DOCSLIB.ORG

Wise Detections of Dust in the Habitable Zones of Planet-Bearing Stars

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Wise Detections of Dust in the Habitable Zones of Planet-Bearing Stars The Astrophysical Journal, 757:7 (6pp), 2012 September 20 doi:10.1088/0004-637X/757/1/7 C 2012. The American Astronomical Society. All rights reserved. Printed in the U.S.A. WISE DETECTIONS OF DUST IN THE HABITABLE ZONES OF PLANET-BEARING STARS Farisa Y. Morales1, D. L. Padgett2, G. Bryden1, M. W. Werner1, and E. Furlan3,4 1 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA; [email protected] 2 Goddard Space Flight Center, Greenbelt, MD 20771, USA 3 National Optical Astronomy Observatory, Tucson, AZ 85719, USA Received 2012 May 5; accepted 2012 July 17; published 2012 August 28 ABSTRACT We use data from the Wide-field Infrared Survey Explorer (WISE) all-sky release to explore the incidence of warm dust in the habitable zones around exoplanet-host stars. Dust emission at 12 and/or 22 μm(Tdust ∼ 300 and/or ∼150 K) traces events in the terrestrial planet zones; its existence implies replenishment by evaporation of comets or collisions of asteroids, possibly stirred by larger planets. Of the 591 planetary systems (728 extrasolar planets) in the Exoplanet Encyclopaedia as of 2012 January 31, 350 are robustly detected by WISE at 5σ level. We perform detailed photosphere subtraction using tools developed for Spitzer data and visually inspect all the WISE images to confirm bona fide point sources. We find nine planet-bearing stars show dust excess emission at 12 and/or 22 μm at 3σ level around young, main-sequence, or evolved giant stars. Overall, our results yield an excess incidence of ∼2.6% for stars of all evolutionary stages, but ∼1% for planetary debris disks around main-sequence stars. Besides recovering previously known warm systems, we identify one new excess candidate around the young star UScoCTIO 108. Key words: circumstellar matter – infrared: planetary systems – planets and satellites: formation – stars: individual (UScoCTIO 108) Online-only material: color figures 1. INTRODUCTION Bryden et al. 2009). The relationship between planets and debris is unclear except in the general sense that the debris is indicative The recent release of the Wide-field Infrared Survey Explorer of planetary system formation, so one might expect to see some (WISE; Wright et al. 2010) all-sky survey provides an opportu- association. Several prominent A-type stars with imaged planets nity to explore the incidence of warm circumstellar dust for a also have bright debris disks (Fomalhaut, HR 8799, and β Pic; large sample of stars. The WISE data set covers 100% of the sky Kalas et al. 2008; Marois et al. 2008; Lagrange et al. 2009), at four infrared bands W1,...,W4 centered at 3.4, 4.6, 12, and further suggesting a link between the two phenomena. The 22 μm wavelengths that are sensitive to thermal emission from question is whether the presence of planets enhances, depresses, objects at temperatures similar to our Earth (∼300 K), asteroid or is neutral in terms of the frequency or observability of dust belt, and the interior zodiacal cloud (165–250 K). In this work, systems. we use this all-sky data set to search for dust in the habitable Here, we use WISE data to attempt to find evidence of zones around exoplanet-bearing stars. comet/asteroid activity in the habitable zones of stars known to In the last two decades, over 700 exoplanets have been harbor exoplanets, and thereby examine the link between planets revealed and confirmed, primarily from radial velocity (RV) and debris. Several groups have already searched for similar and transit studies, plus ∼2300 announced candidates for the planet–debris relationships using WISE.Krivovetal.