DOCSLIB.ORG

Observations of Clusters Using the Strömvil System. I. Standard Areas

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Observations of Clusters Using the Strömvil System. I. Standard Areas Baltic Astronomy, vol. 5, 445~450, 1996. OBSERVATIONS OF CLUSTERS USING THE STRÖMVIL SYSTEM. I. STANDARD AREAS A. G. Davis Philip1-2, R. P. Boyle3 and V. Straizys4 1 Union College, Schenectady, NY 12308, U.S.A. 2 Institute for Space Observations, 1125 Oxford PL, Schenectady, NY 12308, U.S.A. 3 Vatican Observatory Research Group, Steward Observatory, University of Arizona, Tucson, AZ 85721, U.S.A. 4 Institute of Theoretical Physics and Astronomy, Gostauto 12, Vilnius 2600, Lithuania Received September 1, 1995. Abstract. A set of standard areas of the Strömvil system is de- scribed. Preliminary values of the color indices of standard stars for photoelectric work may be obtained from their published values in both parent (uvby and Vilnius) systems. Stays in 19 open clusters already observed in both systems may be used as preliminary stan- dards. Standard areas for the CCD work are to be measured anew. For this, a set of 12 compact open clusters and globular clusters have been selected, six areas in each hemisphere, mostly at declinations +30 deg and -30 deg. The 10-20 arcmin areas will contain stan- dard stars of 10-16 mag. They will be good for fixing the zero-point of magnitudes and color indices, for the determination of extinction coefficients in the Earth's atmosphere and for the determination of color equations between instrumental CCD systems and the standard Strömvil system. The first observations in this program are planned with the new 1.8-m Vatican telescope on Mt. Graham, Arizona. Key words: techniques: photometric — stars: standard — Galaxy: areas, open clusters, globular clusters 446 A. G. Davis Philip, R. P. Boyle and V. Straizys 1. INTRODUCTION Straizys, Crawford & Philip (1996) have proposed a photometric system, named Strömvil, which combines the Vilnius and Strömgren systems. Table 1 presents data concerning the passbands in the Strömvil system. The physical justification of the passbands in the new system is described in the paper cited above. The system will achieve better classification possibilities than the uvby system alone over a larger range of spectral types and luminosities, especially in the presence of interstellar reddening. Although the Vilnius system gives classification for stars of all spectral types, by switching four of its passbands to four passbands of the Strömgren system we can make use of the very extensive uvby photometric database. For thousands of stars only three additional measures (in Ρ, Ζ and S) will create a set of seven color indices which will allow a classification of stars of all spectral types. Table 1. Mean wavelengths and half-widths of passbands of the Strömvil photometric system. Passband 35 37 41 47 52 55 66 λο (nm) 350 374 411 467 516 547 656 Δλ (nm) 30 26 19 23 21 23 20 2. REQUIREMENTS FOR THE STANDARD STARS For calibration of the system, we need photoelectric observa- tions of relatively bright stars of various spectral classes, luminosi- ties, metallicities and peculiarities. These stars should have accu- rately determined temperatures, surface gravities, absolute magni- tudes, metallicities, rotational velocities and other parameters. For this, as well as for determination of the intrinsic color indices, stars of open and globular clusters are suitable. Since the Strömvil system will be used for the study of faint stars in relatively small areas, we need CCD areas with standard stars for the following purposes: (a) establishing the zero-point of the magnitude scales, (b) determination of color equations between Observations of clusters in the Strömvil system. I. 447 the instrumental and standard systems, (c) determination of the ex- tinction coefficients in the Earth's atmosphere. These stars should be sufficiently faint (>10 mag) to be on the linear part of the CCD response but also sufficiently bright (<16 mag) to be measurable with high precision (< 0.01 mag) on short exposure frames. The areas should contain stars of a wide range of color indices for the determination of color equation. The stars should be almost unred- dened to be useful in finding the intrinsic color equations. Also, these stars should be not of very different apparent brightness, so they can be observed with similar accuracy in one exposure. And last, the standard areas should be sufficiently small (10-20 arcmin) to be used for different sizes of CCD chips on