DOCSLIB.ORG

Exoplanet Detection Around M-Dwarfs with Near Infra-Red Andvisible

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Exoplanet Detection Around M-Dwarfs with Near Infra-Red Andvisible AIX-MARSEILLE UNIVERSITÉ ECOLE DOCTORALE 352 LABORATOIRE D’ASTROPHYSIQUE DE MARSEILLE Thèse présentée pour obtenir le grade universitaire de docteur Discipline : Physique et Sciences de la Matière Spécialité : Astrophysique et Cosmologie Melissa J. HOBSON Exoplanet Detection Around M Dwarfs with Near Infrared and Visible Spectroscopy Détection des exoplanètes autour de naines M par spectroscopie proche infra-rouge et visible Soutenue le 08/10/2019 devant le jury composé de : Eduardo MARTIN Centro de Astrobiología (INTA-CSIC) Rapporteur Peter WHEATLEY Department of Physics, University of Warwick Rapporteur Magali DELEUIL Laboratoire d’Astrophysique de Marseille Présidente du jury Xavier DELFOSSE Institut de Planetologie et d’Astrophysique de Grenoble Examinateur Christophe LOVIS Observatoire de Genève Examinateur Isabelle BOISSE Laboratoire d’Astrophysique de Marseille Co-directrice de thèse François BOUCHY Laboratoire d’Astrophysique de Marseille Directeur de thèse Numéro national de thèse/suffixe local : 2019AIXM0317/049ED352 Cette oeuvre est mise à disposition selon les termes de la Licence Creative Com- mons Attribution - Pas d’Utilisation Commerciale - Pas de Modification 4.0 Internatio- nal. Résumé Récemment, la science exoplanètaire s’est focalisé sur les étoiles M comme cibles intéressantes pour la détection et caractérisation des exoplanètes. Il y a plusieurs rai- sons pour ça : Les naines M sont les étoiles les plus communes de la galaxie ; leur petit taille implique qu’on peut détecter des planètes plus petits qu’autour des étoiles G ; la zone d’habitabilité d’eau liquide est plus proche à l’étoile. La population émergente de planètes autour de naines M montre des caractéristiques intrigantes par rapport aux planètes des étoiles FGK, comme l’absence des Jupiters chauds, et l’incertitude de la corrélation planète-metalicité. L’objectif de cette thèse est d’explorer la détection d’exoplanètes autour de naines M par la méthode de vitesse radiale, dans les domaines du visible et du prochaine infra- rouge. J’ai aussi réalisé un analyse statistique de la population connue de planètes autour de naines M, comme il était au début et à la fin de la thèse. Dans le visible, j’ai travaillé avec le spectrographe SOPHIE à l’Observatoire d’Haute- Provence, comme partie du consortium SOPHIE exoplanètes. Cet groupe, qui regroupe des chercheurs dans multiples institutes en France et des pays voisins, a effectué di- verses programmes de recherche d’exoplanètes, dont une se focalise sur la recherche de planètes autour de naines M (avec spécial attention aux Neptunes et superTerres). J’ai appliqué une algorithme "template-matching" aux cibles de ce sous-programme, et ana- lysé les séries de vitesse radiale résultantes. À partir e cet analyise, j’ai pu confirmer l’im- portance des signaux périodiques que, si bien présents dans l’analyse CCF traditionnel, étaient partiellement cachés par le bruit. J’ai aussi étudié une variété d’indices d’acti- vité, trouvant ceux qui sont mieux adaptés aux spectres de SOPHIE. Les premiers quatre exoplanètes issus de ce sous-programme ont récemment été publiées ; j’ai été première auteur pour deux des trois articles. Dans le prochaine infra-rouge, j’ai travaillé avec le spectropolarimetre SPIRou au Canada France Hawaii Telescope, comme partie du consortium SPIRou. Ce nouvelle instrument a été conçu spécifiquement pour l’observation des naines M, qui sont faibles dans le visible et émettent la plupart de son radiation dans le prochaine infra-rouge. J’ai travaillé sur le développement du système de réduction des données, particulièrement sur la solution en longueur d’onde - c’est à dire, la correspondance entre la position en pixels et la longueur d’onde, qui est crucial pour mesurer des vitesses radiales précises. J’ai développé et testé des façons de combiner différents calibreurs de longueur d’onde, pour obtenir une solution en longueur d’onde précise. Mots clés : exoplanètes, spectroscopie, naines M, vitesses radiales Abstract In recent years, exoplanet science has begun to focus on M-dwarf stars as highly interesting targets for exoplanet detection and characterisation. The reasons for this are multiple: M dwarfs are the most common stars in the galaxy; their small size means smaller exoplanets can be