DOCSLIB.ORG

Natural Sciences Tripos Part III/Mast Astrophysics Project Booklet 2015-2016

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Natural Sciences Tripos Part III/Mast Astrophysics Project Booklet 2015-2016 Natural Sciences Tripos Part III/MASt Astrophysics Project Booklet 2015-2016 Editors: George Efstathiou and Judith Moss Version date: 3rd October 2015 CONTENTS # Supervisors Associated UTO Project Title pp 1 William Alston, Michael Parker [Andy Fabian] Probing the inner regions of accreting 1-2 and Andy Fabian blackholes using principle components analysis 2 William Alston, Matt Middleton [Andy Fabian] The high-frequency rms-flux relation in 3-4 and Andy Fabian accreting black holes 3 Amy Bonsor Mark Wyatt Where are the debris discs orbiting first ascent 5-6 giants? 4 Heather Campbell and Simon Gerry Gilmore Early photometric classication of the Gaia 7-8 Hodgkin Science Alerts 5 Andy Casey Gerry Gilmore Understanding the anomalous and rare Fe-rich 9 stars 6 Morgan Fraser Gerry Gilmore Mining public Pan-STARRS data for faint 11-12 extragalactic transients 7 Morgan Fraser Gerry Gilmore Making stars go bang 13-14 8 Gerry Gilmore, Anna Hourihane [Gerry Gilmore] Improving visualisation of time-series and large 15-16 and Clare Worley data sets 9 Paul Hewett and Manda Banerji [Paul Hewett] A search for the “ghost of Lyman-α” in quasar 17-18 outflows 10 Robert Izzard, Christopher Tout [Christopher Tout] Eccentricity in pre-main sequence binary stars 19 and Anna Zytkow 11 Robert Izzard, Christopher Tout [Christopher Tout] Ionizing flux from X-ray binary stars 21 and Anna Zytkow 12 Paula Jofre and Keith Hawkins Gerry Gilmore Three-dimensional Chemical Cartography of the 23-24 Milky Way 13 Paula Jofre, Quentin Kral and [Gerry Gilmore] Towards creating a standard link between an 25-26 Gerry Gilmore exoplanet and its host star 14 Attila Juhasz Cathie Clarke Observability of circumplanetary discs at near- 27-28 infrared wavelengths 15 Attila Juhasz Cathie Clarke Temporal variability of protoplanetary discs as 29-30 a new diagnostic 16 Grant Kennedy Mark Wyatt Smarter Search for Circumbinary Planets 31-32 17 Quentin Kral and Andrew Mark Wyatt Exploit spacing of Kepler planets to study 33-34 Shannon planet masses 18 Anne Lohfink and Michael Andy Fabian An up-close view of black holes 35-36 Parker 19 Nikku Madhusudhan Cathie Clarke Volcanism on Extrasolar Planets 37 20 Nikku Madhusudhan Mark Wyatt Chemical Diversity of Rocky super-Earths 39 21 Thomas Masseron Gerry Gilmore Molecular curves of growth 41-42 22 Thomas Masseron Gerry Gilmore Constraining the chemistry the first stars of the 43-44 Galaxy 23 Marina Migliaccio and Andres Anthony Challinor Shedding light on the dark: Cross-correlation of Curto the cosmic gamma-ray and microwave 45-46 backgrounds using Fermi-LAT and Planck data 24 Ciro Pinto Andy Fabian The fight between cooling and heating in 47-48 ellipticals, groups and clusters of galaxies 25 Jason Sanders Wyn Evans Chemo-dynamics of the Milky Way using the 49-50 Gaia-ESO survey 26 Jason Sanders Wyn Evans Analytic models of galaxies with kinematically- 51-52 decoupled cores i # Supervisors Associated UTO Project Title pp 27 Christopher Tout, Robert Izzard [Christopher Tout] Single Star Progenitors of Type Ia Supernovae 53-54 and Anna Zytkow 28 Ranjan Vasudevan, Andy Fabian [Andy Fabian] Weighing Supermassive Black Holes in Local 55-56 and Anne Lohfink Active Galaxies 29 Stephen Walker and Andy [Andy Fabian] Understanding the evolution of AGN feedback Fabian in galaxy clusters out to high redshift using X- 57-58 ray observations 30 Nicholas Walton Gerry Gilmore Planetary Nebulae Revealed by Gaia: 59-60 Dynamics and Luminosity Functions 31 Mark Wyatt [Mark Wyatt] Modelling aperiodic dips in Kepler light- 61-62 curves as orbiting dust clumps 32 Anna Zytkow Christopher Tout Conductivity of dense matter and stars with 63-64 neutron cores -- APPENDIX 65-67 ii Introduction This booklet contains descriptions of the individual projects available in the academic year 2015-2016. Each entry contains a brief description of the background to the project along with a summary of the type of work involved and several references where more information can be obtained. The booklet is made available just before the start of the Michaelmas term to give students about 2 weeks to choose which projects they are interested in. George Efstathiou Part III/MASt Astrophysics Course Coordinator, 2015-2016 iii Part III/MASt Astrophysics 2015-2016 Version: 3rd October 2015 1. Probing the inner regions of accreting black holes using principal components analysis Supervisors: Will Alston; H56; email: [email protected] Michael Parker; H52; email: [email protected] Andy Fabian (UTO); H49; email: [email protected] Background Active Galactic Nuclei (AGN) are powered by accretion of matter through a disc which ex- tends deep into the gravitational well of a supermassive black hole (SMBH). A large fraction of the