DOCSLIB.ORG

Hunting for Frozen Super-Earths Via Microlensing

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Hunting for Frozen Super-Earths Via Microlensing Astronomical Science Hunting for Frozen Super-Earths via Microlensing Jean-Philippe Beaulieu1,3 8 Boyden Observatory, University of of cold telluric planets. Its detection Michael Albrow1,4 the Free State, Department of Physics, confirms the power of this method and, Dave Bennett1,5 Bloemfontein, South Africa given our detection efficiency, suggests Stéphane Brillant 1,6 9 Astronomisches Rechen-Institut (ARI), that these recently-detected planets John A. R. Caldwell1,7 Zentrum für Astronomie, Universität may be quite common around M stars, Johannes J. Calitz1,8 Heidelberg, Germany as confirmed by subsequent detection Arnaud Cassan1,9 10 Lawrence Livermore National Labora- of a ~ 13 Earth-mass planet. Using a Kem H. Cook1,10 tory, Livermore, California, USA network of dedicated 1–2-m-class tele- Christian Coutures1,3 11 University of Tasmania, School of scopes, we have entered a new phase Stefan Dieters 1,11 Mathematics and Physics, Hobart, of planet discovery, and will be able to Martin Dominik1,2,12,13 Tasmania, Australia provide constraints on the abundance Dijana Dominis-Prester1,14 12 Scottish Universities Physics Alliance, of frozen Super-Earths in the near future. Jadzia Donatowicz1,15 University of St Andrews, School of Pascal Fouqué1,16 Physics and Astronomy, St Andrews, John Greenhill1,11 United Kingdom The discovery of extrasolar planets is ar- Kym Hill1,11 13 Royal Society University Research guably the most exciting development Matie Hoffman1,8 Fellow in astrophysics during the past decade, Uffe G. Jørgensen1,17 14 University of Rijeka, Physics Depart- rivalled only by the discovery of the cos- Stephen Kane1,18 ment, Faculty of Arts and Sciences, mic acceleration. The unexpected variety Daniel Kubas1,6 Rijeka, Croatia of giant exoplanets, some very close Jean-Baptiste Marquette1,3 15 Technische Universität Wien, Austria to their stars, many with high orbital ec- Ralph Martin1,19 16 Observatoire Midi-Pyrénées, Labora- centricity, has sparked a new generation Pieter Meintjes1,8 toire d’Astrophysique, Université Paul of observers and theorists to address John Menzies1,20 Sabatier, Toulouse, France the question of how planets form in the Karen Pollard1,4 17 Niels Bohr Institutet, Astronomisk context of protostellar accretion discs. Kailash Sahu1,21 Observatorium, København, Denmark Planets are now known to migrate and Christian Vinter1,17 18 Department of Astronomy, University of maybe even be ejected, via planet-disc Joachim Wambsganss1,9 Florida, Gainesville, Florida, USA and planet-planet interactions. We are Andrew Williams1,19 19 Perth Observatory, Perth, Australia beginning to discover how our Solar Sys- Kristian Woller1,17 20 South African Astronomical Observa- tem fits into a broader community of Marta Zub1,9 tory planetary systems, many with very differ- Keith Horne1,2,12 21 Space Telescope Science Institute, ent properties. Microlensing-based Alasdair Allan 2,22 Baltimore, Maryland, USA searches play a critical role by probing for Mike Bode 2,23 22 eSTAR Project, School of Physics, cool planets with masses down to that Daniel M. Bramich1,2,24 University of Exeter, Devon, United of Earth. Of key interest is how planets Martin Burgdorf 2,23 Kingdom are distributed according to mass and or- Stephen Fraser 2,23 23 Astrophysics Research Institute, bital distance (Figure 1) as this information Chris Mottram 2,23 Liverpool John Moores University, provides a crucial test for theories of Nicholas Rattenbury 2,25 Birkenhead, United Kingdom planet formation. Core accretion models Colin Snodgrass 2,6 24 The Isaac Newton Group of Tele- (Ida and Lin, 2005) are today the best Iain Steele 2,23 scopes, Santa Cruz de La Palma, description for the formation of planetary Yiannis Tsapras 2,23 Canary Islands systems: the accretion of planetesimals 25 The University of Manchester, Jodrell leads to the formation of cores, which Bank Observatory, Macclesfield, then start to accrete gas from the primi- 1 PLANET Collaboration Cheshire, United Kingdom tive nebula. This scenario predicts that for 2 RoboNet Collaboration M dwarf stars there is a preferential for- 3 Institut d’Astrophysique de Paris, mation of Earth- to Neptune-mass planets CNRS, Université Pierre et Marie Curie, In order to obtain a census of planets in 1–10 AU orbits. These planets are ex- Paris, France with masses in the range of Earth to pected to form within a few million years. 