detected than around G-type stars; the liquid-water habitable zone is closer to the star, hence these planets are faster and easier to detect. The emerg- ing population of planets hosted by M dwarfs shows intriguing characteristics compared to planets hosted by FGK stars, such as a lack of hot Jupiters, and an uncertain planet- metallicity correlation. The aim of this thesis is to explore the detection of exoplanets around M dwarfs via the radial velocity method, in both the near infrared and visible domains. I also carried out a statistical analysis of the known population of planets around M dwarfs, as it stood both at the start of the thesis and at its conclusion. In the visible, I worked with the SOPHIE spectrograph at the Observatoire de Haute- Provence, as part of the SOPHIE exoplanets consortium. This group, which nucleates researchers in multiple institutes in France and neighbouring countries, has been car- rying out several long-term exoplanet surveys, one of which focuses on the search for planets around M dwarfs (with special attention to Neptunes and superEarths). I ap- plied a template-matching algorithm to the targets of this subprogramme, and analysed the resulting radial velocity time series. Through this analysis, I was able to confirm the significance of periodic signals that, while apparent in the traditional CCF analy- sis, were partially hidden by noise. I also studied a variety of stellar activity indicators, identifying those most suited to SOPHIE spectra. The first four exoplanets from this subprogramme have recently been published; I was lead author for two of the three papers. In the near infrared, I worked with the SPIRou spectropolarimeter at the Canada France Hawaii Telescope, as part of the SPIRou consortium. This new instrument was conceived specifically for the observation of M dwarfs, which are faint in the visible and emit most of their radiation in the infrared. I worked on the development of the data reduction pipeline, with specific focus on the wavelength solution - that is, the corre- spondence between pixel position and wavelength, which is crucial to the measurement of precise radial velocities. I developed and tested ways to combine different wavelength calibrators, for an accurate wavelength solution. Keywords: exoplanets, spectroscopy, M dwarfs, radial velocities Contents Résumé 3 Abstract 4 Contents 5 List of Figures 7 List of Tables 9 Résumé étendue en français 11 0.1 Introduction................................... 11 0.1.1 La méthode de vitesse radiale..................... 12 0.1.2 Recherche d’exoplanètes autour de naines M............. 13 0.2 Recherche en vitesse radiale des naines M avec le spectrographe SOPHIE 14 0.3 Développement du spectropolarimetre SPIRou ............... 16 0.4 Proprietés des planètes autours des naines M ................ 18 0.5 Conclusions................................... 19 Introduction 21 1.1 A brief history of exoplanets.......................... 22 1.2 Characteristics of M-dwarf stars........................ 24 1.3 The radial velocity method .......................... 28 1.3.1 Limitations of the RV method..................... 30 1.3.2 Visible and nIR spectrographs and surveys ............. 32 1.4 M-dwarf stars and their planets (as of 2016)................. 34 1.5 Thesis objectives ................................ 39 2 M-dwarf RV search with the SOPHIE spectrograph 41 2.1 The SOPHIE spectrograph .......................... 42 2.2 The M-dwarf sample.............................. 43 2.3 The template-matching method........................ 45 2.4 Instrumental instabilities............................ 48 2.4.1 Charge transfer inefficiency ...................... 48 2.4.2 Nightly drift .............................. 49 2.4.3 Long-term variation of the zero-point................. 50 2.5 Summary of SOPHIE results on M dwarfs.................. 52 2.5.1 Discovery of new exoplanets...................... 55 2.5.2 Confirmation or non-confirmation of published planets . 81 2.5.3 Stellar activity mitigation....................... 83 2.6 Other contributions to SOPHIE RV programmes.............. 90 2.6.1 High precision RV search for super-Earths.............. 90 2.6.2 Simultaneous FP background correction............... 92 3 Development of the SPIRou nIR spectropolarimeter 95 3.1 The SPIRou spectropolarimeter........................ 96 3.2 The SPIRou Data Reduction System..................... 