DOCSLIB.ORG

The TRAPPIST-1 JWST Community Initiative

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The TRAPPIST-1 JWST Community Initiative The TRAPPIST-1 JWST Community Initiative Michael¨ Gillon1, Victoria Meadows2, Eric Agol2, Adam J. Burgasser3, Drake Deming4, Rene´ Doyon5, Jonathan Fortney6, Laura Kreidberg7, James Owen8, Franck Selsis9, Julien de Wit10, Jacob Lustig-Yaeger2, Benjamin V. Rackham10 1Astrobiology Research Unit, University of Liege,` Belgium 2Department of Astronomy, University of Washington, USA 3Department of Physics, University of California San Diego, USA 4Department of Astronomy, University of Maryland at College Park, USA 5Institute for Research in Exoplanets, University of Montreal, Canada 6Other Worlds Laboratory, University of California Santa Cruz, USA 7Center for Astrophysics — Harvard and Smithsonian, USA 8Department of Physics, Imperial College London, United Kingdom 9Laboratoire d’Astrophysique de Bordeaux, University of Bordeaux, France 10Department of Earth, Atmospheric, and Planetary Sciences, MIT, USA February 17, 2020 he upcoming launch of the James Webb analysis techniques, complementary space-based Space Telescope (JWST) combined with and ground-based observations) and theoretical T the unique features of the TRAPPIST-1 levels (e.g. model developments and comparison, planetary system should enable the young field retrieval techniques, inferences). Depending on of exoplanetology to enter into the realm of tem- the outcome of the first phase of JWST observa- perate Earth-sized worlds. Indeed, the proximity tions of the planets, this initiative could become of the system (12pc) and the small size (0.12 the seed of a major JWST Legacy Program devoted R ) and luminosity (0.05% L ) of its host star to the study of TRAPPIST-1. should make the comparative atmospheric char- acterization of its seven transiting planets within Keywords: planetary systems, star and planet reach of an ambitious JWST program. Given the formation, stars and stellar evolution limited lifetime of JWST, the ecliptic location of the star that limits its visibility to 100d per year, the large number of observational time required 1 JWST & TRAPPIST-1: towards arXiv:2002.04798v2 [astro-ph.EP] 13 Feb 2020 by this study, and the numerous observational and theoretical challenges awaiting it, its full the spectroscopic study of po- success will critically depend on a large level of tentially habitable exoplanets coordination between the involved teams and on the support of a large community. In this context, we present here a community initiative aiming Since the seminal discovery of 51 Pegasi b (Mayor and to develop a well-defined sequential structure Queloz, 1995), more than four thousands exoplanets for the study of the system with JWST and to have been detected at an ever increasing rate, includ- coordinate on every aspect of its preparation ing a steeply growing fraction of planets significantly and implementation, both on the observational smaller than Uranus and Neptune, some even smaller (e.g. study of the instrumental limitations, data than our Earth. In parallel, many projects aiming to characterize exoplanets have developed during the last The TRAPPIST-1 JWST Community Initiative two decades, bringing notably first pieces of informa- tion on the atmospheric properties of several dozens of exoplanets. Most of these atmospheric studies have been made possible by the transiting configuration of the probed planets. Indeed, the special geometrical configuration of transiting planets offers the detailed study of their atmosphere without the cost of spatially resolving them from their host stars (Winn, 2010). The first atmospheric studies of transiting "hot Jupiters" (e.g. Charbonneau, 2009; Sing et al., 2016) and "hot Neptunes" (e.g. Deming et al., 2007; Wakeford et al., 2017) have provided initial glimpses at the atmospheric chemical composition, vertical pressure-temperature profiles, albedos, and circulation patterns of extrasolar Figure 1: Transmission spectra for three photochemically self- worlds (see Madhusudhan, 2019 for a recent review). consistent Earth-like planets around three M dwarfs Within the last decade, such atmospheric studies have with different radii. Original references for the trans- been extended to smaller and/or cooler planets like mission spectra simulations are Segura et al., 2005 the hot rocky worlds 55 Cnc e (Demory et al., 2012; and Schwieterman et al., 2016 for AD Leo, Meadows Demory et al., 2016) and LHS3844 b (Kreidberg et al., et al., 2018 for Proxima Cen, and Meadows et al. 