telescopes of different focal lengths. It is not easy to find areas satisfying all these requirements. Areas at high galactic latitudes usually do not contain hot stars and at low galactic latitudes faint stars are all reddened by interstellar dust. Most of the close and unreddened open clusters have much too large angular sizes to be imaged on a single CCD frame. Distant open clusters are usually considerably reddened. In open clusters the reddest main sequence stars are very faint relative to member early-type stars. However, there are some old open clusters of the M 67 type which contain both red giants and blue stragglers at about the same appar- ent visual magnitude. Some of them are at high galactic latitudes and, therefore, unreddened. Also, they are mostly distant objects and thus have small angular size. The M 67 cluster contains seven or eight blue stragglers and is a very good area for CCD cameras embracing a 20' field. In some cases, the intermediate-age open clus- ters of the NGC 7789 type with small interstellar reddening are also acceptable. However, unreddened open clusters of small angular size are rare and it is not possible to find them in various right ascensions to be comfortably accessible all the year round. Other candidates for standards are globular clusters. Many of them contain horizontal branches with blue and red stars at simi- lar apparent magnitudes. In the ultraviolet, the blue HB stars are sufficiently bright, being of comparable brightness as the red giants. The angular sizes of globular clusters match the areas covered by CCD chips. The considerable crowding of stars in a globular cluster core mandates that standard stars should be selected in their outer regions. Globular clusters have a metal deficiency relative to the majority of field stars and open clusters. However, color equations 448 A. G. Davis Philip, R. P. Boyle and V. Straizys Table 2. Open clusters observed in the Strömgren and Vilnius systems Name RA(2000) Dec(2000) NGC 129 00 29.9 +60 14 NGC 752 01 57.8 +37 41 Alpha Persei 03 22 +48 40 Pleiades 03 47 +24 08 Hyades 04 20 +15 39 Praesepe (M 44) 08 40.1 +20 00 NGC 2682 (M 67) 08 50.4 +12 00 Coma Berenices 12 26 +26 NGC 6494 (M 23) 17 56.8 -19 02 NGC 6611 (M 16) 18 18.8 -13 47 NGC 6633 18 27.9 +06 34 NGC 6705 (M 11) 18 51.1 -06 17 NGC 6811 19 38.2 +46 34: NGC 6910 20 23.1 +40 47 NGC 6913 (M 29) 20 23.9 +38 32 NGC 7039 21 22.2 +45 39" NGC 7092 (M 39) 21 32.2 +48 26 NGC 7686 23 30.2 +49 08 NGC 7789 23 57.0 +56 44 between close photometric systems are not very sensitive to metal- licity differences (Straizys, Kazlauskas et al. 1996). 3. PRELIMINARY SELECTION OF THE STANDARD AREAS Color indices for the Strömvil system can be obtained from the existing measurements in both the parent systems. Strömvil indices 35-55, 41-55 and -55 can be obtained from the Strömgren indices u — y, ν — y and b — y with a correction in zero-point. The Strömvil indices 37-55, 52-55 and 55-66 can be obtained from the Vilnius indices Ρ — V, Ζ — V and V — S without any changes. This has been done by Straizys et al. (1996) in obtaining Strömvil indices for three standard areas. There are about 2000 stars observed in both systems for which we are able to form Strömvil indices. Among them are stars of 19 open clusters which are listed in Table 2. These clusters, especially Observations of clusters in the Strömvil system. I. 449 Table 3. Preliminary standard areas for the Strömvil system in the northern hemisphere Name of central Type of RA (2000) DEC (2000) EB-V Purpose object object h m 0 / mag * NGC 752 OCl 01 57.8 +37 41 0.03 1, 2 NGC 2099 (M 37) OCl 05 52.4 +32 33 0.31 1, 2, 3 NGC 2682 (M 67) OCl 08 50.4 +12 00 0.06: 1, 2, 3 SA 57 Field 13 08.4 +29 28 0.02 1, 2 NGC 6341 (M 92) GC1 17 17.1 +43 09 0.01 1,2,3 NGC 7078 (M 15) GC1 21 30.0 +12 10 0.08 1, 2, 3 * 1. Zero-point of magnitudes and color indices, 2. Atmospheric extinction coefficients, 3. Color equations between the instrumental and standard systems. Table 4. Preliminary standard areas for the Strömvil system in the southern hemisphere Name of central Type of RA (2000) DEC (2000) EB-V Purpose object object h m 0 / mag * NGC 288 GCl 00 52.6 -26 36 0.03 1,2,3 NGC 1904 (M 79) GCl 05 24.3 -24 31 0.01 1, 2, 3 NGC 2818 OCl 09 16.0 -36 36 0.18 1, 2 NGC 5139 (Ω Cen) GCl 13 26.8 -47 19 0.11 1, 2, 3 NGC 6405 (M 6) OCl 17 40.1 -32 13 0.15 1, 2, 3 NGC 7099 (M 30) GCl 21 39.1 -23 12 0.01 1, 2, 3 * see notes to Table 3. those having small angular sizes, can be used as the existing pre- liminary standards of the Strömvil system for CCD work.
