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Spectral Analysis of the Hybrid PG 1159-Type Central Stars of the Planetary Nebulae Abell 43 and NGC 7094
MNRAS 489, 1054–1071 (2019) doi:10.1093/mnras/stz1994 Advance Access publication 2019 July 25 Spectral analysis of the hybrid PG 1159-type central stars of the planetary nebulae Abell 43 and NGC 7094 L. Lobling¨ ,1‹ T. Rauch ,1 M. M. Miller Bertolami,2,3 H. Todt,4 F. Friederich,1 M. Ziegler,1 K. Werner 1 andJ.W.Kruk5 Downloaded from https://academic.oup.com/mnras/article-abstract/489/1/1054/5538811 by Macquarie University user on 29 August 2019 1Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, D-72076 Tubingen,¨ Germany 2Instituto de Astrof´ısica La Plata, CONICET-UNLP, Paseo del Bosque s/n, (B1900FWA) La Plata, Argentina 3Facultad de Ciencias Astronomicas´ y Geof´ısicas, UNLP, Paseo del Bosque s/n, (B1900FWA) La Plata, Argentina 4Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24/25, D-14476 Potsdam, Germany 5NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA Accepted 2019 July 16. Received 2019 June 18; in original form 2019 April 30 ABSTRACT Stellar post asymptotic giant branch (post-AGB) evolution can be completely altered by a final thermal pulse (FTP) which may occur when the star is still leaving the AGB (AFTP), at the departure from the AGB at still constant luminosity (late TP, LTP) or after the entry to the white-dwarf cooling sequence (very late TP, VLTP). Then convection mixes the He- rich material with the H-rich envelope. According to stellar evolution models the result is a star with a surface composition of H ≈ 20 per cent by mass (AFTP), ≈ 1 per cent (LTP), or (almost) no H (VLTP). -
Type Iax Supernovae
Type Iax Supernovae Saurabh W. Jha with Curtis McCully (LCOGT/UCSB), Ryan Foley (UC Santa Cruz), Max Stritzinger (Aarhus), et al. Supernovae Through the Ages Rapa Nui August 12, 2016 78 GARNAVICH ET AL. Vol. 509 H with a Gaussian prior based on our own Type Ia SNs this result beyond a cosmological-constant model because 0 result including our estimate of the systematic error from of the possible time dependence ofax. But for an equation the Cepheid distance scale, H \ 65 ^ 7 km s~1 Mpc~1 of state Ðxed after recombination, the combined constraints (R98a). It is important to note0 that the Type Ia SNs con- continue to be consistent with a Ñat geometry as long as straints on()m, ) ) are independent of the distance scale ax [ [0.6. With better estimates of the systematic errors in but that the CMB" constraints are not. We then combine the Type Ia SN data and new measurements of the CMB marginalized likelihood functions of the CMB and Type Ia anisotropy, these preliminary indications should quickly SNs data. The result is shown inFigure 3. Again, we must turn into very strong constraints(Tegmark et al. 1998). caution that systematic errors in either the Type Ia SNs CONCLUSIONS data(R98a) or the CMB could a†ect this result. 6. Nevertheless, it is heartening to see that the combined The current results from the High-z Supernova Search constraint favors a location in this parameter space that has Team suggest that there is an additional energy component not been ruled out by other observations, though there may sharing the universe with gravitating matter. -
Stars and Their Spectra: an Introduction to the Spectral Sequence Second Edition James B
Cambridge University Press 978-0-521-89954-3 - Stars and Their Spectra: An Introduction to the Spectral Sequence Second Edition James B. Kaler Index More information Star index Stars are arranged by the Latin genitive of their constellation of residence, with other star names interspersed alphabetically. Within a constellation, Bayer Greek letters are given first, followed by Roman letters, Flamsteed numbers, variable stars arranged in traditional order (see Section 1.11), and then other names that take on genitive form. Stellar spectra are indicated by an asterisk. The best-known proper names have priority over their Greek-letter names. Spectra of the Sun and of nebulae are included as well. Abell 21 nucleus, see a Aurigae, see Capella Abell 78 nucleus, 327* ε Aurigae, 178, 186 Achernar, 9, 243, 264, 274 z Aurigae, 177, 186 Acrux, see Alpha Crucis Z