DOCSLIB.ORG

Search, Characterization, and Properties of Brown Dwarfs

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Search, Characterization, and Properties of Brown Dwarfs University of Central Florida STARS Electronic Theses and Dissertations, 2004-2019 2009 Search, Characterization, And Properties Of Brown Dwarfs Ramarao Tata University of Central Florida Part of the Physics Commons Find similar works at: https://stars.library.ucf.edu/etd University of Central Florida Libraries http://library.ucf.edu This Doctoral Dissertation (Open Access) is brought to you for free and open access by STARS. It has been accepted for inclusion in Electronic Theses and Dissertations, 2004-2019 by an authorized administrator of STARS. For more information, please contact [email protected]. STARS Citation Tata, Ramarao, "Search, Characterization, And Properties Of Brown Dwarfs" (2009). Electronic Theses and Dissertations, 2004-2019. 3944. https://stars.library.ucf.edu/etd/3944 Search, Characterization, and Properties of Brown Dwarfs by Ramarao Tata M.S. University of Central Florida, 2005 B.Tech. Sri Venkateshwara University, 2002 A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Physics in the College of Sciences at the University of Central Florida Orlando, Florida Fall Term 2009 Major Professor: Eduardo L. Mart´ın ABSTRACT Brown dwarfs (BD) were mere theoretical astrophysical objects for more than three decades (Kumar (1962)) till their first observational detection in 1995 (Rebolo et al. (1995), Nakajima et al. (1995)). These objects are intermediate in mass between stars and planets. Since their observational discovery these objects have been studied thoroughly and holisti- cally. Various methods for searching and characterizing these objects in different regions of the sky have been put forward and tested with great success. Theoretical models describing their physical, atmospheric and chemical processes and properties have been proposed and have been validated with a large number of observational results. The work presented in this dissertation is a compilation of synoptic studies of ultracool dwarfs(UDs)1. A search for wide binaries around solar type stars in upper scorpio OB association • (Upper Sco) do indicate (the survey is not yet complete) a deficit of BD binaries at these large separations (< 5AU). Twenty six new UDs were discovered at low galactic latitudes in our survey from • archival data and a novel technique using reduced proper motion. 1 We use the term “ultracool dwarfs” as the mass of most of the objects mentioned is unknown, which is required to classify an object as a brown dwarf. We define objects later than M7 as ultra cool dwarfs iii Six field UDs were discovered by spectroscopic follow-up of the candidates selected • from a deep survey. Optical interferometry was used to independently determine the orbit of the compan- • ion of HD33636 which was initially determined using Hubble Space Telescope(HST) astrometry and radial velocity found. Some inconsistency in the HST determined orbit and mass. Optical linear polarization in UDs was used to investigate the dust properties in their • atmospheres. A trend in polarization as predicted by theoretical models was validated, and atmospheric dust grain sizes and projected rotational velocities for these objects were estimated Comprehensive studies of UDs are proving to be crucial not only in our understanding of UDs but also for star and planet formation as brown dwarfs represent their lower and upper mass boundaries, respectively. iv To my beloved wife, Nicole Tata, for her support and motivation. v Acknowledgments I would like to acknowledge the support of all my collaborators in each of the projects. 1. Chapter2: Jerome Guilet and Rohit Deshpande have contributed in this project with data reduction and analysis. 2. Chapter3: CTIO facility was utilized for some of the observations. NOAO travel funding is also appreciated. This project was a collaborative effort led by Phan-Bao Ngoc. 3. Chapter4: I thank the VLTI staff for granting us the opportunity to test our new idea. Carla Gil and Eder Martioli’s collaboration is acknowledged. 