(2011) Kepler mission (Batalha et al. 2012) awaiting confirmation.5 used data from the preliminary WISE release, covering 57% The majority of these planets are in systems very different from of the sky, to search for dust around 52 systems with transiting our own, with Neptune-size or bigger planets, too large and exoplanets finding zero 3σ excess detections in any single WISE often too close to the host star to be habitable. On the other band (where σ refers to the fractional infrared excess statistical hand, a significant fraction of planetary debris disks have warm significance). But by combining <3σ excesses in W3 and W4, dust (Tdust ∼ 200 K). Following up on results from Infrared Krivov et al. (2011) identify two candidate excess detections Astronomical Satellite and Infrared Space Observatory, surveys that remain to be confirmed. With the Kepler Objects of by the Spitzer Space Telescope (Werner et al. 2004) found that Interest (KOI) Catalogue of candidate transiting exoplanets (not many nearby stars are surrounded by dust that is thought to be necessarily planet bearing), Lawler & Gladman (2012) find the generated by collisions between asteroids and/or sublimation fraction of stars with warm excesses to be ∼3% using the of comets. Of the ∼350 debris disks measured individually with recently released all-sky WISE survey. Also using the all-sky Spitzer (Chen et al. 2005;Suetal.2006; Beichman et al. 2006; WISE release and Kepler’s KOIs, Ribas et al. (2012) identify Trilling et al. 2008; Carpenter et al. 2009; Plavchan et al. 2009), 13 transiting planet systems with IR excess (>2σ ) at 12 and/or ∼70 are known to have warm components with Tdust > 150 K 22 μm, out of a 546 star sample. Only four are 3σ detections (Morales et al. 2011). for a corresponding detection rate of ∼0.7%. Among the Spitzer discoveries are the first systems known to Unlike the previous work, our study makes use of the WISE have both orbiting dust and exoplanets (Beichman et al. 2005; all-sky release and focuses on the set of confirmed exoplanets, including not just transiting planets, but also those detected by 4 Visitor, Infrared Processing and Analysis Center, Caltech, Pasadena, CA RV measurements or by direct imaging. We do not consider 91125, USA. 5 Extrasolar Planets Encyclopaedia, http://exoplanet.eu/ the Kepler candidate objects, but our sample does overlap with 1 The Astrophysical Journal, 757:7 (6pp), 2012 September 20 Morales et al. Figure 1. Color–magnitude diagram for planet-bearing stars in our sample, color-coded by planet discovery method. The 202 out of 350 planet-bearing stars in our sample plotted here, mostly from transiting (“Tran”) and RV studies, have WISE W4 photometry with S/NTotal 3. In the legend, “Ima” stands for the direct imaging method used to identify substellar-mass companions, and “Ast” for astrometry. Most are main-sequence stars without excess emission and found between the vertical dashed lines ([3.4] − [22] ≈ 0.2), while interesting excess candidates populate the region with [3.4] − [22] > ∼0.2. Also included are the well-known “Fab Four” debris disks, Vega, Fomalhaut, β Pic, Eri (asterisks), and 66 well-characterized Spitzer warm debris disk (triangles) from Morales et al. (2011) labeled “M11” in the legend. A visual inspection of WISE images of the non-labeled green triangles with [3.4] − [22] > ∼0.2 reveals that their W1 data are contaminated by excess flux from diffraction halo artifacts and/or the W4 data are contaminated by background emission. 