the system.

scholarly journals Constraining Planetary Migration Mechanisms in Systems of Giant Planets

2013 ◽  
Vol 8 (S299) ◽  
pp. 386-390
Author(s):  
Rebekah I. Dawson ◽  
Ruth A. Murray-Clay ◽  
John Asher Johnson
Keyword(s):  
Giant Planet ◽  
Giant Planets ◽  
Tidal Dissipation ◽  
Hot Jupiters ◽  
Short Period ◽  
Pile Up ◽  
Planetary Migration ◽  
Multi Body ◽  
Host Stars

AbstractIt was once widely believed that planets formed peacefully in situ in their proto-planetary disks and subsequently remain in place. Instead, growing evidence suggests that many giant planets undergo dynamical rearrangement that results in planets migrating inward in the disk, far from their birthplaces. However, it remains debated whether this migration is caused by smooth planet-disk interactions or violent multi-body interactions. Both classes of model can produce Jupiter-mass planets orbiting within 0.1 AU of their host stars, also known as hot Jupiters. In the latter class of model, another planet or star in the system perturbs the Jupiter onto a highly eccentric orbit, which tidal dissipation subsequently shrinks and circularizes during close passages to the star. We assess the prevalence of smooth vs. violent migration through two studies. First, motivated by the predictions of Socrates et al. (2012), we search for super-eccentric hot Jupiter progenitors by using the “photoeccentric effect” to measure the eccentricities of Kepler giant planet candidates from their transit light curves. We find a significant lack of super- eccentric proto-hot Jupiters compared to the number expected, allowing us to place an upper limit on the fraction of hot Jupiters created by stellar binaries. Second, if both planet-disk and multi-body interactions commonly cause giant planet migration, physical properties of the proto-planetary environment may determine which is triggered. We identify three trends in which giant planets orbiting metal rich stars show signatures of planet-planet interactions: (1) gas giants orbiting within 1 AU of metal-rich stars have a range of eccentricities, whereas those orbiting metal- poor stars are restricted to lower eccentricities; (2) metal-rich stars host most eccentric proto-hot Jupiters undergoing tidal circularization; and (3) the pile-up of short-period giant planets, missing in the Kepler sample, is a feature of metal-rich stars and is largely recovered for giants orbiting metal-rich Kepler host stars. These two studies suggest that both disk migration and planet-planet interactions may be widespread, with the latter occurring primarily in metal-rich planetary systems where multiple giant planets can form. Funded by NSF-GRFP DGE-1144152.

scholarly journals Revisiting the eccentricities of hot Jupiters

2010 ◽  
Vol 6 (S276) ◽  
pp. 243-247
Author(s):  
Nawal Husnoo ◽  
Frédéric Pont ◽  
Tsevi Mazeh ◽  
Daniel Fabrycky ◽  
Guillaume Hébrard ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Circular Orbits ◽  
Hot Jupiters ◽  
Transiting Planets ◽  
Eccentric Orbits ◽  
Tidal Theory ◽  
Short Period ◽  
Formation And Evolution ◽  
Orbital Periods ◽  
Radial Velocity Data

AbstractMost short period transiting exoplanets have circular orbits, as expected from an estimation of the circularisation timescale using classical tidal theory. Interestingly, a small number of short period transiting exoplanets seem to have orbits with a small eccentricity. Such systems are valuable as they may indicate that some key physics is missing from formation and evolution models. We have analysed the results of a campaign of radial velocity measurements of known transiting planets with the SOPHIE and HARPS spectrographs using Bayesian methods and obtained new constraints on the orbital elements of 12 known transiting exoplanets. We also reanalysed the radial velocity data for another 42 transiting systems and show that some of the eccentric orbits reported in the Literature are compatible with a circular orbit. As a result, we show that the systems with circular and eccentric orbits are clearly separated on a plot of the planetary mass versus orbital period. We also show that planets following the trend where heavier hot Jupiters have shorter orbital periods (the “mass-period relation” of hot Jupiters), also tend to have circular orbits, with no confirmed exception to this rule so far.

