DOCSLIB.ORG

The Young Open Cluster Collinder 359 ( = Melotte 186) Was Selected

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Young Open Cluster Collinder 359 ( = Melotte 186) Was Selected A PHOTOMETRIC STUDY OF THE YOUNG CLUSTER COLLINDER 359 N. LODIEU (1), BOUVIER (2) & M. J. McCAUGHREAN (1) .J. (1) Astmphysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany (2) Laboratoire d'Astrophysique de Grenoble, BP 53, 38041 Grenoble Cedex, France We present the first deep optical wide-field imaging survey of the young open cluster Collinder 359, complemented by near-infrared fo llow-up observations. We have surveyed 1.6 square degree in the cluster in the I and z filters with the CFH12K on the Canada.-France­ Hawaii 3.G-m telescope down to completeness and detection limits in both filters of 22.0 and 24.0, respectively. Ba.sect on their location in the optical (J,J-z) colour-magnitude diagram, we have extracted new cluster member candidates in Collinder 359 spanning 1.3-0.04 M0, as­ suming an age of 80 Myr and a distance of 500 pc for the cluster. We have derived the cluster luminosity and mass functions using the latest evolutionary models from the Lyon group: the best fit to the slope of the cluster mass function, when expressed as the mass spectrum, is a= 0.30 ± 0.20 over the 0.55-0.035 M0 mass range. The derived slope appeais flatter than the estimates in the Pleiades and a Per open clusters. Keywords: Open clusters and associations: individual: Collinder 359 - Stars: low-mass, brown dwarfs - Stars: luminosity function, mass function -- Techniques: photometric 1 The young open cluster Collinder 359 The young open cluster Collinder 359 ( = Melotte 186) was selected as a pre-main-sequence open cluster within the framework of a CFHT Key Programme to study the sensitivity of the low-mass stellar and substellar IMF to time and environment. The cluster is located in the Ophiuchus constellation around the supergiant 67 Oph. Collinder 359 was relatively unstudied and very little literature is available about it: in particular, no modern optical survey exists of the cluster core. The cluster was first seen on the Franklin-Adams Charts Plates and described by Melotte in 1915 21 as a large scattered group of bright stars around 67 Oph, covering an area of about 6 57 square de?;re<>s. In his catalogue of open clusters, Collinder (l\J31) 9 described the cluster as a group of about 15 stars with no appreciable concentration on the sky and 110 well-defined outline. A list of probable candidates was given in Collinder's paper, along with coordinates, magnitudes, and spectral types. The membership of these objects was, however, not well established and more than half of them were later rej ected by Van't Veer (1980) 30 and Rucinski (1987) 25 . Based on isochrone fitting, the distance of the cluster was estimated between 200 and 300 parsecs while the parallax measurements from HIPPARCOS suggested a distance of approximately 270 pc 15. A recent analysis of the cluster by Kharchenko et al. (2004, personal communication) derived a much larger distance of 650 pc, based on a larger number of objects included in the HIPPARCOS and Tycho 2 catalogues. The age of the cluster has previously been estimated as 30 l'viyr31 , as confirmed by Kharchenko et al. (2004). 2 The optical wide-field survey A Canada-France-Hawaii Te lescope Key Programme (30 nights over 2 years) centred on wide­ field optical imaging of young, intermediate-age, and older open clusters was carried out within the framework of the European Research Training Network "The Formation and Evolution of Young Stellar Clusters" , to examine the sensitivity of the low-mass stellar and substellar IMF to time and environment. The survey was conducted with a large-CCD mosaic camera (CFH12K) in the I and z filtersdown to detection and completeness limits of I = 24.0 and 22.0, respectively. Five CFHl 2K frames were obtained on 18 and 20 June 2002 in Collinder 359 in the I and z filters, covering a total area of 1.6 square degrees in the cluster. Fields A, B, C, and D were covered on 18 June 2002 under photometric conditions with seeing � 0.8 arcsec. The final field, fieldE, was observed on 20 June 2002 under non-photometric conditions. Three sets of exposures were taken for each field-of-view: short, medium, and long exposures with integration times of 2, 30, and about 900 seconds, respectively. The long exposures were exposed 3 x 300 and 3 x 360 seconds in the I and z filter, respectively. The initial data reduction was provided by the Elixir pipeline, including bias subtraction, flat-fielding, correction for scattered light in both filters, combining the dithered frames in case of long exposures, and astrometric calibration. Zero-points were also provided by the pipeline from a repeated monitoring of several standard stars. The photometry was extracted with the SExtractor package coupled with a PSF fittingroutine (kindly provided by E. Bertin 6). 