On the Detection of Extrasolar Moons and Rings
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Exomoon Habitability Constrained by Illumination and Tidal Heating
submitted to Astrobiology: April 6, 2012 accepted by Astrobiology: September 8, 2012 published in Astrobiology: January 24, 2013 this updated draft: October 30, 2013 doi:10.1089/ast.2012.0859 Exomoon habitability constrained by illumination and tidal heating René HellerI , Rory BarnesII,III I Leibniz-Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany, [email protected] II Astronomy Department, University of Washington, Box 951580, Seattle, WA 98195, [email protected] III NASA Astrobiology Institute – Virtual Planetary Laboratory Lead Team, USA Abstract The detection of moons orbiting extrasolar planets (“exomoons”) has now become feasible. Once they are discovered in the circumstellar habitable zone, questions about their habitability will emerge. Exomoons are likely to be tidally locked to their planet and hence experience days much shorter than their orbital period around the star and have seasons, all of which works in favor of habitability. These satellites can receive more illumination per area than their host planets, as the planet reflects stellar light and emits thermal photons. On the contrary, eclipses can significantly alter local climates on exomoons by reducing stellar illumination. In addition to radiative heating, tidal heating can be very large on exomoons, possibly even large enough for sterilization. We identify combinations of physical and orbital parameters for which radiative and tidal heating are strong enough to trigger a runaway greenhouse. By analogy with the circumstellar habitable zone, these constraints define a circumplanetary “habitable edge”. We apply our model to hypothetical moons around the recently discovered exoplanet Kepler-22b and the giant planet candidate KOI211.01 and describe, for the first time, the orbits of habitable exomoons. -
The Subsurface Habitability of Small, Icy Exomoons J
A&A 636, A50 (2020) Astronomy https://doi.org/10.1051/0004-6361/201937035 & © ESO 2020 Astrophysics The subsurface habitability of small, icy exomoons J. N. K. Y. Tjoa1,?, M. Mueller1,2,3, and F. F. S. van der Tak1,2 1 Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands e-mail: [email protected] 2 SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen, The Netherlands 3 Leiden Observatory, Leiden University, Niels Bohrweg 2, 2300 RA Leiden, The Netherlands Received 1 November 2019 / Accepted 8 March 2020 ABSTRACT Context. Assuming our Solar System as typical, exomoons may outnumber exoplanets. If their habitability fraction is similar, they would thus constitute the largest portion of habitable real estate in the Universe. Icy moons in our Solar System, such as Europa and Enceladus, have already been shown to possess liquid water, a prerequisite for life on Earth. Aims. We intend to investigate under what thermal and orbital circumstances small, icy moons may sustain subsurface oceans and thus be “subsurface habitable”. We pay specific attention to tidal heating, which may keep a moon liquid far beyond the conservative habitable zone. Methods. We made use of a phenomenological approach to tidal heating. We computed the orbit averaged flux from both stellar and planetary (both thermal and reflected stellar) illumination. We then calculated subsurface temperatures depending on illumination and thermal conduction to the surface through the ice shell and an insulating layer of regolith. We adopted a conduction only model, ignoring volcanism and ice shell convection as an outlet for internal heat. -
Arxiv:2009.06280V1 [Astro-Ph.EP] 14 Sep 2020
