The TOI-763 System: Sub-Neptunes Orbiting a Sun-Like Star
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A Review of Possible Planetary Atmospheres in the TRAPPIST-1 System
Space Sci Rev (2020) 216:100 https://doi.org/10.1007/s11214-020-00719-1 A Review of Possible Planetary Atmospheres in the TRAPPIST-1 System Martin Turbet1 · Emeline Bolmont1 · Vincent Bourrier1 · Brice-Olivier Demory2 · Jérémy Leconte3 · James Owen4 · Eric T. Wolf5 Received: 14 January 2020 / Accepted: 4 July 2020 / Published online: 23 July 2020 © The Author(s) 2020 Abstract TRAPPIST-1 is a fantastic nearby (∼39.14 light years) planetary system made of at least seven transiting terrestrial-size, terrestrial-mass planets all receiving a moderate amount of irradiation. To date, this is the most observationally favourable system of po- tentially habitable planets known to exist. Since the announcement of the discovery of the TRAPPIST-1 planetary system in 2016, a growing number of techniques and approaches have been used and proposed to characterize its true nature. Here we have compiled a state- of-the-art overview of all the observational and theoretical constraints that have been ob- tained so far using these techniques and approaches. The goal is to get a better understanding of whether or not TRAPPIST-1 planets can have atmospheres, and if so, what they are made of. For this, we surveyed the literature on TRAPPIST-1 about topics as broad as irradiation environment, planet formation and migration, orbital stability, effects of tides and Transit Timing Variations, transit observations, stellar contamination, density measurements, and numerical climate and escape models. Each of these topics adds a brick to our understand- ing of the likely—or on the contrary unlikely—atmospheres of the seven known planets of the system. -
Lecture 3 - Minimum Mass Model of Solar Nebula
Lecture 3 - Minimum mass model of solar nebula o Topics to be covered: o Composition and condensation o Surface density profile o Minimum mass of solar nebula PY4A01 Solar System Science Minimum Mass Solar Nebula (MMSN) o MMSN is not a nebula, but a protoplanetary disc. Protoplanetary disk Nebula o Gives minimum mass of solid material to build the 8 planets. PY4A01 Solar System Science Minimum mass of the solar nebula o Can make approximation of minimum amount of solar nebula material that must have been present to form planets. Know: 1. Current masses, composition, location and radii of the planets. 2. Cosmic elemental abundances. 3. Condensation temperatures of material. o Given % of material that condenses, can calculate minimum mass of original nebula from which the planets formed. • Figure from Page 115 of “Physics & Chemistry of the Solar System” by Lewis o Steps 1-8: metals & rock, steps 9-13: ices PY4A01 Solar System Science Nebula composition o Assume solar/cosmic abundances: Representative Main nebular Fraction of elements Low-T material nebular mass H, He Gas 98.4 % H2, He C, N, O Volatiles (ices) 1.2 % H2O, CH4, NH3 Si, Mg, Fe Refractories 0.3 % (metals, silicates) PY4A01 Solar System Science Minimum mass for terrestrial planets o Mercury:~5.43 g cm-3 => complete condensation of Fe (~0.285% Mnebula). 0.285% Mnebula = 100 % Mmercury => Mnebula = (100/ 0.285) Mmercury = 350 Mmercury o Venus: ~5.24 g cm-3 => condensation from Fe and silicates (~0.37% Mnebula). =>(100% / 0.37% ) Mvenus = 270 Mvenus o Earth/Mars: 0.43% of material condensed at cooler temperatures. -
Exoplanet Discovery Methods (1) Direct Imaging Today: Star Wobbles (2) Astrometry → Position (3) Radial Velocity → Velocity
Exoplanet Discovery Methods (1) Direct imaging Today: Star Wobbles (2) Astrometry → position (3) Radial velocity → velocity Later: (4) Transits (5) Gravitational microlensing (6) Pulsar timing Kepler Orbits Kepler 1: Planet orbit is an ellipse with star at one focus Star’s view: (Newton showed this is due to gravity’s inverse-square law). Kepler 2: Planet seeps out equal area in equal time (angular momentum conservation). Planet’s view: Planet at the focus. Star sweeps equal area in equal time Inertial Frame: Star and planet both orbit around the centre of mass. Kepler Orbits M = M" + mp = total mass a = ap + a" = semi # major axis ap mp = a" M" = a M Centre of Mass P = orbit period a b a % P ( 2 a3 = G M ' * Kepler's 3rd Law b & 2$ ) a - b e + = eccentricity 0 = circular 1 = parabolic a ! Astrometry • Look for a periodic “wobble” in the angular position of host star • Light from the star+planet is dominated by star • Measure star’s motion in the plane of the sky