3 Identifii:;ation of cluster member candidates Photometry has been extracted in the I and z filters, allowing us to draw a colour-magnitude diagram (I, I-z) shown in Figure 1. To take into account the uncertainties in the age and the distance of the cluster, we have selected all objects located to the right of the combined Next Gen+ Dusty isochrones from the Lyon group 4 8, assuming a distance of 650 pc and an age of 80 Myr for the cluster. This value of the age takes into account the possibility of older ages as 26 27 suggested by the lithium test applied to the Pleiades , a Per , and IC2391 2. vVe have examined each cluster member candidate by eye both in the I and z images to reject extended objects, blended sources, and detections affected by bad pixels or bad columns. vVe have extracted a total of 1033 candidates ranging from I= 12.0 to I= 22.5 over 1.6 square degree area surveyed in Collinder 359. The new candidates are displayed as filled circles in Figure 1 and span masses between 1.3 and 0.04 M0 according to the tracks. We have also cross-correlated our sample of optically-selected candidates with the 2TvIASS database. All objects brighter than I= 17 have a 2MASS counterpart, and, therefore, near­ infrared magnitudes. In addition, we have obtained K'-band photometry with the infrared 58 .� '-- .i.' Fig re 1: Colour-magnitude diagram (I, for the intermediate-age open cluster Collinder 359 over the full 1.G squareu degree area surveyed by the CFH12K1-z) camera. The large filled dots am all optically-selected cluster member candidates spanning 1.3-0.04 Mo. Overplottcd arc NextGen (solid line; Baraffe et al. 1998) the (daolied Dusty line; Cha brier et 2000) and the Cond (dotted line; Chabrier et al . 2000) isochrcmcs for 80 Myr, asotaning a distance of 500 pc al.for the cluster. The dash eel line at I� 20 inclicatr·s stellar/substellar boundary 070 the al 0 \L., . The mass scale (in solar ma.'5es) is giwn on the right side of the graph. reddening vector of 1 is indicated for comparison purposes. The open triangles depicts candidates A proper motion consistentAv = me1nbcrship. with v.,:ith cluster 59 camera (CFHTIR) on the CFH 3.6-m telescope to probe the contamination at and below the substellar limit (I � 20). This procedure rejected some objects exhibiting bluer colours than cluster members in the optical-to-infrared colour-magnitude diagram. We have used our optical survey in Collinder 359 complemented by near-infrared photometry to address the issue regarding the uncertainties on the age and the distance of the cluster. I First, we have followed the approach applied to the Per cluster by Stauffer et al. (2003). By comparing the location of the supergiant 670ph in thea colour-magnitude diagram (Mv, B-V) with theoretical solar metallicity isochrones including moderate overshoot 11, we have inferred an age of 60 ± 20 Myr for Collinder 359. Second, we have cross-correlated our list of candidates with the latest version of the USNO CCD Astrograph Catalog32 which provides proper motion for a large number of candidates. We have retained probable member candidates with photometric and proper motion measurements consistent with cluster membership. The location of these candidates in the colour-magnitude diagram suggested a most likely age of SO Myr and a distance of 500 pc. 4 The cluster luminosity function vVe have derived the cluster luminosity function using the list of cancliclatesextracted from the colour-magnitude diagram, assuming an ageof SO Myr and a distance of 500 pc for Collincler 359 (Figure 2). The luminosity function is drawn from all probable candidates whose optical and near-infrared photometry are consistent with cluster membership. M, 6.5 8.5 10.5 12.5 14.5 "' 0 v; n(i; E :J z o non-smoothed 15 17 19 21 23 Figure 2: The cluster luminosity function drawn for thecandidates selected to the right of the isochrones, assuming an age of 80 Myr and a distance of 500 pc for Collinder 359. The open squares represent the number of stars per bin of 0.5 magnitude whereas the filled circles indicate the number of stars in a 1.0 magnitude bin with an interval of 0.5 magnitudes. Poisson errors are indicated by vertical lines. We have employed two approaches to derive the cluster luminosity function. The first approach consisted in counting the number of stars per bin of 0.5 mag (open squares in Figure 2). The second approach "smoothed" the luminosity function to better characterise the faint encl, 60 i.e. we have counted the number of stars per interval of 1.0 magnitude by step of 0.5 magnitude (filled circles in Figure 2).