2019) or the more temperate mini-Neptunes GJ1214 b (in prep) for TRAPPIST-1. (Kreidberg et al., 2014) and K2-18 b (Benneke et al., 2019). Extending further such studies to rocky worlds or- the star as one moves down the main-sequence. For biting within the circumstellar habitable zone (HZ) of the latest-type red dwarfs, this zone corresponds to their star (e.g. Kasting, Whitmire, and Reynolds, 1993) orbital periods of only a few days, making possible to would make it possible to probe the atmospheric and stack dozens if not hundreds of eclipse observations surface conditions of potentially habitable worlds, to within the JWST lifetime, and thus to maximize the explore their atmospheric compositions for chemical final signal-to-noise. disequilibria of biological origins (Schwieterman et al., Such considerations motivated the emergence of sev- 2018), and, maybe, to reveal the existence of life be- eral projects aiming to search the nearest M-dwarfs yond our solar system. This extension is not possible for transits before the launch of JWST, e.g. MEarth with the astronomical facilities currently in operation, (Nutzman and Charbonneau, 2008) or TESS (Deming including with the Hubble Space Telescope (HST), but et al., 2009). Among them, the ground-based survey it could be initiated from 2021 with the launch of JWST. SPECULOOS (Gillon, 2018; Burdanov et al., 2018; Del- Thanks to its much improved infrared spectral cover- rez et al., 2018) chose to gamble on ‘ultracool’ (i.e. age, sensitivity, and resolution over HST, JWST should later than M6) dwarf stars, at the bottom of the main- in theory be able to probe by eclipse (i.e. transit or oc- sequence, despite that most theoretical expectations cultation) spectroscopy the atmospheric composition presented such super-low-mass (≤ 0:1M ) stars as un- of a transiting temperate planet similar in size and likely to form short-period rocky planets similar in size mass to Earth. Nevertheless, signal-to-noise considera- to Earth (e.g. Raymond, Scalo, and Meadows, 2007). tions result in the possibility of such an achievement While SPECULOOS started officially its operation in only for a planet transiting a very nearby (up to 10- 2019 (Jehin et al., 2018; Ducrot and Gillon, 2019), 20 pc) and very-late-type (∼M5 and later) M-dwarf it was in fact initiated in 2011 as a prototype survey (Charbonneau, 2009; Kaltenegger and Traub, 2009; targeting a limited sample of fifty nearby ultracool de Wit and Seager, 2013). Indeed, the same planet dwarfs with the TRAPPIST 60cm robotic telescope in orbiting a bigger star will produce smaller transmission Chile (Gillon et al., 2013). This prototype aimed only and emission signals, and this drop is very sharp when to assess the feasibility of SPECULOOS, but it did much one gets away from the bottom of the main-sequence. better than that. Indeed, in 2015, it detected three For instance, Figure1 shows transmission spectra for transiting Earth-sized planets in orbit around a Jupiter- three photochemically self-consistent Earth-like plan- sized M8-type star 12 parsec away (Gillon et al., 2016). ets around three different M dwarfs with different radii. In 2016, the intensive photometric follow-up of the star The relative transit depth of the prominent near-IR (renamed TRAPPIST-1) - with a critical contribution CH4 bands of an Earth-like planet orbiting an M8-type of the Spitzer Space Telescope - revealed that it was dwarf star is expected to be ∼50ppm, but only ∼5 ppm in fact orbited by seven transiting Earth-sized planets, for a M3.5V host star. The floor noise of JWST instru- all of them close or within the HZ of the star (Gillon ments is expected to be of at least 10 ppm (Fauchez et al., 2017). With semi-major axes ranging from 1 et al., 2019a), this ‘JWST opportunity’ is thus clearly to 6% of an astronomical unit, these planets form a limited to the latest-type red dwarfs. This conclusion super compact planetary system whose long-term sta- is strengthened by the habitable zone moving closer to bility is ensured by its resonant architecture (Luger Page 2 of 23 The TRAPPIST-1 JWST Community Initiative et al., 2017). While transit photometry brought pre- et al., 2020). To assess this ‘better target to come’ cise measurements of the planets’ sizes (Delrez et al., hypothesis, we cross-matched the Gaia DR2 catalog 2018), their strong mutual interactions made possible (Gaia Collaboration et al., 2018) with the 2MASS point- to infer initial estimates of their masses using the tran- source catalog (Skrutskie et al., 2006) to build a list sit timing variations method (TTVs; Agol et al., 2005; of M-dwarfs and L-dwarfs within 40pc (see AnnexA). Holman and Murray, 2005), the resulting densities sug- For each of them, we estimated the basic physical pa- gesting rocky compositions maybe more volatile-rich rameters (mass, size, effective temperature), and then than Earth’s (Grimm et al., 2018, Agol et al. in prep.). computed the value of a metric for JWST transmission The discovery of TRAPPIST-1 was followed by sev- spectroscopy in the near-infrared (with NIRSPEC in eral theoretical studies aiming to assess the potential prism mode) of a putative transiting ‘Earth-like’ planet, of JWST to probe the atmospheric composition of its i.e. with the same mass, size, and equilibrium tem- planets (Barstow and Irwin, 2016; Morley et al., 2017; perature (Teq) than our planet. We also performed Batalha et al., 2018; Krissansen-Totton et al., 2018; the same exercise for occultation photometry in the Wunderlich et al., 2019; Fauchez et al., 2019a; Lustig- mid-infrared (with MIRI in imaging mode) for an Earth- Yaeger, Meadows, and Lincowski, 2019).
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]
  • Modeling Super-Earth Atmospheres in Preparation for Upcoming Extremely Large Telescopes
    Modeling Super-Earth Atmospheres In Preparation for Upcoming Extremely Large Telescopes Maggie Thompson1 Jonathan Fortney1, Andy Skemer1, Tyler Robinson2, Theodora Karalidi1, Steph Sallum1 1University of California, Santa Cruz, CA; 2Northern Arizona University, Flagstaff, AZ ExoPAG 19 January 6, 2019 Seattle, Washington Image Credit: NASA Ames/JPL-Caltech/T. Pyle Roadmap Research Goals & Current Atmosphere Modeling Selecting Super-Earths for State of Super-Earth Tool (Past & Present) Follow-Up Observations Detection Preliminary Assessment of Future Observatories for Conclusions & Upcoming Instruments’ Super-Earths Future Work Capabilities for Super-Earths M. Thompson — ExoPAG 19 01/06/19 Research Goals • Extend previous modeling tool to simulate super-Earth planet atmospheres around M, K and G stars • Apply modified code to explore the parameter space of actual and synthetic super-Earths to select most suitable set of confirmed exoplanets for follow-up observations with JWST and next-generation ground-based telescopes • Inform the design of advanced instruments such as the Planetary Systems Imager (PSI), a proposed second-generation instrument for TMT/GMT M. Thompson — ExoPAG 19 01/06/19 Current State of Super-Earth Detections (1) Neptune Mass Range of Interest Earth Data from NASA Exoplanet Archive M. Thompson — ExoPAG 19 01/06/19 Current State of Super-Earth Detections (2) A Approximate Habitable Zone Host Star Spectral Type F G K M Data from NASA Exoplanet Archive M. Thompson — ExoPAG 19 01/06/19 Atmosphere Modeling Tool Evolution of Atmosphere Model • Solar System Planets & Moons ~ 1980’s (e.g., McKay et al. 1989) • Brown Dwarfs ~ 2000’s (e.g., Burrows et al. 2001) • Hot Jupiters & Other Giant Exoplanets ~ 2000’s (e.g., Fortney et al.
    [Show full text]
  • The Nearest Stars: a Guided Tour by Sherwood Harrington, Astronomical Society of the Pacific
    www.astrosociety.org/uitc No. 5 - Spring 1986 © 1986, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112. The Nearest Stars: A Guided Tour by Sherwood Harrington, Astronomical Society of the Pacific A tour through our stellar neighborhood As evening twilight fades during April and early May, a brilliant, blue-white star can be seen low in the sky toward the southwest. That star is called Sirius, and it is the brightest star in Earth's nighttime sky. Sirius looks so bright in part because it is a relatively powerful light producer; if our Sun were suddenly replaced by Sirius, our daylight on Earth would be more than 20 times as bright as it is now! But the other reason Sirius is so brilliant in our nighttime sky is that it is so close; Sirius is the nearest neighbor star to the Sun that can be seen with the unaided eye from the Northern Hemisphere. "Close'' in the interstellar realm, though, is a very relative term. If you were to model the Sun as a basketball, then our planet Earth would be about the size of an apple seed 30 yards away from it — and even the nearest other star (alpha Centauri, visible from the Southern Hemisphere) would be 6,000 miles away. Distances among the stars are so large that it is helpful to express them using the light-year — the distance light travels in one year — as a measuring unit. In this way of expressing distances, alpha Centauri is about four light-years away, and Sirius is about eight and a half light- years distant.
