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RADIAL VELOCITIES in the ZODIACAL DUST CLOUD
A SURVEY OF RADIAL VELOCITIES in the ZODIACAL DUST CLOUD Brian Harold May Astrophysics Group Department of Physics Imperial College London Thesis submitted for the Degree of Doctor of Philosophy to Imperial College of Science, Technology and Medicine London · 2007 · 2 Abstract This thesis documents the building of a pressure-scanned Fabry-Perot Spectrometer, equipped with a photomultiplier and pulse-counting electronics, and its deployment at the Observatorio del Teide at Izaña in Tenerife, at an altitude of 7,700 feet (2567 m), for the purpose of recording high-resolution spectra of the Zodiacal Light. The aim was to achieve the first systematic mapping of the MgI absorption line in the Night Sky, as a function of position in heliocentric coordinates, covering especially the plane of the ecliptic, for a wide variety of elongations from the Sun. More than 250 scans of both morning and evening Zodiacal Light were obtained, in two observing periods – September-October 1971, and April 1972. The scans, as expected, showed profiles modified by components variously Doppler-shifted with respect to the unshifted shape seen in daylight. Unexpectedly, MgI emission was also discovered. These observations covered for the first time a span of elongations from 25º East, through 180º (the Gegenschein), to 27º West, and recorded average shifts of up to six tenths of an angstrom, corresponding to a maximum radial velocity relative to the Earth of about 40 km/s. The set of spectra obtained is in this thesis compared with predictions made from a number of different models of a dust cloud, assuming various distributions of dust density as a function of position and particle size, and differing assumptions about their speed and direction. -
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. -
Cosmological Aspects of Planetary Habitability
Cosmological aspects of planetary habitability Yu. A. Shchekinov Department of Space Physics, SFU, Rostov on Don, Russia [email protected] M. Safonova, J. Murthy Indian Institute of Astrophysics, Bangalore, India [email protected], [email protected] ABSTRACT The habitable zone (HZ) is defined as the region around a star where a planet can support liquid water on its surface, which, together with an oxygen atmo- sphere, is presumed to be necessary (and sufficient) to develop and sustain life on the planet. Currently, about twenty potentially habitable planets are listed. The most intriguing question driving all these studies is whether planets within habitable zones host extraterrestrial life. It is implicitly assumed that a planet in the habitable zone bears biota. How- ever along with the two usual indicators of habitability, an oxygen atmosphere and liquid water on the surface, an additional one – the age — has to be taken into account when the question of the existence of life (or even a simple biota) on a planet is addressed. The importance of planetary age for the existence of life as we know it follows from the fact that the primary process, the photosynthesis, is endothermic with an activation energy higher than temperatures in habitable zones. Therefore on planets in habitable zones, due to variations in their albedo, orbits, diameters and other crucial parameters, the onset of photosynthesis may arXiv:1404.0641v1 [astro-ph.EP] 2 Apr 2014 take much longer time than the planetary age. Recently, several exoplanets orbiting Population II stars with ages of 12–13 Gyr were discovered. -
Geodynamics and Rate of Volcanism on Massive Earth-Like Planets
The Astrophysical Journal, 700:1732–1749, 2009 August 1 doi:10.1088/0004-637X/700/2/1732 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A. GEODYNAMICS AND RATE OF VOLCANISM ON MASSIVE EARTH-LIKE PLANETS E. S. Kite1,3, M. Manga1,3, and E. Gaidos2 1 Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA 94720, USA; [email protected] 2 Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI 96822, USA Received 2008 September 12; accepted 2009 May 29; published 2009 July 16 ABSTRACT We provide estimates of volcanism versus time for planets with Earth-like composition and masses 0.25–25 M⊕, as a step toward predicting atmospheric mass on extrasolar rocky planets. Volcanism requires melting of the silicate mantle. We use a thermal evolution model, calibrated against Earth, in combination with standard melting models, to explore the dependence of convection-driven decompression mantle melting on planet mass. We show that (1) volcanism is likely to proceed on massive planets with plate tectonics over the main-sequence lifetime of the parent star; (2) crustal thickness (and melting rate normalized to planet mass) is weakly dependent on planet mass; (3) stagnant lid planets live fast (they have higher rates of melting than their plate tectonic counterparts early in their thermal evolution), but die young (melting shuts down after a few Gyr); (4) plate tectonics may not operate on high-mass planets because of the production of buoyant crust which is difficult to subduct; and (5) melting is necessary but insufficient for efficient volcanic degassing—volatiles partition into the earliest, deepest melts, which may be denser than the residue and sink to the base of the mantle on young, massive planets. -