Load more

Recommended publications
  • 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.
    [Show full text]
  • The [Y/Mg] Clock Works for Evolved Solar Metallicity Stars ? D
    Astronomy & Astrophysics manuscript no. clusters_le c ESO 2017 July 28, 2017 The [Y/Mg] clock works for evolved solar metallicity stars ? D. Slumstrup1, F. Grundahl1, K. Brogaard1; 2, A. O. Thygesen3, P. E. Nissen1, J. Jessen-Hansen1, V. Van Eylen4, and M. G. Pedersen5 1 Stellar Astrophysics Centre (SAC). Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus, Denmark e-mail: [email protected] 2 School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK 3 California Institute of Technology, 1200 E. California Blvd, MC 249-17, Pasadena, CA 91125, USA 4 Leiden Observatory, Leiden University, 2333CA Leiden, The Netherlands 5 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium Received 3 July 2017 / Accepted 20 July2017 ABSTRACT Aims. Previously [Y/Mg] has been proven to be an age indicator for solar twins. Here, we investigate if this relation also holds for helium-core-burning stars of solar metallicity. Methods. High resolution and high signal-to-noise ratio (S/N) spectroscopic data of stars in the helium-core-burning phase have been obtained with the FIES spectrograph on the NOT 2:56 m telescope and the HIRES spectrograph on the Keck I 10 m telescope. They have been analyzed to determine the chemical abundances of four open clusters with close to solar metallicity; NGC 6811, NGC 6819, M67 and NGC 188. The abundances are derived from equivalent widths of spectral lines using ATLAS9 model atmospheres with parameters determined from the excitation and ionization balance of Fe lines. Results from asteroseismology and binary studies were used as priors on the atmospheric parameters, where especially the log g is determined to much higher precision than what is possible with spectroscopy.
    [Show full text]
  • A Basic Requirement for Studying the Heavens Is Determining Where In
    Abasic requirement for studying the heavens is determining where in the sky things are. To specify sky positions, astronomers have developed several coordinate systems. Each uses a coordinate grid projected on to the celestial sphere, in analogy to the geographic coordinate system used on the surface of the Earth. The coordinate systems differ only in their choice of the fundamental plane, which divides the sky into two equal hemispheres along a great circle (the fundamental plane of the geographic system is the Earth's equator) . Each coordinate system is named for its choice of fundamental plane. The equatorial coordinate system is probably the most widely used celestial coordinate system. It is also the one most closely related to the geographic coordinate system, because they use the same fun­ damental plane and the same poles. The projection of the Earth's equator onto the celestial sphere is called the celestial equator. Similarly, projecting the geographic poles on to the celest ial sphere defines the north and south celestial poles. However, there is an important difference between the equatorial and geographic coordinate systems: the geographic system is fixed to the Earth; it rotates as the Earth does . The equatorial system is fixed to the stars, so it appears to rotate across the sky with the stars, but of course it's really the Earth rotating under the fixed sky. The latitudinal (latitude-like) angle of the equatorial system is called declination (Dec for short) . It measures the angle of an object above or below the celestial equator. The longitud inal angle is called the right ascension (RA for short).