    [Show full text]
  • PEAS: the PLANET AS EXOPLANET ANALOG SPECTROGRAPH. E. C. Martin1 and A
    Exoplanets in our Backyard 2020 (LPI Contrib. No. 2195) 3006.pdf PEAS: THE PLANET AS EXOPLANET ANALOG SPECTROGRAPH. E. C. Martin1 and A. J. Skemer1, 1Department of Astronomy & Astrophysics, University of California, Santa Cruz, CA ([email protected]) Introduction: Exoplanets are abundant in our Galaxy • Produce 2D surface maps of Venus, Mars, Jupi- and yet characterizing them remains a technical chal- ter, Saturn, Uranus, Neptune lenGe. Solar System planets provide an opportunity to • Produce fiducial measurements that will be used test the practical limitations of exoplanet observations to plan instruments for future exoplanet mis- with hiGh siGnal-to-noise data, and ancillary data (such sions, such as HabEx/LUVOIR and TMT. as 2D maps and in situ measurements) that we cannot Long term: access for exoplanets. However, data on Solar System • Time-series observations of Solar System plan- planets differ from exoplanets in that Solar System ets to explore variability and weather patterns planets are spatially resolved while exoplanets are all on planets unresolved point-sources. • Comparison to historical data (e.g. [4]) There have been several recent efforts to validate techniques for interpreting exoplanet observations by • Study planetary seismoloGy (oscillation modes) binning images of Solar System planets to a single of Solar System planets pixel: For example, Cowan et al. [1] used images from the EPOXI mission to study Earth’s Globally averaGed PEAS Instrument Design Planetary light collect- properties as it rotated; MayorGa et al. [2] used data ed by the telescope will be split into a spectroGraph from the Cassini spacecraft’s fly-by of Jupiter to ob- system and an imaGinG system for simultaneous obser- serve Globally averaGed reflected liGht phase curves; vations.
    [Show full text]
  • The Exoplanet Revolution
    FEATURES THE EXOPLANET REVOLUTION l Yamila Miguel – Leiden Observatory, Leiden, The Netherlands – DOI: https://doi.org/10.1051/epn/2019506 Hot Jupiters, super-Earths, lava-worlds and the search for life beyond our solar system: the exoplanet revolution started almost 30 years ago and is now taking off. re there other planets like the Earth out discovered the astonishing number of 4000 exoplanets, there? This is probably one of the oldest and counting. Every new discovery shows an amazing questions of humanity. For centuries and diversity that impacts in the perception and understand- Auntil the 90s, we only knew of the existence ing of our own solar system. of 8 planets. But today we live in a privileged time. For the first time in history we know that there are other How to find exoplanets? planets orbiting distant stars. Finding exoplanets is an extremely difficult task. These The first planet orbiting a star similar to the Sun was planets shine mostly due to the reflection of the stellar . Artist’s impression discovered in 1995 -only 24 years ago- and it started light in their atmospheres and their light is incredibly of COROT-7b. a revolution in Astronomy. Today astronomers have weak compared to that of their host stars. For this reason, © ESO/L. Calçada EPN 50/5&6 41 FEATURES THE Exoplanet REVolution observing exoplanets directly is extremely difficult and allows astronomers to calculate the planet’s density, astronomers had to develop indirect techniques that infer important to start assessing planetary compositions the presence of the planet. and diversity. Two of the most successful techniques to discov- er exoplanets are the "Transits" and "Radial Veloci- The Exoplanet Zoo ties" techniques.