2M1207 and UScoCTIO108 are substantially fainter than the rest of the planet–star–dust systems; this “limit” is due to the apparent magnitudes of the confirmed companions rather than the WISE detection limits. (A color version of this figure is available in the online journal.) Krivov et al. (2011) and Ribas et al. (2012) for a handful of et al. 2010). Figure 1 is a color–magnitude diagram color-coded confirmed transiting systems. by planet discovery method, to illustrate how stars with infrared For comparison, Padgett et al. (2012) searched for circumstel- excess emission can be initially identified. Most stars do not lar warm dust using the WISE all-sky data set, while considering have excess (i.e., [3.4] − [22] ∼ 0), but the WISE fluxes reveal all Hipparcos stars within 120 pc, as well as Tycho stars with an interesting sample of objects with [3.4] − [22] > ∼ 0.2. proper motions >30 mas yr−1. Their results suggest that the fre- quency of warm excess emission associated with stellar sources 3. ANALYSIS is 2% at the WISE sensitivity limits. In Section 2, we describe the data for our chosen sample of 3.1. SED Fitting target stars. Based on this data, we next (Section 3) determine which planet-bearing stars have evidence for warm dust by To measure excess emission at the WISE wavelengths, we fitting the spectral energy distribution (SED) and visually require a precise method to subtract off the stellar photosphere. inspecting the WISE images. In Section 4, we interpret the results We start by compiling near-IR Two Micron All Sky Survey and summarize our findings in Section 5. (2MASS) data (cross-correlated with the WISE catalog) and optical Tycho photometry (Høg et al. 2000) from the NASA 7 2. SAMPLE SELECTION AND THE WISE DATA Exoplanet Archive. For the SED fitting, we use previously de- veloped advanced tools built to study large samples of debris Our starting target list consists of 591 planetary systems (with disks as seen by Spitzer (Morales et al. 2009, 2011). These tools 728 extrasolar planets) given in the Exoplanet Encyclopaedia as χ 2 fit the SEDs of each of the 350 exoplanet-bearing stars to of 2012 January 31 (Schneider et al. 2011). The Schneider et al. derive the photosphere and disk contributions. The latter can be compilation includes planetary-mass companions detected us- approximated by a blackbody corresponding to the characteris- ing all methods presently utilized, i.e., RV or astrometry, tran- tic temperature of the dust grains, and NextGen models are used sit studies, micro-lensing, pulsar timing, and direct imaging.
Load more

Recommended publications
  • Arxiv:1910.11169V1 [Astro-Ph.EP] 24 Oct 2019 Metchev Et Al.(2004) Due to the Detection of a Strong Mid- Tinuum and at HCO+ and CO Gas Emission Lines
    Astronomy & Astrophysics manuscript no. PDS70_v2 c ESO 2019 October 25, 2019 VLT/SPHERE exploration of the young multiplanetary system PDS70? D. Mesa1, M. Keppler2, F. Cantalloube2, L. Rodet3, B. Charnay4, R. Gratton1, M. Langlois5; 6, A. Boccaletti4, M. Bonnefoy3, A. Vigan6, O. Flasseur7, J. Bae8, M. Benisty3; 9, G. Chauvin3; 9, J. de Boer10, S. Desidera1, T. Henning2, A.-M. Lagrange3, M. Meyer11, J. Milli12, A. Müller2, B. Pairet13, A. Zurlo14; 15; 6, S. Antoniucci16, J.-L. Baudino17, S. Brown Sevilla2, E. Cascone18, A. Cheetham19, R.U. Claudi1, P. Delorme3, V. D’Orazi1, M. Feldt2, J. Hagelberg19, M. Janson20, Q. Kral4, E. Lagadec21, C. Lazzoni1, R. Ligi22, A.-L. Maire2; 23, P. Martinez21, F. Menard3, N. Meunier3, C. Perrot4; 24; 25, S. Petrus3, C. Pinte26; 3, E.L. Rickman19, S. Rochat3, D. Rouan4, M. Samland2; 20, J.-F. Sauvage27; 6, T. Schmidt4; 28, S. Udry19, L. Weber19, F. Wildi19 (Affiliations can be found after the references) Received / accepted ABSTRACT Context. PDS 70 is a young (5.4 Myr), nearby (∼113 pc) star hosting a known transition disk with a large gap. Recent observations with SPHERE and NACO in the near-infrared (NIR) allowed us to detect a planetary mass companion, PDS 70 b, within the disk cavity. Moreover, observations in Hα with MagAO and MUSE revealed emission associated to PDS 70 b and to another new companion candidate, PDS 70 c, at a larger separation from the star. PDS 70 is the only multiple planetary system at its formation stage detected so far through direct imaging. Aims. Our aim is to confirm the discovery of the second planet PDS 70 c using SPHERE at VLT, to further characterize its physical properties, and search for additional point sources in this young planetary system.
