DOCSLIB.ORG

Characterizing Exocomet Composition Thanks to Spectroscopy and Photometry (Ground and Space-Based)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Characterizing exocomet composition thanks to spectroscopy and photometry (ground and space-based) Flavien Kiefer Institut d'Astrophysique de Paris Exocomets worshop - 14 may 2019 Contents 1. Gas detections 1.1. Spectroscopic detections 1.2. Metals and carbon : comparison with Sun, Halley and chondrites 1.3. Difficulties of spectroscopy 2. Dust detections 2.1. Photometry of exocomet transits 2.2. Simulations and measure of dust production rate 2.3. Few systems with dust detected 3. Conclusions & Perspectives Gas detections with spectroscopy • First observations of exocomets in the Beta Pic system with ground-based visible spectroscopy (1987,90's up to now) • Detection of calcium (with Ca II) -> an ingredient of comets (silicate dust) in the Solar system with mass abundance ~1%. • Variability, saturation, redshift -> small gaseous clouds in motion towards the star • UV spectroscopy with HST and GHRS then STIS and COS (1994 and so on up until 2019) • Detection of other metals : Al, Fe, Mg mainly, all ionized and some strongly ionized (Al III, CIV). • Volatiles (ices) : C I, CII, and C IV • Spectroscopy of the disk : detection of CO, C etc. • Carbon-rich (Roberge+2006) and oxygen-rich (Brandeker+ 2016) • Clumps of CO in the disk (Wyatt+ 2014) • Presence of the metals detected in exocomets The historical observations of variability in Beta Pic Ca II K line by Ferlet+ (1987) with the Echelle Spectrograph at La Silla Ferlet+ (1987) First difficulties : - Short term variability < 1 day - Strong blends The same spectrum 27 years later with HARPS and more than 1500 spectra... Kiefer+ 2014 When we divide by the reference spectrum accounting for the circumstellar line Shallow absorptions : Often saturated High velocity Large width & Blend Deep absorptions : >50 % of the stellar disk Low velocity Blend w/ disk & saturation Always difficult to deal with the center of the CS line Almost saturated Ca II K line partial coverage Ca II H line Not saturated Saturated Kiefer+ 2014 Ca II K and Fe I simultaneous Welsh & Montgomery 2016 Ca II / Fe I ~ 0.25 with N(Ca II)~1012 cm-2 But Fe I << Fe II (x10-100) (Kiefer+ 2019) Ca / Fe ~ 0.0025-0.025 Fe II variations in Beta Pic in UV band (HST) Vidal-Madjar+ 1994, Lagrange+ 1995 Fe II variations in different lines Fe II variations at different dates - Strong blends, - Day-to-day variability, - Saturations, - Cannot relie on column densities... Al III variations in Beta Pic (UV with HST) Vidal-Madjar+ 1994 19 Dec. 1992 at 15:41 20 Dec. 1992 at 08:09 • Highly ionized species, • Different saturation regimes at different redshifts, • Small coverage of the stellar disk <50 % • UV flux is not sufficient for an A-star like Beta Pic to explain ionisation of Al II or C III. • known as the Al III problem (Beta Pic papers IV, V, VIII, XIII, XIV) • The presence of a shock surface (Beust & Tagger 1993) at the front the ejected coma in the stellar direction solves the issue. -> many collisions -> A new semi-analytical model of exocomet cloud Mg II variations in Beta Pic (UV with HST) Vidal-Madjar+ 1994 • Saturated lines • Small covering fraction of stellar disk ~50% • High redshift -> 200 km/s • star grazers at less than 5 Rstar to Beta Pic • Typical asymetrical shape => well reproduced by simulations Carbon detections (UV with HST) CI Roberge+ 2000 CI multiplets Other difficult (non) detections in UV... Vidal-Madjar+ 1994, Lagrange+ 1995, Kiefer+ (in prep.) Zn II OH Very very tiny... Nope... this is not OH... this is probably Ti II Do you see something ??? Two CO lines but only the disk... and noise ! Roberge+ 2006, Nature Roberge+ 2006, Nature Only Mg I Vidal-Madjar+ 1994 Fe II + Mg I + Zn II + Al III Lagrange+ 1995 Fe II + Ca II + Mn II Jolly+ 1998 Welsh & Montgomery 2016 - 50 km/s Ca II + C II Welsh & Montgomery 2016 Ca II + Fe I Roberge+ 2006, Nature Mg II/Mg I > 100 Roberge+ 2006 Vidal-Madjar+ 1994 Fe II + Mg I + Zn II + Al III Lagrange+ 1995 Fe II + Ca II + Mn II Jolly+ 1998 Welsh & Montgomery 2016 - 50 km/s Ca II + C II Welsh & Montgomery 2016 Ca II + Fe I UV variations in another A-star : 49 Ceti Miles+ 2016 C II, OI, Fe II dominant ions C/Fe > 10 C/O > 1.5 Volatile rich comets ? Other source of carbon ? Welsh & Montgomery 2016 - 50 km/s • Metals + carbon abundances in exocomets and in the disk of Beta Pic better compatible with Halley comet than with CI-chondrites => volatile rich objects (CO ice ?) => other carbon reservoirs ? • C & O neat overabundance in the disk ➡ A possible clue to the presence of massive amounts of CO ice in exocomet of Beta Pic. ➡ Possibly not enough to explain the excessive abundance of oxygen (Brandeker+ 2016) ➡ Means of gas braking to explain that the gas is not constantly falling onto the star. • CO absorptions detected in the inner disk + the diverse emissions in the outer disk • Yet we don't have CO or OH direct detections in exocomets... The main difficulties of spectroscopy • Absorption lines are often saturated => cannot use the curve of growth and derive column densities • Divide stellar continuum when many absorptions + blend => need a good reference spectrum, => only achievable when lots of spectra (see eg. Ca II) • Obtaining (quasi) simultaneous measurements in different bands. => Possible with eg. HST + ground-based. • Careful, one comet at less than 1 au need less than 6h to transit the stellar disk (high day-to-day, or hour-to-hour variability) • Difficult to interpret the absorptions in term of column densities (except if not saturated). Dust detection with photometry from space (Kepler, TESS...) • Dust apart from ices is one of the main ingredient of a comet in the solar system. • The various metals evaporated and observed in spectroscopy are originating from the dust. • The dust form a tail in the anti-stellar direction with a deformation due to the orbital motion of the comet. • Dust can be seen transiting with photometry. Several observations in Kepler systems (Rappaport+ 2017, Boyajian+ 2016, Kiefer+ 2017), or in Beta Pic (Zieba et al. 2019). • Composition of dust unknown: Olivine ? Pyroxène ? Halley-like ? KIC11084727 (Kepler) Rappaport+ 2018 Beta Pic (TESS) Zieba+ 2019 PC multi-coeur (simu) Lecavelier+ 1999 KIC8462852 (Kepler) Kiefer+ 2017 KIC3542116 (Kepler) Rappaport+ 2018 KIC11084727 (Rappaport+ 2018) Simu by Lecavelier Grain size ~0.1-1µm Distance ~0.5 au Dust rate ~107 kg/s This is 100 times larger than for Hale-Bopp, but for F3- star and at less than 1 au from the star. • Simulations of the 0.2%-deep Beta Pic transit event of Zieba+ (2019) would also lead to dust production rate about 107 kg/s (compatible with spectroscopy) • KIC8462852, strings of comets have production rates of the Hale-Bopp type (106 kg/s at 1 au), Kiefer+ 2017 Summary and conclusion On the composition of exocomets • Many metals (ions mostly) and carbon, • Abundances similar to Halley comet, • But saturation of spectral absorption lines (to be taken w/ care), • But different redshits, different cloud size and opacities, • Shock front ahead the coma to explain highly ionized Al and C, • Dust production rate on the order of 107 perhaps 108 kg/s. • Good compatibility of dust model with data of grain of size 0.1-1µm Issues and still unknown features: • Yet no simultaneous absorptions in spectroscopy and photometry, • Difficult measurements of gas species of a same exocomet, • Dust/gas ratio ? • Abundances of species in dust ? • OH, water ? CO ? • Isotopes ratios ? 12C/13C, D/H.... I EXOCOMETS.
Recommended publications
  • Cometary Impactors on the TRAPPIST-1 Planets Can Destroy All Planetary Atmospheres and Rebuild Secondary Atmospheres on Planets F, G, H