4. Chapter5: I thank the WHT staff for making these observations possible. This project is a collaboration between, Eduardo Martin, Sujan Sengupta, Maria Rosa Zapatero, Phan-Bao Ngoc, and Herve Buoy and was led by me. I also acknowledge the extensive use of publicly available astronomy resources such as NOAO-IRAF, Simbad, Vizier, Aladin and STARALT. vi TABLE OF CONTENTS LIST OF FIGURES . viii LIST OF TABLES . ix CHAPTER 1 INTRODUCTION . 1 CHAPTER 2 A SEARCH FOR BROWN DWARF COMPANIONS OF SOLAR- TYPE STARS IN UPPER SCO . 6 2.1 BACKGROUND . 6 2.2 METHOD . 7 2.3 RESULTS . 19 CHAPTER 3 DISCOVERY OF NEW NEARBY L AND LATE-M DWARFS AT LOW GALACTIC LATITUDE FROM THE DENIS DATABASE . 27 3.1 BACKGROUND . 27 3.2 METHOD . 28 3.3 RESULTS . 39 vii CHAPTER 4 USING VLTI OPTICAL INTERFEROMETRY TO VERIFY HST-ASTROMETRY DERIVED MASS AND ORBITAL PARAMETERS OF THE COMPANION OF HD33636 . 47 4.1 BACKGROUND . 47 4.2 METHOD . 49 4.3 RESULTS . 55 CHAPTER 5 OPTICAL LINEAR POLARIZATION IN ULTRA COOL DWARFS: A TOOL TO PROBE DUST IN ULTRA COOL DWARF ATMOSPHERES 64 5.1 BACKGROUND . 64 5.2 METHOD . 65 5.3 RESULTS . 75 CHAPTER 6 DISCUSSION . 82 LIST OF REFERENCES 87 viii LIST OF FIGURES 2.1 Reduced and stacked I band image of one of the sources V1121Oph . 9 2.2 Reduced and stacked H band image of one of the sources V1121Oph . 10 2.3 DENIS catalog magnitude vs I band instrumental magnitude for sources in the field of view of one of the targets . 11 2.4 2MASS catalog magnitude vs H band instrumental magnitude for sources in the field of view of one of the targets . 12 2.5 I band magnitude distribution of all the sources in the area of interest (1.5 arcmin box) around all of the targets . 13 2.6 H band magnitude distribution of all the sources in the area of interest (1.5 arcmin box) around all of the targets . 14 2.7 Separation distribution of all the sources in the area of interest (1.5 arcmin box) around all of the targets . 15 2.8 Initial selection Color-Magnitude Diagram . 16 2.9 Optical spectra of Upper Sco BD candidates . 21 2.10 Color-Magnitude Diagram of our candidates and current status of the project 23 ix 2.11 Color-Magnitude diagrams showing all the candidates . 25 2.12 Color-Magnitude diagrams showing all the candidates . 26 3.1 (MJ , I - J) color-magnitude diagram for late-M and L dwarfs with known trigonometric parallaxes . 29 3.2 (I - J, J - K) color-color diagram for our 29 late-M and L dwarf candidates . 31 3.3 I-band reduced proper motions versus I - J . 38 3.4 Spectra of the 26 M8-L5.5 ultracool dwarfs are plotted by increasing spectral type . 41 3.5 Number of ultracool dwarfs per 2.5 pc spectrophotometric distance bin over 4,800 square degrees . 45 4.1 A schematic representation of a 2-element interferometer. 51 4.2 AMBER data reduction work flow . 53 4.3 One of the averaged frame of HD33636 . 54 4.4 Squared visibility vs wavelength plot . 58 4.5 Flux vs wavelength plot . 59 4.6 Closure phase vs wavelength plot . 60 4.7 Model fit for the visibility measurements . 61 4.8 Apparent orbit of HD33636 and its companion. 62 x 4.9 Angular separation vs Orbital inclination . 63 5.1 Reduced data frame . 67 5.2 Best model fit of the observed data . 77 5.3 Spectral energy distribution of 2MASS J17312974+2721233 . 78 xi LIST OF TABLES 2.1 Ultracool dwarf candidates . 17 2.1 Ultracool dwarf candidates . 18 2.1 Ultracool dwarf candidates . 19 3.1 DENIS ultracool dwarf candidates . 33 3.1 DENIS ultracool dwarf candidates . 34 3.2 DENIS ultracool dwarf candidates measured proper motions . 35 3.2 DENIS ultracool dwarf candidates measured proper motions . 36 3.3 26 nearby L, and late-M dwarfs . 42 3.3 26 nearby L, and late-M dwarfs . 44 5.1 Target list . 74 5.2 Polarization measurements . 76 5.3 Model fit . 79 5.4 IRAC photometry of 2MASS J17312974+2721233 . 