Analysis of Exoplanetary Transit Light Curves Joshua Adam Carter
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Lurking in the Shadows: Wide-Separation Gas Giants As Tracers of Planet Formation
Lurking in the Shadows: Wide-Separation Gas Giants as Tracers of Planet Formation Thesis by Marta Levesque Bryan In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 2018 Defended May 1, 2018 ii © 2018 Marta Levesque Bryan ORCID: [0000-0002-6076-5967] All rights reserved iii ACKNOWLEDGEMENTS First and foremost I would like to thank Heather Knutson, who I had the great privilege of working with as my thesis advisor. Her encouragement, guidance, and perspective helped me navigate many a challenging problem, and my conversations with her were a consistent source of positivity and learning throughout my time at Caltech. I leave graduate school a better scientist and person for having her as a role model. Heather fostered a wonderfully positive and supportive environment for her students, giving us the space to explore and grow - I could not have asked for a better advisor or research experience. I would also like to thank Konstantin Batygin for enthusiastic and illuminating discussions that always left me more excited to explore the result at hand. Thank you as well to Dimitri Mawet for providing both expertise and contagious optimism for some of my latest direct imaging endeavors. Thank you to the rest of my thesis committee, namely Geoff Blake, Evan Kirby, and Chuck Steidel for their support, helpful conversations, and insightful questions. I am grateful to have had the opportunity to collaborate with Brendan Bowler. His talk at Caltech my second year of graduate school introduced me to an unexpected population of massive wide-separation planetary-mass companions, and lead to a long-running collaboration from which several of my thesis projects were born. -
Stellar Magnetic Activity – Star-Planet Interactions
EPJ Web of Conferences 101, 005 02 (2015) DOI: 10.1051/epjconf/2015101005 02 C Owned by the authors, published by EDP Sciences, 2015 Stellar magnetic activity – Star-Planet Interactions Poppenhaeger, K.1,2,a 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambrigde, MA 02138, USA 2 NASA Sagan Fellow Abstract. Stellar magnetic activity is an important factor in the formation and evolution of exoplanets. Magnetic phenomena like stellar flares, coronal mass ejections, and high- energy emission affect the exoplanetary atmosphere and its mass loss over time. One major question is whether the magnetic evolution of exoplanet host stars is the same as for stars without planets; tidal and magnetic interactions of a star and its close-in planets may play a role in this. Stellar magnetic activity also shapes our ability to detect exoplanets with different methods in the first place, and therefore we need to understand it properly to derive an accurate estimate of the existing exoplanet population. I will review recent theoretical and observational results, as well as outline some avenues for future progress. 1 Introduction Stellar magnetic activity is an ubiquitous phenomenon in cool stars. These stars operate a magnetic dynamo that is fueled by stellar rotation and produces highly structured magnetic fields; in the case of stars with a radiative core and a convective outer envelope (spectral type mid-F to early-M), this is an αΩ dynamo, while fully convective stars (mid-M and later) operate a different kind of dynamo, possibly a turbulent or α2 dynamo. These magnetic fields manifest themselves observationally in a variety of phenomena. -
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
CONSTELLATION VULPECULA, the (LITTLE) FOX Vulpecula Is a Faint Constellation in the Northern Sky
CONSTELLATION VULPECULA, THE (LITTLE) FOX Vulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the northern Summer Triangle (an asterism consisting of the bright stars Deneb in Cygnus (the Swan), Vega in Lyra (the Lyre) and Altair in Aquila (the Eagle). Vulpecula was introduced by the Polish astronomer Johannes Hevelius in the late 17th century. It is not associated with any figure in mythology. Hevelius originally named the constellation Vulpecula cum ansere, or Vulpecula et Anser, which means the little fox with the goose. The constellation was depicted as a fox holding a goose in its jaws. The stars were later separated to form two constellations, Anser and Vulpecula, and then merged back together into the present-day Vulpecula constellation. The goose was left out of the constellation’s name, but instead the brightest star, Alpha Vulpeculae, carries the name Anser. It is one of the seven constellations created by Hevelius. The fox and the goose shown as ‘Vulpec. & Anser’ on the Atlas Coelestis of John Flamsteed (1729). The Fox and Goose is a traditional pub name in Britain. STARS There are no stars brighter than 4th magnitude in this constellation. The brightest star is: Alpha Vulpeculae, a magnitude 4.44m red giant at a distance of 297 light-years. The star is an optical binary (separation of 413.7") that can be split using binoculars. The star also carries the traditional name Anser, which refers to the goose the little fox holds in its jaws. -