luminosity of AGN is emitted as X-rays, which originate from the immediate vicinity of the SMBH. Accreting black holes show variations over a broad range of timescales, with the X-rays exhibiting the most rapid and large amplitude variability. As the characteristic time scales of variability scale inversely with distance from the black hole, the variations on the shortest time scales are expected to originate from the most inner regions and therefore carry vital information about the two fundamental properties of black holes: mass and spin. The radiative emission from the inner regions is released through several mechanisms, including comptonisation in a corona of hot electrons, a blackbody disc spectrum and reflection of the coronal emission on the disc. This is sometimes complicated by absorption by material along the line-of-site. What we measure with X-ray satellites is the sum of all the variable emission components. In order to infer properties of the black hole and the accretion process, we must separate these processes, which can be done using advanced signal processing techniques. The project aims to disentangle the variable emission components in an AGN using principal components analysis (PCA). PCA decomposes a dataset into a set of orthogonal eigenvectors, or principal components (PCs). When applied to X-ray data, the variability of the source spectrum is broken down into a set of variable spectral components. If the source variability consists of a linear sum of uncorrelated and spectrally distinct physical components then an exact description of the physical components is obtained. This provides a model independent way of determining the nature of the X-ray emission, allowing us to correctly determine parameters of the black hole, such as its spin. We will apply PCA to the Seyfert galaxy, PG1244+026, on which we recently obtained 600 ks (that's a lot!) of high quality X-ray data with the XMM-Newton satellite. Nature of the project work This is an observational data analysis project involving the use of new XMM-Newton X-ray data. Python will be the main programming language used, as well as the standard X- ray analysis software, XSPEC. This software is easy to use, and example scripts will be provided. An outline of the project is as follows: • Reduction of archival XMM-Newton data to produce spectra and light curves • Decomposing the spectral variability using principal components analysis (PCA) • Identifying the PCA components using simulations of spectral variability • Fitting the X-ray spectrum using xspec to determine system parameters Project No. 1 Page No. 1 Part III/MASt Astrophysics 2015-2016 Version: 3rd October 2015 0.15 0.1 0 0.2 Flux 0 − 0.2 Normalised 0.2 0 − 0.2 0.5 1 2 5 10 Energy (keV) Figure 1: Left : Schematic of the black hole — accretion disc geometry (Fabian 2013,IAUS,290). The yellow star represents the ‘corona’ where the primary X-ray emis- sion is produced. This then illuminates the disc to create the reflection spectrum. This component is expected to be delayed due to the extra path taken by the photons. Right : An example of the PCA method applied to the Seyfert galaxy, MCG-6-30-15 (Parker et al 2014). The primary component (top) represents the changing normalisation of the primary power-law emission. The second component represents the spectral pivoting (in energy) of this power-law, and the third component is identified as ionised reflection of the power-law emission from the accretion disc. By understanding the variable emission components we can then rule out any other contributions to the spectrum, such as from absorption. Useful texts Articles can be found online by searching for author and year at http://adsabs.harvard. edu/abstract_service.html or by following the link to arXiv. • For an overview of the X-ray variability see the review by McHardy (2010, http:// arxiv.org/abs/0909.2579). • For an overview of the X-ray spectral components in AGN see Fabian (2006, http:// arxiv.org/abs/astro-ph/0511537) and Fabian (2013, http://arxiv.org/abs/1211. 2146). • For a detailed look at the use of PCA analysis on X-ray data and the work that will be involved in this project see Parker et al (2014, http://arxiv.org/abs/1310.1945) and Parker et al., (2015, http://arxiv.org/abs/1411.4054) and references therein. Project No. 1 Page No. 2 Part III/MASt Astrophysics 2015-2016 Version: 3rd October 2015 2. The high-frequency rms-flux relation in n accreting black holes Supervisors: Will Alston; Office: H56; email: [email protected] Matt Middleton; Office: H52; email: [email protected] Andy Fabian (UTO); Office: H49; email: [email protected] Background Active Galactic Nuclei (AGN) are powered by accretion of matter through a disc which extends deep into the gravitational well of a supermassive black hole (SMBH). Accreting black holes show variations over a broad range of timescales, with the X-rays exhibiting the most rapid and large amplitude variability.