    [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]
  • Monday, November 13, 2017 WHAT DOES IT MEAN to BE HABITABLE? 8:15 A.M. MHRGC Salons ABCD 8:15 A.M. Jang-Condell H. * Welcome C
    Monday, November 13, 2017 WHAT DOES IT MEAN TO BE HABITABLE? 8:15 a.m. MHRGC Salons ABCD 8:15 a.m. Jang-Condell H. * Welcome Chair: Stephen Kane 8:30 a.m. Forget F. * Turbet M. Selsis F. Leconte J. Definition and Characterization of the Habitable Zone [#4057] We review the concept of habitable zone (HZ), why it is useful, and how to characterize it. The HZ could be nicknamed the “Hunting Zone” because its primary objective is now to help astronomers plan observations. This has interesting consequences. 9:00 a.m. Rushby A. J. Johnson M. Mills B. J. W. Watson A. J. Claire M. W. Long Term Planetary Habitability and the Carbonate-Silicate Cycle [#4026] We develop a coupled carbonate-silicate and stellar evolution model to investigate the effect of planet size on the operation of the long-term carbon cycle, and determine that larger planets are generally warmer for a given incident flux. 9:20 a.m. Dong C. F. * Huang Z. G. Jin M. Lingam M. Ma Y. J. Toth G. van der Holst B. Airapetian V. Cohen O. Gombosi T. Are “Habitable” Exoplanets Really Habitable? A Perspective from Atmospheric Loss [#4021] We will discuss the impact of exoplanetary space weather on the climate and habitability, which offers fresh insights concerning the habitability of exoplanets, especially those orbiting M-dwarfs, such as Proxima b and the TRAPPIST-1 system. 9:40 a.m. Fisher T. M. * Walker S. I. Desch S. J. Hartnett H. E. Glaser S. Limitations of Primary Productivity on “Aqua Planets:” Implications for Detectability [#4109] While ocean-covered planets have been considered a strong candidate for the search for life, the lack of surface weathering may lead to phosphorus scarcity and low primary productivity, making aqua planet biospheres difficult to detect.
    [Show full text]
  • W359 E31 RS.Pdf
    WOLF 359 "SÉCURITÉ" by Gabriel Urbina (Writer's Note: The following takes place on Day 864 of the Hephaestus Mission) INT. U.S.S. URANIA - FLIGHT DECK - 1400 HOURS We come in on the STEADY HUM of a ship's engine. There's various BEEPS and DINGS from a control console. Sharp-eared listeners might notice that things sound considerably sleeker and smoother than what we're used to. Someone TYPES into a console, and hits a SWITCH. There's a discrete burst of STATIC, followed by - JACOBI Sécurité, sécurité, sécurité. U.S.S. Hephaestus Station, this is the U.S.S. Urania. Be advised that we are on an intercept vector. Request you avoid any course corrections or exterior activity. Please advise your intentions. He hits a BUTTON. For a BEAT he just awaits the reply. JACOBI (CONT'D) Still no reply, sir. You really think someone's alive in there? I mean... look at that thing. It's only duct tape and sheer stubbornness keeping it together. KEPLER No. They're there. Rebroadcast, and transmit the command authentication codes. JACOBI Aye-aye. (hits the radio switch) Sécurité, sécurité, sécurité. U.S.S. Hephaestus, this is the U.S.S. Urania. I say again: we are on an approach vector to your current position. Authentication code: Victor-Uniform-Lima-Charlie- Alpha-November. Please advise your intentions. BEAT. And then - KRRRCH! MINKOWSKI (over radio receiver) U.S.S. Urania, this is Hephaestus Actual. Continue on current course, and use vector zero one decimal nine for your final approach. 2. JACOBI Copy that, Hephaestus Actual.