    [Show full text]
  • The Nearest Stars: a Guided Tour by Sherwood Harrington, Astronomical Society of the Pacific
    www.astrosociety.org/uitc No. 5 - Spring 1986 © 1986, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112. The Nearest Stars: A Guided Tour by Sherwood Harrington, Astronomical Society of the Pacific A tour through our stellar neighborhood As evening twilight fades during April and early May, a brilliant, blue-white star can be seen low in the sky toward the southwest. That star is called Sirius, and it is the brightest star in Earth's nighttime sky. Sirius looks so bright in part because it is a relatively powerful light producer; if our Sun were suddenly replaced by Sirius, our daylight on Earth would be more than 20 times as bright as it is now! But the other reason Sirius is so brilliant in our nighttime sky is that it is so close; Sirius is the nearest neighbor star to the Sun that can be seen with the unaided eye from the Northern Hemisphere. "Close'' in the interstellar realm, though, is a very relative term. If you were to model the Sun as a basketball, then our planet Earth would be about the size of an apple seed 30 yards away from it — and even the nearest other star (alpha Centauri, visible from the Southern Hemisphere) would be 6,000 miles away. Distances among the stars are so large that it is helpful to express them using the light-year — the distance light travels in one year — as a measuring unit. In this way of expressing distances, alpha Centauri is about four light-years away, and Sirius is about eight and a half light- years distant.
    [Show full text]
  • Protoplanetary Disks and Debris Disks
    Protoplanetary Disks and Debris Disks David J. Wilner Harvard-Smithsonian Center for Astrophysics Sean Andrews Meredith Hughes Chunhua Qi June 12, 2009 Millimeter and Submillimeter Astronomy, Taipei Image: NASA/JPL-Caltech/T. Pyle (SSC) Circumstellar Disks • inevitable consequence of gravity + angular momentum • integral part of star and planet formation paradigm 4 10 yr 105 yr 7 10 yr 108 yr 100 AU cloud collapse protostar protoplanetary disk planetary system and debris disk Marrois et al. 2008 J. Jørgensen Isella et al. 2007 Alves et al. 2001 2 This Talk • context: “protoplanetary” and “debris” disks • tool: submillimeter dust continuum emission • some recent SMA studies and implications 1. high resolution ρ Oph disk imaging survey - S. Andrews, D. Wilner, A.M. Hughes, C. Qi, K. Dullemond (arxiv:0906.0730) 2. resolved disk polarimetry: TW Hya, HD 163296 - A.M. Hughes, D. Wilner, J. Cho, D. Marrone, A. Lazarian, S. Andrews, R. Rao 3. debris disk imaging: HD 107146 - D. Wilner, J. Williams, S. Andrews, A.M. Hughes, C. Qi 3 “Protoplanetary” → “Debris” McCaughrean et al. 1995; Burrows et al. 1996 Corder et al 2009; Greaves et al. 2005 V. Pietu; Isella et al. 2007 Kalas et al. 2008; Marois et al. 2008 • age ~1 to 10 Myr • age up to Gyrs • gas and trace dust • dust and trace gas • dust particles are sticking, • planetesimals are colliding, growing into planetesimals creating new dust particles • mass 0.001 to 0.1 M • mass <1 Mmoon • mass distribution? • dust distribution → planets? • accretion/dispersal physics? • dynamical history? 4 Submillimeter Dust Emission x-ray uv optical infrared submm cm hot gas/accr.
