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News NotesCompiled by Martin Beech (beechm@uregina.ca) and OrlaAaquist (AaquistO@macewan.ca)Arecibo, Alive and Kicking?<strong>Last</strong> September, the Washington Post informed us that thelargest and most sensitive radio telescope on Earth wouldhave to close if it could not find outside funding for halfof its already reduced $8 million budget in the next three years.When I first encountered this bit of news, my first thought wasthat perhaps the Royal Astronomical Society of Canada couldget a proposal together to save the Arecibo Observatory. Then Iremembered that none of the RASC Centres, except Edmonton,has any money, so I put the thought aside. Two months later, wewere told that U of T was thinking of closing the David DunlapObservatory. Apparently, the RASC loves the DDO, because acall went out to Canadian amateur astronomers to help savethis historic observatory. The possible demolition of the DDOhas been in the RASC news circles ever since and probably bythe time that this publication of JRASC gets downloaded onyour computer we will have learned of its fate. But what aboutthe fate of Arecibo and the National Astronomy and IonosphereCenter, NAIC?Until I visited Dr. Russ Taylor at the University of Calgarylast December, I had completely forgotten about the possibleclosure of this outpost of radio astronomy. Russ told me abouta project, in which he was involved, to use the Arecibo telescopein conjunction with something called ALFA to carry out asurvey of the sky visible from Puerto Rico. I gathered from Russthat ALFA refers to a new Arecibo L-band Feed Array, whichis a cluster of seven cooled dual-polarization feeds that willallow large-scale full-stokes spectro-polarimetric studies of thesky with unprecedented sensitivity. I know that some of youwould have preferred ALFA to have been a new healthy type ofSwedish dog food, but a few of our hard-core readers will havejust received a significant adrenalin rush and will want to readthe above sentence a few times before continuing.In the past, use of the Arecibo telescope as a surveyinstrument has been limited by the relatively small field of viewin a single observation, but ALFA, with its seven feeds, has amuch larger field of view. This new system will have a broadappeal within the astronomical community and it is hopedthat it will drive research at Arecibo for the next 10 to 15 years.So, under the threat of reduced funding, scientists convenedin Washington on 2007 September 12 and 13, to identify keyscience that is possible with the new system and hopefullyto get the National Science Foundation to reconsider theirextreme budget cuts. A summary of this meeting is posted inthe NAIC Newsletter #42. According to this newsletter “muchThe Journal is a bi-monthly publication of the Royal Astronomical Society of Canadaand is devoted to the advancement of astronomy and allied sciences. It contains articleson Canadian astronomers and current activities of the RASC and its Centres, researchand review papers by professional and amateur astronomers, and articles of a historical,biographical, or educational nature of general interest to the astronomical community.All contributions are welcome, but the editors reserve the right to edit material priorto publication. Research papers are reviewed prior to publication, and professionalastronomers with institutional affiliations are asked to pay publication charges of$100 per page. Such charges are waived for RASC members who do not have access toprofessional funds as well as for solicited articles. Manuscripts and other submittedmaterial may be in English or French, and should be sent to the Editor-in-Chief.Editor-in-ChiefJay Anderson136 Dupont StToronto ON M5R 1V2, CanadaInternet: editor@rasc.caWeb site: www.rasc.caTelephone: (416) 924-7973Fax: (416) 924-2911Associate Editor, ResearchDouglas HubeInternet: dhube@phys.ualberta.caAssociate Editor, GeneralMichael AttasInternet: attasm@aecl.caAssistant EditorsMichael AllenMartin BeechPierre BoulosRalph ChouDaniel HudonPatrick KellyEditorial AssistantSuzanne E. MoreauInternet: semore@sympatico.caProduction ManagerJames EdgarInternet: jamesedgar@sasktel.netContributing EditorsMartin Beech (News Notes)Warren Finlay (Deep-Sky Contemplations)Geoff Gaherty (Through My Eyepiece)Doug Hube (Deep-Sky Contemplations)Richard Huziak (Variable Stars)Bruce McCurdy (Orbital Oddities)Philip Mozel (A Moment With…)Guy Nason (Carpe Umbram)Leslie Sage (Second Light)Gerry Smerchanski (Gerry’s Meanderings)David Turner (Reviews)Don Van Akker (Gizmos)ProofreadersOssama El BadawyMargaret BronsTerry LeederKim LeitchSuzanne MoreauMaureen OkunDesign/ProductionBrian G. Segal, Redgull IncorporatedAdvertisingJames EdgarInternet: jamesedgar@sasktel.netPrintingMaritime Digital ColourThe Journal of The Royal Astronomical Society of Canada is published at an annualsubscription rate of $80.00 by The Royal Astronomical Society of Canada. Membership,which includes the publications (for personal use), is open to anyone interested inastronomy. Applications for subscriptions to the Journal or membership in the RASC,and information on how to acquire back issues of the Journal can be obtained from:The Royal Astronomical Society of Canada136 Dupont StToronto ON M5R 1V2, CanadaInternet: nationaloffice@rasc.caWeb site: www.rasc.caTelephone: (416) 924-7973Fax: (416) 924-2911Canadian Publications Mail Registration No. 09818Canada Post: Send address changes to 136 Dupont St, Toronto ON M5R 1V2Canada Post Publication Agreement No. 40069313We acknowledge the financial support of the Government of Canada, through thePublications Assistance Program (PAP), toward our mailing costs.U.S. POSTMASTER: Send address changes to IMS of NY, PO Box 1518, Champlain NY12919. U.S. Periodicals Registration Number 010-751.Periodicals postage paid at Champlain NY and additional mailing offices.The Journal is printed on recycled stock.© 2008 The Royal Astronomical Society of Canada. All rights reserved. ISSN 0035-872X46 Building for the International Year of Astronomy (IYA2009)JRASC April / avril 2008