79 xii CHAPTER 1 INTRODUCTION Brown dwarfs are sub-stellar objects with masses less than what is required to maintain hydrogen nuclear fusion in their cores. There is still some debate on how to differentiate Brown dwarfs from massive planets.The most commonly used mass range for brown dwarfs is between 13M 78M , which represents the deuterium burning limit and the hydrogen J − J burning limit, respectively. Brown dwarfs’ mere existence from theory (Kumar (1962)) to their discovery took more than three decades. In the last fifteen years a lot of progress has been made in our under- standing of these objects. Ultra cool dwarfs (later than spectral type M7) search criteria could vary on parameters such as age, distance, metallicity etc., but most of the common methods involve multi-color imaging surveys. Once a UD candidate is identified based on multi-color imaging (color-color and/or color-magnitude diagrams), its temperature or mass needs to be estimated. It turns out that in most cases the temperature estimation is rela- tively easy to make based on the spectral types. Two new spectral types, the L type and the T type, were proposed (Mart´ın et al. (1999) & Kirkpatrick et al. (1999)) after the discovery of the first brown dwarfs. The L type is defined in the red optical region by strengthening metal hydride bands (FeH, MgH, CrH, CaH), prominent alkali lines (K I - 7655/7699A˚, Rb 1 I - 7800/7948A˚, Cs I - 8521/8943A˚), and weakening metal-oxide bands (VO, TiO). The T dwarfs are characterized by the presence of methane bands, weakening metal hydrides, and broad alkali metal absorption features.
Load more

Recommended publications
  • Polarimetry in Bistatic Configuration for Ultra High Frequency Radar Measurements on Forest Environment Etienne Everaere
    Polarimetry in Bistatic Configuration for Ultra High Frequency Radar Measurements on Forest Environment Etienne Everaere To cite this version: Etienne Everaere. Polarimetry in Bistatic Configuration for Ultra High Frequency Radar Measure- ments on Forest Environment. Optics [physics.optics]. Ecole Polytechnique, 2015. English. tel- 01199522 HAL Id: tel-01199522 https://hal.archives-ouvertes.fr/tel-01199522 Submitted on 15 Sep 2015 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. École Doctorale de l’École Polytechnie Thèse présentée pour obtenir le grade de docteur de l’École Polytechnique spécialité physique par Étienne Everaere Polarimetry in Bistatic Conguration for Ultra High Frequency Radar Measurements on Forest Environment Directeur de thèse : Antonello De Martino Soutenue le 6 mai 2015 devant le jury composé de : Rapporteurs : François Goudail - Professeur à l’Institut d’optique Graduate School Fabio Rocca - Professeur à L’École Polytechnique de Milan Examinateurs : Élise Colin-K÷niguer - Ingénieur de recherche à l’ONERA Carole Nahum - Responsable
    [Show full text]
  • Biosignatures Search in Habitable Planets
    galaxies Review Biosignatures Search in Habitable Planets Riccardo Claudi 1,* and Eleonora Alei 1,2 1 INAF-Astronomical Observatory of Padova, Vicolo Osservatorio, 5, 35122 Padova, Italy 2 Physics and Astronomy Department, Padova University, 35131 Padova, Italy * Correspondence: [email protected] Received: 2 August 2019; Accepted: 25 September 2019; Published: 29 September 2019 Abstract: The search for life has had a new enthusiastic restart in the last two decades thanks to the large number of new worlds discovered. The about 4100 exoplanets found so far, show a large diversity of planets, from hot giants to rocky planets orbiting small and cold stars. Most of them are very different from those of the Solar System and one of the striking case is that of the super-Earths, rocky planets with masses ranging between 1 and 10 M⊕ with dimensions up to twice those of Earth. In the right environment, these planets could be the cradle of alien life that could modify the chemical composition of their atmospheres. So, the search for life signatures requires as the first step the knowledge of planet atmospheres, the main objective of future exoplanetary space explorations. Indeed, the quest for the determination of the chemical composition of those planetary atmospheres rises also more general interest than that given by the mere directory of the atmospheric compounds. It opens out to the more general speculation on what such detection might tell us about the presence of life on those planets. As, for now, we have only one example of life in the universe, we are bound to study terrestrial organisms to assess possibilities of life on other planets and guide our search for possible extinct or extant life on other planetary bodies.