    [Show full text]
  • Astro2020 Science White Paper Modeling Debris Disk Evolution
    Astro2020 Science White Paper Modeling Debris Disk Evolution Thematic Areas Planetary Systems Formation and Evolution of Compact Objects Star and Planet Formation Cosmology and Fundamental Physics Galaxy Evolution Resolved Stellar Populations and their Environments Stars and Stellar Evolution Multi-Messenger Astronomy and Astrophysics Principal Author András Gáspár Steward Observatory, The University of Arizona [email protected] 1-(520)-621-1797 Co-Authors Dániel Apai, Jean-Charles Augereau, Nicholas P. Ballering, Charles A. Beichman, Anthony Boc- caletti, Mark Booth, Brendan P. Bowler, Geoffrey Bryden, Christine H. Chen, Thayne Currie, William C. Danchi, John Debes, Denis Defrère, Steve Ertel, Alan P. Jackson, Paul G. Kalas, Grant M. Kennedy, Matthew A. Kenworthy, Jinyoung Serena Kim, Florian Kirchschlager, Quentin Kral, Sebastiaan Krijt, Alexander V. Krivov, Marc J. Kuchner, Jarron M. Leisenring, Torsten Löhne, Wladimir Lyra, Meredith A. MacGregor, Luca Matrà, Dimitri Mawet, Bertrand Mennes- son, Tiffany Meshkat, Amaya Moro-Martín, Erika R. Nesvold, George H. Rieke, Aki Roberge, Glenn Schneider, Andrew Shannon, Christopher C. Stark, Kate Y. L. Su, Philippe Thébault, David J. Wilner, Mark C. Wyatt, Marie Ygouf, Andrew N. Youdin Co-Signers Virginie Faramaz, Kevin Flaherty, Hannah Jang-Condell, Jérémy Lebreton, Sebastián Marino, Jonathan P. Marshall, Rafael Millan-Gabet, Peter Plavchan, Luisa M. Rebull, Jacob White Abstract Understanding the formation, evolution, diversity, and architectures of planetary systems requires detailed knowledge of all of their components. The past decade has shown a remarkable increase in the number of known exoplanets and debris disks, i.e., populations of circumstellar planetes- imals and dust roughly analogous to our solar system’s Kuiper belt, asteroid belt, and zodiacal dust.
    [Show full text]
  • The Radio Continuum View of Centaurus Acentaurus A
    TheThe radioradio continuumcontinuum viewview ofof CentaurusCentaurus AA Ron Ekers CSIRO The Many Faces of Centaurus A Sydney, 29 June 2009 Ilana's composite Morganti et al. 1999 9° 10' Burns et al. xx image courtesy Norbert Junkes (MPIfR) WhyWhy CentaurusCentaurus AA isis specialspecial ■ the first extragalactic radio source ■ the brightest source in the Southern Hemisphere ■ the second double lobed source discovered ± after Cygnus A ■ the closest Radio Galaxy ■ the closest AGN ■ the closest SMBH ± VLBI resolution 0.01pc, 100 Rs ■ A spectacular galaxy EvolutionEvolution ofof thethe ModelsModels ■ Radio sources ± Static magnetic field 1960 ± Evolutionary sequence 1970 ± Continuous injection ± Continuous reacceleration ■ Energy source ± Galaxy collisions 1950's ± Nuclear accretions 1960- ± Accretion triggered by collisions 1980- CentaurusCentaurus AA thethe closestclosest AGNAGN ■ Distance 3.4Mpc ■ Next closest comparable AGN M87 17Mpc ! ■ Average distance to a L=1024 W Hz-1 radio galaxies ± 10Mpc ± So we are lucky (or influenced!) ■ Much easier to study at all wavelengths ■ Subtends a large angular size ± Good linear resolution ± Background probes SomeSome RadioRadio GalaxiesGalaxies Name Size Log Log (kpc) Luminosity Energy (ergs sec-1) (ergs) Centaurus A 470 41.7 59.9 Cygnus A 200 45.2 60.6 M87 80 42.0 58.6 M82 1 39.5 55.2 PolarizationPolarization inin CentaurusCentaurus AA Bracewell 1962 ■ April 1962 ■ Parkes 64m just completed ■ Discovered by Bracewell ± Published Cooper and Price ± Visitors Log ± Not a National Facilities yet! ■ Connie
    [Show full text]
  • TESS Discovery of a Super-Earth and Three Sub-Neptunes Hosted by the Bright, Sun-Like Star HD 108236
    Swarthmore College Works Physics & Astronomy Faculty Works Physics & Astronomy 2-1-2021 TESS Discovery Of A Super-Earth And Three Sub-Neptunes Hosted By The Bright, Sun-Like Star HD 108236 T. Daylan K. Pinglé J. Wright M. N. Günther K. G. Stassun Follow this and additional works at: https://works.swarthmore.edu/fac-physics See P nextart of page the forAstr additionalophysics andauthors Astr onomy Commons Let us know how access to these works benefits ouy Recommended Citation T. Daylan, K. Pinglé, J. Wright, M. N. Günther, K. G. Stassun, S. R. Kane, A. Vanderburg, D. Jontof-Hutter, J. E. Rodriguez, A. Shporer, C. X. Huang, T. Mikal-Evans, M. Badenas-Agusti, K. A. Collins, B. V. Rackham, S. N. Quinn, R. Cloutier, K. I. Collins, P. Guerra, Eric L.N. Jensen, J. F. Kielkopf, B. Massey, R. P. Schwarz, D. Charbonneau, J. J. Lissauer, J. M. Irwin, Ö Baştürk, B. Fulton, A. Soubkiou, B. Zouhair, S. B. Howell, C. Ziegler, C. Briceño, N. Law, A. W. Mann, N. Scott, E. Furlan, D. R. Ciardi, R. Matson, C. Hellier, D. R. Anderson, R. P. Butler, J. D. Crane, J. K. Teske, S. A. Shectman, M. H. Kristiansen, I. A. Terentev, H. M. Schwengeler, G. R. Ricker, R. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, Z. K. Berta-Thompson, L. G. Bouma, W. Fong, G. Furesz, C. E. Henze, E. H. Morgan, E. Quintana, E. B. Ting, and J. D. Twicken. (2021). "TESS Discovery Of A Super-Earth And Three Sub-Neptunes Hosted By The Bright, Sun-Like Star HD 108236".
    [Show full text]
  • Exep Science Plan Appendix (SPA) (This Document)
    ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 1 of 61 Created By: David A. Breda Date Program TDEM System Engineer Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology Dr. Nick Siegler Date Program Chief Technologist Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology Concurred By: Dr. Gary Blackwood Date Program Manager Exoplanet Exploration Program NASA/Jet Propulsion Laboratory California Institute of Technology EXOPDr.LANET Douglas Hudgins E XPLORATION PROGRAMDate Program Scientist Exoplanet Exploration Program ScienceScience Plan Mission DirectorateAppendix NASA Headquarters Karl Stapelfeldt, Program Chief Scientist Eric Mamajek, Deputy Program Chief Scientist Exoplanet Exploration Program JPL CL#19-0790 JPL Document No: 1735632 ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 2 of 61 Approved by: Dr. Gary Blackwood Date Program Manager, Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory Dr. Douglas Hudgins Date Program Scientist Exoplanet Exploration Program Science Mission Directorate NASA Headquarters Created by: Dr. Karl Stapelfeldt Chief Program Scientist Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory California Institute of Technology Dr. Eric Mamajek Deputy Program Chief Scientist Exoplanet Exploration Program Office NASA/Jet Propulsion Laboratory California Institute of Technology This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. © 2018 California Institute of Technology. Government sponsorship acknowledged. Exoplanet Exploration Program JPL CL#19-0790 ExEP Science Plan, Rev A JPL D: 1735632 Release Date: February 15, 2019 Page 3 of 61 Table of Contents 1.
    [Show full text]
  • Solar System Debris Disk - S2D2
    Solar System Debris Disk - S2D2 Image credit: NASA/JPL-Caltech Proposal for Science Themes of ESA's L2 and L3 Missions Ralf Srama Universität Stuttgart, Institut für Raumfahrtsysteme Raumfahrtzentrum Baden Württemberg Pfaffenwaldring 29, 70569 Stuttgart [email protected] Tel. +49 711 6856 2511, Fax +49 711 685 63596 http://www.irs.uni-stuttgart.de 2 Solar System Debris Disk - S2D2 Contributors Eberhard Grün, Max-Planck-Institut für Kernphysik, Heidelberg, Germany Alexander Krivov, Astrophysikalisches Institut, Univ. Jena, Germany Rachel Soja, Institut für Raumfahrtsysteme, Univ. Stuttgart, Germany Veerle Sterken, Institut für Raumfahrtsysteme, Univ. Stuttgart, Germany Zoltan Sternovsky, LASP, Univ. of Colorado, Boulder, USA. Supporters listed at http://www.dsi.uni-stuttgart.de/cosmicdust/missions/debrisdisk/index.html 3 Solar System Debris Disk - S2D2 Summary from direct observations of the parent bodies. The sizes of these parent bodies range from Understanding the conditions for planet Near Earth Asteroids with sizes of a few 10 m, formation is the primary theme of ESA's to km-sized comet nuclei, to over 1000 km- Cosmic Vision plan. Planets and left-over sized Trans-Neptunian Objects. The inner small solar system bodies are witnesses and zodiacal dust cloud has been probed by remote samples of the processing in different regions sensing instruments at visible and infrared of the protoplanetary disk. Small bodies fill the wavelengths, micro crater counts, in situ dust whole solar system from the surface of the analyzers, meteor observations and recent sun, to the fringes of the solar system, and to sample return missions. Nevertheless, the the neighboring stellar system. This is covered dynamical and compositional interrelations by the second theme of Cosmic Vision.