99 3.3 Validation tests and commissioning......................102 3.4 Wavelength calibration development .....................103 3.4.1 Hollow-cathode lamps .........................103 3.4.2 Combination with Fabry-Pérot reference . 107 3.5 Validation and performances of the wavelength solution . 110 3.5.1 Impact of previous calibrations....................111 3.5.2 Performances of the HC wavelength solution . 114 3.5.3 Combined HC-FP wavelength solution . 115 3.5.4 Impact on RV error ..........................117 3.5.5 Upcoming changes to the Data Reduction System . 119 3.6 SPIRou science programs ...........................120 3.6.1 Spirou Legacy Survey .........................120 3.6.2 Synergy with SOPHIE.........................122 4 Properties of M-dwarf planets as of 2019 125 4.1 Overview and growth of the M dwarf planet population sample . 126 4.2 Stellar
Load more

Recommended publications
  • The Discovery of Exoplanets
    L'Univers, S´eminairePoincar´eXX (2015) 113 { 137 S´eminairePoincar´e New Worlds Ahead: The Discovery of Exoplanets Arnaud Cassan Universit´ePierre et Marie Curie Institut d'Astrophysique de Paris 98bis boulevard Arago 75014 Paris, France Abstract. Exoplanets are planets orbiting stars other than the Sun. In 1995, the discovery of the first exoplanet orbiting a solar-type star paved the way to an exoplanet detection rush, which revealed an astonishing diversity of possible worlds. These detections led us to completely renew planet formation and evolu- tion theories. Several detection techniques have revealed a wealth of surprising properties characterizing exoplanets that are not found in our own planetary system. After two decades of exoplanet search, these new worlds are found to be ubiquitous throughout the Milky Way. A positive sign that life has developed elsewhere than on Earth? 1 The Solar system paradigm: the end of certainties Looking at the Solar system, striking facts appear clearly: all seven planets orbit in the same plane (the ecliptic), all have almost circular orbits, the Sun rotation is perpendicular to this plane, and the direction of the Sun rotation is the same as the planets revolution around the Sun. These observations gave birth to the Solar nebula theory, which was proposed by Kant and Laplace more that two hundred years ago, but, although correct, it has been for decades the subject of many debates. In this theory, the Solar system was formed by the collapse of an approximately spheric giant interstellar cloud of gas and dust, which eventually flattened in the plane perpendicular to its initial rotation axis.
    [Show full text]
  • New Voyage to Rendezvous with a Small Asteroid Rotating with a Short Period
    Hayabusa2 Extended Mission: New Voyage to Rendezvous with a Small Asteroid Rotating with a Short Period M. Hirabayashi1, Y. Mimasu2, N. Sakatani3, S. Watanabe4, Y. Tsuda2, T. Saiki2, S. Kikuchi2, T. Kouyama5, M. Yoshikawa2, S. Tanaka2, S. Nakazawa2, Y. Takei2, F. Terui2, H. Takeuchi2, A. Fujii2, T. Iwata2, K. Tsumura6, S. Matsuura7, Y. Shimaki2, S. Urakawa8, Y. Ishibashi9, S. Hasegawa2, M. Ishiguro10, D. Kuroda11, S. Okumura8, S. Sugita12, T. Okada2, S. Kameda3, S. Kamata13, A. Higuchi14, H. Senshu15, H. Noda16, K. Matsumoto16, R. Suetsugu17, T. Hirai15, K. Kitazato18, D. Farnocchia19, S.P. Naidu19, D.J. Tholen20, C.W. Hergenrother21, R.J. Whiteley22, N. A. Moskovitz23, P.A. Abell24, and the Hayabusa2 extended mission study group. 1Auburn University, Auburn, AL, USA ([email protected]) 2Japan Aerospace Exploration Agency, Kanagawa, Japan 3Rikkyo University, Tokyo, Japan 4Nagoya University, Aichi, Japan 5National Institute of Advanced Industrial Science and Technology, Tokyo, Japan 6Tokyo City University, Tokyo, Japan 7Kwansei Gakuin University, Hyogo, Japan 8Japan Spaceguard Association, Okayama, Japan 9Hosei University, Tokyo, Japan 10Seoul National University, Seoul, South Korea 11Kyoto University, Kyoto, Japan 12University of Tokyo, Tokyo, Japan 13Hokkaido University, Hokkaido, Japan 14University of Occupational and Environmental Health, Fukuoka, Japan 15Chiba Institute of Technology, Chiba, Japan 16National Astronomical Observatory of Japan, Iwate, Japan 17National Institute of Technology, Oshima College, Yamaguchi, Japan 18University of Aizu, Fukushima, Japan 19Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA 20University of Hawai’i, Manoa, HI, USA 21University of Arizona, Tucson, AZ, USA 22Asgard Research, Denver, CO, USA 23Lowell Observatory, Flagstaff, AZ, USA 24NASA Johnson Space Center, Houston, TX, USA 1 Highlights 1.
