Can Brown Dwarfs Survive on Close Orbits Around Convective Stars? C
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XIII Publications, Presentations
XIII Publications, Presentations 1. Refereed Publications E., Kawamura, A., Nguyen Luong, Q., Sanhueza, P., Kurono, Y.: 2015, The 2014 ALMA Long Baseline Campaign: First Results from Aasi, J., et al. including Fujimoto, M.-K., Hayama, K., Kawamura, High Angular Resolution Observations toward the HL Tau Region, S., Mori, T., Nishida, E., Nishizawa, A.: 2015, Characterization of ApJ, 808, L3. the LIGO detectors during their sixth science run, Classical Quantum ALMA Partnership, et al. including Asaki, Y., Hirota, A., Nakanishi, Gravity, 32, 115012. K., Espada, D., Kameno, S., Sawada, T., Takahashi, S., Ao, Y., Abbott, B. P., et al. including Flaminio, R., LIGO Scientific Hatsukade, B., Matsuda, Y., Iono, D., Kurono, Y.: 2015, The 2014 Collaboration, Virgo Collaboration: 2016, Astrophysical Implications ALMA Long Baseline Campaign: Observations of the Strongly of the Binary Black Hole Merger GW150914, ApJ, 818, L22. Lensed Submillimeter Galaxy HATLAS J090311.6+003906 at z = Abbott, B. P., et al. including Flaminio, R., LIGO Scientific 3.042, ApJ, 808, L4. Collaboration, Virgo Collaboration: 2016, Observation of ALMA Partnership, et al. including Asaki, Y., Hirota, A., Nakanishi, Gravitational Waves from a Binary Black Hole Merger, Phys. Rev. K., Espada, D., Kameno, S., Sawada, T., Takahashi, S., Kurono, Lett., 116, 061102. Y., Tatematsu, K.: 2015, The 2014 ALMA Long Baseline Campaign: Abbott, B. P., et al. including Flaminio, R., LIGO Scientific Observations of Asteroid 3 Juno at 60 Kilometer Resolution, ApJ, Collaboration, Virgo Collaboration: 2016, GW150914: Implications 808, L2. for the Stochastic Gravitational-Wave Background from Binary Black Alonso-Herrero, A., et al. including Imanishi, M.: 2016, A mid-infrared Holes, Phys. -
Last Time: Planet Finding
Last Time: Planet Finding • Radial velocity method • Parent star’s Doppler shi • Planet minimum mass, orbital period, semi- major axis, orbital eccentricity • UnAl Kepler Mission, was the method with the most planets Last Time: Planet Finding • Transits – eclipse of the parent star: • Planetary radius, orbital period, semi-major axis • Now the most common way to find planets Last Time: Planet Finding • Direct Imaging • Planetary brightness, distance from parent star at that moment • About 10 planets detected Last Time: Planet Finding • Lensing • Planetary mass and, distance from parent star at that moment • You want to look towards the center of the galaxy where there is a high density of stars Last Time: Planet Finding • Astrometry • Tiny changes in star’s posiAon are not yet measurable • Would give you planet’s mass, orbit, and eccentricity One more important thing to add: • Giant planets (which are easiest to detect) are preferenAally found around stars that are abundant in iron – “metallicity” • Iron is the easiest heavy element to measure in a star • Heavy-element rich planetary systems make planets more easily 13.2 The Nature of Extrasolar Planets Our goals for learning: • What have we learned about extrasolar planets? • How do extrasolar planets compare with planets in our solar system? Measurable Properties • Orbital period, distance, and orbital shape • Planet mass, size, and density • Planetary temperature • Composition Orbits of Extrasolar Planets • Nearly all of the detected planets have orbits smaller than Jupiter’s. • This is a selection effect: Planets at greater distances are harder to detect with the Doppler technique. Orbits of Extrasolar Planets • Orbits of some extrasolar planets are much more elongated (have a greater eccentricity) than those in our solar system. -
Curriculum Vitae - 24 March 2020
Dr. Eric E. Mamajek Curriculum Vitae - 24 March 2020 Jet Propulsion Laboratory Phone: (818) 354-2153 4800 Oak Grove Drive FAX: (818) 393-4950 MS 321-162 [email protected] Pasadena, CA 91109-8099 https://science.jpl.nasa.gov/people/Mamajek/ Positions 2020- Discipline Program Manager - Exoplanets, Astro. & Physics Directorate, JPL/Caltech 2016- Deputy Program Chief Scientist, NASA Exoplanet Exploration Program, JPL/Caltech 2017- Professor of Physics & Astronomy (Research), University of Rochester 2016-2017 Visiting Professor, Physics & Astronomy, University of Rochester 2016 Professor, Physics & Astronomy, University of Rochester 2013-2016 Associate Professor, Physics & Astronomy, University of Rochester 2011-2012 Associate Astronomer, NOAO, Cerro Tololo Inter-American Observatory 2008-2013 Assistant Professor, Physics & Astronomy, University of Rochester (on leave 2011-2012) 2004-2008 Clay Postdoctoral Fellow, Harvard-Smithsonian Center for Astrophysics 2000-2004 Graduate Research Assistant, University of Arizona, Astronomy 1999-2000 Graduate Teaching Assistant, University of Arizona, Astronomy 1998-1999 J. William Fulbright Fellow, Australia, ADFA/UNSW School of Physics Languages English (native), Spanish (advanced) Education 2004 Ph.D. The University of Arizona, Astronomy 2001 M.S. The University of Arizona, Astronomy 2000 M.Sc. The University of New South Wales, ADFA, Physics 1998 B.S. The Pennsylvania State University, Astronomy & Astrophysics, Physics 1993 H.S. Bethel Park High School Research Interests Formation and Evolution -