4 University of Canterbury, Department Jupiter, eight telescopes are being used More massive planet (Jupiter) formation of Physics and Astronomy, by the combined microlensing cam- is hampered by a longer formation time Christchurch, New Zealand paign of the PLANET and RoboNet col- (10 Myr) during which the gas evaporates 5 University of Notre Dame, Department laborations for high-cadence photo- and is no longer available to be accreted. of Physics, Notre Dame, Indiana, USA metric round-the-clock follow-up of 6 ESO ongoing events, alerted by the OGLE There is a wide variety of planets and at 7 McDonald Observatory, Fort Davis, and MOA surveys. In 2005 we detected first sight it appears that our system Texas, USA a planet of 5.5 Earth masses at 2.6 AU is very special. However, our view of the from its parent 0.22 MA M star. This whole picture is still blurred by obser- object is the first member of a new class vational biases inherent to the detection The Messenger 128 – June 2007 33 Astronomical Science Beaulieu J.-P. et al., Hunting for Frozen Super-Earths via Microlensing techniques using transits and radial ve- Known exoplanets: 11 + 180 + 4 = 195 (January 2007) locities. Both methods are more sensitive Orbit period in years (for Solar-mass star) to massive planets close to their parent 3 d 30 d 1yr 10 yr 100 yr star. Doppler measurements and the 4 Doppler: 180 space transit missions, such as COROT, 10 can already, or will shortly, be able to de- 1000 tect Neptune-mass planets close to their t, µFUN parent star. Direct detections fill the other J extreme of very large separations which 100 S are unknown in our Solar System. It is ET/RoboNe Kec therefore necessary to use different tech- k, VL N 10 TI U niques, each probing different areas of , HAT SIM the planet-mass versus orbital distance OGLE, TrES, WASP parameter space. 1 V E MPF OGLE, MOA, PLAN Planet mass in Earths Kepler Already with ground-based observations, 0.1 M the microlensing technique is sensitive M to cool planets with masses down to that 0.01 Transits: 11 (+ 3) Microlensing: 4 of the Earth orbiting 0.1–1 MA stars, the Astrometry: 0 most common stars of our Galaxy, in or- P bits of 1–10 AU. Currently, over 700 micro- 0.01 0.1 1 10 100 lensing events towards the Galactic Bulge Orbit radius in Astronomical Units (AU) are alerted in real time by the OGLE and MOA surveys each year. During these Figure 1 (above): Exoplanet discovery space (planet Figure 2 (below): The left panel shows the caustic events, a source star is temporarily mag- mass versus orbit size) showing the 8 planets from structure of a star/planet lens, with two possible tra- our Solar System (labelled as letters), 180 Doppler jectories of a source star. The right panel shows nified by the gravitational potential of wobble planets (black triangles), 11 transit planets the corresponding observed light curves. Hitting the an intervening lens star passing near the (blue circled crosses), and 4 microlensing planets planetary caustic, or passing close to it, induces a line of sight, with an impact parameter (red circled crosses). Also outlined are the regions short-lived but clearly detectable photometric signal. smaller than the Einstein ring radius RE, a that can be probed by different methods: Doppler, transits; astrometry; and microlensing from the quantity which depends on the mass of ground and space. Microlensing is a cost-efficient the lens, and the geometry of the align- way to measure the mass function of cool planets ment. For a source star in the Bulge, with down to the mass of the Earth. a 0.3 MA lens, RE ~ 2 AU, the projected angular Einstein ring radius is ~ 1 mas, and 0.10 Mass ratio q = 0.002 Impact angle = 271.0 (deg) Impact angle = 50.0 (deg) the time to transit RE is typically 20–30 Separation d = 1.2 days, but can be in the range 5–100 days. 17.5 0.05 A planet orbiting the lens star generates a Planetary caustic E Central caustic 18.0 caustic structure in the source plane, with θ / 2 0.00 one small caustic around the centre of θ -Band magnitude mass of the system, the central caustic, I –0.05 and one or two larger caustics further 18.5 away, the planetary caustics. If the source star happens to reach the vicinity of one –0.10 of the caustics, its magnification is signifi- –0.10 –0.05 0.00 0.05 0.10 2520 2540 2560 2580 HJD - 2.450.000 cantly altered as compared to a single θ1/θE lens, resulting in a brief peak or dip in the observed light curve. the detection of planets in such events space to derive the planet/star mass ratio becomes highly efficient (Griest and q, and the projected separation d in units The duration of such planetary lensing Safizadeh 1998). In contrast, planetary of RE. In general, model distributions for anomalies scales with the square root of caustics are only approached for a spe- the spatial mass density of the Milky Way, the planet’s mass, lasting typically a cific range of orientations of the source the velocities of potential lens and source few hours (for an Earth) to 2–3 days (for a trajectory, but the characterisation of a stars, and a mass function of the lens Jupiter).