scholarly journals Transiting Planets in the Galactic Bulge from SWEEPS Survey and Implications

2008 ◽  
Vol 4 (S253) ◽  
pp. 45-53 ◽  
Author(s):  
Kailash C. Sahu ◽  
Stefano Casertano ◽  
Jeff Valenti ◽  
Howard E. Bond ◽  
Thomas M. Brown ◽  
...  
Keyword(s):  
Extrasolar Planets ◽  
Hubble Space Telescope ◽  
Monitoring Program ◽  
Solar Neighborhood ◽  
Galactic Bulge ◽  
M Dwarfs ◽  
Low Mass Stars ◽  
Transiting Planets ◽  
Short Period ◽  
Low Mass

AbstractThe SWEEPS (Sagittarius Window Eclipsing Extrasolar Planet Search) program was aimed at detecting planets around stars in the Galactic bulge, not only to determine their physical properties, but also to determine whether the properties of planets found in the solar neighborhood, such as their frequency and the metallicity dependence, also hold for the planets in the Galactic bulge. We used the Hubble Space Telescope to monitor 180,000 F, G, K, and M dwarfs in the Galactic bulge continuously for 7 days in order to look for transiting planets. We discovered 16 candidate transiting extrasolar planets with periods of 0.6 to 4.2 days, including a possible new class of ultra-short period planets (USPPs) with P < 1 day. The facts that (i) the coverage in the monitoring program is continuous, (ii) most of the stars are at a known distance (in the Galctic bulge), (iii) monitoring was carried out in 2 passbands, and (iv) the images have high spatial resolution, were crucial in minimizing and estimating the false positive rates. We estimate that at least 45% of the candidates are genuine planets. Radial velocity observations of the two brightest host stars further support the planetary nature of the transiting companions. These results suggest that the planet frequency in the Galactic bulge is similar to that in the solar neighborhood. They also suggest that higher metallicity favors planet formation even in the Galactic bulge. The USPPs occur only around low-mass stars which may suggest that close-in planets around higher-mass stars are irradiately evaporated, or that planets are able to migrate to and survive in close-in orbits only around such old and low-mass stars.

scholarly journals The analysis of SuperWASP photometric data for the overcontact binary QW Gem

2013 ◽  
pp. 47-51 ◽  
Author(s):  
A. Cséki
Keyword(s):  
Radial Velocity ◽  
Surface Brightness ◽  
Photometric Data ◽  
Physical Parameters ◽  
Eclipsing Binary ◽  
Photometric Observations ◽  
Modeling Code

The paper presents an analysis of photometric observations of the eclipsing binary QW Gem. The orbital and physical parameters of the system are derived using the modeling code by G. Djurasevic. Photometric observations are obtained from the SuperWASP public archive and the spectroscopic elements are adopted from a recently published radial velocity study. The results suggest that QW Gem is a binary in overcontact configuration, consisting of two stars of similar surface brightness but in different evolutionary stages.

scholarly journals Nonlinear tidal flows in short-period planets

2019 ◽  
Vol 82 ◽  
pp. 43-50
Author(s):  
A.J. Barker
Keyword(s):  
Extrasolar Planets ◽  
Spin Orbit ◽  
Tidal Evolution ◽  
Tidal Dissipation ◽  
Hot Jupiters ◽  
Fluid Instability ◽  
Short Period ◽  
Elliptical Instability ◽  
Turbulent Damping ◽  
Tidal Deformations