    [Show full text]
  • Observing Exoplanets
    Observing Exoplanets Olivier Guyon University of Arizona Astrobiology Center, National Institutes for Natural Sciences (NINS) Subaru Telescope, National Astronomical Observatory of Japan, National Institutes for Natural Sciences (NINS) Nov 29, 2017 My Background Astronomer / Optical scientist at University of Arizona and Subaru Telescope (National Astronomical Observatory of Japan, Telescope located in Hawaii) I develop instrumentation to find and study exoplanet, for ground-based telescopes and space missions My interest is focused on habitable planets and search for life outside our solar system At Subaru Telescope, I lead the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument. 2 ALL known Planets until 1989 Approximately 10% of stars have a potentially habitable planet 200 billion stars in our galaxy → approximately 20 billion habitable planets Imagine 200 explorers, each spending 20s on each habitable planet, 24hr a day, 7 days a week. It would take >60yr to explore all habitable planets in our galaxy alone. x 100,000,000,000 galaxies in the observable universe Habitable planets Potentially habitable planet : – Planet mass sufficiently large to retain atmosphere, but sufficiently low to avoid becoming gaseous giant – Planet distance to star allows surface temperature suitable for liquid water (habitable zone) Habitable zone = zone within which Earth-like planet could harbor life Location of habitable zone is function of star luminosity L. For constant stellar flux, distance to star scales as L1/2 Examples: Sun → habitable zone is at ~1 AU Rigel (B type star) Proxima Centauri (M type star) Habitable planets Potentially habitable planet : – Planet mass sufficiently large to retain atmosphere, but sufficiently low to avoid becoming gaseous giant – Planet distance to star allows surface temperature suitable for liquid water (habitable zone) Habitable zone = zone within which Earth-like planet could harbor life Location of habitable zone is function of star luminosity L.
    [Show full text]
  • The X-Ray Imaging Polarimetry Explorer
    Call for a Medium-size mission opportunity in ESA‟s Science Programme for a launch in 2025 (M4) XXIIPPEE The X-ray Imaging Polarimetry Explorer Lead Proposer: Paolo Soffitta (INAF-IAPS, Italy) Contents 1. Executive summary ................................................................................................................................................ 3 2. Science case ........................................................................................................................................................... 5 3. Scientific requirements ........................................................................................................................................ 15 4. Proposed scientific instruments............................................................................................................................ 20 5. Proposed mission configuration and profile ........................................................................................................ 35 6. Management scheme ............................................................................................................................................ 45 7. Costing ................................................................................................................................................................. 50 8. Annex ................................................................................................................................................................... 52 Page 1 XIPE is proposed
    [Show full text]
  • Looking for New Earth in the Coming Decade
    Detection of Earth-like Planets with NWO With discoveries like methane on Mars (Mumma et al. 2009) and super-Earth planets orbiting nearby stars (Howard et al. 2009), the fields of exobiology and exoplanetary science are breaking new ground on almost a weekly basis. These two fields will one day merge, with the high goal of discovering Earth-like planets orbiting nearby stars and the subsequent search for signs of life on those planets. The Kepler mission will soon place clear bounds on the frequency of terrestrial-sized planets (Basri et al. 2008). Beyond that, the great challenge is to determine their true natures. Are terrestrial exoplanets anything like Earth, with life forms able to thrive even on the surface? What is the range of conditions under which Earth-like and other habitable worlds can arise? Every stellar system in the solar neighborhood is entirely unique, and it is almost certain that anything that can happen, will. With current and near-term technology, we can make great strides in finding and characterizing planets in the habitable zones of nearby stars. Given reasonable mission specifications for the New Worlds Observer, the layout of the stars in the solar neighborhood, and their variable characteristics (especially exozodiacal dust) a direct imaging mission can detect and characterize dozens of Earths. Not only does direct imaging achieve detection of planets in a single visit, but photometry, spectroscopy, polarimetry and time-variability in those signals place strong constraints on how those planets compare to our own, including plausible ranges in planet mass and atmospheric and internal structure.