Load more

Recommended publications
  • Your Guide to the Universe
    Contents 1. The Sun 3 11. The Place of our Solar System in the Universe 27 2. Why Do We Study the Sun? 4 12. Space Exploration 28 2.1. Top 10 Facts About the Sun: 4 13. South Africa and Space Exploration 30 2.2. A Closer Look at the Sun 5 14. Famous Astronomers 31 3. The Solar System 6 15. Famous Women Astronomers 32 4. The Planets 7 16. Women Astronomers in South Africa 33 4.1. Mercury 8 17. Astronomers in South African History 33 4.2. Venus 9 18. Astronomy In South Africa 34 4.3. Earth 10 18.1. History 34 4.4. Mars 11 18.2. Modern Times 35 4.5. Jupiter 12 18.3. Radio Astronomy 36 4.6. Saturn 13 18.4. The Square Kilometre Array Radio Telescope 37 4.7. Uranus 14 18.5. Geodesy 38 4.8. Neptune 15 4.9. Pluto and Dwarf planets 16 4.10. Asteroids 17 4.11. Moon 18 4.12. Meteoroids, Meteors and Meteorites 19 4.13. Comets 20 5. Stars 21 6. Exoplanets 22 7. Galaxies 23 8. The Milky Way Galaxy 24 9. The Universe and the Big Bang 25 10. Cosmology 26 The Sun We look at the Sun rising every day. It’s bright, it’s big and it warms us up. Our Sun happens to be the brightest object in our Solar System and naturally we are really curious to know more about it. The Sun’s heat and light provide the energy for life to exist on Earth.
    [Show full text]
  • 7Th ASSA Symposium
    7th ASSA Symposium - Program 28-30 September 2006 This program was the actual schedule of the 2006 ASSA Symposium, hosted by ASSA Bloemfontein Centre, in association with Boyden Observatory. The Thursday and Friday sessions took place at Boyden Observatory and the Saturday’s at the Geology Department (UFS) and at the Observatory Theatre on Naval Hill. THURSDAY 28 September 2006 09h00: Arrival at Boyden Observatory 10h00: Welcoming speeches (Organising committee, ASSA Council, Boyden Observatory) 10h30: Information session: The New Amateur Astronomer, by Phillip Coetzer 11h00: Tea break 11h20: Presentation: An Introduction to the History of Boyden Observatory, by Dawie van Jaarsveldt. 12h00: Panel discussion: Serious Amateur Astronomy: Linking with Professionals (Panel members: Tim Cooper, Brian Fraser, Pat Seitzer). Opportunity for questions and answers. 13h00: Lunch 13h45: Presentation by keynote speaker - Tim Cooper, ASSA. "The Contribution of Southern African Amateur Observations to Professional Astronomical Studies" 14h45: ASSA Deep Sky Section Director, by Magda Streicher 15h00: Tea Break 15h20: Demonstration: Astrophotography and CCD operations Presenters: Pat van Heerden, Department of Physics, UFS – “Introduction to CCD operations” Hannes Calitz, Boyden Observatory – “CCD image processing” Chris Middleton, ASSA – “Hardware & equipment in Astrophotography” 16h50: Explore Boyden Observatory on your own, photo opportunities, Boyden Treasure Hunt 18h00: Evening meal 19h10: Open air night sky show on the auditorium 19h30: Boyden Observatory Special Tour of the Facilities: Visiting the historical 10 inch Metcalf telescope, the Alvin Clark 13 inch, the UFS-Boyden 60 inch, the Main building and historic library 20h30: Astronomy in action: - "The Art of Deep Sky", through the 13 inch Alvin Clark refractors (Magda Streicher) - Astrophysics: demonstrating exoplanet search with the 3rd largest optical telescope in South Africa - On the observation platform: telescope viewing, sky watching, talk to the experts..