Astronomy & Astrophysics manuscript no. vis_hd20_hd18 c ESO 2020 September 15, 2020 Discriminating between hazy and clear hot-Jupiter atmospheres with CARMENES A. Sánchez-López1, M. López-Puertas2, I. A. G. Snellen1, E. Nagel3, F. F. Bauer2, E. Pallé4; 5, L. Tal-Or6; 9, P. J. Amado2, J. A. Caballero7, S. Czesla8, L. Nortmann9, A. Reiners9, I. Ribas10; 11, A. Quirrenbach12, J. Aceituno13, V. J. S. Béjar4; 5, N. Casasayas-Barris4; 5, Th. Henning14, K. Molaverdikhani14, D. Montes15, M. Stangret4; 5, M. R. Zapatero Osorio16, and M. Zechmeister9 1 Leiden Observatory, Leiden University, Postbus 9513, 2300 RA, Leiden, The Netherlands e-mail: [email protected] 2 Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain 3 Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany 4 Instituto de Astrofísica de Canarias (IAC), Calle Vía Láctea s/n, 38200 La Laguna, Tenerife, Spain 5 Departamento de Astrofísica, Universidad de La Laguna, 38026 La Laguna, Tenerife, Spain 6 Department of Physics, Ariel University, Ariel 40700, Israel 7 Centro de Astrobiología (CSIC-INTA), ESAC, Camino bajo del castillo s/n, 28692 Villanueva de la Cañada, Madrid, Spain 8 Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, 21029 Hamburg, Germany 9 Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany 10 Institut de Ciències de l’Espai (CSIC-IEEC), Campus UAB, c/ de Can Magrans s/n, 08193 Bellaterra, Barcelona, Spain 11 Institut d’Estudis Espacials -
Evidence of Energy-, Recombination-, and Photon-Limited Escape Regimes in Giant Planet H/He Atmospheres M
A&A 648, L7 (2021) Astronomy https://doi.org/10.1051/0004-6361/202140423 & c ESO 2021 Astrophysics LETTER TO THE EDITOR Evidence of energy-, recombination-, and photon-limited escape regimes in giant planet H/He atmospheres M. Lampón1, M. López-Puertas1, S. Czesla2, A. Sánchez-López3, L. M. Lara1, M. Salz2, J. Sanz-Forcada4, K. Molaverdikhani5,6, A. Quirrenbach6, E. Pallé7,8, J. A. Caballero4, Th. Henning5, L. Nortmann9, P. J. Amado1, D. Montes10, A. Reiners9, and I. Ribas11,12 1 Instituto de Astrofísica de Andalucía (IAA-CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain e-mail: [email protected] 2 Hamburger Sternwarte, Universität Hamburg,Gojenbergsweg 112, 21029 Hamburg, Germany 3 Leiden Observatory, Leiden University, Postbus 9513, 2300 RA Leiden, The Netherlands 4 Centro de Astrobiología (CSIC-INTA), ESAC, Camino bajo del castillo s/n, 28692, Villanueva de la Cañada Madrid, Spain 5 Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany 6 Landessternwarte, Zentrum für Astronomie der Universität Heidelberg, Königstuhl 12, 69117 Heidelberg, Germany 7 Instituto de Astrofísica de Canarias (IAC), Calle Vía Láctea s/n, 38200, La Laguna Tenerife, Spain 8 Departamento de Astrofísica, Universidad de La Laguna, 38026, La Laguna Tenerife, Spain 9 Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany 10 Departamento de Física de la Tierra y Astrofísica & IPARCOS-UCM (Instituto de Física de Partículas y del Cosmos de la UCM), Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid, Spain 11 Institut de Ciències de l’Espai (CSIC-IEEC), Campus UAB, c/ de Can Magrans s/n, 08193 Bellaterra, Barcelona, Spain 12 Institut d’Estudis Espacials de Catalunya (IEEC), 08034 Barcelona, Spain Received 26 January 2021 / Accepted 19 March 2021 ABSTRACT Hydrodynamic escape is the most efficient atmospheric mechanism of planetary mass loss and has a large impact on planetary evolution. -
Abstracts of the 50Th DDA Meeting (Boulder, CO)
Abstracts of the 50th DDA Meeting (Boulder, CO) American Astronomical Society June, 2019 100 — Dynamics on Asteroids break-up event around a Lagrange point. 100.01 — Simulations of a Synthetic Eurybates 100.02 — High-Fidelity Testing of Binary Asteroid Collisional Family Formation with Applications to 1999 KW4 Timothy Holt1; David Nesvorny2; Jonathan Horner1; Alex B. Davis1; Daniel Scheeres1 Rachel King1; Brad Carter1; Leigh Brookshaw1 1 Aerospace Engineering Sciences, University of Colorado Boulder 1 Centre for Astrophysics, University of Southern Queensland (Boulder, Colorado, United States) (Longmont, Colorado, United States) 2 Southwest Research Institute (Boulder, Connecticut, United The commonly accepted formation process for asym- States) metric binary asteroids is the spin up and eventual fission of rubble pile asteroids as proposed by Walsh, Of the six recognized collisional families in the Jo- Richardson and Michel (Walsh et al., Nature 2008) vian Trojan swarms, the Eurybates family is the and Scheeres (Scheeres, Icarus 2007). In this theory largest, with over 200 recognized members. Located a rubble pile asteroid is spun up by YORP until it around the Jovian L4 Lagrange point, librations of reaches a critical spin rate and experiences a mass the members make this family an interesting study shedding event forming a close, low-eccentricity in orbital dynamics. The Jovian Trojans are thought satellite. Further work by Jacobson and Scheeres to have been captured during an early period of in- used a planar, two-ellipsoid model to analyze the stability in the Solar system. The parent body of the evolutionary pathways of such a formation event family, 3548 Eurybates is one of the targets for the from the moment the bodies initially fission (Jacob- LUCY spacecraft, and our work will provide a dy- son and Scheeres, Icarus 2011). -
