DOCSLIB.ORG

Astrophysics in 2004

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Publications of the Astronomical Society of the Pacific, 117:311–394, 2005 April ᭧ 2005. The Astronomical Society of the Pacific. All rights reserved. Printed in U.S.A. Invited Review Astrophysics in 2004 Virginia Trimble Department of Physics and Astronomy, University of California, Irvine, CA 92697-4575; [email protected] and Markus Aschwanden Lockheed Martin Advanced Technology Center, Solar and Astrophysics Lab, Organization ADBS, Building 252, 3251 Hanover Street, Palo Alto, CA 94304 Received and accepted 2005 January 24; published 2005 April 15 ABSTRACT. In this 14th edition of ApXX,1 we bring you the Sun (§ 2) and Stars (§ 4), the Moon and Planets (§ 3), a truly binary pulsar (§ 5), a kinematic apology (§ 6), the whole universe (§§ 7 and 8), reconsideration of old settled (§ 9) and unsettled (§ 10) issues, and some things that happen only on Earth, some indeed only in these reviews (§§ 10 and 11). 1. INTRODUCTION Monthly Notes of the Astronomical Society of South Africa, The sequence of events leading up to Ap04 is very much and Journal of the Royal Astronomical Society of Canada. the same as in previous years. We read some papers, take some notes, make some selections, and write. Somewhere along the way, with luck, we also think. 1.1. Up Section 2 was assembled using papers found on the Astro- physics Data System (ADS), maintained with support from Our assumption is that the more astronomers and the more NASA. These include Solar Physics, Geophysics Research Let- facilities they have, the better. Thus the following successful ters, Journal of Geophysical Research, Astroparticle Physics, launches, inaugurations, and such all count as good news: Acta Astronomica Sinica, Chinese Journal of Astronomy and (1) Messenger to Mercury on 3 August, (2) two Chinese mag- Astrophysics, Advances in Space Science,andSpace Science netospheric satellites in January and July, (3) a new Kavli Reviews, as well as those used for the other sections. Institute for Cosmological Physics at the University of Chicago, Used in compiling sections 3–13 were the issues that (4) the April decision of Russia to join ESA, (5) the beginning reached library shelves (or, increasingly, V. T.’s mailbox) be- of actual data collection by Gravity Probe B on 27 August, 4 tween 1 October 2003 and 30 September 2004 of Nature, months into the 13-month mission (and we can’t wait to hear Science, Physical Review Letters,theAstrophysical Journal what its catchy new name will be when it is declared a success), (plus Letters and Supplement Series), Monthly Notices of the in the way that Muses C became Hayabusa after its May 2003 Royal Astronomical Society, Astronomy and Astrophysics launch, (6) the launch of Rosetta on 2 March, (7) the increase (plus Reviews), Astronomical Journal, Acta Astronomica, Re- to 30% (in 2001) of US high school students taking physics, vista Mexicana de Astronom´aı y Astrof´sicaı , Astrophysics (8) the capture of comet dust by Stardust on 2 January (it is and Space Sciences, Astronomy Reports, Astronomy Letters, due back in 2006 with its bits of Comet Wild 2), (9) the 60 Astrofizica, Astronomische Nachrichten, Publications of the antennas of LOFAR in place in fall 2004, (10) Shenzhou 5, Astronomical Society of Japan, Journal of Astrophysics and which put a third country into manned space programs on 15 Astronomy, Bulletin of the Astronomical Society of India, October 2003, (11) the expanded Sudbury facility planned by Contributions of the Astronomical Observatory Skalnate the Canadian Foundation for Innovation, (12) Mars arrivals by Pleso, New Astronomy (plus Reviews), IAU Circulars, and, Nozumi (13 December), Beagle 2 (25 December), Spirit of course, Publications of the Astronomical Society of the (4 June), and Opportunity (24–25 June), (13) an upturn in Pacific. Journals read less systematically and irregularly cited numbers of graduate students enrolled in engineering, science, include Observatory, Journal of the American Association of etc., nicely, as usual, mirror imaging the state of the economy, Variable Star Observers, ESO Messenger, Astronomy and and (14) the participants in IAU Colloquium 196, who, contrary Geophysics, Mercury, New Scientist, Sky & Telescope, to forecasts by a peer review group, had clear weather to see the 2004 transit of Venus from the same location where Jer- 1 Astrophysics in 1991 to 2003 appeared in volumes 104–116 of PASP. emiah Horrocks had been the first to record seeing such an They are cited here as Ap91, etc. event in 1639. 