    Cometary Impactors on the TRAPPIST-1 Planets Can Destroy All Planetary Atmospheres and Rebuild Secondary Atmospheres on Planets F, G, H

    Mon. Not. R. Astron. Soc. 000, 1{28 (2002) Printed 4 July 2018 (MN LATEX style file v2.2) Cometary impactors on the TRAPPIST-1 planets can destroy all planetary atmospheres and rebuild secondary atmospheres on planets f, g, h Quentin Kral,1? Mark C. Wyatt,1 Amaury H.M.J. Triaud,1;2 Sebastian Marino, 1 Philippe Th´ebault, 3 Oliver Shorttle, 1;4 1Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 2School of Physics & Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK 3LESIA-Observatoire de Paris, UPMC Univ. Paris 06, Univ. Paris-Diderot, France 4Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK Accepted 1928 December 15. Received 1928 December 14; in original form 1928 October 11 ABSTRACT The TRAPPIST-1 system is unique in that it has a chain of seven terrestrial Earth-like planets located close to or in its habitable zone. In this paper, we study the effect of potential cometary impacts on the TRAPPIST-1 planets and how they would affect the primordial atmospheres of these planets. We consider both atmospheric mass loss and volatile delivery with a view to assessing whether any sort of life has a chance to develop. We ran N-body simulations to investigate the orbital evolution of potential impacting comets, to determine which planets are more likely to be impacted and the distributions of impact velocities. We consider three scenarios that could potentially throw comets into the inner region (i.e within 0.1au where the seven planets are located) from an (as yet undetected) outer belt similar to the Kuiper belt or an Oort cloud: Planet scattering, the Kozai-Lidov mechanism and Galactic tides.
  • Perturbation of the Oort Cloud by Close Stellar Encounter with Gliese 710

    Perturbation of the Oort Cloud by Close Stellar Encounter with Gliese 710

    Bachelor Thesis University of Groningen Kapteyn Astronomical Institute Perturbation of the Oort Cloud by Close Stellar Encounter with Gliese 710 August 5, 2019 Author: Rens Juris Tesink Supervisors: Kateryna Frantseva and Nickolas Oberg Abstract Context: Our Sun is thought to have an Oort cloud, a spherically symmetric shell of roughly 1011 comets orbiting with semi major axes between ∼ 5 × 103 AU and 1 × 105 AU. It is thought to be possible that other stars also possess comet clouds. Gliese 710 is a star expected to have a close encounter with the Sun in 1.35 Myrs. Aims: To simulate the comet clouds around the Sun and Gliese 710 and investigate the effect of the close encounter. Method: Two REBOUND N-body simulations were used with the help of Gaia DR2 data. Simulation 1 had a total integration time of 4 Myr, a time-step of 1 yr, and 10,000 comets in each comet cloud. And Simulation 2 had a total integration time of 80,000 yr, a time-step of 0.01 yr, and 100,000 comets in each comet cloud. Results: Simulation 2 revealed a 1.7% increase in the semi-major axis at time of closest approach and a population loss of 0.019% - 0.117% for the Oort cloud. There was no statistically significant net change of the inclination of the comets during this encounter and a 0.14% increase in the eccentricity at the time of closest approach. Contents 1 Introduction 3 1.1 Comets . .3 1.2 New comets and the Oort cloud . .5 1.3 Structure of the Oort cloud .
  • Week 5: January 26-February 1, 2020