    [Show full text]
  • Allseits, John, “A Moving Experience: 850 Miles from Alabama to Illinois”
    ATS Thematic Workshop, Cincinnati Observatory, May 2-4, 2008 as of 4/29/08 page 1 of 17 Abstracts of talks (alphabetically by presenter) Allseits, John, “A Moving Experience: 850 Miles From Alabama to Illinois” The speaker will present a brief, illustrated account of retrieving and transporting a 1950 vintage, 10-inch f/15 J.W. Fecker refractor from its original home atop the University of Alabama, to rural northwest Illinois, with lessons and recommendations gleaned from the project. He will also outline a perhaps radical concept for a “halfway house” facility for telescopes in urgent need of temporary storage, when the owners of an observatory’s land have decided the bulldozers must roll... John Allseits has been an avid ATM (amateur telescope maker) and amateur astronomer since 1967. He has been collecting and restoring vintage telescopes since 1985. He has been active in several astronomical groups, including as historian for the Chicago Astronomical Society. John is currently working on constructing his personal observatory/planetarium facility on 40 acres in rural northwest Illinois. A charter member of the Antique Telescope Society, John is married to fellow ATS member Lisa; they have one son, Patrick, age 8. Augustine, John, “How Far to Go in an Instrument Restoration: Some Thoughts from Personal Experience” All material things are temporary because time marches on and takes its toll. Optical instruments such as antique telescopes are not exempt. However, those responsible for an antique optical instrument surely would like to know how to keep the instrument in their care looking and working great without doing any technical or historical harm through maintenance.
    [Show full text]
  • 1. the Sun Is the Largest and Brightest Object in the Universe. A
    SAASTA ASTROTM QUIZ 2017 ROUND 1 School Name: __________________ PLEASE ANSWER YOUR QUESTIONS ON THIS PROVIDED QUESTION PAPER. EACH QUESTION IS FOLLOWED BY ANSWERS MARKED A AND B, OR A, B, C AND D. ONLY ONE ANSWER IS CORRECT. CHOOSE THE MOST CORRECT ANSWER AND CIRCLE IT CLEARLY. THANK YOU & ALL OF THE BEST. 1. The Sun is the largest and brightest object in the universe. A. True B. False 2. The period that the Earth takes to revolve once around the Sun is approximately a _______ A. day B. year C. week D. month 3. Which of the following objects is the smallest in size? A. Pluto B. Mercury C. Earth D. Venus 4. Which planet in our Solar System spins the fastest? A. Saturn B. Earth C. Mercury D. Jupiter 5. On which of the following objects does a day last for less than 10 Earth hours? A. Mars B. Saturn C. Jupiter D. Neptune SAASTA ASTROTM QUIZ 2017 ROUND 1 School Name: __________________ 6. The area that separates inner planets from the outer ones is referred to as the __________________ A. Kuiper belt B. Oort belt C. Asteroid belt D. Terrestrial belt 7. Approximately by what angle is the Earth's rotation axis tilted to the plane of its orbit around the Sun? A. 25.3 degrees B. 33.5 degrees C. 23.5 degrees D. 35.3 degrees 8. The direction and angle of the tilt of the Earth ________ A. Always change in accordance to the season B. Do not change C. Change in accordance to the weather D.