311 312 TRIMBLE & ASCHWANDEN 1.2. Down stellar photometer in mid December, (2) the American Terres- Conversely, losses of things, at any stage from preliminary trial Planet Finder and European Darwin (devices for direct budgets, to launches, to planned and unplanned mission ter- imaging) remain on the books at year’s end for deployment minations count as bad news, Sadly, a few entities appear in somewhere around 2020, and Eddington had slipped back into both the previous subsection and this one, including (1) No- the queue at midyear (though with its goal peculiarly described zumi,whichflew on past Mars in October, unable to stop, as “measuring the frequency of omitted light” Nature 429, 698), (2) Beagle 2, which never phoned home after leaving its Con- (3) RHESSI and INTEGRAL received special issues of appro- estoga wagon-equivalent (but leaving much ill feeling on all priate journals (ApJ Letters 595, No. 2, and A&A 411, No. 1, sides, e.g., Nature, 430, 954), and (3) Contour (a briefly “up” respectively), (3) Operations at the Gran Sasso Lab are slowly in August 2002) has now been understood to have died in three being restored to normal, but, in mid-May, Borexino was still separate pieces after overheating by exhaust gases and melting. on hold, and the Gallium Neutrino Observatory gone for good; And some other losses: (1) SWAS collected its last (sub- imagine all those wasted neutrinos who devoted their lives to millimeter) data on 23 July, (2) Midori II, an Earth-observation reaching terrestrial experiments, only to find no one waiting probe began to observe Earth from very close up on 31 October, for them. How many neutrinos? Well, just about all the solar B8 ones we had been expecting, according to S. N. Ahmed et (3) STIS, the Space Telescope Imaging Spectrograph on (cu- 7 riously) the Space Telescope closed up shop during the summer, al. (Physical Review Letters 92, 1813), and for the Be , proton- to be followed most of us very much fear by the entire HST proton, CNO, and other neutrino fluxes, we will just have to within the next couple of years, (4) SNOE,theStudent Nitro- possess our souls in patience. A next-generation neutrino ex- Oxide Explorer, ceased Exploring (atmospheric composition, periment is back in the plans in Japan after personal interven- we think, rather than students) on 13 December 2003 after a tion by Nobel Prize winner Masatoshi Koshiba (Nature 429, mission of 5 years and 290 days. It was allowed to burn up 746). Well, isn’t that what Nobel Prizes are for? on re-entry and so is presumably now part of the atmosphere is so assiduously explored. (5) Eddington, a high-precision pho- 1.4. Astronomers’ Ups and Downs tometric mission designed to looked for planetary transits and There were undoubtedly several hundred new ones, world- quivering stars has been removed from the ESA queue; various wide, receiving Ph.D.’s, including the first mainstream astron- NASA plans for investigations of “deep space” have also been omy Ph.D. from the University of California, Irvine, to Dr. delayed or worse, (6) Genesis, after collecting solar wind par- Tammy Bosler for work on the use of the infrared calcium ticles for months on end, returned to Earth on 8 September infrared triplet feature as an abundance indicator for stellar unfortunately at about 193 miles per hour (an upside-down population studies. accelerometer having failed to initiate parachute deployment), The losses were perhaps not quite so many, because there and they were picking bits of it out of the desert floor for were not so many Ph.D.’s given in 1950 or thereabouts, and weeks, (7) Los Alamos National Lab, closed for security con- again we note only one: Dr. Janet Mattei, long-time director 238 cerns, and so unable to assemble the required quantity of Pu of the American Association of Variable Star Observers and pellets to power an upcoming Pluto mission (carrying Pluto- an irreplaceable bridge between the amateur and professional nium to Pluto may or may not make you think of carrying communities. coals to Newcastle, which is, however, now a net importer), Two new concepts appear in Ap04, somewhere between up (8) Biosphere II, closing for lack of funding, fresh air, enthu- and down: The Garrison Keillor paper, proposal, or whatever, siasm, and so forth, (9) the Cambridge primate center, with meaning (like his joke book), pretty good, and the green dot, planning suspended at the beginning of calendar 2004 (the a symbol of surprise placed next to a few dozen papers during primates were probably not asked), (9) the New York WE-6 the elder author’s initial note-taking. All green dot papers have numbers, from which one had for one’s entire life been able been cited somewhere in the following pages. to learn upcoming weather and “At the tone, the time will be…” (New Yorker, 12 April, p. 29), ceased to operate on 24 March 2. THE SUN (the California equivalent disappeared long ago), and (10) one less Ph.D.-level physicist, because the University of Constance 2.1. The Solar Interior (Germany) took back that of J. H. Schoen for “undignified 2.1.1.
Recommended publications
  • Aalseth Aaron Aarup Aasen Aasheim Abair Abanatha Abandschon Abarca Abarr Abate Abba Abbas Abbate Abbe Abbett Abbey Abbott Abbs