Load more

Recommended publications
  • The Wonders of Star Formafion
    The Wonders of Star Forma;on A tribute to Hans Zinnecker Edinburgh, Scotland 3-7 September, 2018 i John McIntyre Conference Centre Edinburgh UK 3rd - 7th September 2018 SOC Anthony Whitworth (Cardiff, UK, Co-Chair) Ken Rice (Edinburgh, UK, Co-Chair) Bo Reipurth (Hawaii, USA) Cathie Clarke (Cambridge, UK) Ian Bonnell (St Andrews, UK) Mark McCaughrean (ESA) Stephanie Walch (Cologne, Germany) Hal Yorke (USRA, USA) John Bally (Colorado, USA) Dimitris Stamatellos (UCLAN, UK) LOC Lyndsey Ballantyne Ken Rice ii Contents General Information 1 Information for Speakers . .1 Information for Posters . .1 WiFi Access . .1 Social Media . .1 Open forum: The Challenges Ahead . .2 Timetable . .3 Floorplan . .4 Getting Around Edinburgh . .5 Dining Options . .6 Excursions . .7 Useful Information . .7 Code of Conduct . .8 Talk Abstracts 9 Poster List & Abstracts 87 iii iv General Information Information for Speakers You are welcome to use your own laptops, but we will also be providing a Mac with OS X and a Windows machine for speakers to use. We can accomodate PDF, Keynote and Powerpoint. Please ensure you have uploaded and tested your talk on the computers prior to your session beginning, or have tested your own laptop/device. All contributed talks are 15 minutes plus 5 minutes for questions, while invited review talks are 30 minutes plus 10 minutes for questions. Session chairs will give appropriate warnings when you are approaching your time limit. To ensure the smooth running of each session, please keep to time. Thank you! Information for Posters Posters are allocated a numbered board based on the session to which they've been allocated.
    [Show full text]
  • Bondi-Hoyle Accretion
    A Review of Bondi–Hoyle–Lyttleton Accretion Richard Edgar a aStockholms observatorium, AlbaNova universitetscentrum, SE-106 91, Stockholm, Sweden Abstract If a point mass moves through a uniform gas cloud, at what rate does it accrete ma- terial? This is the question studied by Bondi, Hoyle and Lyttleton. This paper draws together the work performed in this area since the problem was first studied. Time has shown that, despite the simplifications made, Bondi, Hoyle and Lyttleton made quite accurate predictions for the accretion rate. Bondi–Hoyle–Lyttleton accretion has found application in many fields of astronomy, and these are also discussed. Key words: accretion PACS: 95.30.Lz, 97.10.Gz, 98.35.Mp, 98.62.Mw 1 Introduction arXiv:astro-ph/0406166v2 21 Jun 2004 In its purest form, Bondi–Hoyle–Lyttleton accretion concerns the supersonic motion of a point mass through a gas cloud. The cloud is assumed to be free of self-gravity, and to be uniform at infinity. Gravity focuses material behind the point mass, which can then accrete some of the gas. This problem has found applications in many areas of astronomy, and this paper is an attempt to address the lack of a general review of the subject. I start with a short summary of the original work of Bondi, Hoyle and Lyt- tleton, followed by a discussion of the numerical simulations performed. Some issues in Bondi–Hoyle–Lyttleton accretion are discussed, before a brief sum- mary of the fields in which the geometry has proved useful. Email address: [email protected] (Richard Edgar).