    [Show full text]
  • Detection and Characterization of Circumstellar Material with a WFIRST Or EXO-C Coronagraphic Instrument: Simulations and Observational Methods
    Detection and characterization of circumstellar material with a WFIRST or EXO-C coronagraphic instrument: simulations and observational methods Glenn Schneider Dean C. Hines Glenn Schneider, Dean C. Hines, “Detection and characterization of circumstellar material with a WFIRST or EXO-C coronagraphic instrument: simulations and observational methods,” J. Astron. Telesc. Instrum. Syst. 2(1), 011022 (2016), doi: 10.1117/1.JATIS.2.1.011022. Downloaded From: http://astronomicaltelescopes.spiedigitallibrary.org/ on 01/14/2017 Terms of Use: http://spiedigitallibrary.org/ss/termsofuse.aspx Journal of Astronomical Telescopes, Instruments, and Systems 2(1), 011022 (Jan–Mar 2016) Detection and characterization of circumstellar material with a WFIRST or EXO-C coronagraphic instrument: simulations and observational methods Glenn Schneidera,* and Dean C. Hinesb aThe University of Arizona, Steward Observatory and the Department of Astronomy, North Cherry Avenue, Tucson, Arizona 85712, United States bSpace Telescope Science Institute, 3700 San Martin Drive, Baltimore, Maryland 21218, United States Abstract. The capabilities of a high (∼10−9 resel−1) contrast narrow-field coronagraphic instrument (CGI) on a space-based WFIRST-C or probe-class EXO-C/S mission are particularly and importantly germane to symbiotic studies of the systems of circumstellar material from which planets have emerged and interact with throughout their lifetimes. The small particle populations in “disks” of co-orbiting materials can trace the presence of planets through dynamical
    [Show full text]
  • Exoplanet Exploration Collaboration Initiative TP Exoplanets Final Report
    EXO Exoplanet Exploration Collaboration Initiative TP Exoplanets Final Report Ca Ca Ca H Ca Fe Fe Fe H Fe Mg Fe Na O2 H O2 The cover shows the transit of an Earth like planet passing in front of a Sun like star. When a planet transits its star in this way, it is possible to see through its thin layer of atmosphere and measure its spectrum. The lines at the bottom of the page show the absorption spectrum of the Earth in front of the Sun, the signature of life as we know it. Seeing our Earth as just one possibly habitable planet among many billions fundamentally changes the perception of our place among the stars. "The 2014 Space Studies Program of the International Space University was hosted by the École de technologie supérieure (ÉTS) and the École des Hautes études commerciales (HEC), Montréal, Québec, Canada." While all care has been taken in the preparation of this report, ISU does not take any responsibility for the accuracy of its content. Electronic copies of the Final Report and the Executive Summary can be downloaded from the ISU Library website at http://isulibrary.isunet.edu/ International Space University Strasbourg Central Campus Parc d’Innovation 1 rue Jean-Dominique Cassini 67400 Illkirch-Graffenstaden Tel +33 (0)3 88 65 54 30 Fax +33 (0)3 88 65 54 47 e-mail: [email protected] website: www.isunet.edu France Unless otherwise credited, figures and images were created by TP Exoplanets. Exoplanets Final Report Page i ACKNOWLEDGEMENTS The International Space University Summer Session Program 2014 and the work on the
    [Show full text]
  • Arxiv:2001.10147V1
    Magnetic fields in isolated and interacting white dwarfs Lilia Ferrario1 and Dayal Wickramasinghe2 Mathematical Sciences Institute, The Australian National University, Canberra, ACT 2601, Australia Adela Kawka3 International Centre for Radio Astronomy Research, Curtin University, Perth, WA 6102, Australia Abstract The magnetic white dwarfs (MWDs) are found either isolated or in inter- acting binaries. The isolated MWDs divide into two groups: a high field group (105 − 109 G) comprising some 13 ± 4% of all white dwarfs (WDs), and a low field group (B < 105 G) whose incidence is currently under investigation. The situation may be similar in magnetic binaries because the bright accretion discs in low field systems hide the photosphere of their WDs thus preventing the study of their magnetic fields’ strength and structure. Considerable research has been devoted to the vexed question on the origin of magnetic fields. One hypothesis is that WD magnetic fields are of fossil origin, that is, their progenitors are the magnetic main-sequence Ap/Bp stars and magnetic flux is conserved during their evolution. The other hypothesis is that magnetic fields arise from binary interaction, through differential rotation, during common envelope evolution. If the two stars merge the end product is a single high-field MWD. If close binaries survive and the primary develops a strong field, they may later evolve into the arXiv:2001.10147v1 [astro-ph.SR] 28 Jan 2020 magnetic cataclysmic variables (MCVs). The recently discovered population of hot, carbon-rich WDs exhibiting an incidence of magnetism of up to about 70% and a variability from a few minutes to a couple of days may support the [email protected] [email protected] [email protected] Preprint submitted to Journal of LATEX Templates January 29, 2020 merging binary hypothesis.