Survival of Satellites During the Migration of a Hot Jupiter: the Influence of Tides
EPSC Abstracts Vol. 13, EPSC-DPS2019-1590-1, 2019 EPSC-DPS Joint Meeting 2019 c Author(s) 2019. CC Attribution 4.0 license. Survival of satellites during the migration of a Hot Jupiter: the influence of tides Emeline Bolmont (1), Apurva V. Oza (2), Sergi Blanco-Cuaresma (3), Christoph Mordasini (2), Pierre Auclair-Desrotour (2), Adrien Leleu (2) (1) Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, CH-1290 Sauverny, Switzerland ([email protected]) (2) Physikalisches Institut, Universität Bern, Gesellschaftsstr. 6, 3012, Bern, Switzerland (3) Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA Abstract 2. The model We explore the origin and stability of extrasolar satel- lites orbiting close-in gas giants, by investigating if the Tidal interactions 1 M⊙ satellite can survive the migration of the planet in the 1 MIo protoplanetary disk. To accomplish this objective, we 1 MJup used Posidonius, a N-Body code with an integrated tidal model, which we expanded to account for the migration of the gas giant in a disk. Preliminary re- Inner edge of disk: ain sults suggest the survival of the satellite is rare, which Type 2 migration: !mig would indicate that if such satellites do exist, capture is a more likely process. Figure 1: Schema of the simulation set up: A Io-like satellite orbits around a Jupiter-like planet with a solar- 1. Introduction like host star. Satellites around Hot Jupiters were first thought to be lost by falling onto their planet over Gyr timescales (e.g. [1]). This is due to the low tidal dissipation factor of Jupiter (Q 106, [10]), likely to be caused by the 2.1. -
Brown Dwarf: White Dwarf: Hertzsprung -Russell Diagram (H-R
Types of Stars Spectral Classifications: Based on the luminosity and effective temperature , the stars are categorized depending upon their positions in the HR diagram. Hertzsprung -Russell Diagram (H-R Diagram) : 1. The H-R Diagram is a graphical tool that astronomers use to classify stars according to their luminosity (i.e. brightness), spectral type, color, temperature and evolutionary stage. 2. HR diagram is a plot of luminosity of stars versus its effective temperature. 3. Most of the stars occupy the region in the diagram along the line called the main sequence. During that stage stars are fusing hydrogen in their cores. Various Types of Stars Brown Dwarf: White Dwarf: Brown dwarfs are sub-stellar objects After a star like the sun exhausts its nuclear that are not massive enough to sustain fuel, it loses its outer layer as a "planetary nuclear fusion processes. nebula" and leaves behind the remnant "white Since, comparatively they are very cold dwarf" core. objects, it is difficult to detect them. Stars with initial masses Now there are ongoing efforts to study M < 8Msun will end as white dwarfs. them in infrared wavelengths. A typical white dwarf is about the size of the This picture shows a brown dwarf around Earth. a star HD3651 located 36Ly away in It is very dense and hot. A spoonful of white constellation of Pisces. dwarf material on Earth would weigh as much as First directly detected Brown Dwarf HD 3651B. few tons. Image by: ESO The image is of Helix nebula towards constellation of Aquarius hosts a White Dwarf Helix Nebula 6500Ly away. -
The Formation of Brown Dwarfs 459
Whitworth et al.: The Formation of Brown Dwarfs 459 The Formation of Brown Dwarfs: Theory Anthony Whitworth Cardiff University Matthew R. Bate University of Exeter Åke Nordlund University of Copenhagen Bo Reipurth University of Hawaii Hans Zinnecker Astrophysikalisches Institut, Potsdam We review five mechanisms for forming brown dwarfs: (1) turbulent fragmentation of molec- ular clouds, producing very-low-mass prestellar cores by shock compression; (2) collapse and fragmentation of more massive prestellar cores; (3) disk fragmentation; (4) premature ejection of protostellar embryos from their natal cores; and (5) photoerosion of pre-existing cores over- run by HII regions. These mechanisms are not mutually exclusive. Their relative importance probably depends on environment, and should be judged by their ability to reproduce the brown dwarf IMF, the distribution and kinematics of newly formed brown dwarfs, the binary statis- tics of brown dwarfs, the ability of brown dwarfs to retain disks, and hence their ability to sustain accretion and outflows. This will require more sophisticated numerical modeling than is presently possible, in particular more realistic initial conditions and more realistic treatments of radiation transport, angular momentum transport, and magnetic fields. We discuss the mini- mum mass for brown dwarfs, and how brown dwarfs should be distinguished from planets. 