    Week 5: January 26-February 1, 2020

    5# Ice & Stone 2020 Week 5: January 26-February 1, 2020 Presented by The Earthrise Institute About Ice And Stone 2020 It is my pleasure to welcome all educators, students, topics include: main-belt asteroids, near-Earth asteroids, and anybody else who might be interested, to Ice and “Great Comets,” spacecraft visits (both past and Stone 2020. This is an educational package I have put future), meteorites, and “small bodies” in popular together to cover the so-called “small bodies” of the literature and music. solar system, which in general means asteroids and comets, although this also includes the small moons of Throughout 2020 there will be various comets that are the various planets as well as meteors, meteorites, and visible in our skies and various asteroids passing by Earth interplanetary dust. Although these objects may be -- some of which are already known, some of which “small” compared to the planets of our solar system, will be discovered “in the act” -- and there will also be they are nevertheless of high interest and importance various asteroids of the main asteroid belt that are visible for several reasons, including: as well as “occultations” of stars by various asteroids visible from certain locations on Earth’s surface. Ice a) they are believed to be the “leftovers” from the and Stone 2020 will make note of these occasions and formation of the solar system, so studying them provides appearances as they take place. The “Comet Resource valuable insights into our origins, including Earth and of Center” at the Earthrise web site contains information life on Earth, including ourselves; about the brighter comets that are visible in the sky at any given time and, for those who are interested, I will b) we have learned that this process isn’t over yet, and also occasionally share information about the goings-on that there are still objects out there that can impact in my life as I observe these comets.
  • An Exocomet in the Fomalhaut System: Simulating Gas and Dust Emission in a Debris Disk

    An Exocomet in the Fomalhaut System: Simulating Gas and Dust Emission in a Debris Disk

    EPSC Abstracts Vol. 13, EPSC-DPS2019-1649-1, 2019 EPSC-DPS Joint Meeting 2019 c Author(s) 2019. CC Attribution 4.0 license. An exocomet in the Fomalhaut system: simulating gas and dust emission in a debris disk Maria Teresa Capria (1), Diego Turrini (1) and Edoardo Rognini (1) (1) INAF-IAPS, Rome, Italy (mariateresa.capria @inaf.it) Abstract by the sublimation of the ices and undergo the drag exerted by the escaping gas. The model is being used A thermophysical model is being used to simulate the to compute the amount of gas and dust released from behaviour of a cometary nucleus following an orbit the nucleus along an orbit, both in presence and in the Fomlhaut debris disc. We study the amount of absence of gas from the circumstellar disc. The CO gas and dust released during a typical orbit, and chosen orbit has the aphelion at 170 au and the compare them with the ALMA observations. We also perihelion at 140 au. We are willing to study the evaluate the survival of the body on a very long time amount of CO gas and dust released during a typical span. orbit, and compare these emissions with the ALMA observations. We are also willing to derive the total mass lost by the exocomet during an orbit and study 1. Introduction its long-time activity of the comet, in order to A number of debris disks around main sequence stars evaluate the survival of the body on a very long time have are now been identified [1], and in some of span.
  • The Appearance and Disappearance of Exocomet Gas Absorption

    The Appearance and Disappearance of Exocomet Gas Absorption

    Hindawi Publishing Corporation Advances in Astronomy Volume 2015, Article ID 980323, 20 pages http://dx.doi.org/10.1155/2015/980323 Research Article The Appearance and Disappearance of Exocomet Gas Absorption Barry Y. Welsh1 and Sharon L. Montgomery2 1 Experimental Astrophysics Group, Space Sciences Laboratory, University of California, 7 Gauss Way, Berkeley, CA 94720, USA 2Department of Chemistry, Mathematics & Physics, Clarion University, Clarion, PA 16214, USA Correspondence should be addressed to Barry Y. Welsh; [email protected] Received 30 March 2015; Accepted 9 June 2015 Academic Editor: De-Fu Bu Copyright © 2015 B. Y. Welsh and S. L. Montgomery. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. CaII K-line (3933 A)˚ absorption profiles observed towards 15 A-type and two B-type stars with known (or suspected) debris disks, in addition to archival spectral data for three A-type stars, are presented. Inspection of the extracted CaII K-line absorption lines has determined that one late B-type (HD 58647) and four new A-type (HD 56537, HD 64145, HD 108767, and HD 109573) stellar systems exhibit short-term (night-to-night) absorption variation within these profiles. This variability is due to the liberation of gas from falling evaporating bodies (the so-called FEBs activity) on the grazing approach of exocomets towards their parent star. Also we present archival spectra of the FeI 3860 A˚ and CaII K-lines towards Pictoris (HD 39060) that, for the first time, reveal the absorption signatures of FEB activity at similar velocities in both line profiles.
  • XV Congresso Nazionale Di Scienze Planetarie PRESIDENTE DEL CONGRESSO: Giovanni Pratesi