    [Show full text]
  • High Energy Astrophysics in Southern Africa 2014: a Multi-Frequency Perspective of New Frontiers in High Energy Astrophysics in Southern Africa
    7 High Energy Astrophysics in Southern Africa 2014: A multi-frequency perspective of new frontiers in High Energy Astrophysics in Southern Africa Boyden Observatory, April 24-25, 2014 Organizing Institutions University of the Free State, Bloemfontein, South Africa North-West University, Potchefstroom Campus, Potchefstroom, South Africa Scientific Organizing Committee M. Bottcher¨ (North-West University), P.J. Meintjes (University of the Free State), B. van Soelen (University of the Free State), Local Organizing Committee Markus Bottcher¨ (North-West University), Pieter J Meintjes (University of the Free State), Brian van Soelen (University of the Free State), Alida Odendaal (University of the Free State), Hendrik (Pat) van Heerden (University of the Free State), Jacques Maritz (University of the Free State), Lizelke Klindt (University of the Free State), Izak van der Westhuizen (University of the Free State), Yolandie Loots (University of the Free State), Karen Cronje (University of the Free State) 8 Dedication The organizers of the High Energy Astrophysics in Southern Africa 2014 meeting would like to dedicate this proceedings to Dr Michael Gaylard. Mike was a driving force in radio astronomy and science in South Africa for over three decades. At this meeting in April 2014, Mike presented a talk on the Opportunities for Radio Observations of Southern Sources with an emphasis on high energy astronomy, where he once again displayed his excitement for astronomy, and its future, in South Africa and Africa. His passing, on the 14th of August 2014, is a terrible loss and he will be sorely missed. Local Organizing Committee With the passing of Mike Gaylard, South Africa has lost one of its great leaders in astronomy.
    [Show full text]
  • Iau Commission C3 Newsletter
    IAU COMMISSION C3 NEWSLETTER HISTORY OF ASTRONOMY Welcome to the winter solstice edition of the newsletter We wish everyone health and happiness in the new year. of IAU Commission C3 (History of Astronomy). This The next issue of the newsletter will be in June 2021. issue features the announcement of a new Project Group Please send our Secretary any news you would like us to and reports of pre-existing Working Groups and Project include. Groups since the last newsletter in June 2020. It contains Sara Schechner, Secretary news of upcoming conferences, reports of recent Wayne Orchiston, President meetings, a list of notable publications, and tables of Christiaan Sterken, Vice-President content from a journal devoted to the history of astronomy. The newsletter also contains announcements of research and PhD opportunities in the history of TABLE OF CONTENTS astronomy as well as an introduction to a new Ourania Network. And of course, you will find news from Reports of Working Groups & Project Groups 2 members, announcements of awards, and obituaries. Making History 15 Oral History 24 We are excited to introduce some new sections to the Art & Exhibitions 26 newsletter. The “Making History” section includes Announcements 30 reports on the Astronomy Genealogy Project (AstroGen), Awards and Honors 34 analysis of the Vatican Observatory’s guest book, and the News from Members 35 rescue of a medieval manuscript by Lewis of Caerleon. In In Memoriam 37 the “Oral History” section, there is a first-hand account Notable Publications 39 of the founding of the Journal of Astronomical History and Journal Contents 41 Heritage.
    [Show full text]
  • Announcements New Scientist Live
    The Orbit Issue 302 Newsletter of the Worthing Astronomical Society Dec 2015 Forthcoming Meeting Speakers and subjects: 16th December 2015 - Video Announcements TUESDAY OBSERVING EVENINGS I am very pleased to inform you that the observatory is operational again. Members evening resume with effect from Tuesday the 15th December from 7.30pm till around 11.00pm and every Tuesday thereafter. If in doubt about the sky conditions I can be reached on 01903 505346 during the day or on the observatory mobile 07754821357. All are welcome. Further to this members should be aware that at the moment the only person that has access to the observatory is Graham Boots who has fitted a combination lock and is the only person who knows the access code. The Executive Committee has requested that he either provides the access code or replaces the lock with the previous key lock. It is the intent of the Executive Committees to provide training in the use of the observatory for any member wishing to undertake it. Suitably qualified members would then have unrestricted access to this facility. To avoid any clash of interests a Booking System will be implemented on the Web Site. LUNAR OCCULTATION OF ALDEBAREN On Wednesday 23rd December 2015 the first magnitude orange red giant star Aldebaran will be occulted by the twelve day old moon (almost full) at 18h 10m GMT and reappear at 19h 12m GMT at our location. These times are fairly precise for Worthing. This event can be observed with the naked eye although binoculars or a small telescope will be useful.