    [Show full text]
  • Gli Ammassi Di Galassie
    Universo in Fiore 2017 CORSO BASE I GIGANTI DEL COSMO: GLI AMMASSI DI GALASSIE Sabrina De Grandi [email protected] Organizzazione spaziale delle galassie Ammassi Gruppi Galassie 100 mila a.l. ~30 kpc 3 milioni a.l. ~ 103 kpc 20 milioni a.l. ~ 7x103 kpc I primi cataloghi di ammassi Fino agli anni ’80: ispezione visuale di lastre fotografiche alla ricerca di sovradensita` di galassie. Es. di lastre fotografiche: • PSS: National Geographic Society-Palomar Observatory Sky Survey (Telescopio 5m Hale, Mt. Wilson US) • UKST: Schmidt telescope IIIa-J plates (Telescopio 1.2m, UK-Australia),… I cataloghi di Abell (1958) e Zwicky (1961-1968) Il catalogo piu` usato: Abell (1958) Emisfero Nord (2712) e A.C.O. (1989) Emisfero Sud (1364). 1958: Abell ispeziono` di 104 deg2 di lastre PSS (Luna ~0.25 deg2) Criteri principali: • almeno 30 galassie • compatto (0.02<z<0.2) • piano galattico escluso Dagli anni ’90: • algoritmi automatici di identificazione al posto dell’occhio umano. • Non più lastre fotografiche, ma immagini digitali (CCD) • SDSS (Sloan Digital Sky Survey), iniziata nel 2000 e tutt’ora in atto (35% del cielo osservato, 500 milioni di oggetti, catalogo di ammassi • Accesso libero ai dati (nel Telescopio dedicato ad 2015: 13o Data Release) Apache Point 2.5m (US) Immagine SDSS dell’ammasso A2142 MACS J1206.2-0847 DIAMETRO tipico di un ammasso di galassie ~ 20 milioni anni luce ~ 7 Mpc SPICA (훼 costellazione della Vergine) MACS J1206.2-0847 DIAMETRO tipico di un ammasso di galassie ~ 20 milioni anni luce ~ 7 Mpc ma… DISTANZA di MACS J1206 ~ 4.5 miliardi di anni luce ~ 1500 Mpc Dove si trova la Via Lattea in questa struttura universale? ovvero Noi ci troviamo in un Ammasso di galassie? Il Gruppo Locale 100.000 a.l.
    [Show full text]
  • The Sky This Week
    The sky this week April 20 to April 26, 2020 By Joe Grida, Technical Informaon Officer, ASSA ([email protected]) elcome to the fourth edion of The Sky this Week. It is designed to keep you looking up during these rather uncertain mes. We can’t get together for Members’ Viewing Nights, so I thought I’d write this W to give you some ideas of observing targets that you can chase on any clear night this coming week. As I said in my recent Starwatch* column in The Adverser newspaper: “Even with the restricons in place, stargazing is something that you can do easily on your own. It helps to relieve stress and will keep your sense of perspecve. It’s prey hard to walk away from a night under the stars without a jusfiable sense of awe. And also without sensing a real, albeit tenuous, connecon with the cosmos at large”. * Published on the last Friday of each month Naked eye star walk Over in the eastern late evening sky, Scorpius, the Scorpion (one of the few constellaons in our sky that actually resembles what it is supposed to represent) is difficult to miss. He will keep us company over the coming chilly winter months. Its brightest star, Antares, is a huge star of gargantuan proporons. If we replaced our Sun with it, then all the planets from Mercury through to Jupiter would all find themselves engulfed within it! Just below the tail of Scorpius, you can find the star clusters designated M6 and M7. Take the trouble to observe these with binoculars.