    Aalseth Aaron Aarup Aasen Aasheim Abair Abanatha Abandschon Abarca Abarr Abate Abba Abbas Abbate Abbe Abbett Abbey Abbott Abbs

    BUSCAPRONTA www.buscapronta.com ARQUIVO 35 DE PESQUISAS GENEALÓGICAS 306 PÁGINAS – MÉDIA DE 98.500 SOBRENOMES/OCORRÊNCIA Para pesquisar, utilize a ferramenta EDITAR/LOCALIZAR do WORD. A cada vez que você clicar ENTER e aparecer o sobrenome pesquisado GRIFADO (FUNDO PRETO) corresponderá um endereço Internet correspondente que foi pesquisado por nossa equipe. Ao solicitar seus endereços de acesso Internet, informe o SOBRENOME PESQUISADO, o número do ARQUIVO BUSCAPRONTA DIV ou BUSCAPRONTA GEN correspondente e o número de vezes em que encontrou o SOBRENOME PESQUISADO. Número eventualmente existente à direita do sobrenome (e na mesma linha) indica número de pessoas com aquele sobrenome cujas informações genealógicas são apresentadas. O valor de cada endereço Internet solicitado está em nosso site www.buscapronta.com . Para dados especificamente de registros gerais pesquise nos arquivos BUSCAPRONTA DIV. ATENÇÃO: Quando pesquisar em nossos arquivos, ao digitar o sobrenome procurado, faça- o, sempre que julgar necessário, COM E SEM os acentos agudo, grave, circunflexo, crase, til e trema. Sobrenomes com (ç) cedilha, digite também somente com (c) ou com dois esses (ss). Sobrenomes com dois esses (ss), digite com somente um esse (s) e com (ç). (ZZ) digite, também (Z) e vice-versa. (LL) digite, também (L) e vice-versa. Van Wolfgang – pesquise Wolfgang (faça o mesmo com outros complementos: Van der, De la etc) Sobrenomes compostos ( Mendes Caldeira) pesquise separadamente: MENDES e depois CALDEIRA. Tendo dificuldade com caracter Ø HAMMERSHØY – pesquise HAMMERSH HØJBJERG – pesquise JBJERG BUSCAPRONTA não reproduz dados genealógicos das pessoas, sendo necessário acessar os documentos Internet correspondentes para obter tais dados e informações. DESEJAMOS PLENO SUCESSO EM SUA PESQUISA.
  • Arxiv:2012.09981V1 [Astro-Ph.SR] 17 Dec 2020 2 O