    [Show full text]
  • LIST of PUBLICATIONS Aryabhatta Research Institute of Observational Sciences ARIES (An Autonomous Scientific Research Institute
    LIST OF PUBLICATIONS Aryabhatta Research Institute of Observational Sciences ARIES (An Autonomous Scientific Research Institute of Department of Science and Technology, Govt. of India) Manora Peak, Naini Tal - 263 129, India (1955−2020) ABBREVIATIONS AA: Astronomy and Astrophysics AASS: Astronomy and Astrophysics Supplement Series ACTA: Acta Astronomica AJ: Astronomical Journal ANG: Annals de Geophysique Ap. J.: Astrophysical Journal ASP: Astronomical Society of Pacific ASR: Advances in Space Research ASS: Astrophysics and Space Science AE: Atmospheric Environment ASL: Atmospheric Science Letters BA: Baltic Astronomy BAC: Bulletin Astronomical Institute of Czechoslovakia BASI: Bulletin of the Astronomical Society of India BIVS: Bulletin of the Indian Vacuum Society BNIS: Bulletin of National Institute of Sciences CJAA: Chinese Journal of Astronomy and Astrophysics CS: Current Science EPS: Earth Planets Space GRL : Geophysical Research Letters IAU: International Astronomical Union IBVS: Information Bulletin on Variable Stars IJHS: Indian Journal of History of Science IJPAP: Indian Journal of Pure and Applied Physics IJRSP: Indian Journal of Radio and Space Physics INSA: Indian National Science Academy JAA: Journal of Astrophysics and Astronomy JAMC: Journal of Applied Meterology and Climatology JATP: Journal of Atmospheric and Terrestrial Physics JBAA: Journal of British Astronomical Association JCAP: Journal of Cosmology and Astroparticle Physics JESS : Jr. of Earth System Science JGR : Journal of Geophysical Research JIGR: Journal of Indian
    [Show full text]
  • Asteroseismic Inferences on Red Giants in Open Clusters NGC 6791, NGC 6819, and NGC 6811 Using Kepler
    A&A 530, A100 (2011) Astronomy DOI: 10.1051/0004-6361/201016303 & c ESO 2011 Astrophysics Asteroseismic inferences on red giants in open clusters NGC 6791, NGC 6819, and NGC 6811 using Kepler S. Hekker1,2, S. Basu3, D. Stello4, T. Kallinger5, F. Grundahl6,S.Mathur7,R.A.García8, B. Mosser9,D.Huber4, T. R. Bedding4,R.Szabó10, J. De Ridder11,W.J.Chaplin2, Y. Elsworth2,S.J.Hale2, J. Christensen-Dalsgaard6 , R. L. Gilliland12, M. Still13, S. McCauliff14, and E. V. Quintana15 1 Astronomical Institute “Anton Pannekoek”, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands e-mail: [email protected] 2 School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK 3 Department of Astronomy, Yale University, PO Box 208101, New Haven CT 06520-8101, USA 4 Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006, Australia 5 Department of Physics and Astronomy, University of British Colombia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada 6 Department of Physics and Astronomy, Building 1520, Aarhus University, 8000 Aarhus C, Denmark 7 High Altitude Observatory, NCAR, PO Box 3000, Boulder, CO 80307, USA 8 Laboratoire AIM, CEA/DSM-CNRS, Université Paris 7 Diderot, IRFU/SAp, Centre de Saclay, 91191 Gif-sur-Yvette, France 9 LESIA, UMR8109, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, 92195 Meudon Cedex, France 10 Konkoly Observatory of the Hungarian Academy of Sciences, Konkoly Thege Miklós út 15-17, 1121 Budapest, Hungary 11 Instituut voor Sterrenkunde, K.U. Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium 12 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 13 Bay Area Environmental Research Institute/Nasa Ames Research Center, Moffett Field, CA 94035, USA 14 Orbital Sciences Corporation/Nasa Ames Research Center, Moffett Field, CA 94035, USA 15 SETI Institute/Nasa Ames Research Center, Moffett Field, CA 94035, USA Received 13 December 2010 / Accepted 19 April 2011 ABSTRACT Context.