    [Show full text]
  • 10. Scientific Programme 10.1
    10. SCIENTIFIC PROGRAMME 10.1. OVERVIEW (a) Invited Discourses Plenary Hall B 18:00-19:30 ID1 “The Zoo of Galaxies” Karen Masters, University of Portsmouth, UK Monday, 20 August ID2 “Supernovae, the Accelerating Cosmos, and Dark Energy” Brian Schmidt, ANU, Australia Wednesday, 22 August ID3 “The Herschel View of Star Formation” Philippe André, CEA Saclay, France Wednesday, 29 August ID4 “Past, Present and Future of Chinese Astronomy” Cheng Fang, Nanjing University, China Nanjing Thursday, 30 August (b) Plenary Symposium Review Talks Plenary Hall B (B) 8:30-10:00 Or Rooms 309A+B (3) IAUS 288 Astrophysics from Antarctica John Storey (3) Mon. 20 IAUS 289 The Cosmic Distance Scale: Past, Present and Future Wendy Freedman (3) Mon. 27 IAUS 290 Probing General Relativity using Accreting Black Holes Andy Fabian (B) Wed. 22 IAUS 291 Pulsars are Cool – seriously Scott Ransom (3) Thu. 23 Magnetars: neutron stars with magnetic storms Nanda Rea (3) Thu. 23 Probing Gravitation with Pulsars Michael Kremer (3) Thu. 23 IAUS 292 From Gas to Stars over Cosmic Time Mordacai-Mark Mac Low (B) Tue. 21 IAUS 293 The Kepler Mission: NASA’s ExoEarth Census Natalie Batalha (3) Tue. 28 IAUS 294 The Origin and Evolution of Cosmic Magnetism Bryan Gaensler (B) Wed. 29 IAUS 295 Black Holes in Galaxies John Kormendy (B) Thu. 30 (c) Symposia - Week 1 IAUS 288 Astrophysics from Antartica IAUS 290 Accretion on all scales IAUS 291 Neutron Stars and Pulsars IAUS 292 Molecular gas, Dust, and Star Formation in Galaxies (d) Symposia –Week 2 IAUS 289 Advancing the Physics of Cosmic
    [Show full text]
  • The Star Clusters Young & Old Newsletter
    SCYON The Star Clusters Young & Old Newsletter edited by Holger Baumgardt and Ernst Paunzen SCYON can be found at URL: http://www.univie.ac.at/scyon/ SCYONIssueNo.54 February28,2012 EDITORIAL This is the 54th issue of the SCYON newsletter. Todays issue contains 14 abstracts from refereed publications and conference proceedings and a summary of Xiaoying Pang’s PhD thesis on the stellar mass function and mass segregation in NGC 3603. We also have conference announcements for a Saas-Fee winter school on star clusters in March, a workshop on young star clusters in Italy in July this year, the MODEST 12 workshop in Kobe in August 2012 and IAU Symposium 239 on cosmic distance scales also in August 2012. We finally have a job offer for a postdoctoral position at the Pontificia Universidad Catolica de Chile. As usual, we would like to thank all who sent us their contributions. Holger Baumgardt and Ernst Paunzen ................................................... ................................................. CONTENTS Editorial .......................................... ...............................................1 SCYON policy ........................................ ...........................................2 Mirror sites ........................................ ..............................................2 Abstract from/submitted to REFEREED JOURNALS ........... ................................3 1. Star Forming Regions ............................... ........................................3 2. Galactic Open Clusters............................