Correlations Between the Stellar, Planetary, and Debris Components of Exoplanet Systems Observed by Herschel⋆
A&A 565, A15 (2014) Astronomy DOI: 10.1051/0004-6361/201323058 & c ESO 2014 Astrophysics Correlations between the stellar, planetary, and debris components of exoplanet systems observed by Herschel J. P. Marshall1,2, A. Moro-Martín3,4, C. Eiroa1, G. Kennedy5,A.Mora6, B. Sibthorpe7, J.-F. Lestrade8, J. Maldonado1,9, J. Sanz-Forcada10,M.C.Wyatt5,B.Matthews11,12,J.Horner2,13,14, B. Montesinos10,G.Bryden15, C. del Burgo16,J.S.Greaves17,R.J.Ivison18,19, G. Meeus1, G. Olofsson20, G. L. Pilbratt21, and G. J. White22,23 (Affiliations can be found after the references) Received 15 November 2013 / Accepted 6 March 2014 ABSTRACT Context. Stars form surrounded by gas- and dust-rich protoplanetary discs. Generally, these discs dissipate over a few (3–10) Myr, leaving a faint tenuous debris disc composed of second-generation dust produced by the attrition of larger bodies formed in the protoplanetary disc. Giant planets detected in radial velocity and transit surveys of main-sequence stars also form within the protoplanetary disc, whilst super-Earths now detectable may form once the gas has dissipated. Our own solar system, with its eight planets and two debris belts, is a prime example of an end state of this process. Aims. The Herschel DEBRIS, DUNES, and GT programmes observed 37 exoplanet host stars within 25 pc at 70, 100, and 160 μm with the sensitiv- ity to detect far-infrared excess emission at flux density levels only an order of magnitude greater than that of the solar system’s Edgeworth-Kuiper belt. Here we present an analysis of that sample, using it to more accurately determine the (possible) level of dust emission from these exoplanet host stars and thereafter determine the links between the various components of these exoplanetary systems through statistical analysis. -
1 Director's Message
1 Director’s Message Markus Kissler-Patig 3 Weighing the Black Hole in M101 ULX-1 Stephen Justham and Jifeng Liu 8 World’s Most Powerful Planet Finder Turns its Eye to the Sky: First Light with the Gemini Planet Imager Bruce Macintosh and Peter Michaud 12 Science Highlights Nancy A. Levenson 15 Operations Corner: Update and 2013 Review Andy Adamson 20 Instrumentation Development: Update and 2013 Review Scot Kleinman ON THE COVER: GeminiFocus January 2014 The cover of this issue GeminiFocus is a quarterly publication of Gemini Observatory features first light images from the Gemini 670 N. A‘ohoku Place, Hilo, Hawai‘i 96720 USA Planet Imager that Phone: (808) 974-2500 Fax: (808) 974-2589 were released at the Online viewing address: January 2014 meeting www.gemini.edu/geminifocus of the American Managing Editor: Peter Michaud Astronomical Society Science Editor: Nancy A. Levenson held in Washington, D.C. Associate Editor: Stephen James O’Meara See the press release Designer: Eve Furchgott / Blue Heron Multimedia that accompanied the images starting on Any opinions, findings, and conclusions or recommendations page 8 of this issue. expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Markus Kissler-Patig Director’s Message 2013: A Successful Year for Gemini! As 2013 comes to an end, we can look back at 12 very successful months for Gemini despite strong budget constraints. Indeed, 2013 was the first stage of our three-year transition to a reduced opera- tions budget, and it was marked by a roughly 20 percent cut in contributions from Gemini’s partner countries. -
Disks in Nearby Planetary Systems with JWST and ALMA