    [Show full text]
  • Bennu: Implications for Aqueous Alteration History
    RESEARCH ARTICLES Cite as: H. H. Kaplan et al., Science 10.1126/science.abc3557 (2020). Bright carbonate veins on asteroid (101955) Bennu: Implications for aqueous alteration history H. H. Kaplan1,2*, D. S. Lauretta3, A. A. Simon1, V. E. Hamilton2, D. N. DellaGiustina3, D. R. Golish3, D. C. Reuter1, C. A. Bennett3, K. N. Burke3, H. Campins4, H. C. Connolly Jr. 5,3, J. P. Dworkin1, J. P. Emery6, D. P. Glavin1, T. D. Glotch7, R. Hanna8, K. Ishimaru3, E. R. Jawin9, T. J. McCoy9, N. Porter3, S. A. Sandford10, S. Ferrone11, B. E. Clark11, J.-Y. Li12, X.-D. Zou12, M. G. Daly13, O. S. Barnouin14, J. A. Seabrook13, H. L. Enos3 1NASA Goddard Space Flight Center, Greenbelt, MD, USA. 2Southwest Research Institute, Boulder, CO, USA. 3Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA. 4Department of Physics, University of Central Florida, Orlando, FL, USA. 5Department of Geology, School of Earth and Environment, Rowan University, Glassboro, NJ, USA. 6Department of Astronomy and Planetary Sciences, Northern Arizona University, Flagstaff, AZ, USA. 7Department of Geosciences, Stony Brook University, Stony Brook, NY, USA. 8Jackson School of Geosciences, University of Texas, Austin, TX, USA. 9Smithsonian Institution National Museum of Natural History, Washington, DC, USA. 10NASA Ames Research Center, Mountain View, CA, USA. 11Department of Physics and Astronomy, Ithaca College, Ithaca, NY, USA. 12Planetary Science Institute, Tucson, AZ, Downloaded from USA. 13Centre for Research in Earth and Space Science, York University, Toronto, Ontario, Canada. 14John Hopkins University Applied Physics Laboratory, Laurel, MD, USA. *Corresponding author. E-mail: Email: [email protected] The composition of asteroids and their connection to meteorites provide insight into geologic processes that occurred in the early Solar System.
    [Show full text]
  • 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.
    [Show full text]
  • Gaia Search for Stellar Companions of TESS Objects of Interest
    Received 1 July 2020; Revised 29 August 2020; Accepted 18 September 2020 DOI: xxx/xxxx ARTICLE TYPE Gaia Search for stellar Companions of TESS Objects of Interest M. Mugrauer* | K.-U. Michel 1Astrophysikalisches Institut und Universitäts-Sternwarte Jena The first results of a new survey are reported, which explores the 2nd data release Correspondence of the ESA-Gaia mission, in order to search for stellar companions of (Community) M. Mugrauer, Astrophysikalisches Institut und Universitäts-Sternwarte Jena, TESS Objects of Interest and to characterize their properties. In total, 193 binary and Schillergäßchen 2, D-07745 Jena, Germany. 15 hierarchical triple star systems are presented, detected among 1391 target stars, Email: [email protected] which are located at distances closer than about 500 pc around the Sun. The com- panions and the targets are equidistant and share a common proper motion, as it is expected for gravitationally bound stellar systems, proven with their accurate Gaia astrometry. The companions exhibit masses in the range between about 0.08 M⊙ and 3 M⊙ and are most frequently found in the mass range between 0.13 and 0.6 M⊙. The companions are separated from the targets by about 40 up to 9900 au, and their frequency continually decreases with increasing separation. While most of the detected companions are late K to mid M dwarfs, also 5 white dwarf companions were identified in this survey, whose true nature is revealed by their photometric properties. KEYWORDS: binaries: visual, white dwarfs, stars: individual (TOI 249 C, TOI 1259 B, TOI 1624 B, TOI 1703 B, CTOI 53309262 B) 1 INTRODUCTION explored the 2nd data release of the European Space Agency (ESA) Gaia mission (Gaia DR2 from hereon, Gaia Collabora- A key aspect in the diversity of exoplanets is the multiplicity tion, Brown, Vallenari, et al., 2018), which provides manifold of their host stars.