Simon Porter , Will Grundy
Post-Capture Evolution of Potentially Habitable Exomoons Simon Porter1,2, Will Grundy1 1Lowell Observatory, Flagstaff, Arizona 2School of Earth and Space Exploration, Arizona State University [email protected] and spin vector were initially pointed at random di- Table 1: Relative fraction of end states for fully Abstract !"# $%& " '(" !"# $%& # '(# rections on the sky. The exoplanets had a ran- evolved exomoon systems dom obliquity < 5 deg and was at a stellarcentric The satellites of extrasolar planets (exomoons) Star Planet Moon Survived Retrograde Separated Impacted distance such that the equilibrium temperature was have been recently proposed as astrobiological tar- Earth 43% 52% 21% 35% equal to Earth. The simulations were run until they Jupiter Mars 44% 45% 18% 37% gets. Triton has been proposed to have been cap- 5 either reached an eccentricity below 10 or the pe- Titan 42% 47% 21% 36% tured through a momentum-exchange reaction [1], − Sun Earth 52% 44% 17% 30% riapse went below the Roche limit (impact) or the and it is possible that a similar event could allow Neptune Mars 44% 45% 18% 36% apoapse exceeded the Hill radius. Stars used were Titan 45% 47% 19% 35% a giant planet to capture a formerly binary terres- Earth 65% 47% 3% 31% the Sun (G2), a main-sequence F0 (1.7 MSun), trial planet or planetesimal. We therefore attempt to Jupiter Mars 59% 46% 4% 35% and a main-sequence M0 (0.47 MSun). Exoplan- Titan 61% 48% 3% 34% model the dynamical evolution of a terrestrial planet !"# $%& " !"# $%& " ' F0 ets used had the mass of either Jupiter or Neptune, Earth 77% 44% 4% 18% captured into orbit around a giant planet in the hab- and exomoons with the mass of Earth, Mars, and Neptune Mars 67% 44% 4% 28% itable zone of a star. -
Gravitational Microlensing by Exoplanets and Exomoons
INTERNATIONAL SPACE SCIENCE INSTITUTE SPATIUM Published by the Association Pro ISSI No. 45, May 2020 Gravitational Microlensing by Exoplanets and Exomoons 200216_Spatium_45_2020_(001_016).indd 1 16.05.20 11:11 Editorial Since Copernicus (1473–1543) was world view abruptly. They seemed not able to measure brightness not to be inhabited as previously Impressum variations of the stars due to Earth’s assumed, and life appeared not to revolutionary motion around the be a matter of course. Astrophys- Sun, he inferred that stars must be ics and interdisciplinary science ISSN 2297–5888 (Print) very far away from Earth. During recognised the very special condi- ISSN 2297–590X (Online) the 16th and 17th Centuries schol- tions required to create life. More- ars began gradually to realise that over, these conditions need to be Spatium the Universe, i.e., the sphere of very selective and restricting, de- Published by the fixed stars enclosing our Solar pending not only on physical and Association Pro ISSI System, might not be finite but chemical parameters but particu- infinite. Philosophical arguments larly on stable and stabilising hab- by Thomas Digges (1546–1595) or itable environments in space and Giordano Bruno (1548–1600) sup- on ground. ported this view. Galileo (1564– Today, the existence of extra-ter- Association Pro ISSI 1642) provided evidence from ob- restrial life seems to be quite likely Hallerstrasse 6, CH-3012 Bern servations of the Milky Way using for statistical reasons. However, it Phone +41 (0)31 631 48 96 his telescope. is very hard to find evidence from see In his Cosmotheoros posthumously bio-markers identified in exoplan- www.issibern.ch/pro-issi.html published in 1698, Christiaan Huy- etary spectra as long as it is not clear for the whole Spatium series gens (1629–1695) estimated the dis- what life actually is. -