Disks in Nearby Planetary Systems with JWST and ALMA Meredith A. MacGregor NSF Postdoctoral Fellow Carnegie Department of Terrestrial Magnetism 233rd AAS Meeting ExoPAG 19 January 6, 2019 MacGregor Circumstellar Disk Evolution molecular cloud 0 Myr main sequence star + planets (?) + debris disk (?) Star Formation > 10 Myr pre-main sequence star + protoplanetary disk Planet Formation 1-10 Myr MacGregor Debris Disks: Observables First extrasolar debris disk detected as “excess” infrared emission by IRAS (Aumann et al. 1984) SPHERE/VLT Herschel ALMA VLA Boccaletti et al (2015), Matthews et al. (2015), MacGregor et al. (2013), MacGregor et al. (2016a) Now, resolved at wavelengthsfrom from Herschel optical DUNES (scattered light) to millimeter and radio (thermal emission) MacGregor Planet-Disk Interactions Planets orbiting a star can gravitationally perturb an outer debris disk Expect to see a variety of structures: warps, clumps, eccentricities, central offsets, sharp edges, etc. Goal: Probe for wide separation planets using debris disk structure HD 15115 β Pictoris Kuiper Belt Asymmetry Warp Resonance Kalas et al. (2007) Lagrange et al. (2010) Jewitt et al. (2009) MacGregor Debris Disks Before ALMA Epsilon Eridani HD 95086 Tau Ceti Beta PictorisHR 4796A HD 107146 AU Mic Greaves+ (2014) Su+ (2015) Lawler+ (2014) Vandenbussche+ (2010) Koerner+ (1998) Hughes+ (2011) Matthews+ (2015) 49 Ceti HD 181327 HD 21997 Fomalhaut HD 10647 (q1 Eri) Eta Corvi HR 8799 Roberge+ (2013) Lebreton+ (2012) Moor+ (2015) Acke+ (2012) Liseau+ (2010) Lebreton+ (2016) -
The HARPS Search for Earth-Like Planets in the Habitable Zone I
A&A 534, A58 (2011) Astronomy DOI: 10.1051/0004-6361/201117055 & c ESO 2011 Astrophysics The HARPS search for Earth-like planets in the habitable zone I. Very low-mass planets around HD 20794, HD 85512, and HD 192310, F. Pepe1,C.Lovis1, D. Ségransan1,W.Benz2, F. Bouchy3,4, X. Dumusque1, M. Mayor1,D.Queloz1, N. C. Santos5,6,andS.Udry1 1 Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Versoix, Switzerland e-mail: [email protected] 2 Physikalisches Institut Universität Bern, Sidlerstrasse 5, 3012 Bern, Switzerland 3 Institut d’Astrophysique de Paris, UMR7095 CNRS, Université Pierre & Marie Curie, 98bis Bd Arago, 75014 Paris, France 4 Observatoire de Haute-Provence/CNRS, 04870 St. Michel l’Observatoire, France 5 Centro de Astrofísica da Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal 6 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Portugal Received 8 April 2011 / Accepted 15 August 2011 ABSTRACT Context. In 2009 we started an intense radial-velocity monitoring of a few nearby, slowly-rotating and quiet solar-type stars within the dedicated HARPS-Upgrade GTO program. Aims. The goal of this campaign is to gather very-precise radial-velocity data with high cadence and continuity to detect tiny signatures of very-low-mass stars that are potentially present in the habitable zone of their parent stars. Methods. Ten stars were selected among the most stable stars of the original HARPS high-precision program that are uniformly spread in hour angle, such that three to four of them are observable at any time of the year. -
AMD-Stability and the Classification of Planetary Systems
A&A 605, A72 (2017) DOI: 10.1051/0004-6361/201630022 Astronomy c ESO 2017 Astrophysics& AMD-stability and the classification of planetary systems? J. Laskar and A. C. Petit ASD/IMCCE, CNRS-UMR 8028, Observatoire de Paris, PSL, UPMC, 77 Avenue Denfert-Rochereau, 75014 Paris, France e-mail: [email protected] Received 7 November 2016 / Accepted 23 January 2017 ABSTRACT We present here in full detail the evolution of the angular momentum deficit (AMD) during collisions as it was described in Laskar (2000, Phys. Rev. Lett., 84, 3240). Since then, the AMD has been revealed to be a key parameter for the understanding of the outcome of planetary formation models. We define here the AMD-stability criterion that can be easily verified on a newly discovered planetary system. We show how AMD-stability can be used to establish a classification of the multiplanet systems in order to exhibit the planetary systems that are long-term stable because they are AMD-stable, and those that are AMD-unstable which then require some additional dynamical studies to conclude on their stability. The AMD-stability classification is applied to the 131 multiplanet systems from The Extrasolar Planet Encyclopaedia database for which the orbital elements are sufficiently well known. Key words. chaos – celestial mechanics – planets and satellites: dynamical evolution and stability – planets and satellites: formation – planets and satellites: general 1. Introduction motion resonances (MMR, Wisdom 1980; Deck et al. 2013; Ramos et al. 2015) could justify the Hill-type criteria, but the The increasing number of planetary systems has made it nec- results on the overlap of the MMR island are valid only for close essary to search for a possible classification of these planetary orbits and for short-term stability. -
The Hd 40307 Planetary System: Super-Earths Or Mini-Neptunes?
