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Lurking in the Shadows: Wide-Separation Gas Giants As Tracers of Planet Formation
Lurking in the Shadows: Wide-Separation Gas Giants as Tracers of Planet Formation Thesis by Marta Levesque Bryan In Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy CALIFORNIA INSTITUTE OF TECHNOLOGY Pasadena, California 2018 Defended May 1, 2018 ii © 2018 Marta Levesque Bryan ORCID: [0000-0002-6076-5967] All rights reserved iii ACKNOWLEDGEMENTS First and foremost I would like to thank Heather Knutson, who I had the great privilege of working with as my thesis advisor. Her encouragement, guidance, and perspective helped me navigate many a challenging problem, and my conversations with her were a consistent source of positivity and learning throughout my time at Caltech. I leave graduate school a better scientist and person for having her as a role model. Heather fostered a wonderfully positive and supportive environment for her students, giving us the space to explore and grow - I could not have asked for a better advisor or research experience. I would also like to thank Konstantin Batygin for enthusiastic and illuminating discussions that always left me more excited to explore the result at hand. Thank you as well to Dimitri Mawet for providing both expertise and contagious optimism for some of my latest direct imaging endeavors. Thank you to the rest of my thesis committee, namely Geoff Blake, Evan Kirby, and Chuck Steidel for their support, helpful conversations, and insightful questions. I am grateful to have had the opportunity to collaborate with Brendan Bowler. His talk at Caltech my second year of graduate school introduced me to an unexpected population of massive wide-separation planetary-mass companions, and lead to a long-running collaboration from which several of my thesis projects were born. -
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 -
Extrasolar Planetsplanets
ExtrasolarExtrasolar PlanetsPlanets Gemini Observatory Artwork by Lynette Cook Open issues have to form planets in ~ few Myrs 1) how did the gas disk disperse? 2) how are planetesimals made? Are dust grains suffiently stifky? 3) what makes fhrondrules? 4) How do planetesimals survive follisions? 5) What is Jupiter's role in the fate of other planets? 6) Do giant planets only form outside frost lines? If so, how to explain the extra-solar hot Jupiters? 7).... Build-up: Protoplanetary disks Of the stars near the Sun, ~5% have Jupiter-mass planets. (Fraftion will infrease with longer time span.) Proto-planetary Disks observed around > 50% young stars (< 10 Myrs) mostly detected through infrared emission in excess of the expected near-black-body from the star. some are directly imaged in scattered light (HST) Left-overs: debris disks The inner Solar system is flled with zodiafal dusts (ground-down asteroids & comets) Would not be observable for other stars. Yet, ~10% of stars observed to have dusty debris disks. Older stars have less dust, so likely a transient phenomenon. Also, the dust seen in sfattered and reprofessed light will be blown away 2 d = LIR/L ~ 1 / t quifkly, so it must be replenished for * some time. Some debris disks show “rings” or “edges,” suggesting dynamifal imprints of planets and/or nearby stars? Planet formation in action? HL Tau with ALMA The dusty disk of β Piftoris -- warps, "comets" striking, evaporated metals The dusty disk of β Piftoris -- warps, "comets" striking, evaporated metals ESO press release 42/08 Properties of exoplanets: RV studies show Unexpefted variation! 1) Large range of masses low masses: limited by sensitivity; high masses: real fut-of at ~10 MJ. -
Extrasolar Planets
Extrasolar Planets Open issues have to form planets in ~ few Myrs 1) how did the gas disk disperse? 2) how are planetesimals made? Are dust grains suffiently stifky? 3) what makes fhrondrules? 4) How do planetesimals survive follisions? 5) What is Jupiter's role in the fate of other planets? 6) Do giant planets only form outside frost lines? If so, how to explain the extra-solar hot Jupiters? 7).... Gemini Observatory Artwork by Lynette Cook Build-up: Left-overs: Protoplanetary disks debris disks Of the stars near the Sun, ~5% have Jupiter-mass planets. The inner Solar system is (Fraftion will infrease with longer time span.) flled with zodiafal dusts (ground-down asteroids & comets) Proto-planetary Disks observed around > 50% young stars (< 10 Myrs) Would not be observable for other stars. mostly detected through infrared Yet, ~10% of stars observed emission in excess of the expected to have dusty debris disks. near-black-body Older stars have less dust, from the star. so likely a transient phenomenon. Also, the dust seen in sfattered and some are directly reprofessed light will be blown away 2 d = LIR/L ~ 1 / t imaged in scattered quifkly, so it must be replenished for * light (HST) some time. Some debris disks show “rings” or “edges,” suggesting dynamifal imprints of planets and/or nearby stars? The dusty disk of β Piftoris -- warps, "comets" striking, evaporated metals Planet formation in action? HL Tau with ALMA The dusty disk of β Piftoris -- warps, "comets" striking, evaporated metals Properties of exoplanets: RV studies show Unexpefted variation! 1) Large range of masses low masses: limited by sensitivity; high masses: real fut-of at ~10 MJ. -
Arxiv:0808.3207V1 [Astro-Ph] 23 Aug 2008 Nfgr .Nwonsaswr Rtdrcl Icvrdi C in Discovered Directly H first Were and Surroun Stars Variability Area Newborn the of 4
Handbook of Star Forming Regions Vol. II Astronomical Society of the Pacific, 2008 Bo Reipurth, ed. Chamaeleon Kevin L. Luhman Department of Astronomy and Astrophysics The Pennsylvania State University University Park, PA 16802, USA Abstract. The dark clouds in the constellation of Chamaeleon have distances of 160-180pc from the Sun and a total mass of ∼5000 M⊙. The three main clouds, Cha I, II, and III, have angular sizes of a few square degrees and maximum extinctions of AV ∼ 5-10. Most of the star formation in these clouds is occurring in Cha I, with the remainder in Cha II. The current census of Cha I contains 237 known members, 33 of which have spectral types indicative of brown dwarfs (>M6). Approximately 50 members of Cha II have been identified, including a few brown dwarfs. When interpreted with the evolutionary models of Chabrier and Baraffe, the H-R diagram for Cha I exhibits a median age of ∼2 Myr, making it coeval with IC 348 and slightly older than Taurus (∼1 Myr). TheIMF ofChaI reachesa maximumat a massof0.1-0.15 M⊙, and thus closely resembles the IMFs in IC 348 and the Orion Nebula Cluster. The disk fraction in Cha I is roughly constant at ∼ 50% from 0.01 to 0.3 M⊙ and increases to ∼ 65% at higher masses. In comparison, IC 348 has a similar disk fraction at low masses but a much lower disk fraction at M ∼> 1 M⊙, indicating that solar-type stars have longer disk lifetimes in Cha I. 1. Introduction The southern constellation of Chamaeleon contains one of the nearest groups of dark clouds to the Sun (d ∼ 160-180 pc). -