Aurigae, 186, 269* Adhara, see Epsilon Canis Majoris AB Aurigae, 255 Albireo, 26 Alcor, 26, 177, 241, 243, 272* Barnard’s Star, 129–130, 131 Aldebaran, 9, 27, 80*, 163, 165 Betelgeuse, 2, 9, 16, 18, 20, 73, 74*, 79, Algol, 20, 26, 176–177, 271*, 333, 366 80*, 88, 104–105, 106*, 110*, 113, Altair, 9, 236, 241, 250 115, 118, 122, 187, 216, 264 a Andromedae, 273, 273* image of, 114 b Andromedae, 164 BDþ284211, 285* g Andromedae, 26 Bl 253* u Andromedae A, 218* a Boo¨tis, see Arcturus u Andromedae B, 109* g Boo¨tis, 243 Z Andromedae, 337 Z Boo¨tis, 185 Antares, 10, 73, 104–105, 113, 115, 118, l Boo¨tis, 254, 280, 314 122, 174* s Boo¨tis, 218* 53 Aquarii A, 195 53 Aquarii B, 195 T Camelopardalis, -
New Type of Black Hole Detected in Massive Collision That Sent Gravitational Waves with a 'Bang'
New type of black hole detected in massive collision that sent gravitational waves with a 'bang' By Ashley Strickland, CNN Updated 1200 GMT (2000 HKT) September 2, 2020 <img alt="Galaxy NGC 4485 collided with its larger galactic neighbor NGC 4490 millions of years ago, leading to the creation of new stars seen in the right side of the image." class="media__image" src="//cdn.cnn.com/cnnnext/dam/assets/190516104725-ngc-4485-nasa-super-169.jpg"> Photos: Wonders of the universe Galaxy NGC 4485 collided with its larger galactic neighbor NGC 4490 millions of years ago, leading to the creation of new stars seen in the right side of the image. Hide Caption 98 of 195 <img alt="Astronomers developed a mosaic of the distant universe, called the Hubble Legacy Field, that documents 16 years of observations from the Hubble Space Telescope. The image contains 200,000 galaxies that stretch back through 13.3 billion years of time to just 500 million years after the Big Bang. " class="media__image" src="//cdn.cnn.com/cnnnext/dam/assets/190502151952-0502-wonders-of-the-universe-super-169.jpg"> Photos: Wonders of the universe Astronomers developed a mosaic of the distant universe, called the Hubble Legacy Field, that documents 16 years of observations from the Hubble Space Telescope. The image contains 200,000 galaxies that stretch back through 13.3 billion years of time to just 500 million years after the Big Bang. Hide Caption 99 of 195 <img alt="A ground-based telescope&amp;#39;s view of the Large Magellanic Cloud, a neighboring galaxy of our Milky Way. -
Variable Star Section Circular
The British Astronomical Association Variable Star Section Circular No. 177 September 2018 Office: Burlington House, Piccadilly, London W1J 0DU Contents Observers Workshop – Variable Stars, Photometry and Spectroscopy 3 From the Director 4 CV&E News – Gary Poyner 6 AC Herculis – Shaun Albrighton 8 R CrB in 2018 – the longest fully substantiated fade – John Toone 10 KIC 9832227, a potential Luminous Red Nova in 2022 – David Boyd 11 KK Per, an irregular variable hiding a secret - Geoff Chaplin 13 Joint BAA/AAVSO meeting on Variable Stars – Andy Wilson 15 A Zooniverse project to classify periodic variable stars from SuperWASP - Andrew Norton 30 Eclipsing Binary News – Des Loughney 34 Autumn Eclipsing Binaries – Christopher Lloyd 36 Items on offer from Melvyn Taylor’s library – Alex Pratt 44 Section Publications 45 Contributing to the VSSC 45 Section Officers 46 Cover images Vend47 or ASASSN-V J195442.95+172212.6 2018 August 14.294, iTel 0.62m Planewave CDK @ f6.5 + FLI PL09--- CCD. 60 secs lum. Martin Mobberley Spectrum taken with a LISA spectroscope on Aug 16.875UT. C-11. Total exposure 1.1hr David Boyd Click on images to see in larger scale 2 Back to contents Observers' Workshop - Variable Stars, Photometry and Spectroscopy. Venue: Burlington House, Piccadilly, London, W1J 0DU (click to see map) Date: Saturday, 2018, September 29 - 10:00 to 17:30 For information about booking for this meeting, click here. A workshop to help you get the best from observing the stars, be it visually, with a CCD or DSLR or by using a spectroscope. The topics covered will include: • Visual observing with binoculars or a telescope • DSLR and CCD observing • What you can learn from spectroscopy And amongst those topics the types of star covered will include, CV and Eruptive Stars, Pulsating Stars and Eclipsing Binaries. -