The Astrophysical Journal, 695:1006–1011, 2009 April 20 doi:10.1088/0004-637X/695/2/1006 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A. THE HD 40307 PLANETARY SYSTEM: SUPER-EARTHS OR MINI-NEPTUNES? Rory Barnes1, Brian Jackson1, Sean N. Raymond2,4, Andrew A. West3, and Richard Greenberg1 1 Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA 2 Center for Astrophysics and Space Astronomy, University of Colorado, Boulder, CO 80309, USA 3 Astronomy Department, University of California, 601 Campbell Hall, Berkeley, CA 94720-3411, USA Received 2008 July 9; accepted 2009 January 15; published 2009 April 6 ABSTRACT Three planets with minimum masses less than 10 M⊕ orbit the star HD 40307, suggesting these planets may be rocky. However, with only radial velocity data, it is impossible to determine if these planets are rocky or gaseous. Here we exploit various dynamical features of the system in order to assess the physical properties of the planets. Observations allow for circular orbits, but a numerical integration shows that the eccentricities must be at least 10−4. Also, planets b and c are so close to the star that tidal effects are significant. If planet b has tidal parameters similar to the terrestrial planets in the solar system and a remnant eccentricity larger than 10−3, then, going back in time, the system would have been unstable within the lifetime of the star (which we estimate to be 6.1 ± 1.6 Gyr). Moreover, if the eccentricities are that large and the inner planet is rocky, then its tidal heating may be an order of magnitude greater than extremely volcanic Io, on a per unit surface area basis. -
Cycle 14 Approved Programs
Cycle 14 Approved Programs as of 04/05/05 Science First Name Last Name Type Phase II ID Institution Country Title Category Physical Processes in Orion's Veil: A High Resolution Nicholas Abel AR 10636 University of Kentucky USA Star Formation UV Absorption Study of the Line of Sight Towards the Trapezium University of Eric Agol GO 10486 USA Cosmology A Cosmic String Lens Candidate Washington University of Eric Agol AR 10637 USA Cool Stars Finding Terrestrial Planets with HST Washington Space Telescope NGC 4449: a Testbed for Starbursts in the Low- and Alessandra Aloisi GO 10585 Science Institute - USA Galaxies High-Redshift Universe ESA Space Telescope The Rosetta Stone without a Distance: Hunting for Alessandra Aloisi GO 10586 Science Institute - USA Galaxies Cepheids in the "Primordial" Galaxy I Zw 18 ESA University of Timing Studies of the X-ray Binary Populations in Scott Anderson GO 10615 USA Hot Stars Washington Globular Clusters The Johns Hopkins A Search for Debris Disks in the Coeval Beta Pictoris David Ardila GO 10487 USA Star Formation University Moving Group University of Colorado Thomas Ayres AR 10638 USA Cool Stars StarCAT at Boulder Studies of Europa's Plasma Interactions and Gilda Ballester AR 10639 University of Arizona USA Solar System Atmosphere with HST/STIS FUV Images Edward Baltz GO 10543 Stanford University USA Galaxies Microlensing in M87 and the Virgo Cluster University of HST Observations of MilliJansky Radio Sources from the Robert Becker AR 10640 USA Galaxies California - Davis VLA FIRST Survey European Southern -