of the identified science builds on the large-scale surveyscurrently being done with the Arecibo L-band Feed Array(ALFA). These include (1) a pulsar survey that is sensitive tocompact relativistic binary pulsars and millisecond pulsars; (2)surveys for extragalactic hydrogen that are determining the HImass function in the local Universe among many other results;(3) galactic surveys of hydrogen to probe turbulence in theinterstellar medium; (4) Faraday tomography of galactic andextragalactic magnetic fields; and (5) SETI.” Taylor, at the U ofC, is involved with a survey of galactic magnetic fields dubbedthe GALFA Continuum Transit Survey (GALFACTS). This is afive-year project, which “promises a transformational advancein our understanding of the magnetic field of the Milky Wayand to serve as a ‘pathfinder’ to the Square Kilometre Array(SKA) in the area of cosmic magnetism.”NAIC still has lots of hurdles to overcome, but progressis being made. The outcome of the US National ScienceFoundation’s ten-year review process in 2010 will be central tothe future of Arecibo, but for now it looks like the professionalsdo not need the help of the RASC, so we can focus our efforts onsaving the DDO.References1. www.naic.edu/alfa/2. www.naic.edu/~ehowell/newslet/dec2007/Newsletter42-shortened.pdf3. www.ucalgary.ca/ras/GALFACTS/Figure 1 — The newly painted Arecibo telescope receiver platformhousing ALFA. Image from NAIC Newsletter # 42.Stars with Pure Carbon AtmospheresAstronomers have discovered white dwarf stars with purecarbon atmospheres. The stars are possibly part of a previouslyunknown sequence of stellar evolution. They may have evolvedfrom stars that are not quite massive enough to explode assupernovae but are just on the borderline. All but the mostmassive two or three percent of stars eventually die as whitedwarfs rather than explode as supernovae.When a star burns helium, it leaves “ashes” of carbon andoxygen. When its nuclear fuel is exhausted, the star then diesto become a white dwarf. Astronomers believe that most whitedwarf stars have a core made of carbon and oxygen, which ishidden from view by a surrounding atmosphere of hydrogen orhelium. They didn’t expect, therefore, to find stars with carbonatmospheres. “We’ve found stars with no detectable traces ofhelium and hydrogen in their atmospheres,” said Universityof Arizona Steward Observatory astronomer Patrick Dufour.“We might actually be observing directly a bare stellar core. Wepossibly have a window on what used to be the star’s nuclearfurnace and are seeing the ashes of the nuclear reaction thatonce took place.”Dufour, along with James Liebert (Université de Montréal)and colleagues at the Paris Observatory, published the resultsin the November 22 issue of Nature. The stars were discoveredamong 10,000 new white-dwarf stars found in the Sloan DigitalSky Survey. The survey, known as the SDSS, found about fourtimes as many white-dwarf stars as previously known. Liebertidentified a few dozen of the newfound stars as DQ white dwarfsin 2003. When observed in optical light, DQ stars appear to bemostly helium and carbon. Astronomers believe that convectionin the helium zone dredges up carbon from the star’s carbonoxygencore.Dufour developed a model to analyze the atmospheresof DQ stars as part of his doctoral research at the Universitéde Montréal. His model simulated cool DQ stars — stars attemperatures between 5000 and 12,000 K. For reference, ourSun’s surface temperature is around 5780 K. When Dufourjoined Steward Observatory in January, he updated his codeto analyze hotter stars, stars as hot as 24,000 K. “When I firststarted modeling the atmospheres of these hotter DQ stars,my first thought was that these are helium-rich stars withtraces of carbon, just like the cooler ones,” Dufour said. “Butas I started analyzing the stars with the higher temperaturemodel, I realized that even if I increased the carbon abundance,the model still didn’t agree with the SDSS data.” In May 2007,“out of pure desperation, I decided to try modeling a purecarbonatmosphere. It worked,” Dufour added. “I found that if Icalculated a pure carbon atmosphere model, it reproduces theThe Royal Astronomical Society of Canada is dedicated to the advancement of astronomy and its related sciences; the Journal espouses thescientific method and supports dissemination of information, discoveries, and theories based on that well-tested method.April / Avril 2008JRASCBuilding for the International Year of Astronomy (IYA2009)47
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