due to the orbiting planet • Must correct measurements for parallax and proper motion of star • Doppler (radial velocity) more sensitive to planets close to the star • Astrometry more sensitive to planets far from the star Stellar wobble: Star and planet orbit around centre of mass. Radius of star’s orbit scales with planet’s mass: a m a M * = p p = * a M* + mp a M* + mp Angular displacement for a star at distance d: a & mp ) & a) "# = $ % ( + ( + ! d ' M* * ' d* (Assumes small angles and mp << M* ) ! Scaling to Jupiter and the Sun, this gives: ,1 -1 % mp ( % M ( % a ( % d ( "# $ 0.5 ' * ' + * ' * ' * mas & mJ ) & Msun ) & 5AU) & 10pc) Note: • Units are milliarcseconds -> very small effect • Amplitude increases at large orbital separation, a ! • Amplitude decreases with distance to star d. -
Abstracts Connecting to the Boston University Network
20th Cambridge Workshop: Cool Stars, Stellar Systems, and the Sun July 29 - Aug 3, 2018 Boston / Cambridge, USA Abstracts Connecting to the Boston University Network 1. Select network ”BU Guest (unencrypted)” 2. Once connected, open a web browser and try to navigate to a website. You should be redirected to https://safeconnect.bu.edu:9443 for registration. If the page does not automatically redirect, go to bu.edu to be brought to the login page. 3. Enter the login information: Guest Username: CoolStars20 Password: CoolStars20 Click to accept the conditions then log in. ii Foreword Our story starts on January 31, 1980 when a small group of about 50 astronomers came to- gether, organized by Andrea Dupree, to discuss the results from the new high-energy satel- lites IUE and Einstein. Called “Cool Stars, Stellar Systems, and the Sun,” the meeting empha- sized the solar stellar connection and focused discussion on “several topics … in which the similarity is manifest: the structures of chromospheres and coronae, stellar activity, and the phenomena of mass loss,” according to the preface of the resulting, “Special Report of the Smithsonian Astrophysical Observatory.” We could easily have chosen the same topics for this meeting. Over the summer of 1980, the group met again in Bonas, France and then back in Cambridge in 1981. Nearly 40 years on, I am comfortable saying these workshops have evolved to be the premier conference series for cool star research. Cool Stars has been held largely biennially, alternating between North America and Europe. Over that time, the field of stellar astro- physics has been upended several times, first by results from Hubble, then ROSAT, then Keck and other large aperture ground-based adaptive optics telescopes. -
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. -
Spectra As Windows Into Exoplanet Atmospheres
SPECIAL FEATURE: PERSPECTIVE PERSPECTIVE SPECIAL FEATURE: Spectra as windows into exoplanet atmospheres Adam S. Burrows1 Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 Edited by Neta A. Bahcall, Princeton University, Princeton, NJ, and approved December 2, 2013 (received for review April 11, 2013) Understanding a planet’s atmosphere is a necessary condition for understanding not only the planet itself, but also its formation, structure, evolution, and habitability. This requirement puts a premium on obtaining spectra and developing credible interpretative tools with which to retrieve vital planetary information. However, for exoplanets, these twin goals are far from being realized. In this paper, I provide a personal perspective on exoplanet theory and remote sensing via photometry and low-resolution spectroscopy. Although not a review in any sense, this paper highlights the limitations in our knowledge of compositions, thermal profiles, and the effects of stellar irradiation, focusing on, but not restricted to, transiting giant planets. I suggest that the true function of the recent past of exoplanet atmospheric research has been not to constrain planet properties for all time, but to train a new generation of scientists who, by rapid trial and error, are fast establishing a solid future foundation for a robust science of exoplanets. planetary science | characterization The study of exoplanets has increased expo- by no means commensurate with the effort exoplanetology, and this expectation is in part nentially since 1995, a trend that in the short expended. true. The solar system has been a great, per- term shows no signs of abating. Astronomers An important aspect of exoplanets that haps necessary, teacher. -
A Review on Substellar Objects Below the Deuterium Burning Mass Limit: Planets, Brown Dwarfs Or What?