    [Show full text]
  • A Review on Substellar Objects Below the Deuterium Burning Mass Limit: Planets, Brown Dwarfs Or What?
    geosciences Review A Review on Substellar Objects below the Deuterium Burning Mass Limit: Planets, Brown Dwarfs or What? José A. Caballero Centro de Astrobiología (CSIC-INTA), ESAC, Camino Bajo del Castillo s/n, E-28692 Villanueva de la Cañada, Madrid, Spain; [email protected] Received: 23 August 2018; Accepted: 10 September 2018; Published: 28 September 2018 Abstract: “Free-floating, non-deuterium-burning, substellar objects” are isolated bodies of a few Jupiter masses found in very young open clusters and associations, nearby young moving groups, and in the immediate vicinity of the Sun. They are neither brown dwarfs nor planets. In this paper, their nomenclature, history of discovery, sites of detection, formation mechanisms, and future directions of research are reviewed. Most free-floating, non-deuterium-burning, substellar objects share the same formation mechanism as low-mass stars and brown dwarfs, but there are still a few caveats, such as the value of the opacity mass limit, the minimum mass at which an isolated body can form via turbulent fragmentation from a cloud. The least massive free-floating substellar objects found to date have masses of about 0.004 Msol, but current and future surveys should aim at breaking this record. For that, we may need LSST, Euclid and WFIRST. Keywords: planetary systems; stars: brown dwarfs; stars: low mass; galaxy: solar neighborhood; galaxy: open clusters and associations 1. Introduction I can’t answer why (I’m not a gangstar) But I can tell you how (I’m not a flam star) We were born upside-down (I’m a star’s star) Born the wrong way ’round (I’m not a white star) I’m a blackstar, I’m not a gangstar I’m a blackstar, I’m a blackstar I’m not a pornstar, I’m not a wandering star I’m a blackstar, I’m a blackstar Blackstar, F (2016), David Bowie The tenth star of George van Biesbroeck’s catalogue of high, common, proper motion companions, vB 10, was from the end of the Second World War to the early 1980s, and had an entry on the least massive star known [1–3].
    [Show full text]
  • An Early Detection of Blue Luminescence by Neutral Pahs in the Direction of the Yellow Hypergiant HR 5171A?
    A&A 583, A98 (2015) Astronomy DOI: 10.1051/0004-6361/201526392 & c ESO 2015 Astrophysics An early detection of blue luminescence by neutral PAHs in the direction of the yellow hypergiant HR 5171A? A. M. van Genderen1, H. Nieuwenhuijzen2, and A. Lobel3 1 Leiden Observatory, Leiden University, Postbus 9513, 2300RA Leiden, The Netherlands e-mail: [email protected] 2 SRON Laboratory for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands 3 Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium Received 23 April 2015 / Accepted 23 August 2015 ABSTRACT Aims. We re-examined photometry (VBLUW, UBV, uvby) of the yellow hypergiant HR 5171A made a few decades ago. In that study no proper explanation could be given for the enigmatic brightness excesses in the L band (VBLUW system, λeff = 3838 Å). In the present paper, we suggest that this might have been caused by blue luminescence (BL), an emission feature of neutral polycyclic aromatic hydrocarbon molecules (PAHs), discovered in 2004. It is a fact that the highest emission peaks of the BL lie in the L band. Our goals were to investigate other possible causes, and to derive the fluxes of the emission. Methods. We used two-colour diagrams based on atmosphere models, spectral energy distributions, and different extinctions and extinction laws, depending on the location of the supposed BL source: either in Gum48d on the background or in the envelope of HR 5171A. Results. False L–excess sources, such as a hot companion, a nearby star, or some instrumental effect, could be excluded. Also, emission features from a hot chromosphere are not plausible.
    [Show full text]