Correlations Between the Stellar, Planetary, and Debris Components of Exoplanet Systems Observed by Herschel⋆
A&A 565, A15 (2014) Astronomy DOI: 10.1051/0004-6361/201323058 & c ESO 2014 Astrophysics Correlations between the stellar, planetary, and debris components of exoplanet systems observed by Herschel J. P. Marshall1,2, A. Moro-Martín3,4, C. Eiroa1, G. Kennedy5,A.Mora6, B. Sibthorpe7, J.-F. Lestrade8, J. Maldonado1,9, J. Sanz-Forcada10,M.C.Wyatt5,B.Matthews11,12,J.Horner2,13,14, B. Montesinos10,G.Bryden15, C. del Burgo16,J.S.Greaves17,R.J.Ivison18,19, G. Meeus1, G. Olofsson20, G. L. Pilbratt21, and G. J. White22,23 (Affiliations can be found after the references) Received 15 November 2013 / Accepted 6 March 2014 ABSTRACT Context. Stars form surrounded by gas- and dust-rich protoplanetary discs. Generally, these discs dissipate over a few (3–10) Myr, leaving a faint tenuous debris disc composed of second-generation dust produced by the attrition of larger bodies formed in the protoplanetary disc. Giant planets detected in radial velocity and transit surveys of main-sequence stars also form within the protoplanetary disc, whilst super-Earths now detectable may form once the gas has dissipated. Our own solar system, with its eight planets and two debris belts, is a prime example of an end state of this process. Aims. The Herschel DEBRIS, DUNES, and GT programmes observed 37 exoplanet host stars within 25 pc at 70, 100, and 160 μm with the sensitiv- ity to detect far-infrared excess emission at flux density levels only an order of magnitude greater than that of the solar system’s Edgeworth-Kuiper belt. Here we present an analysis of that sample, using it to more accurately determine the (possible) level of dust emission from these exoplanet host stars and thereafter determine the links between the various components of these exoplanetary systems through statistical analysis. -
A Search for Variability and Transit Signatures In
A SEARCH FOR VARIABILITY AND TRANSIT SIGNATURES IN HIPPARCOS PHOTOMETRIC DATA A thesis presented to the faculty of 3 ^ San Francisco State University Zo\% In partial fulfilment of W* The Requirements for The Degree Master of Science In Physics: Astronomy by Badrinath Thirumalachari San JVancisco, California December 2018 Copyright by Badrinath Thirumalachari 2018 CERTIFICATION OF APPROVAL I certify that I have read A SEARCH FOR VARIABILITY AND TRANSIT SIGNATURES IN HIPPARCOS PHOTOMETRIC DATA by Badrinath Thirumalachari and that in my opinion this work meets the criteria for approving a thesis submitted in partial fulfillment of the requirements for the degree: Master of Science in Physics: Astronomy at San Francisco State University. fov- Dr. Stephen Kane, Ph.D. Astrophysics Associate Professor of Planetary Astrophysics Dr. Uo&eph Barranco, Ph.D. .%trtJphysics Chairfe Associate Professor of Physics K + A Q , L a . Dr. Ron Marzke, Ph.D. Astronomy Assoc. Dean of College of Science & Engineering A SEARCH FOR VARIABILITY AND TRANSIT SIGNATURES IN HIPPARCOS PHOTOMETRIC DATA Badrinath Thirumalachari San Francisco State University 2018 The study and characterization of exoplanets has picked up pace rapidly over the past few decades with the invention of newer techniques and instruments. Detecting transits in stellar photometric data around stars already known to harbor exoplanets is crucial for exoplanet characterization. Due to these advancements we now have oceans of data and coming up with an automated way of performing exoplanet characterization is a challenge. In this thesis I describe one such method to search for transits in Hipparcos dataset containing photometric data for over 118000 stars. The radial velocity method has discovered a lot of planets around bright host stars and a follow up transit detection will give us the density of the exoplanet. -
197 3Apj. . .186.1107S the Astrophysical Journal, 186:1107