    XV Congresso Nazionale Di Scienze Planetarie PRESIDENTE DEL CONGRESSO: Giovanni Pratesi

    https://doi.org/10.3301/ABSGI.2019.01 Firenze, 4-8 Febbraio 2019 ABSTRACT BOOK a cura della Società Geologica Italiana XV Congresso Nazionale di Scienze Planetarie PRESIDENTE DEL CONGRESSO: Giovanni Pratesi. COMITATO SCIENTIFICO: Giovanni Pratesi, Emanuele Pace, Marco Benvenuti, John Brucato, Fabrizio Capaccioni, Sandro Conticelli, Aldo Dell’Oro, Carlo Alberto Garzonio, Daniele Gardiol, Monica Lazzarin, Alessandro Marconi, Lucia Mari- nangeli, Giuseppina Micela, Ettore Perozzi, Alessandro Rossi, Alessandra Rotundi. COMITATO ORGANIZZATORE: Cristian Carli, Mario Di Martino, Livia Giacomini, Vanni Moggi Cecchi, Emanuele Pace, Giovanni Pratesi, Giovanni Valsecchi. CURATORI DEL VOLUME Giovanni Pratesi, Fabrizio Capaccioni, Emanuele Pace, John Brucato, Marco Benvenuti, Sandro Conti- celli, Aldo Dell’Oro, Daniele Gardiol, Carlo Alberto Garzonio, Monica Lazzarin, Alessandro Marconi, Lucia Marinangeli, Giuseppina Micela, Ettore Perozzi, Alessandro Rossi, Alessandra Rotundi. Papers, data, figures, maps and any other material published are covered by the copyright own by the Società Geologica Italiana. DISCLAIMER: The Società Geologica Italiana, the Editors are not responsible for the ideas, opinions, and contents of the papers published; the authors of each paper are responsible for the ideas opinions and con- tents published. La Società Geologica Italiana, i curatori scientifici non sono responsabili delle opinioni espresse e delle affermazioni pubblicate negli articoli: l’autore/i è/sono il/i solo/i responsabile/i. ABSTRACT INDEX EDUCARE ALLA
  • Oumuamua (A/2017U1) – a Confirmation of Links Between Galactic Planetary Systems

    Oumuamua (A/2017U1) – a Confirmation of Links Between Galactic Planetary Systems

    Advances in Astrophysics, Vol. 3, No. 1, February 2018 https://dx.doi.org/10.22606/adap.2018.31003 43 Oumuamua (A/2017U1) – A Confirmation of Links between Galactic Planetary Systems N. Chandra Wickramasinghe1,2,3, Edward J. Steele4,2, Daryl. H. Wallis1, Robert Temple5, Gensuke Tokoro2,3, Janaki T. Wickramasinghe1 1Buckingham Centre for Astrobiology, University of Buckingham, UK 2Centre for Astrobiology, University of Ruhuna, Matara, Sri Lanka 3Institute for the Study of Panspermia and Astrobiology, Gifu, Japan 4CY O'Connor ERADE Village Foundation, Piara Waters,WA, Australia 5The History of Chinese Culture Foundation, Conway Hall, London, UK Email: [email protected] Abstract. The detection of an extra-solar asteroid/comet/bolide reaching the inner solar system in a hyperbolic orbit confirms the existence of a continuing material link with alien planetary systems. The Aristotelean view that the Earth and life upon are isolated from the external universe is now further challenged. Keywords: Comets, planets, life 1 Introduction Recent observations from the Kepler Mission have revealed that planetary systems similar to our solar system are exceedingly commonplace in the galaxy. The total tally of habitable exoplanets has been given as upwards of 100 billion (Kopperapu et al., 2013) [1]. Since comets and asteroids form an integral component of our solar system it would be reasonable to infer that they are also common in other planetary systems. The detection of such exocomets is, however, not easy and only in one case, the Kepler star KIC2542116, is there direct evidence of transiting comets (Rappaport et al., 2017) [2]. 2 Long-period Comets Comets belong to the family of minor bodies of the solar system that include asteroids, meteoroids, bodies in the Kuiper Belt and the Oort cloud, small planetary satellites and Trans-Neptunian Objects, including the planetoid Sedna.
  • Cometary Impactors on the TRAPPIST-1 Planets Can Destroy All Planetary Atmospheres and Rebuild Secondary Atmospheres on Planets F, G, and H