    [Show full text]
  • Mandm Direct Spreads
    Touring the moonlit Spring Skies... Observations from Saturday 11th May 2019 8.30pm - 2.15am Equipment used: TEC 140, tracking Nova Hitch Alt-Az with slow-mo controls and encoders on a Berlebach Planet, iPad Air2 running SkySafari Pro 5, Nexus WiFi, 10 and 21mm Ethos, Baader BBHS diagonal, Lumicon 2” UHC and OIII filters in a True-Tech manual filter wheel. Mixed forecasts, Clear Outside suggesting 27% cloud around midnight, Xasteria saying clear, Clear Outside loaded from within Xasteria offering something in-between (how do you get that, hey!?) and Meteoblue forecasting clear skies from 11 but with poor ‘Index 2’ and Jet Stream readings.... Having neglected visual astronomy for many months (having spent my time finally getting the imaging gear to play ball), I spent forty odd minutes re-learning how to set everything back up - in fact, it be on offer with the moon in attendance... took longer than it does to wheel out the imaging gear. Times have changed, my usual (100% visual) observing buddy was having a go at imaging (spectroscopy), so I was on my own for this evening. It meant I’d have to keep my own notes for a change, but also allow me to go at my own pace as I reacquainted myself with the night sky. By 8.30 I was ready to go, clear skies, still a shade of blue with a half moon hanging over in the south western sky. Temperature rapidly dropping. 21mm eyepiece in place easily held the entire moon. Fantastic details, sharp, contrasty, zero colour..
    [Show full text]
  • Open Clusters
    Open Clusters Open clusters (also known as galactic clusters) are of tremendous importance to the science of astronomy, if not to astrophysics and cosmology generally. Star clusters serve as the "laboratories" of astronomy, with stars now all at nearly the same distance and all created at essentially the same time. Each cluster thus is a running experiment, where we can observe the effects of composition, age, and environment. We are hobbled by seeing only a snapshot in time of each cluster, but taken collectively we can understand their evolution, and that of their included stars. These clusters are also important tracers of the Milky Way and other parent galaxies. They help us to understand their current structure and derive theories of the creation and evolution of galaxies. Just as importantly, starting from just the Hyades and the Pleiades, and then going to more distance clusters, open clusters serve to define the distance scale of the Milky Way, and from there all other galaxies and the entire universe. However, there is far more to the study of star clusters than that. Anyone who has looked at a cluster through a telescope or binoculars has realized that these are objects of immense beauty and symmetry. Whether a cluster like the Pleiades seen with delicate beauty with the unaided eye or in a small telescope or binoculars, or a cluster like NGC 7789 whose thousands of stars are seen with overpowering wonder in a large telescope, open clusters can only bring awe and amazement to the viewer. These sights are available to all.
    [Show full text]
  • And – Objektauswahl NGC Teil 1
    And – Objektauswahl NGC Teil 1 NGC 5 NGC 49 NGC 79 NGC 97 NGC 184 NGC 233 NGC 389 NGC 531 Teil 1 NGC 11 NGC 51 NGC 80 NGC 108 NGC 205 NGC 243 NGC 393 NGC 536 NGC 13 NGC 67 NGC 81 NGC 109 NGC 206 NGC 252 NGC 404 NGC 542 Teil 2 NGC 19 NGC 68 NGC 83 NGC 112 NGC 214 NGC 258 NGC 425 NGC 551 NGC 20 NGC 69 NGC 85 NGC 140 NGC 218 NGC 260 NGC 431 NGC 561 NGC 27 NGC 70 NGC 86 NGC 149 NGC 221 NGC 262 NGC 477 NGC 562 NGC 29 NGC 71 NGC 90 NGC 160 NGC 224 NGC 272 NGC 512 NGC 573 NGC 39 NGC 72 NGC 93 NGC 169 NGC 226 NGC 280 NGC 523 NGC 590 NGC 43 NGC 74 NGC 94 NGC 181 NGC 228 NGC 304 NGC 528 NGC 591 NGC 48 NGC 76 NGC 96 NGC 183 NGC 229 NGC 317 NGC 529 NGC 605 Sternbild- Zur Objektauswahl: Nummer anklicken Übersicht Zur Übersichtskarte: Objekt in Aufsuchkarte anklicken Zum Detailfoto: Objekt in Übersichtskarte anklicken And – Objektauswahl NGC Teil 2 NGC 620 NGC 709 NGC 759 NGC 891 NGC 923 NGC 1000 NGC 7440 NGC 7836 Teil 1 NGC 662 NGC 710 NGC 797 NGC 898 NGC 933 NGC 7445 NGC 668 NGC 712 NGC 801 NGC 906 NGC 937 NGC 7446 Teil 2 NGC 679 NGC 714 NGC 812 NGC 909 NGC 946 NGC 7449 NGC 687 NGC 717 NGC 818 NGC 910 NGC 956 NGC 7618 NGC 700 NGC 721 NGC 828 NGC 911 NGC 980 NGC 7640 NGC 703 NGC 732 NGC 834 NGC 912 NGC 982 NGC 7662 NGC 704 NGC 746 NGC 841 NGC 913 NGC 995 NGC 7686 NGC 705 NGC 752 NGC 845 NGC 914 NGC 996 NGC 7707 NGC 708 NGC 753 NGC 846 NGC 920 NGC 999 NGC 7831 Sternbild- Zur Objektauswahl: Nummer anklicken Übersicht Zur Übersichtskarte: Objekt in Aufsuchkarte anklicken Zum Detailfoto: Objekt in Übersichtskarte anklicken Auswahl And SternbildübersichtAnd