Planetary Nebulae: Observational Properties, Mimics and Diagnostics
CSIRO PUBLISHING www.publish.csiro.au/journals/pasa Publications of the Astronomical Society of Australia, 2010, 27, 129–148 Planetary Nebulae: Observational Properties, Mimics and Diagnostics David J. FrewA,C,D and Quentin A. ParkerA,B A Department of Physics, Macquarie University, North Ryde, NSW 2109 B Anglo–Australian Observatory, Epping, NSW 1710 C Perth Observatory, Bickley, WA 6076 D Corresponding author. Email: [email protected] Received 2009 July 19, accepted 2010 January 21 Abstract: The total number of true, likely and possible planetary nebulae (PN) now known in the Milky Way is nearly 3000, double the number known a decade ago. The new discoveries are a legacy of the recent availability of wide field, narrowband imaging surveys, primarily in the light of H-alpha. In this paper, we summarise the various PN discovery techniques, and give an overview of the many types of objects which mimic PN and which appear as contaminants in both Galactic and extragalactic samples. Much improved discrimination of classical PN from their mimics is now possible based on the wide variety of high-quality multiwavelength data sets that are now available. We offer improved taxonomic and observational definitions for the PN phenomenon based on evaluation of these better diagnostic capabilities. However, we note that evidence is increasing that the PN phenomenon is heterogeneous, and PN are likely to be formed from multiple evolutionary scenarios. In particular, the relationships between some collimated symbiotic outflows and bipolar PN remain uncertain. Keywords: catalogs — planetary nebulae: general — stars: AGB and post-AGB — stars: fundamental parameters — surveys — techniques: photometric, spectroscopic 1 Introduction The total number of currently known Galactic PN is A classical planetary nebula (PN) is a shell of ionized nearly 3000, which includes all known confirmed PN from gas, ejected from a star of low to intermediate mass (∼1 the catalogues of Acker et al. -
Planetary Nebulae: Observational Properties, Mimics and Diagnostics
CSIRO PUBLISHING www.publish.csiro.au/journals/pasa Publications of the Astronomical Society of Australia, 2010, 27, 129–148 Planetary Nebulae: Observational Properties, Mimics and Diagnostics David J. FrewA,C,D and Quentin A. ParkerA,B A Department of Physics, Macquarie University, North Ryde, NSW 2109 B Anglo–Australian Observatory, Epping, NSW 1710 C Perth Observatory, Bickley, WA 6076 D Corresponding author. Email: [email protected] Received 2009 July 19, accepted 2010 January 21 Abstract: The total number of true, likely and possible planetary nebulae (PN) now known in the Milky Way is nearly 3000, double the number known a decade ago. The new discoveries are a legacy of the recent availability of wide field, narrowband imaging surveys, primarily in the light of H-alpha. In this paper, we summarise the various PN discovery techniques, and give an overview of the many types of objects which mimic PN and which appear as contaminants in both Galactic and extragalactic samples. Much improved discrimination of classical PN from their mimics is now possible based on the wide variety of high-quality multiwavelength data sets that are now available. We offer improved taxonomic and observational definitions for the PN phenomenon based on evaluation of these better diagnostic capabilities. However, we note that evidence is increasing that the PN phenomenon is heterogeneous, and PN are likely to be formed from multiple evolutionary scenarios. In particular, the relationships between some collimated symbiotic outflows and bipolar PN remain uncertain. Keywords: catalogs — planetary nebulae: general — stars: AGB and post-AGB — stars: fundamental parameters — surveys — techniques: photometric, spectroscopic 1 Introduction The total number of currently known Galactic PN is A classical planetary nebula (PN) is a shell of ionized nearly 3000, which includes all known confirmed PN from gas, ejected from a star of low to intermediate mass (∼1 the catalogues of Acker et al. -
NASA Townhall AAS 225Th Meeting Seattle, WA