I discuss two related nonlinear mechanisms of tidal dissipation that require finite tidal deformations for their operation: the elliptical instability and the precessional instability. Both are likely to be important for the tidal evolution of short-period extrasolar planets. The elliptical instability is a fluid instability of elliptical streamlines, such as in tidally deformed non-synchronously rotating or non-circularly orbiting planets. I summarise the results of local and global simulations that indicate this mechanism to be important for tidal spin synchronisation, planetary spin-orbit alignment and orbital circularisation for the shortest period hot Jupiters. The precessional instability is a fluid instability that occurs in planets undergoing axial precession, such as those with spin-orbit misalignments (non-zero obliquities). I summarise the outcome of local MHD simulations designed to study the turbulent damping of axial precession, which suggest this mechanism to be important in driving tidal evolution of the spin-orbit angle for hot Jupiters. Avenues for future work are also discussed.

scholarly journals The formation of close-in planets by the slingshot model

2007 ◽  
Vol 3 (S249) ◽  
pp. 279-284
Author(s):  
Makiko Nagasawa ◽  
Shigeru Ida ◽  
Taisuke Bessho
Keyword(s):  
Planetary Orbit ◽  
Tidal Dissipation ◽  
Transiting Planets ◽  
Short Period ◽  
Jovian Planets ◽  
Tide Effect

AbstractWe investigated the efficiency of planet scatterings in producing close-in planets by a direct inclusion of the dynamical tide effect into the simulations. We considered a system consists of three Jovian planets. Through a planet-planet scattering, one of the planets is sent into shorter orbit. If the eccentricity of the scattered planet is enough high, the tidal dissipation from the star makes the planetary orbit circular. We found that the short-period planets are formed at about 30% cases in our simulation and that Kozai mechanism plays an important role. In the Kozai mechanism, the high inclination obtained by planet-planet scattering is transformed to the eccentricity. It leads the pericenter of the innermost planet to approach the star close enough for tidal circularization. The formed close-in planets by this process have a widely spread inclination distribution. The degree of contribution of the process for the formation of close-in planets will be revealed by more observations of Rossiter-McLaughlin effects for transiting planets.

scholarly journals A hot Saturn on an eccentric orbit around the giant star K2-132

2018 ◽  
Vol 613 ◽  
pp. A76 ◽  
Author(s):  
M. I. Jones ◽  
R. Brahm ◽  
N. Espinoza ◽  
A. Jordán ◽  
F. Rojas ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Semimajor Axis ◽  
Physical Parameters ◽  
Giant Star ◽  
Orbital Parameters ◽  
Hot Jupiters ◽  
Giant Stars ◽  
Short Period ◽  
Interesting Object ◽  
Solar Type

Although the majority of radial velocity detected planets have been found orbiting solar-type stars, a fraction of them have been discovered around giant stars. These planetary systems have revealed different orbital properties when compared to solar-type star companions. In particular, radial velocity surveys have shown that there is a lack of giant planets in close-in orbits around giant stars, in contrast to the known population of hot Jupiters orbiting solar-type stars. It has been theorized that the reason for this distinctive feature in the semimajor axis distribution is the result of the stellar evolution and/or that it is due to the effect of a different formation/evolution scenario for planets around intermediate-mass stars. However, in the past few years a handful of transiting short-period planets (P ≲ 10 days) have been found around giant stars, thanks to the high-precision photometric data obtained initially by the Kepler mission, and later by its two-wheel extension K2. These new discoveries have allowed us for the first time to study the orbital properties and physical parameters of these intriguing and elusive substellar companions. In this paper we report on an independent discovery of a transiting planet in field 10 of the K2 mission, also reported recently by Grunblatt et al. (2017, AJ, 154, 254). The host star has recently evolved to the giant phase, and has the following atmospheric parameters: Teff = 4878 ± 70 K, log g = 3.289 ± 0.004, and [Fe/H] = −0.11 ± 0.05 dex. The main orbital parameters of K2-132 b, obtained with all the available data for the system are: P = 9.1708 ± 0.0025 d, e = 0.290 ± 0.049, Mp = 0.495 ± 0.007 MJ and Rp = 1.089 ± 0.006 RJ. This is the fifth known planet orbiting any giant star with a < 0.1, and the most eccentric one among them, making K2-132 b a very interesting object.

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