Atmospheric Mass Loss of Extrasolar Planets Orbiting Magnetically Active
MNRAS 000, 1–?? (2017) Preprint 8 August 2018 Compiled using MNRAS LATEX style file v3.0 Atmospheric mass loss of extrasolar planets orbiting magnetically active host stars Lalitha Sairam,1⋆ J. H. M. M. Schmitt,2 and Spandan Dash3 1Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034, India 2Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg 3Indian Institute of Science, C.V Raman Avenue, Yeshwantpur, Bangalore 560 012, India Accepted XXX. Received YYY; in original form ZZZ ABSTRACT Magnetic stellar activity of exoplanet hosts can lead to the production of large amounts of high-energy emission, which irradiates extrasolar planets, located in the immediate vicinity of such stars. This radiation is absorbed in the planets’ upper atmospheres, which consequently heat up and evaporate, possibly leading to an irradiation-induced mass-loss. We present a study of the high-energy emission in the four magnetically ac- tive planet-bearing host stars Kepler-63, Kepler-210, WASP-19, and HAT-P-11, based on new XMM-Newton observations. We find that the X-ray luminosities of these stars are rather high with orders of magnitude above the level of the active Sun. The total XUV irradiation of these planets is expected to be stronger than that of well stud- ied hot Jupiters. Using the estimated XUV luminosities as the energy input to the planetary atmospheres, we obtain upper limits for the total mass loss in these hot Jupiters. Key words: stars: activity – stars: coronae – stars: low-mass, late-type, planetary systems – stars: individual: Kepler-63, Kepler-210, WASP-19, HAT-P-11 1 INTRODUCTION through Jeans escape, the observations of atmospheric mass loss in HD 209458 b (Vidal-Madjar et al. -
The Nature of the Giant Exomoon Candidate Kepler-1625 B-I René Heller
A&A 610, A39 (2018) https://doi.org/10.1051/0004-6361/201731760 Astronomy & © ESO 2018 Astrophysics The nature of the giant exomoon candidate Kepler-1625 b-i René Heller Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany e-mail: [email protected] Received 11 August 2017 / Accepted 21 November 2017 ABSTRACT The recent announcement of a Neptune-sized exomoon candidate around the transiting Jupiter-sized object Kepler-1625 b could indi- cate the presence of a hitherto unknown kind of gas giant moon, if confirmed. Three transits of Kepler-1625 b have been observed, allowing estimates of the radii of both objects. Mass estimates, however, have not been backed up by radial velocity measurements of the host star. Here we investigate possible mass regimes of the transiting system that could produce the observed signatures and study them in the context of moon formation in the solar system, i.e., via impacts, capture, or in-situ accretion. The radius of Kepler-1625 b suggests it could be anything from a gas giant planet somewhat more massive than Saturn (0:4 MJup) to a brown dwarf (BD; up to 75 MJup) or even a very-low-mass star (VLMS; 112 MJup ≈ 0:11 M ). The proposed companion would certainly have a planetary mass. Possible extreme scenarios range from a highly inflated Earth-mass gas satellite to an atmosphere-free water–rock companion of about +19:2 180 M⊕. Furthermore, the planet–moon dynamics during the transits suggest a total system mass of 17:6−12:6 MJup. -
On the Detection of Exomoons in Photometric Time Series
On the Detection of Exomoons in Photometric Time Series Dissertation zur Erlangung des mathematisch-naturwissenschaftlichen Doktorgrades “Doctor rerum naturalium” der Georg-August-Universität Göttingen im Promotionsprogramm PROPHYS der Georg-August University School of Science (GAUSS) vorgelegt von Kai Oliver Rodenbeck aus Göttingen, Deutschland Göttingen, 2019 Betreuungsausschuss Prof. Dr. Laurent Gizon Max-Planck-Institut für Sonnensystemforschung, Göttingen, Deutschland und Institut für Astrophysik, Georg-August-Universität, Göttingen, Deutschland Prof. Dr. Stefan Dreizler Institut für Astrophysik, Georg-August-Universität, Göttingen, Deutschland Dr. Warrick H. Ball School of Physics and Astronomy, University of Birmingham, UK vormals Institut für Astrophysik, Georg-August-Universität, Göttingen, Deutschland Mitglieder