    [Show full text]
  • 00E the Construction of the Universe Symphony
    The basic construction of the Universe Symphony. There are 30 asterisms (Suites) in the Universe Symphony. I divided the asterisms into 15 groups. The asterisms in the same group, lay close to each other. Asterisms!! in Constellation!Stars!Objects nearby 01 The W!!!Cassiopeia!!Segin !!!!!!!Ruchbah !!!!!!!Marj !!!!!!!Schedar !!!!!!!Caph !!!!!!!!!Sailboat Cluster !!!!!!!!!Gamma Cassiopeia Nebula !!!!!!!!!NGC 129 !!!!!!!!!M 103 !!!!!!!!!NGC 637 !!!!!!!!!NGC 654 !!!!!!!!!NGC 659 !!!!!!!!!PacMan Nebula !!!!!!!!!Owl Cluster !!!!!!!!!NGC 663 Asterisms!! in Constellation!Stars!!Objects nearby 02 Northern Fly!!Aries!!!41 Arietis !!!!!!!39 Arietis!!! !!!!!!!35 Arietis !!!!!!!!!!NGC 1056 02 Whale’s Head!!Cetus!! ! Menkar !!!!!!!Lambda Ceti! !!!!!!!Mu Ceti !!!!!!!Xi2 Ceti !!!!!!!Kaffalijidhma !!!!!!!!!!IC 302 !!!!!!!!!!NGC 990 !!!!!!!!!!NGC 1024 !!!!!!!!!!NGC 1026 !!!!!!!!!!NGC 1070 !!!!!!!!!!NGC 1085 !!!!!!!!!!NGC 1107 !!!!!!!!!!NGC 1137 !!!!!!!!!!NGC 1143 !!!!!!!!!!NGC 1144 !!!!!!!!!!NGC 1153 Asterisms!! in Constellation Stars!!Objects nearby 03 Hyades!!!Taurus! Aldebaran !!!!!! Theta 2 Tauri !!!!!! Gamma Tauri !!!!!! Delta 1 Tauri !!!!!! Epsilon Tauri !!!!!!!!!Struve’s Lost Nebula !!!!!!!!!Hind’s Variable Nebula !!!!!!!!!IC 374 03 Kids!!!Auriga! Almaaz !!!!!! Hoedus II !!!!!! Hoedus I !!!!!!!!!The Kite Cluster !!!!!!!!!IC 397 03 Pleiades!! ! Taurus! Pleione (Seven Sisters)!! ! ! Atlas !!!!!! Alcyone !!!!!! Merope !!!!!! Electra !!!!!! Celaeno !!!!!! Taygeta !!!!!! Asterope !!!!!! Maia !!!!!!!!!Maia Nebula !!!!!!!!!Merope Nebula !!!!!!!!!Merope
    [Show full text]
  • Angular Momentum Evolution of Young Low-Mass Stars and Brown Dwarfs: Observations and Theory
    Angular momentum evolution of young low-mass stars and brown dwarfs: observations and theory Jer´ omeˆ Bouvier Observatoire de Grenoble Sean P. Matt Exeter University Subhanjoy Mohanty Imperial College London Aleks Scholz University of St Andrews Keivan G. Stassun Vanderbilt University Claudio Zanni Osservatorio Astrofisico di Torino This chapter aims at providing the most complete review of both the emerging concepts and the latest observational results regarding the angular momentum evolution of young low-mass stars and brown dwarfs. In the time since Protostars & Planets V, there have been major developments in the availability of rotation period measurements at multiple ages and in different star-forming environments that are essential for testing theory. In parallel, substantial theoretical developments have been carried out in the last few years, including the physics of the star-disk interaction, numerical simulations of stellar winds, and the investigation of angular momentum transport processes in stellar interiors. This chapter reviews both the recent observational and theoretical advances that prompted the development of renewed angular momentum evolution models for cool stars and brown dwarfs. While the main observational trends of the rotational history of low mass objects seem to be accounted for by these new models, a number of critical open issues remain that are outlined in this review. 1. INTRODUCTION vational and theoretical sides, on the issue of the angular momentum evolution of young stellar objects since Pro- The angular momentum content of a newly born star is tostars & Planets V. On the observational side, thousands one of the fundamental quantities, like mass and metallic- of new rotational periods have been derived for stars over ity, that durably impacts on the star’s properties and evolu- the entire mass range from solar-type stars down to brown tion.