    Arxiv:2012.09981V1 [Astro-Ph.SR] 17 Dec 2020 2 O

    Contrib. Astron. Obs. Skalnat´ePleso XX, 1 { 20, (2020) DOI: to be assigned later Flare stars in nearby Galactic open clusters based on TESS data Olga Maryeva1;2, Kamil Bicz3, Caiyun Xia4, Martina Baratella5, Patrik Cechvalaˇ 6 and Krisztian Vida7 1 Astronomical Institute of the Czech Academy of Sciences 251 65 Ondˇrejov,The Czech Republic(E-mail: [email protected]) 2 Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr. 13, 119234, Moscow, Russia 3 Astronomical Institute, University of Wroc law, Kopernika 11, 51-622 Wroc law, Poland 4 Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotl´aˇrsk´a2, 611 37 Brno, Czech Republic 5 Dipartimento di Fisica e Astronomia Galileo Galilei, Vicolo Osservatorio 3, 35122, Padova, Italy, (E-mail: [email protected]) 6 Department of Astronomy, Physics of the Earth and Meteorology, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynsk´adolina F-2, 842 48 Bratislava, Slovakia 7 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, H-1121 Budapest, Konkoly Thege Mikl´os´ut15-17, Hungary Received: September ??, 2020; Accepted: ????????? ??, 2020 Abstract. The study is devoted to search for flare stars among confirmed members of Galactic open clusters using high-cadence photometry from TESS mission. We analyzed 957 high-cadence light curves of members from 136 open clusters. As a result, 56 flare stars were found, among them 8 hot B-A type ob- jects. Of all flares, 63 % were detected in sample of cool stars (Teff < 5000 K), and 29 % { in stars of spectral type G, while 23 % in K-type stars and ap- proximately 34% of all detected flares are in M-type stars.
  • Filter Performance Comparisons for Some Common Nebulae

    Filter Performance Comparisons for Some Common Nebulae

    Filter Performance Comparisons For Some Common Nebulae By Dave Knisely Light Pollution and various “nebula” filters have been around since the late 1970’s, and amateurs have been using them ever since to bring out detail (and even some objects) which were difficult to impossible to see before in modest apertures. When I started using them in the early 1980’s, specific information about which filter might work on a given object (or even whether certain filters were useful at all) was often hard to come by. Even those accounts that were available often had incomplete or inaccurate information. Getting some observational experience with the Lumicon line of filters helped, but there were still some unanswered questions. I wondered how the various filters would rank on- average against each other for a large number of objects, and whether there was a “best overall” filter. In particular, I also wondered if the much-maligned H-Beta filter was useful on more objects than the two or three targets most often mentioned in publications. In the summer of 1999, I decided to begin some more comprehensive observations to try and answer these questions and determine how to best use these filters overall. I formulated a basic survey covering a moderate number of emission and planetary nebulae to obtain some statistics on filter performance to try to address the following questions: 1. How do the various filter types compare as to what (on average) they show on a given nebula? 2. Is there one overall “best” nebula filter which will work on the largest number of objects? 3.
  • The Solar System and Its Place in the Galaxy in Encyclopedia of the Solar System by Paul R

    The Solar System and Its Place in the Galaxy in Encyclopedia of the Solar System by Paul R

    Giant Molecular Clouds http://www.astro.ncu.edu.tw/irlab/projects/project.htm Æ Galactic Open Clusters Æ Galactic Structure Æ GMCs The Solar System and its Place in the Galaxy In Encyclopedia of the Solar System By Paul R. Weissman http://www.academicpress.com/refer/solar/Contents/chap1.htm Stars in the galactic disk have different characteristic velocities as a function of their stellar classification, and hence age. Low-mass, older stars, like the Sun, have relatively high random velocities and as a result c an move farther out of the galactic plane. Younger, more massive stars have lower mean velocities and thus smaller scale heights above and below the plane. Giant molecular clouds, the birthplace of stars, also have low mean velocities and thus are confined to regions relatively close to the galactic plane. The disk rotates clockwise as viewed from "galactic north," at a relatively constant velocity of 160-220 km/sec. This motion is distinctly non-Keplerian, the result of the very nonspherical mass distribution. The rotation velocity for a circular galactic orbit in the galactic plane defines the Local Standard of Rest (LSR). The LSR is then used as the reference frame for describing local stellar dynamics. The Sun and the solar system are located approxi-mately 8.5 kpc from the galactic center, and 10-20 pc above the central plane of the galactic disk. The circular orbit velocity at the Sun's distance from the galactic center is 220 km/sec, and the Sun and the solar system are moving at approximately 17 to 22 km/sec relative to the LSR.
  • Luminous Blue Variables