The Astrophysical Journal, 186:1107-1125, 1973 December 15 .186.1107S . © 1973. The American Astronomical Society. All rights reserved. Printed in U.S.A. 3ApJ. 197 PHASE EQUILIBRIA IN MOLECULAR HYDROGEN-HELIUM MIXTURES AT HIGH PRESSURES* W. B. Streett Science Research Laboratory, U.S. Military Academy, West Point, New York Received 1973 June 11 ABSTRACT Experiments on phase behavior in hydrogen-helium mixtures have been carried out at pressures up to 9.3 kilobars, at temperatures from 26° to 100° K. Two distinct fluid phases are shown to exist at supercritical temperatures and high pressures. Both the trend of the experimental results and an analysis based on the van der Waals theory of mixtures suggest that this fluid-fluid phase separation persists at temperatures and pressures beyond the range of these experiments, perhaps even to the limits of stability of the molecular phases. The results confirm earlier predictions concerning the form of the hydrogen-helium phase diagram in the region of pressure-induced solidification of the molecular phases at supercritical temperatures. The implications of this phase diagram for planetary interiors are discussed. Subject headings: gas dynamics — interiors, planetary — molecules I. INTRODUCTION The properties of hydrogen-helium mixtures are of interest for several reasons. From a theoretical standpoint, they are of interest because they are composed of the two elements with the simplest atomic and molecular structures, and would seem to be among the mixtures most amenable to a theoretical treatment based on first principles. However, it is fair to say that a satisfactory theory of dense mixtures of molecular hydrogen and helium has yet to be developed. -
Effects of Helium Phase Separation on the Evolution of Extrasolar Giant Planets
Accepted to ApJ, February, 2004 A Preprint typeset using L TEX style emulateapj v. 11/12/01 EFFECTS OF HELIUM PHASE SEPARATION ON THE EVOLUTION OF EXTRASOLAR GIANT PLANETS Jonathan J. Fortney1, W. B. Hubbard1 Accepted to ApJ, February, 2004 ABSTRACT We build on recent new evolutionary models of Jupiter and Saturn and here extend our calculations to investigate the evolution of extrasolar giant planets of mass 0.15 to 3.0 MJ. Our inhomogeneous thermal history models show that the possible phase separation of helium from liquid metallic hydrogen in the deep interiors of these planets can lead to luminosities ∼ 2 times greater than have been predicted by homogeneous models. For our chosen phase diagram this phase separation will begin to affect the planets’ evolution at ∼ 700 Myr for a 0.15 MJ object and ∼ 10 Gyr for a 3.0 MJ object. We show how phase separation affects the luminosity, effective temperature, radii, and atmospheric helium mass fraction as a function of age for planets of various masses, with and without heavy element cores, and with and without the effect of modest stellar irradiation. This phase separation process will likely not affect giant planets within a few AU of their parent star, as these planets will cool to their equilibrium temperatures, determined by stellar heating, before the onset of phase separation. We discuss the detectability of these objects and the likelihood that the energy provided by helium phase separation can change the timescales for formation and settling of ammonia clouds by several Gyr. We discuss how correctly incorporating stellar irradiation into giant planet atmosphere and albedo modeling may lead to a consistent evolutionary history for Jupiter and Saturn. -
The HARPS Search for Earth-Like Planets in the Habitable Zone I
A&A 534, A58 (2011) Astronomy DOI: 10.1051/0004-6361/201117055 & c ESO 2011 Astrophysics The HARPS search for Earth-like planets in the habitable zone I. Very low-mass planets around HD 20794, HD 85512, and HD 192310, F. Pepe1,C.Lovis1, D. Ségransan1,W.Benz2, F. Bouchy3,4, X. Dumusque1, M. Mayor1,D.Queloz1, N. C. Santos5,6,andS.Udry1 1 Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Versoix, Switzerland e-mail: [email protected] 2 Physikalisches Institut Universität Bern, Sidlerstrasse 5, 3012 Bern, Switzerland 3 Institut d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie, 98bis Bd Arago, 75014 Paris, France 4 Observatoire de Haute-Provence/CNRS, 04870 St. Michel l’Observatoire, France 5 Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal 6 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Portugal Received 8 April 2011 / Accepted 15 August 2011 ABSTRACT Context. In 2009 we started an intense radial-velocity monitoring of a few nearby, slowly-rotating and quiet solar-type stars within the dedicated HARPS-Upgrade GTO program. Aims. The goal of this campaign is to gather very-precise radial-velocity data with high cadence and continuity to detect tiny signatures of very-low-mass stars that are potentially present in the habitable zone of their parent stars. Methods. Ten stars were selected among the most stable stars of the original HARPS high-precision program that are uniformly spread in hour angle, such that three to four of them are observable at any time of the year. -
AMD-Stability and the Classification of Planetary Systems