    [Show full text]
  • THE MAGELLANIC CLOUDS NEWSLETTER an Electronic Publication Dedicated to the Magellanic Clouds, and Astrophysical Phenomena Therein
    THE MAGELLANIC CLOUDS NEWSLETTER An electronic publication dedicated to the Magellanic Clouds, and astrophysical phenomena therein No. 104 — 2 April 2010 http://www.astro.keele.ac.uk/MCnews Editor: Jacco van Loon Editorial Dear Colleagues, It is my pleasure to present you the 104th issue of the Magellanic Clouds Newsletter. Marvel at the MAD images of the heart of the Tarantula Nebula’s nest of massive stars, or be amazed by the three (sic!) papers on SN 1987 A alone (plus one about its surrounding field) and the two papers on supernova remnants and their progenitors by Maoz & Badenes (and Draine). The PDF version of this newsletter contains a two-page advertisement for a special issue of the Royal Society’s Philo- sophical Transactions, on the topic of star clusters. There is an attractive discount being offered on buying this book. This issue does not feature a cover picture as no suggestions were received. They remain very welcome for future issues. The next issue is planned to be distributed on the 1st of June 2010. Editorially Yours, Jacco van Loon 1 Refereed Journal Papers VLT-MAD observations of the core of 30 Doradus M.A. Campbell1, C.J. Evans2,1, A.D. Mackey1, M. Gieles3, J. Alves4, J. Ascenso5, N. Bastian6 and A.J. Longmore2 1Institute for Astronomy, The University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK 2UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK 3European Southern Observatory, Casilla 19001, Santiago 19, Chile 4Calar Alto Observatory-Centro Astron´omico Hispano-Alem´an, C/ Jes´us Durb´an Rem´on 2-2, 04004 Almeria, Spain 5Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA 6Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK We present H- and Ks-band imaging of three fields at the centre of 30 Doradus in the Large Magellanic Cloud, obtained as part of the Science Demonstration programme with the Multi-conjugate Adaptive optics Demonstrator (MAD) at the Very Large Telescope.
    [Show full text]
  • A Likely Planet-Induced Gap in the Disk Around T Cha
    MNRAS 000,1{6 (2017) Preprint 29 November 2017 Compiled using MNRAS LATEX style file v3.0 A likely planet-induced gap in the disk around T Cha Nathanial P. Hendler,1? Paola Pinilla,2 Ilaria Pascucci,1;3 Adriana Pohl,4;5 Gijs Mulders,1;3 Thomas Henning,4 Ruobing Dong,2 Cathie Clarke,6 James Owen,7 David Hollenbach8 1Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721, USA 2Department of Astronomy/Steward Observatory, The University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721, USA 3Earths in Other Solar Systems Team, NASA Nexus for Exoplanet System Science. 4Max Planck Institute for Astronomy, KA}unigstuhl~ 17, D-69117 Heidelberg, Germany 5Heidelberg University, Institute of Theoretical Astrophysics, Albert-Ueberle-Str. 2, D-69120 Heidelberg, Germany 6Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, United Kingdom 7Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540, USA 8SETI Institute, Mountain View, CA 94043, USA 29 November 2017 ABSTRACT We present high resolution (0:1100 × 0:0600) 3 mm ALMA observations of the highly inclined transition disk around the star T Cha. Our continuum image reveals multiple dust structures: an inner disk, a spatially resolved dust gap, and an outer ring. When fitting sky-brightness models to the real component of the 3 mm visibilities, we infer that the inner emission is compact (≤ 1 au in radius), the gap width is between 18- 28 au, and the emission from the outer ring peaks at ∼ 36 au. We compare our ALMA image with previously published 1.6µm VLT/SPHERE imagery.
    [Show full text]
  • Manda Banerji Is a Royal Society University Research Fellow And
    Manda Banerji: Cathie Clarke: Manda Banerji is a Royal Society University Research Fellow and Associate Professor I was educated at a state school in Penzance, in Astronomy at the University of Southampton. Prior to this she spent ten years as Cornwall and was an undergraduate at Clare a postdoctoral researcher at the Institute of Astronomy in Cambridge including College Cambridge where I received a First Class holding an STFC Ernest Rutherford Fellowship during that time. Her research aims to degree in Physics. After a DPhil at understand the co-evolution of galaxies and their central supermassive black holes Oxford, entitled `Accretion discs in binary star and through the exploitation of very large photometric and spectroscopic sky surveys galactic potentials’, I went to the University of primarily at optical and infrared wavelengths. She holds leadership roles within California Santa Cruz as a NATO postdoctoral fellow several international survey projects such as the Vera C. Rubin Observatory Legacy and there became interested in star formation and Survey of Space Time (LSST). Outside of research, she is very interested in equity and protoplanetary disc evolution. I returned to diversity issues in academia and chairs the Southampton School of Physics & Cambridge in 1989 and, apart from one year as a Astronomy ED&I Committee. Any spare time these days goes into the exhausting but lecturer in Queen Mary University of London, have incredibly rewarding job of being mum to 18-month old twins. been at the IoA ever since ! During this time I have variously been a postdoc, College research fellow, Carolin Crawford: research council fellow, University Lecturer, Reader Like so many astronomers, my fascination with space took root at an early age from and, since 2008, Professor of Theoretical gazing at the stars from the back garden.