    Luminous Blue Variables

    Review Luminous Blue Variables Kerstin Weis 1* and Dominik J. Bomans 1,2,3 1 Astronomical Institute, Faculty for Physics and Astronomy, Ruhr University Bochum, 44801 Bochum, Germany 2 Department Plasmas with Complex Interactions, Ruhr University Bochum, 44801 Bochum, Germany 3 Ruhr Astroparticle and Plasma Physics (RAPP) Center, 44801 Bochum, Germany Received: 29 October 2019; Accepted: 18 February 2020; Published: 29 February 2020 Abstract: Luminous Blue Variables are massive evolved stars, here we introduce this outstanding class of objects. Described are the specific characteristics, the evolutionary state and what they are connected to other phases and types of massive stars. Our current knowledge of LBVs is limited by the fact that in comparison to other stellar classes and phases only a few “true” LBVs are known. This results from the lack of a unique, fast and always reliable identification scheme for LBVs. It literally takes time to get a true classification of a LBV. In addition the short duration of the LBV phase makes it even harder to catch and identify a star as LBV. We summarize here what is known so far, give an overview of the LBV population and the list of LBV host galaxies. LBV are clearly an important and still not fully understood phase in the live of (very) massive stars, especially due to the large and time variable mass loss during the LBV phase. We like to emphasize again the problem how to clearly identify LBV and that there are more than just one type of LBVs: The giant eruption LBVs or h Car analogs and the S Dor cycle LBVs.
  • Planetary Nebulae

    Planetary Nebulae

    Planetary Nebulae A planetary nebula is a kind of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from old red giant stars late in their lives. The term "planetary nebula" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years. The mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energizes the shell of nebulous gas around the central star, appearing as a bright colored planetary nebula at several discrete visible wavelengths. Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances. In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies.
  • Brown Dwarf: White Dwarf: Hertzsprung -Russell Diagram (H-R

    Brown Dwarf: White Dwarf: Hertzsprung -Russell Diagram (H-R

    Types of Stars Spectral Classifications: Based on the luminosity and effective temperature , the stars are categorized depending upon their positions in the HR diagram. Hertzsprung -Russell Diagram (H-R Diagram) : 1. The H-R Diagram is a graphical tool that astronomers use to classify stars according to their luminosity (i.e. brightness), spectral type, color, temperature and evolutionary stage. 2. HR diagram is a plot of luminosity of stars versus its effective temperature. 3. Most of the stars occupy the region in the diagram along the line called the main sequence. During that stage stars are fusing hydrogen in their cores. Various Types of Stars Brown Dwarf: White Dwarf: Brown dwarfs are sub-stellar objects After a star like the sun exhausts its nuclear that are not massive enough to sustain fuel, it loses its outer layer as a "planetary nuclear fusion processes. nebula" and leaves behind the remnant "white Since, comparatively they are very cold dwarf" core. objects, it is difficult to detect them. Stars with initial masses Now there are ongoing efforts to study M < 8Msun will end as white dwarfs. them in infrared wavelengths. A typical white dwarf is about the size of the This picture shows a brown dwarf around Earth. a star HD3651 located 36Ly away in It is very dense and hot. A spoonful of white constellation of Pisces. dwarf material on Earth would weigh as much as First directly detected Brown Dwarf HD 3651B. few tons. Image by: ESO The image is of Helix nebula towards constellation of Aquarius hosts a White Dwarf Helix Nebula 6500Ly away.
  • Stellar Dynamics and Stellar Phenomena Near a Massive Black Hole