NASA HQ Staff @ AAS Meeting: John Grunsfeld Paul Hertz Dominic Benford Keith Chamberlin NASA Townhall Felicia Chou Mike Garcia AAS 225th Meeting Hashima Hasan Doug Hudgins Billy Lightsey Mario Perez Seattle, WA Christina Richey Wilt Sanders Eric Smith Linda Sparke January 7, 2015 Martin Still Amber Straughn Eric Tollestrup Debra Wallace Paul Hertz Director, Astrophysics Division Science Mission Directorate @PHertzNASA This presentation is posted at http://science.nasa.gov/astrophysics/documents/ 1 Visiting Experienced Scientists at NASA HQ Looking for a few good astrophysicists…. • Seeking one or more experienced scientists - to take leave from their U.S. home institution - for a 2-year visiting position (can extend up to 6 years) - to work in Astrophysics at NASA Headquarters • Duties include - Management of the Astrophysics grants programs; - Planning, development, and management of NASA missions; - Strategic planning for the future of NASA astrophysics. • Requires Ph.D. or equivalent, relevant research experience, familiarity with NASA research award programs and/or missions, and the ability to communicate effectively. • For additional info, talk with any of the Astrophysics HQ staff. Apply by January 31, 2015 http://jobregister.aas.org/job_view?JobID=46612 2 Why Astrophysics? Astrophysics is humankind’s scientific endeavor to understand the universe and our place in it. 1. How did our universe 2. How did galaxies, stars, 3. Are We Alone? begin and evolve? and planets come to be? These national strategic drivers are enduring 1972 1982 -
Zombie Star' 6 August 2014
Hubble finds supernova star system linked to potential 'zombie star' 6 August 2014 dwarf, a process that ignited a nuclear reaction and released this weak supernova blast. This supernova, Type Iax, is less common than its brighter cousin, Type Ia. Astronomers have identified more than 30 of these mini-supernovas that may leave behind a surviving white dwarf. "Astronomers have been searching for decades for the star systems that produce Type Ia supernova explosions," said scientist Saurabh Jha of Rutgers University in Piscataway, New Jersey. "Type Ia's are important because they're used to measure vast cosmic distances and the expansion of the universe. But we have very few constraints on how any white dwarf explodes. The similarities between Type Iax's and normal Type Ia's make understanding Type Iax progenitors important, especially because no Type Ia progenitor has been conclusively identified. This discovery shows us one way that you can get a white dwarf explosion." The two inset images show before-and-after images The team's results will appear in the Thursday, captured by NASA’s Hubble Space Telescope of Aug. 7 edition of the journal Nature. Supernova 2012Z in the spiral galaxy NGC 1309. The white X at the top of the main image marks the location The weak supernova, dubbed SN 2012Z, resides in of the supernova in the galaxy. Credit: NASA, ESA the host galaxy NGC 1309 which is 110 million light- years away. It was discovered in the Lick Observatory Supernova Search in January 2012. Luckily, Hubble's Advanced Camera for Surveys (Phys.org) —Using NASA's Hubble Space also observed NGC 1309 for several years prior the Telescope, a team of astronomers has spotted a supernova outburst, which allowed scientists to star system that could have left behind a "zombie compare before-and-after images. -
Arxiv:2001.08266V1 [Astro-Ph.SR] 22 Jan 2020
Astronomy & Astrophysics manuscript no. aanda c ESO 2020 January 24, 2020 Searching for central stars of planetary nebulae in Gaia DR2 N. Chornay and N. A. Walton Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, United Kingdom e-mail: [email protected], e-mail: [email protected] January 24, 2020 ABSTRACT Context. Accurate distance measurements are fundamental to the study of Planetary Nebulae (PNe) but have long been elusive. The most accurate and model-independent distance measurements for galactic PNe come from the trigonometric parallaxes of their central stars, which were only available for a few tens of objects prior to the Gaia mission. Aims. Accurate identification of PN central stars in the Gaia source catalogues is a critical prerequisite for leveraging the unprece- dented scope and precision of the trigonometric parallaxes measured by Gaia. Our aim is to build a complete