    [Show full text]
  • The TRAPPIST-1 JWST Community Initiative
    Bulletin of the AAS • Vol. 52, Issue 2 The TRAPPIST-1 JWST Community Initiative Michaël Gillon1, Victoria Meadows2, Eric Agol2, Adam J. Burgasser3, Drake Deming4, René Doyon5, Jonathan Fortney6, Laura Kreidberg7, James Owen8, Franck Selsis9, Julien de Wit10, Jacob Lustig-Yaeger11, Benjamin V. Rackham10 1Astrobiology Research Unit, University of Liège, Belgium, 2Department of Astronomy, University of Washington, USA, 3Department of Physics, University of California San Diego, USA, 4Department of Astronomy, University of Maryland at College Park, USA, 5Institute for Research in Exoplanets, University of Montreal, Canada, 6Other Worlds Laboratory, University of California Santa Cruz, USA, 7Center for Astrophysics | Harvard and Smithsonian, USA, 8Department of Physics, Imperial College London, United Kingdom, 9Laboratoire d’Astrophysique de Bordeaux, University of Bordeaux, France, 10Department of Earth, Atmospheric, and Planetary Sciences, MIT, USA, 11Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA Published on: Dec 02, 2020 License: Creative Commons Attribution 4.0 International License (CC-BY 4.0) Bulletin of the AAS • Vol. 52, Issue 2 The TRAPPIST-1 JWST Community Initiative ABSTRACT The upcoming launch of the James Webb Space Telescope (JWST) combined with the unique features of the TRAPPIST-1 planetary system should enable the young field of exoplanetology to enter into the realm of temperate Earth-sized worlds. Indeed, the proximity of the system (12pc) and the small size (0.12 R ) and luminosity (0.05% L ) of its host star should make the comparative atmospheric characterization of its seven transiting planets within reach of an ambitious JWST program. Given the limited lifetime of JWST, the ecliptic location of the star that limits its visibility to 100d per year, the large number of observational time required by this study, and the numerous observational and theoretical challenges awaiting it, its full success will critically depend on a large level of coordination between the involved teams and on the support of a large community.
    [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]
  • Exoplanet Community Report
    JPL Publication 09‐3 Exoplanet Community Report Edited by: P. R. Lawson, W. A. Traub and S. C. Unwin National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology Pasadena, California March 2009 The work described in this publication was performed at a number of organizations, including the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). Publication was provided by the Jet Propulsion Laboratory. Compiling and publication support was provided by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement by the United States Government, or the Jet Propulsion Laboratory, California Institute of Technology. © 2009. All rights reserved. The exoplanet community’s top priority is that a line of probe­class missions for exoplanets be established, leading to a flagship mission at the earliest opportunity. iii Contents 1 EXECUTIVE SUMMARY.................................................................................................................. 1 1.1 INTRODUCTION...............................................................................................................................................1 1.2 EXOPLANET FORUM 2008: THE PROCESS OF CONSENSUS BEGINS.....................................................2
    [Show full text]
  • Open Batalha-Dissertation.Pdf
    The Pennsylvania State University The Graduate School Eberly College of Science A SYNERGISTIC APPROACH TO INTERPRETING PLANETARY ATMOSPHERES A Dissertation in Astronomy and Astrophysics by Natasha E. Batalha © 2017 Natasha E. Batalha Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy August 2017 The dissertation of Natasha E. Batalha was reviewed and approved∗ by the following: Steinn Sigurdsson Professor of Astronomy and Astrophysics Dissertation Co-Advisor, Co-Chair of Committee James Kasting Professor of Geosciences Dissertation Co-Advisor, Co-Chair of Committee Jason Wright Professor of Astronomy and Astrophysics Eric Ford Professor of Astronomy and Astrophysics Chris Forest Professor of Meteorology Avi Mandell NASA Goddard Space Flight Center, Research Scientist Special Signatory Michael Eracleous Professor of Astronomy and Astrophysics Graduate Program Chair ∗Signatures are on file in the Graduate School. ii Abstract We will soon have the technological capability to measure the atmospheric compo- sition of temperate Earth-sized planets orbiting nearby stars. Interpreting these atmospheric signals poses a new challenge to planetary science. In contrast to jovian-like atmospheres, whose bulk compositions consist of hydrogen and helium, terrestrial planet atmospheres are likely comprised of high mean molecular weight secondary atmospheres, which have gone through a high degree of evolution. For example, present-day Mars has a frozen surface with a thin tenuous atmosphere, but 4 billion years ago it may have been warmed by a thick greenhouse atmosphere. Several processes contribute to a planet’s atmospheric evolution: stellar evolution, geological processes, atmospheric escape, biology, etc. Each of these individual processes affects the planetary system as a whole and therefore they all must be considered in the modeling of terrestrial planets.
    [Show full text]