    Stellar Dynamics and Stellar Phenomena Near a Massive Black Hole

    Stellar Dynamics and Stellar Phenomena Near A Massive Black Hole Tal Alexander Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl St, Rehovot, Israel 76100; email: [email protected] | Author's original version. To appear in Annual Review of Astronomy and Astrophysics. See final published version in ARA&A website: www.annualreviews.org/doi/10.1146/annurev-astro-091916-055306 Annu. Rev. Astron. Astrophys. 2017. Keywords 55:1{41 massive black holes, stellar kinematics, stellar dynamics, Galactic This article's doi: Center 10.1146/((please add article doi)) Copyright c 2017 by Annual Reviews. Abstract All rights reserved Most galactic nuclei harbor a massive black hole (MBH), whose birth and evolution are closely linked to those of its host galaxy. The unique conditions near the MBH: high velocity and density in the steep po- tential of a massive singular relativistic object, lead to unusual modes of stellar birth, evolution, dynamics and death. A complex network of dynamical mechanisms, operating on multiple timescales, deflect stars arXiv:1701.04762v1 [astro-ph.GA] 17 Jan 2017 to orbits that intercept the MBH. Such close encounters lead to ener- getic interactions with observable signatures and consequences for the evolution of the MBH and its stellar environment. Galactic nuclei are astrophysical laboratories that test and challenge our understanding of MBH formation, strong gravity, stellar dynamics, and stellar physics. I review from a theoretical perspective the wide range of stellar phe- nomena that occur near MBHs, focusing on the role of stellar dynamics near an isolated MBH in a relaxed stellar cusp.
  • Current Perspectives on Dark Matter

    Current Perspectives on Dark Matter

    Cosmological Signatures of a Mirror Twin Higgs Zackaria Chacko University of Maryland, College Park Curtin, Geller & Tsai Introduction The Twin Higgs framework is a promising approach to the naturalness problem of the Standard Model (SM). In Mirror Twin Higgs models, the SM is extended to include a complete mirror (“twin”) copy of the SM, with its own particle content and gauge groups. The SM and its twin counterpart are related by a discrete Z2 “twin” symmetry. Z2 SMA SMB The mirror particles are completely neutral under the SM strong, weak and electromagnetic forces. Only feel gravity. In Mirror Twin Higgs models, the one loop quadratic divergences that contribute to the Higgs mass are cancelled by twin sector states that carry no charge under the SM gauge groups. Discovery of these states at LHC is therefore difficult. May explain null results. The SM and twin SM primarily interact through the Higgs portal. This interaction is needed for cancellation of quadratic divergences. After electroweak symmetry breaking, SM Higgs and twin Higgs mix. • Higgs couplings to SM states are suppressed by the mixing. • Higgs now has (mixing suppressed) couplings to twin states. A soft breaking of the Z2 symmetry ensures that 퐯B, the VEV of the twin Higgs, is greater than 퐯A, the VEV of the SM Higgs. The mixing angle ~ 퐯A/퐯B. Higgs measurements constrain 퐯A/퐯B ≤ ퟏ/ퟑ. Twin fermions are heavier than SM fermions by a factor of 퐯B/퐯A . Naturalness requires 퐯A/퐯B ≥ ퟏ/ퟓ. (Twin top should not be too heavy.) The Higgs portal interaction has implications for cosmology.
  • The Potential of Planets Orbiting Red Dwarf Stars to Support Oxygenic Photosynthesis and Complex Life

    The Potential of Planets Orbiting Red Dwarf Stars to Support Oxygenic Photosynthesis and Complex Life