der Prüfungskommision Referent: Prof. Dr. Laurent Gizon Max-Planck-Institut für Sonnensystemforschung, Göttingen, Deutschland und Institut für Astrophysik, Georg-August-Universität, Göttingen, Deutschland Korreferent: Prof. Dr. Stefan Dreizler Institut für Astrophysik, Georg-August-Universität, Göttingen, Deutschland Weitere Mitglieder der Prüfungskommission: Prof. Dr. Ulrich Christensen Max-Planck-Institut für Sonnensystemforschung, Göttingen, Deutschland Dr.ir. Saskia Hekker Max-Planck-Institut für Sonnensystemforschung, Göttingen, Deutschland Dr. René Heller Max-Planck-Institut für Sonnensystemforschung, Göttingen, Deutschland Prof. Dr. Wolfram Kollatschny Institut für Astrophysik, Georg-August-Universität, Göttingen, -
THE SEARCH for EXOMOON RADIO EMISSIONS by JOAQUIN P. NOYOLA Presented to the Faculty of the Graduate School of the University Of
THE SEARCH FOR EXOMOON RADIO EMISSIONS by JOAQUIN P. NOYOLA Presented to the Faculty of the Graduate School of The University of Texas at Arlington in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY THE UNIVERSITY OF TEXAS AT ARLINGTON December 2015 Copyright © by Joaquin P. Noyola 2015 All Rights Reserved ii Dedicated to my wife Thao Noyola, my son Layton, my daughter Allison, and our future little ones. iii Acknowledgements I would like to express my sincere gratitude to all the people who have helped throughout my career at UTA, including my advising professors Dr. Zdzislaw Musielak (Ph.D.), and Dr. Qiming Zhang (M.Sc.) for their advice and guidance. Many thanks to my committee members Dr. Andrew Brandt, Dr. Manfred Cuntz, and Dr. Alex Weiss for your interest and for your time. Also many thanks to Dr. Suman Satyal, my collaborator and friend, for all the fruitful discussions we have had throughout the years. I would like to thank my wife, Thao Noyola, for her love, her help, and her understanding through these six years of marriage and graduate school. October 19, 2015 iv Abstract THE SEARCH FOR EXOMOON RADIO EMISSIONS Joaquin P. Noyola, PhD The University of Texas at Arlington, 2015 Supervising Professor: Zdzislaw Musielak The field of exoplanet detection has seen many new developments since the discovery of the first exoplanet. Observational surveys by the NASA Kepler Mission and several other instrument have led to the confirmation of over 1900 exoplanets, and several thousands of exoplanet potential candidates. All this progress, however, has yet to provide the first confirmed exomoon. -
Characterizing Habitable Exo-Moons
Characterizing Habitable Exo-Moons L. Kaltenegger Harvard University, 60 Garden Street, 02138 MA, Cambridge USA Email: [email protected] Abstract We discuss the possibility of screening the atmosphere of exomoons for habitability. We concentrate on Earth-like satellites of extrasolar giant planets (EGP) which orbit in the Habitable Zone (HZ) of their host stars. The detectability of exomoons for EGP in the HZ has recently been shown to be feasible with the Kepler Mission or equivalent photometry using transit duration observations. Transmission spectroscopy of exomoons is a unique potential tool to screen them for habitability in the near future, especially around low mass stars. Using the Earth itself as a proxy we show the potential and limits of spectroscopy to detect biomarkers on an Earth-like exomoon and discuss effects of tidal locking for such potential habitats. Subject key words: occultation, Earth, astrobiology, eclipse, atmospheric effects, techniques: spectroscopic INTRODUCTION the question of whether we could screen Transiting planets are present-day "Rosetta such Earth-mass exomoons remotely for Stones" for understanding extrasolar planets habitability. because they offer the possibility of If the viewing geometry is optimal, i.e. the characterizing giant planet atmospheres (see. exomoon is close to the projected maximum e.g. Tinetti et al. 2007, Swain et al. 2008) and separation, the transit of an exomoon is should provide an access to biomarkers in the comparable to the transit of a planet the atmospheres of Earth-like bodies (Kaltenegger same size around the star (Kaltenegger & & Traub 2009, Deming et al. 2009, Ehrenreich Traub 2009), if the projected semimajor axis et al.