geosciences Review A Review on Substellar Objects below the Deuterium Burning Mass Limit: Planets, Brown Dwarfs or What? José A. Caballero Centro de Astrobiología (CSIC-INTA), ESAC, Camino Bajo del Castillo s/n, E-28692 Villanueva de la Cañada, Madrid, Spain; [email protected] Received: 23 August 2018; Accepted: 10 September 2018; Published: 28 September 2018 Abstract: “Free-floating, non-deuterium-burning, substellar objects” are isolated bodies of a few Jupiter masses found in very young open clusters and associations, nearby young moving groups, and in the immediate vicinity of the Sun. They are neither brown dwarfs nor planets. In this paper, their nomenclature, history of discovery, sites of detection, formation mechanisms, and future directions of research are reviewed. Most free-floating, non-deuterium-burning, substellar objects share the same formation mechanism as low-mass stars and brown dwarfs, but there are still a few caveats, such as the value of the opacity mass limit, the minimum mass at which an isolated body can form via turbulent fragmentation from a cloud. The least massive free-floating substellar objects found to date have masses of about 0.004 Msol, but current and future surveys should aim at breaking this record. For that, we may need LSST, Euclid and WFIRST. Keywords: planetary systems; stars: brown dwarfs; stars: low mass; galaxy: solar neighborhood; galaxy: open clusters and associations 1. Introduction I can’t answer why (I’m not a gangstar) But I can tell you how (I’m not a flam star) We were born upside-down (I’m a star’s star) Born the wrong way ’round (I’m not a white star) I’m a blackstar, I’m not a gangstar I’m a blackstar, I’m a blackstar I’m not a pornstar, I’m not a wandering star I’m a blackstar, I’m a blackstar Blackstar, F (2016), David Bowie The tenth star of George van Biesbroeck’s catalogue of high, common, proper motion companions, vB 10, was from the end of the Second World War to the early 1980s, and had an entry on the least massive star known [1–3]. -
Precise Radial Velocities of Giant Stars
A&A 555, A87 (2013) Astronomy DOI: 10.1051/0004-6361/201321714 & c ESO 2013 Astrophysics Precise radial velocities of giant stars V. A brown dwarf and a planet orbiting the K giant stars τ Geminorum and 91 Aquarii, David S. Mitchell1,2,SabineReffert1, Trifon Trifonov1, Andreas Quirrenbach1, and Debra A. Fischer3 1 Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany 2 Physics Department, California Polytechnic State University, San Luis Obispo, CA 93407, USA e-mail: [email protected] 3 Department of Astronomy, Yale University, New Haven, CT 06511, USA Received 16 April 2013 / Accepted 22 May 2013 ABSTRACT Aims. We aim to detect and characterize substellar companions to K giant stars to further our knowledge of planet formation and stellar evolution of intermediate-mass stars. Methods. For more than a decade we have used Doppler spectroscopy to acquire high-precision radial velocity measurements of K giant stars. All data for this survey were taken at Lick Observatory. Our survey includes 373 G and K giants. Radial velocity data showing periodic variations were fitted with Keplerian orbits using a χ2 minimization technique. Results. We report the presence of two substellar companions to the K giant stars τ Gem and 91 Aqr. The brown dwarf orbiting τ Gem has an orbital period of 305.5±0.1 days, a minimum mass of 20.6 MJ, and an eccentricity of 0.031±0.009. The planet orbiting 91 Aqr has an orbital period of 181.4 ± 0.1 days, a minimum mass of 3.2 MJ, and an eccentricity of 0.027 ± 0.026. -
A Warm Terrestrial Planet with Half the Mass of Venus Transiting a Nearby Star∗
Astronomy & Astrophysics manuscript no. toi175 c ESO 2021 July 13, 2021 A warm terrestrial planet with half the mass of Venus transiting a nearby star∗ y Olivier D. S. Demangeon1; 2 , M. R. Zapatero Osorio10, Y. Alibert6, S. C. C. Barros1; 2, V. Adibekyan1; 2, H. M. Tabernero10; 1, A. Antoniadis-Karnavas1; 2, J. D. Camacho1; 2, A. Suárez Mascareño7; 8, M. Oshagh7; 8, G. Micela15, S. G. Sousa1, C. Lovis5, F. A. Pepe5, R. Rebolo7; 8; 9, S. Cristiani11, N. C. Santos1; 2, R. Allart19; 5, C. Allende Prieto7; 8, D. Bossini1, F. Bouchy5, A. Cabral3; 4, M. Damasso12, P. Di Marcantonio11, V. D’Odorico11; 16, D. Ehrenreich5, J. Faria1; 2, P. Figueira17; 1, R. Génova Santos7; 8, J. Haldemann6, N. Hara5, J. I. González Hernández7; 8, B. Lavie5, J. Lillo-Box10, G. Lo Curto18, C. J. A. P. Martins1, D. Mégevand5, A. Mehner17, P. Molaro11; 16, N. J. Nunes3, E. Pallé7; 8, L. Pasquini18, E. Poretti13; 14, A. Sozzetti12, and S. Udry5 1 Instituto de Astrofísica