    [Show full text]
  • 第 28 届国际天文学联合会大会 Programme Book
    IAU XXVIII GENERAL ASSEMBLY 20-31 AUGUST, 2012 第 28 届国际天文学联合会大会 PROGRAMME BOOK 1 Table of Contents Welcome to IAU Beijing General Assembly XXVIII ........................... 4 Welcome to Beijing, welcome to China! ................................................ 6 1.IAU EXECUTIVE COMMITTEE, HOST ORGANISATIONS, PARTNERS, SPONSORS AND EXHIBITORS ................................ 8 1.1. IAU EXECUTIVE COMMITTEE ..................................................................8 1.2. IAU SECRETARIAT .........................................................................................8 1.3. HOST ORGANISATIONS ................................................................................8 1.4. NATIONAL ADVISORY COMMITTEE ........................................................9 1.5. NATIONAL ORGANISING COMMITTEE ..................................................9 1.6. LOCAL ORGANISING COMMITTEE .......................................................10 1.7. ORGANISATION SUPPORT ........................................................................ 11 1.8. PARTNERS, SPONSORS AND EXHIBITORS ........................................... 11 2.IAU XXVIII GENERAL ASSEMBLY INFORMATION ............... 14 2.1. LOCAL ORGANISING COMMITTEE OFFICE .......................................14 2.2. IAU SECRETARIAT .......................................................................................14 2.3. REGISTRATION DESK – OPENING HOURS ...........................................14 2.4. ON SITE REGISTRATION FEES AND PAYMENTS ................................14
    [Show full text]
  • Imprints of Dynamical Interactions on Brown Dwarf Pairing Statistics and Kinematics
    A&A 400, 1031–1042 (2003) Astronomy DOI: 10.1051/0004-6361:20030073 & c ESO 2003 Astrophysics Imprints of dynamical interactions on brown dwarf pairing statistics and kinematics M. F. Sterzik1 and R. H. Durisen2 1 European Southern Observatory, Casilla 19001, Santiago 19, Chile 2 Department of Astronomy, SW319, Indiana University, Bloomington, Indiana 47405, USA Received 6 December 2002 / Accepted 15 January 2003 Abstract. We present statistically robust predictions of brown dwarf properties arising from dynamical interactions during their early evolution in small clusters. Our conclusions are based on numerical calculations of the internal cluster dynamics as well as on Monte-Carlo models. Accounting for recent observational constraints on the sub-stellar mass function and ini- tial properties in fragmenting star forming clumps, we derive multiplicity fractions, mass ratios, separation distributions, and velocity dispersions. We compare them with observations of brown dwarfs in the field and in young clusters. Observed brown dwarf companion fractions around 15 7% for very low-mass stars as reported recently by Close et al. (2003) are consistent with certain dynamical decay models.± A significantly smaller mean separation distribution for brown dwarf binaries than for binaries of late-type stars can be explained by similar specific energy at the time of cluster formation for all cluster masses. Due to their higher velocity dispersions, brown-dwarfs and low-mass single stars will undergo time-dependent spatial segregation from higher-mass stars and multiple systems. This will cause mass functions and binary statistics in star forming regions to vary with the age of the region and the volume sampled.
    [Show full text]
  • Circumstellar Discs: What Will Be Next?