    1 The Potential of Planets Orbiting Red Dwarf Stars to Support Oxygenic Photosynthesis and Complex Life Joseph Gale1 and Amri Wandel2 The Institute of Life Sciences1and The Racach Institute of Physics2, The Hebrew University of Jerusalem, 91904, Israel. [email protected] [email protected] Accepted for publication in the International Journal of Astrobiology Abstract We review and reassess the latest findings on the existence of extra-solar system planets and their potential of having environmental conditions that could support Earth-like life. Within the last two decades, the multi-millennial question of the existence of extra-Solar- system planets has been resolved with the discovery of numerous planets orbiting nearby stars, many of which are Earth-sized (and some even with moderate surface temperatures). Of particular interest in our search for clement conditions for extra-solar system life are planets orbiting Red Dwarf (RD) stars, the most numerous stellar type in the Milky Way galaxy. We show that including RDs as potential life supporting host stars could increase the probability of finding biotic planets by a factor of up to a thousand, and reduce the estimate of the distance to our nearest biotic neighbor by up to 10. We argue that multiple star systems need to be taken into account when discussing habitability and the abundance of biotic exoplanets, in particular binaries of which one or both members are RDs. Early considerations indicated that conditions on RD planets would be inimical to life, as their Habitable Zones (where liquid water could exist) would be so close as to make planets tidally locked to their star.
  • UC Irvine UC Irvine Previously Published Works

    UC Irvine UC Irvine Previously Published Works

    UC Irvine UC Irvine Previously Published Works Title Astrophysics in 2006 Permalink https://escholarship.org/uc/item/5760h9v8 Journal Space Science Reviews, 132(1) ISSN 0038-6308 Authors Trimble, V Aschwanden, MJ Hansen, CJ Publication Date 2007-09-01 DOI 10.1007/s11214-007-9224-0 License https://creativecommons.org/licenses/by/4.0/ 4.0 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Space Sci Rev (2007) 132: 1–182 DOI 10.1007/s11214-007-9224-0 Astrophysics in 2006 Virginia Trimble · Markus J. Aschwanden · Carl J. Hansen Received: 11 May 2007 / Accepted: 24 May 2007 / Published online: 23 October 2007 © Springer Science+Business Media B.V. 2007 Abstract The fastest pulsar and the slowest nova; the oldest galaxies and the youngest stars; the weirdest life forms and the commonest dwarfs; the highest energy particles and the lowest energy photons. These were some of the extremes of Astrophysics 2006. We attempt also to bring you updates on things of which there is currently only one (habitable planets, the Sun, and the Universe) and others of which there are always many, like meteors and molecules, black holes and binaries. Keywords Cosmology: general · Galaxies: general · ISM: general · Stars: general · Sun: general · Planets and satellites: general · Astrobiology · Star clusters · Binary stars · Clusters of galaxies · Gamma-ray bursts · Milky Way · Earth · Active galaxies · Supernovae 1 Introduction Astrophysics in 2006 modifies a long tradition by moving to a new journal, which you hold in your (real or virtual) hands. The fifteen previous articles in the series are referenced oc- casionally as Ap91 to Ap05 below and appeared in volumes 104–118 of Publications of V.
  • Signs of Dark Matter May Point to Mirror Matter Candidate 27 April 2010, by Lisa Zyga

    Signs of Dark Matter May Point to Mirror Matter Candidate 27 April 2010, by Lisa Zyga

    Signs of dark matter may point to mirror matter candidate 27 April 2010, by Lisa Zyga (PhysOrg.com) -- Dark matter, which contains the At first, mirror matter may sound a bit like antimatter "missing mass" that's needed to explain why (which is ordinary matter with an opposite charge). galaxies stay together, could take any number of In both theories, the number of known particles forms. The main possible candidates include would double. However, while antimatter interacts MACHOS and WIMPS, but there is no shortage of very strongly with ordinary matter, annihilating itself proposals. Rather, the biggest challenge is finding into photons, mirror matter would interact very some evidence that would support one or more of weakly with ordinary matter. For this reason, some these candidates. Currently, more than 30 physicists have speculated that mirror particles experiments are underway trying to detect a sign of could be candidates for dark matter. Even though dark matter. So far, only two experiments claim to mirror matter would produce light, we would not see have found signals, with the most recent it, and it would be very difficult to detect. observations coming just a month ago. Now, physicist Robert Foot from the University of However, mirror matter would not be impossible to Melbourne has shown that the results of these two detect, and Foot thinks that the DAMA experiment experiments can be simultaneously explained by and the CoGeNT experiment may have detected an intriguing dark matter candidate called mirror mirror matter. In DAMA, scientists observed a piece matter. of sodium iodide, which should generate a photon when struck by a dark matter particle.