    [Show full text]
  • Can There Be Additional Rocky Planets in the Habitable Zone of Tight Binary
    Mon. Not. R. Astron. Soc. 000, 1–10 () Printed 24 September 2018 (MN LATEX style file v2.2) Can there be additional rocky planets in the Habitable Zone of tight binary stars with a known gas giant? B. Funk1⋆, E. Pilat-Lohinger1 and S. Eggl2 1Institute for Astronomy, University of Vienna, Vienna, Austria 2IMCCE, Observatoire de Paris, Paris, France ABSTRACT Locating planets in Habitable Zones (HZs) around other stars is a growing field in contem- porary astronomy. Since a large percentage of all G-M stars in the solar neighborhood are expected to be part of binary or multiple stellar systems, investigations of whether habitable planets are likely to be discovered in such environments are of prime interest to the scientific community. As current exoplanet statistics predicts that the chances are higher to find new worlds in systems that are already known to have planets, we examine four known extrasolar planetary systems in tight binaries in order to determine their capacity to host additional hab- itable terrestrial planets. Those systems are Gliese 86, γ Cephei, HD 41004 and HD 196885. In the case of γ Cephei, our results suggest that only the M dwarf companion could host ad- ditional potentially habitable worlds. Neither could we identify stable, potentially habitable regions around HD 196885A. HD 196885 B can be considered a slightly more promising tar- get in the search forEarth-twins.Gliese 86 A turned out to be a very good candidate, assuming that the system’s history has not been excessively violent. For HD 41004 we have identified admissible stable orbits for habitable planets, but those strongly depend on the parameters of the system.
    [Show full text]
  • The Search for Extrasolar Planets
    zucker 16-12-2005 11:22 Pagina 229 229 The Search for Extrasolar Planets S. Zucker and M. Mayor Observatoire de Genève, Sauverny, Switzerland During the recent decade, the question of the existence of planets orbiting stars other than our Sun has been answered unequivocally. About 150 extrasolar plan- ets have been detected since 1995, and their properties are the subject of wide interest in the research community. Planet formation and evolution theories are adjusting to the constantly emerging data, and astronomers are seeking new ways to widen the sample and enrich the data about the known planets. In September 2002, ISSI organized a workshop focusing on the physics of “Planetary Systems and Planets in Systems”1. The present contribution is an attempt to give a broader overview of the researches in the field of exoplanets and results obtained in the decade after the discovery of the planet 51 Peg b. The existence of planets orbiting other stars was speculated upon even in the 4th century BC, when Epicurus and Aristotle debated it using their early notions about our world. Epicurus claimed that the infinity of the Universe compelled the existence of other worlds. After the Copernican Revolution, Giordano Bruno wrote: “Innumerable suns exist; innumerable earths revolve around these suns in a manner similar to the way the seven planets revolve around our Sun”. Aitken2 examined the observational problem of detecting extrasolar planets. He showed that their detection, either directly or indirectly, lay beyond the techni- cal horizon of his era. The basic difficulty in directly detecting planets lies in the brightness ratio between a typical planet and its host star, a ratio that can be as low as 10-8.