    [Show full text]
  • Four Asteroids Named at Bloemfontein Symposium Brian Fraser
    assa news Four asteroids named at Bloemfontein Symposium Brian Fraser During the planning stage of the 7* ASSA Athens Observatory, John Stefanos symposium that was held in Bloemfon­ Paiaskevopoulos (1889-1951) joined tein in September 2006, it was proposed the Boyden Observatory staff and was that four of the minor planets that had responsible for selecting the site at Ma- been discovered at Boyden observa­ zelspoort, near Bloemfontein. When tory be named for persons who had been death ended his supermtendency this closely involved with the observatory in was one of the finest observatories in some way or other. the southern hemisphere. Nominations were made to the Minor (11781) Alexroberts = 1966 PL Planet Centre in Cambridge, Massachu­ Discovered 1966 Aug. 7 at Bloemfon­ setts and after some correspondence with tein. Brian Marsden, now Director emeritus, it Scots-bom Alexander William Roberts was agreed to put forward the following (1857-1938) emigrated in 1883 to nominations which were accepted and South Africa, where he taught at and announced in the Minor Planet Circulars became principal of Lovedale Training of 9 August 2006. School in Eastern Cape Province. He was one of the most prolific observers (4301) Boyden =1966 PM of variable stars in the southern hemi­ Discovered 1966 Aug. 7 at Bloemfon­ sphere, and his records are maintained tein. at the Boyden Observatory. Massachusetts mechanical engineer Uriah Atherton Boyden (1804-1879) (14310) Shuttleworth = 1966 PP designed an improved turbine wa- Discovered 1966 Aug. 7 at Bloemfon­ terwheel for use'in textile mills. His tein. bequest to build a new observatory at South African businessman Mark a mountain site allowed the Harvard Shuttleworth (b.
    [Show full text]
  • Boyden Observatory [A Concise History]
    Boyden Observatory [A Concise History] By A.H. Jarret, PH.D. Department of Astronomy, University of the Free State Article which appeared in the University of the Free State’s journal “Acta Academica” Nr. 12, 1979. 1. Harvard’s need of a Southern Station The history of Boyden Observatory covers nearly a century, of which for just over 50 years it has been at its present site at Mazelspoort. In 1879 Uriah A. Boyden, who was a mechanical engineer of Boston left in his will a sum of $238,000 to Harvard College for the express purpose of carrying out astronomical observations at such an altitude as to minimize so far as possible the troublesome effects of the earth’s atmosphere. In 1887 it was transferred by the trustees of the fund to the President and fellows of Harvard College for the use of the observatory. From the latitude of Harvard one could only hope to see approximately three quarters of the sky – in order to view the remaining part which is around the southern celestial pole – it is necessary to observe south of the equator. The Director of Harvard College Observatory at that time, Prof. Edward C. Pickering, was very keen to build a southern hemisphere observatory. The establishment of the Boyden Fund made this a possibility. At his instigation one of the Harvard Observatory staff, Prof. Solon I Bailey visited South America in 1889 for the purpose of making preliminary studies for the selection of a station for observations of the southern sky. Help was sought from officials of the Central and Southern Railways of Peru, which reach high altitudes.
    [Show full text]
  • Near-Infrared Brightness of Saturn Richard W
    Georgia Journal of Science Volume 74 No. 2 Scholarly Contributions from the Article 17 Membership and Others 2016 Near-Infrared Brightness of Saturn Richard W. Schmude Jr. Gordon State College, [email protected] Follow this and additional works at: http://digitalcommons.gaacademy.org/gjs Recommended Citation Schmude, Richard W. Jr. (2016) "Near-Infrared Brightness of Saturn," Georgia Journal of Science, Vol. 74, No. 2, Article 17. Available at: http://digitalcommons.gaacademy.org/gjs/vol74/iss2/17 This Research Articles is brought to you for free and open access by Digital Commons @ the Georgia Academy of Science. It has been accepted for inclusion in Georgia Journal of Science by an authorized editor of Digital Commons @ the Georgia Academy of Science. Schmude: Near-Infrared Brightness of Saturn NEAR-INFRARED BRIGHTNESS OF SATURN Richard W. Schmude, Jr., Gordon State College, Barnesville, Georgia, 30204 [email protected] ABSTRACT An SSP-4 photometer and filters transformed to the Mauna Kea J and H system were used in measuring the brightness of Saturn + rings (hereafter “Saturn”) in 2014 and 2015. The selected normalized magnitudes extrapolated to a solar phase angle of 0° are J(1,0) = ‒10.67 ± 0.05 and H(1,0) = ‒10.40 ± 0.05 in 2014 and J(1,0) = ‒10.76 ± 0.03 and H(1,0) = ‒10.51 ± 0.03 in 2015. These appear to be the first published J and H magnitude values for Saturn. Keywords: Saturn, J – H color index, near-infrared photometry INTRODUCTION Over the past 60 years, near-infrared studies of the planets have increased. Harris (1961) reported that Kuiper carried out a study of the energy distribution of the bright planets at wavelengths of between 1.0 and 2.5 m.