e Ciências do Espaço, CAUP, Universidade do Porto, Rua das Estrelas, 4150-762, Porto, Portugal 2 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Rua Campo Alegre, 4169-007, Porto, Portugal 3 Instituto de Astrofísica e Ciências do Espaço, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, PT1749-016 Lisboa, Portugal 4 Departamento de Física da Faculdade de Ciências da Universidade de Lisboa, Edifício C8, 1749-016 Lisboa, Portugal 5 Observatoire de Genève, Université de Genève, Chemin Pegasi, 51, 1290 Sauverny, Switzerland 6 Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland 7 Instituto de Astrofísica de Canarias (IAC), Calle Vía Láctea s/n, E-38205 La Laguna, Tenerife, Spain 8 Departamento de Astrofísica, Universidad de La Laguna (ULL), E-38206 La Laguna, Tenerife, Spain 9 Consejo Superior de Investigaciones Cientícas, Spain 10 Centro de Astrobiología (CSIC-INTA), Crta. -
The Birth and Evolution of Brown Dwarfs
The Birth and Evolution of Brown Dwarfs Tutorial for the CSPF, or should it be CSSF (Center for Stellar and Substellar Formation)? Eduardo L. Martin, IfA Outline • Basic definitions • Scenarios of Brown Dwarf Formation • Brown Dwarfs in Star Formation Regions • Brown Dwarfs around Stars and Brown Dwarfs • Final Remarks KumarKumar 1963; 1963; D’Antona D’Antona & & Mazzitelli Mazzitelli 1995; 1995; Stevenson Stevenson 1991, 1991, Chabrier Chabrier & & Baraffe Baraffe 2000 2000 Mass • A brown dwarf is defined primarily by its mass, irrespective of how it forms. • The low-mass limit of a star, and the high-mass limit of a brown dwarf, correspond to the minimum mass for stable Hydrogen burning. • The HBMM depends on chemical composition and rotation. For solar abundances and no rotation the HBMM=0.075MSun=79MJupiter. • The lower limit of a brown dwarf mass could be at the DBMM=0.012MSun=13MJupiter. SaumonSaumon et et al. al. 1996 1996 Central Temperature • The central temperature of brown dwarfs ceases to increase when electron degeneracy becomes dominant. Further contraction induces cooling rather than heating. • The LiBMM is at 0.06MSun • Brown dwarfs can have unstable nuclear reactions. Radius • The radii of brown dwarfs is dominated by the EOS (classical ionic Coulomb pressure + partial degeneracy of e-). • The mass-radius relationship is smooth -1/8 R=R0m . • Brown dwarfs and planets have similar sizes. Thermal Properties • Arrows indicate H2 formation near the atmosphere. Molecular recombination favors convective instability. • Brown dwarfs are ultracool, fully convective, objects. • The temperatures of brown dwarfs can overlap with those of stars and planets. Density • Brown dwarfs and planets (substellar-mass objects) become denser and cooler with time, when degeneracy dominates. -
Exploring the Realm of Scaled Solar System Analogues with HARPS?,?? D
A&A 615, A175 (2018) Astronomy https://doi.org/10.1051/0004-6361/201832711 & c ESO 2018 Astrophysics Exploring the realm of scaled solar system analogues with HARPS?;?? D. Barbato1,2, A. Sozzetti2, S. Desidera3, M. Damasso2, A. S. Bonomo2, P. Giacobbe2, L. S. Colombo4, C. Lazzoni4,3 , R. Claudi3, R. Gratton3, G. LoCurto5, F. Marzari4, and C. Mordasini6 1 Dipartimento di Fisica, Università degli Studi di Torino, via Pietro Giuria 1, 10125, Torino, Italy e-mail: [email protected] 2 INAF – Osservatorio Astrofisico di Torino, Via Osservatorio 20, 10025, Pino Torinese, Italy 3 INAF – Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, 35122, Padova, Italy 4 Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Vicolo dell’Osservatorio 3, 35122, Padova, Italy 5 European Southern Observatory, Alonso de Córdova 3107, Vitacura, Santiago, Chile 6 Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland Received 8 February 2018 / Accepted 21 April 2018 ABSTRACT Context. The assessment of the frequency of planetary systems reproducing the solar system’s architecture is still an open problem in exoplanetary science. Detailed study of multiplicity and architecture is generally hampered by limitations in quality, temporal extension and observing strategy, causing difficulties in detecting low-mass inner planets in the presence of outer giant planets. Aims. We present the results of high-cadence and high-precision HARPS observations on 20 solar-type stars known to host a single long-period giant planet in order to search for additional inner companions and estimate the occurence rate fp of scaled solar system analogues – in other words, systems featuring lower-mass inner planets in the presence of long-period giant planets. -
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