    [Show full text]
  • Exep Science Plan Appendix (SPA) (This Document)
    ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 1 of 61 Created By: David A. Breda Date Program TDEM System Engineer Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology Dr. Nick Siegler Date Program Chief Technologist Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology Concurred By: Dr. Gary Blackwood Date Program Manager Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology EXOPDr.LANET Douglas Hudgins E XPLORATION PROGRAMDate Program Scientist Exoplanet Exploration Program ScienceScience Plan Mission DirectorateAppendix NASA Headquarters Karl Stapelfeldt, Program Chief Scientist Eric Mamajek, Deputy Program Chief Scientist Exoplanet Exploration Program JPL CL#19-0790 JPL Document No: 1735632 ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 2 of 61 Approved by: Dr. Gary Blackwood Date Program Manager, Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory Dr. Douglas Hudgins Date Program Scientist Exoplanet Exploration Program Science Mission Directorate NASA Headquarters Created by: Dr. Karl Stapelfeldt Chief Program Scientist Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory California Institute of Technology Dr. Eric Mamajek Deputy Program Chief Scientist Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory California Institute of Technology This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. © 2018 California Institute of Technology. Government sponsorship acknowledged. Exoplanet Exploration Program JPL CL#19-0790 ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 3 of 61 Table of Contents 1.
    [Show full text]
  • Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects
    AA57CH15_Madhusudhan ARjats.cls August 7, 2019 14:11 Annual Review of Astronomy and Astrophysics Exoplanetary Atmospheres: Key Insights, Challenges, and Prospects Nikku Madhusudhan Institute of Astronomy, University of Cambridge, Cambridge CB3 0HA, United Kingdom; email: [email protected] Annu. Rev. Astron. Astrophys. 2019. 57:617–63 Keywords The Annual Review of Astronomy and Astrophysics is extrasolar planets, spectroscopy, planet formation, habitability, atmospheric online at astro.annualreviews.org composition https://doi.org/10.1146/annurev-astro-081817- 051846 Abstract Copyright © 2019 by Annual Reviews. Exoplanetary science is on the verge of an unprecedented revolution. The All rights reserved thousands of exoplanets discovered over the past decade have most recently been supplemented by discoveries of potentially habitable planets around nearby low-mass stars. Currently, the field is rapidly progressing toward de- tailed spectroscopic observations to characterize the atmospheres of these planets. Various surveys from space and the ground are expected to detect numerous more exoplanets orbiting nearby stars that make the planets con- ducive for atmospheric characterization. The current state of this frontier of exoplanetary atmospheres may be summarized as follows. We have entered the era of comparative exoplanetology thanks to high-fidelity atmospheric observations now available for tens of exoplanets. Access provided by Florida International University on 01/17/21. For personal use only. Annu. Rev. Astron. Astrophys. 2019.57:617-663. Downloaded from www.annualreviews.org Recent studies reveal a rich diversity of chemical compositions and atmospheric processes hitherto unseen in the Solar System. Elemental abundances of exoplanetary atmospheres place impor- tant constraints on exoplanetary formation and migration histories.
    [Show full text]
  • Habitability of Planets on Eccentric Orbits: Limits of the Mean Flux Approximation
    A&A 591, A106 (2016) Astronomy DOI: 10.1051/0004-6361/201628073 & c ESO 2016 Astrophysics Habitability of planets on eccentric orbits: Limits of the mean flux approximation Emeline Bolmont1, Anne-Sophie Libert1, Jeremy Leconte2; 3; 4, and Franck Selsis5; 6 1 NaXys, Department of Mathematics, University of Namur, 8 Rempart de la Vierge, 5000 Namur, Belgium e-mail: [email protected] 2 Canadian Institute for Theoretical Astrophysics, 60st St George Street, University of Toronto, Toronto, ON, M5S3H8, Canada 3 Banting Fellow 4 Center for Planetary Sciences, Department of Physical & Environmental Sciences, University of Toronto Scarborough, Toronto, ON, M1C 1A4, Canada 5 Univ. Bordeaux, LAB, UMR 5804, 33270 Floirac, France 6 CNRS, LAB, UMR 5804, 33270 Floirac, France Received 4 January 2016 / Accepted 28 April 2016 ABSTRACT Unlike the Earth, which has a small orbital eccentricity, some exoplanets discovered in the insolation habitable zone (HZ) have high orbital eccentricities (e.g., up to an eccentricity of ∼0.97 for HD 20782 b). This raises the question of whether these planets have surface conditions favorable to liquid water. In order to assess the habitability of an eccentric planet, the mean flux approximation is often used. It states that a planet on an eccentric orbit is called habitable if it receives on average a flux compatible with the presence of surface liquid water. However, because the planets experience important insolation variations over one orbit and even spend some time outside the HZ for high eccentricities, the question of their habitability might not be as straightforward. We performed a set of simulations using the global climate model LMDZ to explore the limits of the mean flux approximation when varying the luminosity of the host star and the eccentricity of the planet.