    [Show full text]
  • Simultaneous Optical and Near-Infrared Linear Spectropolarimetry of the Earthshine
    A&A 562, L5 (2014) Astronomy DOI: 10.1051/0004-6361/201323009 & c ESO 2014 Astrophysics Letter to the Editor Simultaneous optical and near-infrared linear spectropolarimetry of the earthshine P. A. Miles-Páez1,2, E. Pallé1,2, and M. R. Zapatero Osorio3 1 Instituto de Astrofísica de Canarias, 38205 La Laguna, Spain e-mail: [pamp;epalle]@iac.es 2 Departamento de Astrofísica, Universidad de La Laguna, Av. Astrofísico Francisco Sánchez, s/n, 38206 La Laguna, Spain 3 Centro de Astrobiología (CSIC-INTA), Carretera de Ajalvir km 4, 28850 Torrejón de Ardoz, Madrid, Spain e-mail: [email protected] Received 7 November 2013 / Accepted 23 January 2014 ABSTRACT Aims. We aim to extend our current observational understanding of the integrated planet Earth spectropolarimetry from the optical to the near-infrared wavelengths. Major biomarkers like O2 and water vapor are strong flux absorbents in the Earth’s atmosphere, and some linear polarization of the reflected stellar light is expected to occur at these wavelengths. Methods. Simultaneous optical (0.4−0.9 μm) and near-infrared (0.9−2.3 μm) linear spectropolarimetric data of the earthshine were acquired by observing the nightside of the waxing Moon. The data have sufficient spectral resolution (2.51 nm in the optical, and 1.83 and 2.91 nm in the near-infrared) to resolve major molecular species present in the Earth’s atmosphere. Results. We find the highest values of linear polarization (≥10%) at the bluest wavelengths, which agrees with other studies. Linear polarization intensity steadily decreases toward red wavelengths reaching a nearly flat value beyond ∼0.8 μm.
    [Show full text]
  • Polarimetry of Exoplanets
    POLARIMETRY OF EXOPLANETS Max Millar -Blanchaer*,a, Suniti Sanghavia, Sloane Wiktorowiczb, Rebecca Jensen-Clemc Vanessa Baileya, Kimberly Bottd, James BreckinriDgee,f, Jeffrey Chilcoteg,h, Nicolas Cowani, Michael FitzgeralDj, Paul Kalasc, TheoDora KaraliDik, Tiffany Katariaa, John Krista, MereDith Kupinskil, Franck Marchisµ, Mark Marleyn, Stan Metchevo, Rebecca Oppenheimerp, Marshall Perrinq, Laurent Pueyoq, Tyler Robinsonr, Sara Seagers, William Sparksq, Robert Stencelt, Gautam Vasishta, Ji Wangf, Jason Wangc, Robert Westa, Schuyler Wolffu, Robert T. Zellema aJet Propulsion Laboratory, California Institute of Technology; bAerospace Corporation; cUniversity of California, Berkeley; dUniversity of Washington, Virtual Planetary Lab; eUniversity of Arizona; fCalifornia Institute of Technology, gStanforD University; hUniversity of Notre Dame; iMcGill University; jUniversity of California, Los Angeles; kUniversity of California, Santa Cruz; lCollege of Optical Sciences, University of Arizona; µSETI Institute; nNASA Ames Research Center; oUniversity of Western Ontario; pAmerican Museum of Natural History; qSpace Telescope Science Institute; rNorthern Arizona University; sMassachusetts Institute of Technology; tUniversity of Denver; uLeiden Observatory *[email protected] | 1 (626) 840 9193 © 2018 California Institute of Technology Executive Summary Polarimetry is an extremely useful tool for the characterization of exoplanets. Polarimetric observations with future telescopes have the potential to revolutionize our understanding of scattering processes in the atmospheres and on the surfaces of planets. In particular, time-series and spectropolarimetric measurements can distinguish between different cloud and surface types. Notably, polarimetry has the ability to constrain planetary albedos and may ultimately be able to reveal the presence of a liquid water surface. To maximize the gain from polarimetric measurements careful attention must be paid to the design and implementation of future instrument designs.