    Cometary Impactors on the TRAPPIST-1 Planets Can Destroy All Planetary Atmospheres and Rebuild Secondary Atmospheres on Planets F, G, and H

    MNRAS 479, 2649–2672 (2018) doi:10.1093/mnras/sty1677 Advance Access publication 2018 June 26 Cometary impactors on the TRAPPIST-1 planets can destroy all planetary atmospheres and rebuild secondary atmospheres on planets f, g, and h Quentin Kral,1‹ Mark C. Wyatt,1 Amaury H. M. J. Triaud,1,2 Sebastian Marino,1 Philippe Thebault´ 3 and Oliver Shorttle1,4 1Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 2School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK 3LESIA-Observatoire de Paris, UPMC Univ. Paris 06, Univ. Paris-Diderot, France 4Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK Accepted 2018 June 19. Received 2018 June 13; in original form 2018 February 14 ABSTRACT The TRAPPIST-1 system is unique in that it has a chain of seven terrestrial Earth-like planets located close to or in its habitable zone. In this paper, we study the effect of potential cometary impacts on the TRAPPIST-1 planets and how they would affect the primordial atmospheres of these planets. We consider both atmospheric mass loss and volatile delivery with a view to assessing whether any sort of life has a chance to develop. We ran N-body simulations to investigate the orbital evolution of potential impacting comets, to determine which planets are more likely to be impacted and the distributions of impact velocities. We consider three scenarios that could potentially throw comets into the inner region (i.e. within 0.1 au where the seven planets are located) from an (as yet undetected) outer belt similar to the Kuiper belt or an Oort cloud: planet scattering, the Kozai–Lidov mechanism, and Galactic tides.
  • On the Dynamics of Comets in Extrasolar Planetary Systems

    On the Dynamics of Comets in Extrasolar Planetary Systems

    On the Dynamics of Comets in Extrasolar Planetary Systems R. Dvorak ∗ B. Loibnegger ∗ M. Cuntz ∗∗ ∗ Institute of Astronomy, University of Vienna, A-1180 Vienna, Austria ∗∗ Department of Physics, University of Texas at Arlington, Arlington, TX 76019, USA Abstract: Since very recently, we acquired knowledge on the existence of comets in extrasolar planetary systems. The formation of comets together with planets around host stars now seems evident. As stars are often born in clusters of interstellar clouds, the interaction between the systems will lead to the exchange of material at the edge of the clouds. Therefore, almost every planetary system should have leftover remnants as a result of planetary formation in form of comets at the edges of those systems. These Oort clouds around stars are often disturbed by different processes (e.g., galactic tides, passing stars, etc.), which consequently scatter bodies from the distant clouds into the system close to the host star. Regarding the Solar System, we observe this outcome in the form of cometary families. This knowledge supports the assumption of the existence of comets around other stars. In the present work, we study the orbital dynamics of hypothetical exocomets, based on detailed computer simulations, in three star-planet systems, which are: HD 10180, 47 UMa, and HD 141399. These systems host one or more Jupiter-like planets, which change the orbits of the incoming comets in characteristic ways. Keywords: astrobiology | comets: general | extrasolar planets | methods: numerical | stars: individual (HD 10180, 47 UMa, HD 141399) 1. INTRODUCTION [e.g., Raymond and Izidoro, 2017] 2 . Considering the large number of comets which entered the inner Solar System For thousands of years the non-predictability of the ap- and collided with the Earth during the last billions of pearance of comets contrary to the motion of the planets, years, it is worth to pursue statistical analyses for these the Sun, and the Moon led astronomers to the assump- events in extrasolar planetary systems as well.
  • Newsletter Submillimeter Array Newsletter Number 26 | July 2018