    Circumstellar discs: What will be next? Quentin Kral, Cathie Clarke and Mark Wyatt Abstract This prospective chapter gives our view on the evolution of the study of circumstellar discs within the next 20 years from both observational and theoretical sides. We first present the expected improvements in our knowledge of protoplan- etary discs as for their masses, sizes, chemistry, the presence of planets as well as the evolutionary processes shaping these discs. We then explore the older debris disc stage and explain what will be learnt concerning their birth, the intrinsic links between these discs and planets, the hot dust and the gas detected around main se- quence stars as well as discs around white dwarfs. Protoplanetary discs Protoplanetary discs are the discs of gas and dust that surround a significant fraction of stars with ages less than a few - 10 Myr. The best studied exam- ples are located in nearby star forming clouds (typically around 150 pc from the Earth) but evidence of discs is found in more distant clusters and even in star forming regions in the Magellanic Clouds. Protoplanetary discs are often termed ‘primordial discs’ in order to indicate that they are composed of mate- rial from the local interstellar medium which has collapsed into a centrifugally supported disc around the young star. Their typical gas and dust inventories (tens of Jupiter masses and tens to hundreds of Earth masses respectively) imply that at this stage they have sufficient material to form (exo-)planetary systems. Nevertheless, it is clear that not all the material in protoplanetary discs is destined to turn into planets.
    [Show full text]
  • Curriculum Vitae of Fei
    Fei Dai Website: http://www.astro.caltech.edu/~fdai Division of Geological and Planetary Sciences Phone: +1-(781)-290-9672 Caltech, 1200 East California Blvd Email: [email protected] Pasadena CA 91125 Education Massachusetts Institute of Technology [2014-2019] Ph.D. in Physics; Advisor: Prof. Joshua N. Winn University of Cambridge, UK [2010-2014] B.A. of Natural Sciences; M.Sci of Physics, First Class Honors Professional Appointment & Research Experience California Institute of Technology [2019-Present] GPS Chair’s Postdoctoral Fellow, Division of Geological and Planetary Sciences Princeton University [2017-2019] Visiting Graduate Student, Department of Astrophysical Sciences Institute of Astronomy, University of Cambridge, UK [2013-2014] Supervisor: Prof. Cathie Clarke Leibniz Institute for Astrophysics, Potsdam, Germany [2013 Summer] DAAD RISE Research Program; Supervisor: Dr. Rainer Arlt Institute of Astronomy, University of Cambridge, UK [2012 Summer] Summer Internship; Supervisor: Dr. Grant Kennedy Publications Total Refereed: 84; 1st-authored: 12; Citations: 1699; h-index: 25; i10-index: 48 First-Author Publications [1] F Dai, A Howard, N Batalha, et al., 2021, The Astronomical Journal, 162, 62, ADS The TESS-Keck Survey. X: TOI-1444b and a Comparative Analysis of the Ultra-short-period Planets with Hot Neptunes [2] F Dai, R Roy, BJ Fulton, et al. 2020, The Astronomical Journal, 160, 193, ADS The TESS-Keck Survey. III. A Stellar Obliquity Measurement of TOI-1726 c [3] F Dai, JN Winn, K Schlaufman, et al., 2020, The Astronomical Journal,
    [Show full text]
  • Short Period Binary Star Formation: Simulating the Fission Model with the Addition of Large Circumstellar Disks
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by University of Oregon Scholars' Bank SHORT PERIOD BINARY STAR FORMATION: SIMULATING THE FISSION MODEL WITH THE ADDITION OF LARGE CIRCUMSTELLAR DISKS by CARL RANNEY A THESIS Presented to the Department of Physics and the Robert D. Clark Honors College in partial fulfillment of the requirements for the degree of Bachelor of Science June 2018 An Abstract of the Thesis of Carl Ranney for the degree of Bachelor of Science in the Department of Physics to be taken June 2018 Title: Short Period Binary Star Formation: Simulating the Fission Model with the Addition of Large Circumstellar Disks Approved: _______________________________________ Doctor James Imamura The purpose of this research is to determine the validity of the fission model of short orbital period binary star formation. The fission model describes the process in which a protostar with a rapid rotation splits into two bodies which then orbit around a common center of mass. The fission model is one of the three major models currently under investigation by the wider astrophysical community as possible sources for the formation of short orbital period binary star systems. While fission has not received much attention in the last two decades due to results found in large scale numerical simulations, the advances in computational power now available allow much more complex simulations that show promise in solving this problem. Rather than looking at single stars, we are simulating the evolution of a rotating protostar with a large circumstellar disk that is approaching a reverse Roche limit, where the mass of the disk starts to pull the protostar apart.
    [Show full text]