    [Show full text]
  • Virtual Planetary Laboratory
    The Virtual Planetary Laboratory Lead Institution: University of Washington, Seattle Team Overview Identifying a habitable or inhabited planet around another star is one of NASA’s greatest long-term goals. Major advances in exoplanet detection place humanity on the brink of finally answering astrobiology’s over-arching question: “Are we alone?”, but there are still many scientific steps required before we can identify a living world beyond our Solar System. The Virtual Planetary Laboratory focuses on under- standing how to recognize whether an extrasolar planet can or does support life. To do this, we use computational models to understand the many factors that affect planetary habitability, and use models, field and laboratory experiments to better understand how life might impact a planetary environment in detectable ways. These results are used to determine the potentially observable planetary character- istics and the telescope measurements required to discriminate between planets with and without life. Our five research objectives are to: • Characterize habitability and biosignatures for an Earth-like planet Principal Investigator: • Characterize the environment, habitability and biosignatures of the Earth Victoria Meadows through time • Develop interdisciplinary, multi-parameter characterization of exoplanet habitability • Determine the impact of life on terrestrial planet environments and the generation of biosignatures • Define required measurements and optimal retrieval methods for exoplanet characterization missions Background Image Credit: NASA/JPL-Caltech Team Website: https://depts.washington.edu/naivpl/content/welcome-virtual-planetary-laboratory NASA Astrobiology Institute 40 Annual Report 2017 2017 Executive Summary To enable NASA’s search for life beyond the Solar System the Virtual Planetary Laboratory Team uses computer models to explore terres- trial exoplanet habitability and biosignatures.
    [Show full text]
  • Abstracts of Extreme Solar Systems 4 (Reykjavik, Iceland)
    Abstracts of Extreme Solar Systems 4 (Reykjavik, Iceland) American Astronomical Society August, 2019 100 — New Discoveries scope (JWST), as well as other large ground-based and space-based telescopes coming online in the next 100.01 — Review of TESS’s First Year Survey and two decades. Future Plans The status of the TESS mission as it completes its first year of survey operations in July 2019 will bere- George Ricker1 viewed. The opportunities enabled by TESS’s unique 1 Kavli Institute, MIT (Cambridge, Massachusetts, United States) lunar-resonant orbit for an extended mission lasting more than a decade will also be presented. Successfully launched in April 2018, NASA’s Tran- siting Exoplanet Survey Satellite (TESS) is well on its way to discovering thousands of exoplanets in orbit 100.02 — The Gemini Planet Imager Exoplanet Sur- around the brightest stars in the sky. During its ini- vey: Giant Planet and Brown Dwarf Demographics tial two-year survey mission, TESS will monitor more from 10-100 AU than 200,000 bright stars in the solar neighborhood at Eric Nielsen1; Robert De Rosa1; Bruce Macintosh1; a two minute cadence for drops in brightness caused Jason Wang2; Jean-Baptiste Ruffio1; Eugene Chiang3; by planetary transits. This first-ever spaceborne all- Mark Marley4; Didier Saumon5; Dmitry Savransky6; sky transit survey is identifying planets ranging in Daniel Fabrycky7; Quinn Konopacky8; Jennifer size from Earth-sized to gas giants, orbiting a wide Patience9; Vanessa Bailey10 variety of host stars, from cool M dwarfs to hot O/B 1 KIPAC, Stanford University (Stanford, California, United States) giants. 2 Jet Propulsion Laboratory, California Institute of Technology TESS stars are typically 30–100 times brighter than (Pasadena, California, United States) those surveyed by the Kepler satellite; thus, TESS 3 Astronomy, California Institute of Technology (Pasadena, Califor- planets are proving far easier to characterize with nia, United States) follow-up observations than those from prior mis- 4 Astronomy, U.C.
    [Show full text]