sample of PN central star detections with minimal contamination. Methods. We develop and apply an automated technique based on the likelihood ratio method to match candidate central stars in Gaia Data Release 2 (DR2) to known PNe in the HASH PN catalogue, taking into account the BP–RP colours of the Gaia sources as well as their positional offsets from the nebula centres. These parameter distributions for both true central stars and background sources are inferred directly from the data. Results. We present a catalogue of over 1000 Gaia sources that our method has automatically identified as likely PN central stars. We demonstrate how the best matches enable us to trace nebula and central star evolution and to validate existing statistical distance scales, and discuss the prospects for further refinement of the matching based on additional data. -
A Catalogue of Integrated H-Alpha Fluxes for 1258 Galactic Planetary Nebulae
Mon. Not. R. Astron. Soc. 000, 1–49 (2012) Printed 13 November 2012 (MN LATEX style file v2.2) A catalogue of integrated Hα fluxes for 1,258 Galactic planetary nebulae David J. Frew1,2⋆, Ivan S. Bojiˇci´c1,2,3 and Q.A. Parker1,2,3 1Department of Physics and Astronomy, Macquarie University, NSW 2109, Australia 2Research Centre in Astronomy, Astrophysics and Astrophotonics, Macquarie University, NSW 2109, Australia 3Australian Astronomical Observatory, PO Box 915, North Ryde, NSW 1670, Australia Accepted ; Received ; in original form ABSTRACT We present a catalogue of new integrated Hα fluxes for 1258 Galactic planetary nebulae (PNe), with the majority, totalling 1234, measured from the Southern Hα Sky Survey Atlas (SHASSA) and/or the Virginia Tech Spectral-line Survey (VTSS). Aperture photometry on the continuum-subtracted digital images was performed to extract Hα+[N ii] fluxes in the case of SHASSA, and Hα fluxes from VTSS. The [N ii] contribution was then deconvolved from the SHASSA flux using spectrophotometric data taken from the literature or derived by us. Comparison with previous work shows that the flux scale presented here has no significant zero-point error. Our catalogue is the largest compilation of homogeneously derived PN fluxes in any waveband yet measured, and will be an important legacy and fresh benchmark for the community. Amongst its many applications, it can be used to determine statistical distances for these PNe, determine new absolute magnitudes for delineating the faint end of the PN luminosity function, provide baseline data for photoionization and hydrodynam- ical modelling, and allow better estimates of Zanstra temperatures for PN central stars with accurate optical photometry. -
Why Astrophysics?
NASA Astrophysics Program Update Paul Hertz Director, Astrophysics Division Science Mission Directorate @PHertzNASA Committee on Astronomy and Astrophysics November 3, 2014 1 Why Astrophysics? Astrophysics is humankind’s scientific endeavor to understand the universe and our place in it. 1. How did our universe 2. How did galaxies, stars, 3. Are We Alone? begin and evolve? and planets come to be? These national strategic drivers are enduring 1972 1982 1991 2001 2010 2 M82X-2: Suspected Black Hole Unmasked as Ultraluminous Pulsar by NuSTAR Image credit: NASA/JPL-Caltech/SAO/NOAO 3 Hubble, Spitzer and Kepler Telescopes Find Clear Skies and Water Vapor on Exo-Neptune Credit: NASA, ESA, and A. Feild (STScI) 4 5 Hubble Space Telescope • Hubble conducted a search for Kuiper Belt Object suitable as New Horizons flyby destination following Pluto flyby. • 154 orbit observing program recommended by TAC conditional on successful 40 orbit pilot program to validate predicted source counts and expected probability of success. The June 2014 pilot was successful with at least two KBOs detected. • The full observing program was completed early August 2014, locating three KBOs the Agency's New Horizon's spacecraft could potentially visit. They are each about 10 times larger than typical comets, but only 1-2% of the size of Pluto. These two multiple-exposure images from NASA's Hubble Space Telescope show Kuiper Belt objects, or KBOs, against a background of stars in the constellation Sagittarius. The two KBOs are roughly 4 billion miles from Earth. Image