    Newsletter Submillimeter Array Newsletter Number 26 | July 2018

    SMA Newsletter Submillimeter Array Newsletter Number 26 | July 2018 CONTENTS FROM THE DIRECTOR 1 From the Director SCIENCE HIGHLIGHTS: Dear SMA Newsletter readers, 2 On the Detection of a Dusty Star-Forming Galaxy in the Early As many readers will know, we are engaged in a major upgrade program, the wSMA, which Universe at Z=6 will dramatically increase the SMA’s bandwidth, polarimetry capability, and operational 4 High-resolution SMA Imaging of Bright Submillimetre Sources efficiency and reliability. Interested readers can find the white paper outlining the science From the SCUBA-2 Cosmology Legacy Survey case for the wSMA as SMA Memo 165 (https://www.cfa.harvard.edu/sma/memos/165.pdf). 8 SMA Observations of Polarized During the past two years, we have conducted a number of engineering studies in support of Dust Emission in Solar-type Class 0 Protostars: Magnetic the wSMA, and have completed the design and prototyping of several critical components Field Properties at Envelope and subsystems. Scales bu Star Formation in a High- pressure Environment: An SMA We recently took a major step towards making the wSMA a reality by awarding the first of View of the Galactic Centre a series of major contracts; this one to High Precision Devices, Inc. Under the terms of this Dust Ridge contract, HPD, working from a conceptual design developed in the Receiver Lab, will produce bn Molecular Reconnaissance of the β Pictoris Exocometary Gas Disk the detailed design, then build and test two prototype cryostat systems including blank bq Resolved Millimeter receiver cartridges to be delivered to SAO next year.
  • Exocomets from a Solar System Perspective

    Exocomets from a Solar System Perspective

    Exocomets from a solar system perspective Strøm, P. A., Bodewits, D., Knight, M. M., Kiefer, F., Jones, G. H., Kral, Q., Matrà, L., Bodman, E., Capria, M. T., Cleeves, I., Fitzsimmons, A., Haghighipour, N., Harrison, J. H. D., Iglesias, D., Kama, M., Linnartz, H., Majumdar, L., de Mooij, E. J. W., Milam, S. N., ... Zieba, S. (2020). Exocomets from a solar system perspective. Publications of the Astronomical Society of the Pacific, 132(1016), 1-19. [101001]. https://doi.org/10.1088/1538- 3873/aba6a0 Published in: Publications of the Astronomical Society of the Pacific Document Version: Publisher's PDF, also known as Version of record Queen's University Belfast - Research Portal: Link to publication record in Queen's University Belfast Research Portal Publisher rights Copyright 2020 the authors. This is an open access article published under a Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The Research Portal is Queen's institutional repository that provides access to Queen's research output. Every effort has been made to ensure that content in the Research Portal does not infringe any person's rights, or applicable UK laws. If you discover content in the Research Portal that you believe breaches copyright or violates any law, please contact [email protected].
  • The Little Dippers: Transits of Star-Grazing Exocomets?

    The Little Dippers: Transits of Star-Grazing Exocomets?

    MNRAS 000,1{14 (2018) Preprint 3 December 2018 Compiled using MNRAS LATEX style file v3.0 The Little Dippers: Transits of Star-grazing Exocomets? M. Ansdell,1;2? E. Gaidos,3 T. L. Jacobs,4 A. Mann,5;6 C. F. Manara,7 G. M. Kennedy,8;9 A. Vanderburg,10;11 M. Kenworthy,12 T. Hirano,13;14 D. M. LaCourse15, C. Hedges16, A. Frasca17 1Center for Integrative Planetary Science, University of California at Berkeley, Berkeley, CA 94720, USA 2Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720, USA 3Department of Geology & Geophysics, University of Hawai`i at M¯anoa, Honolulu, HI, USA 4Amateur Astronomer, 12812 SE 69th Place Bellevue, WA 98006 5Columbia University, Department of Astronomy, 550 West 120th Street, New York, NY 10027 6Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255, USA 7European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Munchen,¨ Germany 8Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK 9Centre for Exoplanets and Habitability, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK 10Department of Astronomy, The University of Texas at Austin, Austin, TX 78712, USA 11NASA Sagan Fellow 12Leiden Observatory, Leiden University, Niels Bohrweg 2, NL-2333 RA Leiden, the Netherlands 13Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan 14Institute for Astronomy, University of Hawai`i at M¯anoa, Honolulu, HI 96822, USA 15Amateur Astronomer, 7507 52nd Place NE, Marysville, WA, 98270 16NASA Ames Research Center, Moffett Blvd, Mountain View, CA 94035, USA 17INAF - Osservatorio Astrofisico di Catania, via S.