1. INTRODUCTION form a smooth continuum with those of low-mass H-burn- ing stars. Understanding how brown dwarfs form is there- The existence of brown dwarfs was first proposed on the- fore the key to understanding what determines the minimum oretical grounds by Kumar (1963) and Hayashi and Nakano mass for star formation. In section 3 we review the basic (1963). -
Reionization the End of the Universe
Reionization The End of the Universe How will the Universe end? Is this the only Universe? What, if anything, will exist after the Universe ends? Universe started out very hot (Big Bang), then expanded: Some say the world will end in fire, Some say in ice. From what I’ve tasted of desire I hold with those who favor fire. But if I had to perish twice, I think I know enough of hate To know that for destruction ice is also great And would suffice. How it ends depends on the geometry of the Universe: Robert Frost 2) More like a saddle than a sphere, with curvature in the opposite The Geometry of Curved Space sense in different dimensions: "negative" curvature. Possibilities: Sum of the 1) Space curves back on itself (like a sphere). "Positive" curvature. Angles < 180 Sum of the Angles > 180 3) A more familiar flat geometry. Sum of the Angles = 180 1 The Geometry of the Universe determines its fate Case 1: high density Universe, spacetime is positively curved Result is “Big Crunch” Fire The Five Ages of the Universe Cases 2 or 3: open Universe (flat or negatively curved) 1) The Primordial Era 2) The Stelliferous Era 3) The Degenerate Era 4) The Black Hole Era Current measurements favor an open Universe 5) The Dark Era Result is infinite expansion Ice 1. The Primordial Era: 10-50 - 105 y The Early Universe Inflation Something triggers the Creation of the Universe at t=0 A problem with microwave background: Microwave background reaches us from all directions. -
Exploring Exoplanet Populations with NASA's Kepler Mission
SPECIAL FEATURE: PERSPECTIVE PERSPECTIVE SPECIAL FEATURE: Exploring exoplanet populations with NASA’s Kepler Mission Natalie M. Batalha1 National Aeronautics and Space Administration Ames Research Center, Moffett Field, 94035 CA Edited by Adam S. Burrows, Princeton University, Princeton, NJ, and accepted by the Editorial Board June 3, 2014 (received for review January 15, 2014) The Kepler Mission is exploring the diversity of planets and planetary systems. Its legacy will be a catalog of discoveries sufficient for computing planet occurrence rates as a function of size, orbital period, star type, and insolation flux.The mission has made significant progress toward achieving that goal. Over 3,500 transiting exoplanets have been identified from the analysis of the first 3 y of data, 100 planets of which are in the habitable zone. The catalog has a high reliability rate (85–90% averaged over the period/radius plane), which is improving as follow-up observations continue. Dynamical (e.g., velocimetry and transit timing) and statistical methods have confirmed and characterized hundreds of planets over a large range of sizes and compositions for both single- and multiple-star systems. Population studies suggest that planets abound in our galaxy and that small planets are particularly frequent. Here, I report on the progress Kepler has made measuring the prevalence of exoplanets orbiting within one astronomical unit of their host stars in support of the National Aeronautics and Space Admin- istration’s long-term goal of finding habitable environments beyond the solar system. planet detection | transit photometry Searching for evidence of life beyond Earth is the Sun would produce an 84-ppm signal Translating Kepler’s discovery catalog into one of the primary goals of science agencies lasting ∼13 h. -
EVOLVED STARS a Vision of the Future Astron