    [Show full text]
  • In the Decade Between 1918 and 1928, Leiden Observatory Changed
    Teach and travel Leiden Observatory and the renaissance of Dutch astronomy in the Interwar years David Baneke1 Introduction On Sunday 3 March 1918 Ernst Frederik van de Sande Bakhuyzen, director of Leiden Observatory, unexpectedly died. Within days Willem de Sitter was appointed acting director, pending further decisions. De Sitter immediately contacted J.C. Kapteyn, the grand old man of Dutch astronomy and his former mentor in Groningen, to discuss the future of the observatory. This was their chance to resurrect the observatory after decades of stagnation. It was also a chance to make astronomy join the ‘second golden age’ of Dutch science that played a prominent role in contemporary cultural nationalism.2 Scientists such as J.D. van der Waals, H.A. Lorentz, Heike Kamerlingh Onnes and Hugo de Vries were considered the direct heirs of Christiaan Huygens and Antoni van Leeuwenhoek, the heroes of the first ‘golden age’ in the seventeenth century. Kapteyn was a national pride too, but he was a lonely figure. He had built his reputation against all odds, having started without any facilities, funding or staff.3 The rest of Dutch astronomy did not share in the successes of the other sciences. The two observatories in Leiden and Utrecht were small and unexciting. A reorganisation and expansion of Leiden Observatory might change that. De Sitter and Kapteyn seized the moment, and they succeeded beyond expectation. During De Sitter’s directorship, from 1918 until 1934, Leiden Observatory changed from a sleepy, run- down institute into an international centre of astronomy.4 It was the home institute of Willem de Sitter, Ejnar Hertzsprung and Jan Oort, and it became a breeding ground for a new generation of astronomers who would become prominent scientists in their own right, including Bart Bok, Gerard Kuiper, Dirk Brouwer, Willem Luyten, Piet Oosterhoff, Willem van den Bos and Adriaan Blaauw.
    [Show full text]
  • Dr Bruce Elmegreen CHAPTER 16
    n Epilogue – Dr Bruce Elmegreen CHAPTER 16 There is what seems to be, and there is what is. We look but we cannot see what is. We build instruments that do our looking and still these instruments cannot see everything. There is no limitless gaze. The horizon curves, the fog muffl es, the lights and structures get fainter and fuzzier with distance. The redshift dims. Peeling back one layer leads only to another. This is the reality of the Universe in which we live. When we think we have it just right, we see an unimagined new rightness beneath. David Block and Kenneth Freeman have been looking and measuring, classifying and pon- dering the Universe for a long time. We are fortunate they shared their story with us. This is a story about the avalanche of insight that follows the discovery of new techniques: of giant telescopes built by hand all around the globe and of the mysteries the builders solved and revealed through their drawings; of the photographic process and the replacement of vision by chemical images; of electronic antennae, cameras, telescopes, and satellites that are sensi- tive to radio, infrared, ultraviolet, x-ray, and gamma ray light. It is a story of the shrouds of the night that were slowly peeled back, of galaxies viewed both inside and out, like the x-ray fi sh in Collette Archer’s painting below. The Universe around us is rich with structure in both density and temperature. Some of this structure reveals itself by the light it radiates, the long or the short wavelengths depending on temperature and extinction, the bright or the dim light depending on dis- tance, opacity, and power.
    [Show full text]