    [Show full text]
  • Oct 2017 Newsletter
    Volume23, Issue 2 NWASNEWS October 2017 Newsletter for the Wiltshire, Swindon, Beckington Sharing the Skies Astronomical Societies and Salisbury Plain Observing Group While we have officially swapped the chair and vice chair roles I will still be editing the Wiltshire Society Page 2 newsletter. Swindon Stargazers 3 The AGM enabled us to pass over duties (ha ha ha) and I would like to thank the Beckington and Astronomy 4 society for the gift of 6 constellation wine Apollo Astronauts in UK. 4 glasses from the society. Debbie Crokker has agreed to become Cassini ends its mission 5 vice Treasurer, and details have been passed to her for tonight. Viewing Logs and Images 6-8 I have unfortunately had to help out a lot with Dark Skies Wales this last few weeks and going forward a few more weeks while Herschel Society Meeting 8 the Director Allan Trow underwent surgery Space News that has lead to more surgery being need- :Data from Opportunity shows ed. We wish him a speedy recovery. equatorial water on Mars. It means I will also be in Spain at the GEO Lunar Observer crash site found observatory while there are paying visitors New dual object found there including a journalist which means I Mystery of Moonquakes solved? Galaxy shapes give keys will miss the next event in Devizes. Rosetta lander last image viewed Also a special birthday event in Devizes Ligo gravity waves. Another found that Pete Glastonbury is helping to organ- Sub surface ice on Vesta ise. This will now be on the 14th October.
    [Show full text]
  • Characterising Open Clusters in the Solar Neighbourhood with the Tycho-Gaia Astrometric Solution? T
    A&A 615, A49 (2018) Astronomy https://doi.org/10.1051/0004-6361/201731251 & © ESO 2018 Astrophysics Characterising open clusters in the solar neighbourhood with the Tycho-Gaia Astrometric Solution? T. Cantat-Gaudin1, A. Vallenari1, R. Sordo1, F. Pensabene1,2, A. Krone-Martins3, A. Moitinho3, C. Jordi4, L. Casamiquela4, L. Balaguer-Núnez4, C. Soubiran5, and N. Brouillet5 1 INAF-Osservatorio Astronomico di Padova, vicolo Osservatorio 5, 35122 Padova, Italy e-mail: [email protected] 2 Dipartimento di Fisica e Astronomia, Università di Padova, vicolo Osservatorio 3, 35122 Padova, Italy 3 SIM, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal 4 Institut de Ciències del Cosmos, Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, 08028 Barcelona, Spain 5 Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, UMR 5804, 33615 Pessac, France Received 26 May 2017 / Accepted 29 January 2018 ABSTRACT Context. The Tycho-Gaia Astrometric Solution (TGAS) subset of the first Gaia catalogue contains an unprecedented sample of proper motions and parallaxes for two million stars brighter than G 12 mag. Aims. We take advantage of the full astrometric solution available∼ for those stars to identify the members of known open clusters and compute mean cluster parameters using either TGAS or the fourth U.S. Naval Observatory CCD Astrograph Catalog (UCAC4) proper motions, and TGAS parallaxes. Methods. We apply an unsupervised membership assignment procedure to select high probability cluster members, we use a Bayesian/Markov Chain Monte Carlo technique to fit stellar isochrones to the observed 2MASS JHKS magnitudes of the member stars and derive cluster parameters (age, metallicity, extinction, distance modulus), and we combine TGAS data with spectroscopic radial velocities to compute full Galactic orbits.
    [Show full text]