A&A 605, A72 (2017) DOI: 10.1051/0004-6361/201630022 Astronomy c ESO 2017 Astrophysics& AMD-stability and the classification of planetary systems? J. Laskar and A. C. Petit ASD/IMCCE, CNRS-UMR 8028, Observatoire de Paris, PSL, UPMC, 77 Avenue Denfert-Rochereau, 75014 Paris, France e-mail: [email protected] Received 7 November 2016 / Accepted 23 January 2017 ABSTRACT We present here in full detail the evolution of the angular momentum deficit (AMD) during collisions as it was described in Laskar (2000, Phys. Rev. Lett., 84, 3240). Since then, the AMD has been revealed to be a key parameter for the understanding of the outcome of planetary formation models. We define here the AMD-stability criterion that can be easily verified on a newly discovered planetary system. We show how AMD-stability can be used to establish a classification of the multiplanet systems in order to exhibit the planetary systems that are long-term stable because they are AMD-stable, and those that are AMD-unstable which then require some additional dynamical studies to conclude on their stability. The AMD-stability classification is applied to the 131 multiplanet systems from The Extrasolar Planet Encyclopaedia database for which the orbital elements are sufficiently well known. Key words. chaos – celestial mechanics – planets and satellites: dynamical evolution and stability – planets and satellites: formation – planets and satellites: general 1. Introduction motion resonances (MMR, Wisdom 1980; Deck et al. 2013; Ramos et al. 2015) could justify the Hill-type criteria, but the The increasing number of planetary systems has made it nec- results on the overlap of the MMR island are valid only for close essary to search for a possible classification of these planetary orbits and for short-term stability. -
Transit Polarimetry of Exoplanetary System HD 189733
Transit Polarimetry of Exoplanetary System HD 189733 N.M. Kostogryz1,3, S.V. Berdyugina1,2, T.M. Yakobchuk3 1Kiepenheuer Institut f¨urSonnenphysik, Sch¨oneckstr. 6, 79104 Freiburg, Germany 2NASA Astrobiology Institute, Institute for Astronomy, University of Hawaii, USA 3Main Astronomical Observatory of NAS of Ukraine, Zabolotnoho str. 27, 03680 Kyiv, Ukraine Abstract. We present and discuss a polarimetric effect caused by a planet transiting the stellar disk thus breaking the symmetry of the light distribution and resulting in linear polarization of the partially eclipsed star. Estimates of this effect for transiting planets have been made only recently. In particular, we demonstrate that the maximum polarization during transits depends strongly on the centre-to-limb variation of the linear polarization of the host star. However, observational and theoretical studies of the limb polarization have largely concentrated on the Sun. Here we solve the radiative transfer problem for polarized light and calculate the centre-to-limb polarization for one of the brightest transiting planet host HD 189733 taking into account various opacities. Using that we simulate the transit effect and estimate the variations of the flux and the linear polarization for HD 189733 during the event. As the spots on the stellar disk also break the limb polarization symmetry we simulate the flux and polarization variation due to the spots on the stellar disk. 1. Introduction HD 189733 is currently the brightest (mV = 7.67mag) star known to harbour a transiting exoplanet (Bouchy et al. 2005). This, along with the short period (2.2 days) and large ratio of planet-to-star radii (Rpl/R⋆ ≈ 0.15), makes it very suitable for different types of observations including polarimetry (Berdyugina et al. -
Part 1: the 1.7 and 3.9 Earth Radii Rule
Hi this is Steve Nerlich from Cheap Astronomy www.cheapastro.com and this is What are exoplanets made of? Part 1: The 1.7 and 3.9 earth Radii rule. As of August 2016, the current count of confirmed exoplanets is up around 3,400 in 2,617 systems – with 590 of those systems confirmed to be multiplanet systems. And the latest thinking is that if you want to understand what exoplanets are made of you need to appreciate the physical limits of planet-hood, which are defined by the boundaries of 1.7 and 3.9 Earth radii . Consider that the make-up of an exoplanet is largely determined by the elemental make up of its protoplanetary disk. While most material in the Universe is hydrogen and helium – these are both tenuous gases. In order to generate enough gravity to hang on to them, you need a lot of mass to start with. So, if you’re Earth, or anything up to 1.7 times the radius of Earth – you’ve got no hope of hanging onto more than a few traces of elemental hydrogen and helium. Indeed, any exoplanet that’s less than 1.7 Earth radii has to be primarily composed of non-volatiles – that is, things that don’t evaporate or blow away easily – to have any chance of gravitationally holding together. A non-volatile exoplanet might be made of rock – which for our Solar System is a primarily silicon/oxygen based mineral matrix, but as we’ll hear, small sub-1.7 Earth radii exoplanets could be made of a whole range of other non-volatile materials.