PUBLISHED: 04 JANUARY 2017 | VOLUME: 1 | ARTICLE NUMBER: 0021 research highlights EVOLVED STARS A vision of the future Astron. Astrophys. 596, A92 (2016) Loop Plume A B EDPS A nearby red giant star potentially hosts a planet with a mass of up to 12 times that of Jupiter. L2 Puppis, a solar analogue five billion years more evolved than the Sun, could give a hint to the future of the Solar System’s planets. Using ALMA, Pierre Kervella has observed L2 Puppis in molecular lines and continuum emission, finding a secondary source that is roughly 2 au away from the primary. This secondary source could be a giant planet or, alternatively, a brown dwarf as massive as 28 Jupiter masses. Further observations in ALMA bands 9 or 10 (λ ≈ 0.3–0.5 mm) can help to constrain the companion’s mass. If confirmed as a planet, it would be the first planet around an asymptotic giant branch star. L2 Puppis (A in the figure) is encircled by an edge-on circumstellar dust disk (inner disk shown in blue; surrounding dust in orange), which raises the question of whether the companion body is pre-existing, or if it has formed recently due to accretion processes within the disk. If pre-existing, the putative planet would have had an orbit similar in extent to that of Mars. Evolutionary models show that eventually this planet will be pulled inside the convective envelope of L2 Puppis by tidal forces. The companion’s interaction with the star’s circumstellar disk has invoked pronounced features above the disk: an extended loop of warm dusty material, and a visible plume, potentially launched by accretion onto a disk of material around the planet itself (B in the figure). -
The Search for Exomoons and the Characterization of Exoplanet Atmospheres
Corso di Laurea Specialistica in Astronomia e Astrofisica The search for exomoons and the characterization of exoplanet atmospheres Relatore interno : dott. Alessandro Melchiorri Relatore esterno : dott.ssa Giovanna Tinetti Candidato: Giammarco Campanella Anno Accademico 2008/2009 The search for exomoons and the characterization of exoplanet atmospheres Giammarco Campanella Dipartimento di Fisica Università degli studi di Roma “La Sapienza” Associate at Department of Physics & Astronomy University College London A thesis submitted for the MSc Degree in Astronomy and Astrophysics September 4th, 2009 Università degli Studi di Roma ―La Sapienza‖ Abstract THE SEARCH FOR EXOMOONS AND THE CHARACTERIZATION OF EXOPLANET ATMOSPHERES by Giammarco Campanella Since planets were first discovered outside our own Solar System in 1992 (around a pulsar) and in 1995 (around a main sequence star), extrasolar planet studies have become one of the most dynamic research fields in astronomy. Our knowledge of extrasolar planets has grown exponentially, from our understanding of their formation and evolution to the development of different methods to detect them. Now that more than 370 exoplanets have been discovered, focus has moved from finding planets to characterise these alien worlds. As well as detecting the atmospheres of these exoplanets, part of the characterisation process undoubtedly involves the search for extrasolar moons. The structure of the thesis is as follows. In Chapter 1 an historical background is provided and some general aspects about ongoing situation in the research field of extrasolar planets are shown. In Chapter 2, various detection techniques such as radial velocity, microlensing, astrometry, circumstellar disks, pulsar timing and magnetospheric emission are described. A special emphasis is given to the transit photometry technique and to the two already operational transit space missions, CoRoT and Kepler. -
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]. -
The Coolest Brown Dwarfs
ClassY - The Coolest Brown Dwarfs CFBDS J005910.90-011401.3 – T9/Y0 - first class Y, 30 light-years distance, Temp 620K, Mass 15-30 M_Jup WISE 0855−0714 – Y2 - coolest at Temp ~ 250K, 7.3 light-years distance, Mass 3-10 M_Jup ClassY - The Coolest Brown Dwarfs CFBDS J005910.90-011401.3 – T9/Y0 - first class Y, 30 light-years distance, Temp 620K, Mass 15-30 M_Jup WISE 0855−0714 – Y2 - coolest at Temp ~ 250K, 7.3 light-years distance, Mass 3-10 M_Jup Why are all brown dwarf stars about the same size, even if the mass ranges from 10-500 M_Jup? Stellar evolution so far Different energy sources during different stages in the star's evolution Protostar phase (KH contraction) MS phase H->He RGB phase (shell H->He) And remember: more massive stars evolve faster during all stages What is this Plot Showing? globular cluster Announcements • Today – More low mass stellar evolution • Thursday – High mass stellar evolution and HW#4 is due • Tuesday Feb 25 – Review • Thursday Feb 27 – Exam#1 Intrinsic variability • Those that vary in brightness as a result of conditions within the star itself. • Found in the instability strip. Any star within these portions of the H-R diagram will become unstable to pulsations. • The different regions produce different kinds of observed phenomena. • Stars may go through these stages several times during their lives. Cause of pulsations • Stars are variable because they are unstable in one way or another: they lack hydrostatic equilibrium beneath surface. • Miras are not well understood, but other, more periodically varying stars are better understood, like the Cepheids: • The ionization zone of He lies at a distance from the center of the star, close to the surface.