    [Show full text]
  • Kuchner, M. & Seager, S., Extrasolar Carbon Planets, Arxiv:Astro-Ph
    Extrasolar Carbon Planets Marc J. Kuchner1 Princeton University Department of Astrophysical Sciences Peyton Hall, Princeton, NJ 08544 S. Seager Carnegie Institution of Washington, 5241 Broad Branch Rd. NW, Washington DC 20015 [email protected] ABSTRACT We suggest that some extrasolar planets . 60 ML will form substantially from silicon carbide and other carbon compounds. Pulsar planets and low-mass white dwarf planets are especially good candidate members of this new class of planets, but these objects could also conceivably form around stars like the Sun. This planet-formation pathway requires only a factor of two local enhancement of the protoplanetary disk’s C/O ratio above solar, a condition that pileups of carbonaceous grains may create in ordinary protoplanetary disks. Hot, Neptune- mass carbon planets should show a significant paucity of water vapor in their spectra compared to hot planets with solar abundances. Cooler, less massive carbon planets may show hydrocarbon-rich spectra and tar-covered surfaces. The high sublimation temperatures of diamond, SiC, and other carbon compounds could protect these planets from carbon depletion at high temperatures. arXiv:astro-ph/0504214v2 2 May 2005 Subject headings: astrobiology — planets and satellites, individual (Mercury, Jupiter) — planetary systems: formation — pulsars, individual (PSR 1257+12) — white dwarfs 1. INTRODUCTION The recent discoveries of Neptune-mass extrasolar planets by the radial velocity method (Santos et al. 2004; McArthur et al. 2004; Butler et al. 2004) and the rapid development 1Hubble Fellow –2– of new technologies to study the compositions of low-mass extrasolar planets (see, e.g., the review by Kuchner & Spergel 2003) have compelled several authors to consider planets with chemistries unlike those found in the solar system (Stevenson 2004) such as water planets (Kuchner 2003; Leger et al.
    [Show full text]
  • Simulating (Sub)Millimeter Observations of Exoplanet Atmospheres in Search of Water
    University of Groningen Kapteyn Astronomical Institute Simulating (Sub)Millimeter Observations of Exoplanet Atmospheres in Search of Water September 5, 2018 Author: N.O. Oberg Supervisor: Prof. Dr. F.F.S. van der Tak Abstract Context: Spectroscopic characterization of exoplanetary atmospheres is a field still in its in- fancy. The detection of molecular spectral features in the atmosphere of several hot-Jupiters and hot-Neptunes has led to the preliminary identification of atmospheric H2O. The Atacama Large Millimiter/Submillimeter Array is particularly well suited in the search for extraterrestrial water, considering its wavelength coverage, sensitivity, resolving power and spectral resolution. Aims: Our aim is to determine the detectability of various spectroscopic signatures of H2O in the (sub)millimeter by a range of current and future observatories and the suitability of (sub)millimeter astronomy for the detection and characterization of exoplanets. Methods: We have created an atmospheric modeling framework based on the HAPI radiative transfer code. We have generated planetary spectra in the (sub)millimeter regime, covering a wide variety of possible exoplanet properties and atmospheric compositions. We have set limits on the detectability of these spectral features and of the planets themselves with emphasis on ALMA. We estimate the capabilities required to study exoplanet atmospheres directly in the (sub)millimeter by using a custom sensitivity calculator. Results: Even trace abundances of atmospheric water vapor can cause high-contrast spectral ab- sorption features in (sub)millimeter transmission spectra of exoplanets, however stellar (sub) millime- ter brightness is insufficient for transit spectroscopy with modern instruments. Excess stellar (sub) millimeter emission due to activity is unlikely to significantly enhance the detectability of planets in transit except in select pre-main-sequence stars.
    [Show full text]