Load more

Recommended publications
  • 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]
  • 121012-AAS-221 Program-14-ALL, Page 253 @ Preflight
    221ST MEETING OF THE AMERICAN ASTRONOMICAL SOCIETY 6-10 January 2013 LONG BEACH, CALIFORNIA Scientific sessions will be held at the: Long Beach Convention Center 300 E. Ocean Blvd. COUNCIL.......................... 2 Long Beach, CA 90802 AAS Paper Sorters EXHIBITORS..................... 4 Aubra Anthony ATTENDEE Alan Boss SERVICES.......................... 9 Blaise Canzian Joanna Corby SCHEDULE.....................12 Rupert Croft Shantanu Desai SATURDAY.....................28 Rick Fienberg Bernhard Fleck SUNDAY..........................30 Erika Grundstrom Nimish P. Hathi MONDAY........................37 Ann Hornschemeier Suzanne H. Jacoby TUESDAY........................98 Bethany Johns Sebastien Lepine WEDNESDAY.............. 158 Katharina Lodders Kevin Marvel THURSDAY.................. 213 Karen Masters Bryan Miller AUTHOR INDEX ........ 245 Nancy Morrison Judit Ries Michael Rutkowski Allyn Smith Joe Tenn Session Numbering Key 100’s Monday 200’s Tuesday 300’s Wednesday 400’s Thursday Sessions are numbered in the Program Book by day and time. Changes after 27 November 2012 are included only in the online program materials. 1 AAS Officers & Councilors Officers Councilors President (2012-2014) (2009-2012) David J. Helfand Quest Univ. Canada Edward F. Guinan Villanova Univ. [email protected] [email protected] PAST President (2012-2013) Patricia Knezek NOAO/WIYN Observatory Debra Elmegreen Vassar College [email protected] [email protected] Robert Mathieu Univ. of Wisconsin Vice President (2009-2015) [email protected] Paula Szkody University of Washington [email protected] (2011-2014) Bruce Balick Univ. of Washington Vice-President (2010-2013) [email protected] Nicholas B. Suntzeff Texas A&M Univ. suntzeff@aas.org Eileen D. Friel Boston Univ. [email protected] Vice President (2011-2014) Edward B. Churchwell Univ. of Wisconsin Angela Speck Univ. of Missouri [email protected] [email protected] Treasurer (2011-2014) (2012-2015) Hervey (Peter) Stockman STScI Nancy S.
    [Show full text]
  • Binocular Universe: Surfing Serpens August 2010 Phil Harrington
    Binocular Universe: Surfing Serpens August 2010 Phil Harrington erpens the Serpent has the unique distinction of being the sky’s only constellation that is sliced in half by a second star group, the constellation Ophiuchus, the Serpent Bearer. To the west of Ophiuchus is Serpens Caput, the Serpent's head. This sparse S area is highlighted by the fine globular cluster M5, which was discussed in the June 2010 edition of this column, as well as several variable stars that are within binocular range. East of Ophiuchus is Serpens Cauda, the Serpent’s tail. But even with the plane of the Milky Way passing through, Serpens Cauda still contains no bright stars and surprisingly few deep-sky objects. But what it lacks in quantity, Serpens Cauda more than makes up for in quality. Above: Summer star map from Star Watch by Phil Harrington Above: Finder chart for this month's Binocular Universe. Chart adapted from Touring the Universe through Binoculars Atlas (TUBA), www.philharrington.net/tuba.htm Let’s begin with open cluster IC 4756, a faint, but large mob of stars that’s perfect for binoculars. Unfortunately, its position is quite far from any handy reference stars, so finding it can be a challenge. Your best bet is to trace a line between Altair, in Aquila the Eagle, and second-magnitude Cebalrai [Beta (β) Ophiuchi]. IC 4756 lies just south of the halfway point between the two. There might not be many bright stars nearby, but the cluster's field overflows with faint stardust. Eighty suns scattered across an apparent diameter nearly twice that of the Full Moon form a faint mist against the backdrop of the summer Milky Way.
    [Show full text]
  • The Valley Skywatcher
    THE VALLEY SKYWATCHER The Official Publication of the Chagrin Valley Astronomical Society CONTENTS Est. 1963 President’s Corner Articles Friends, we are all sad- Bruce Krobusek 2 dened by the recent passing of longtime CVAS member In Memory Of Bruce Krobusek 5 Bruce Krobusek. On The Size Of Chords 9 Bruce was president in Thoughts On The Solar Apex 26 the early days of the club, shepherding it through the times when its future was not assured. He filled many offices for many years and continued to contribute to our success after he relocated to Rochester, New York. Regular Features An avid observer, Bruce was an author on several publications with fellow CVAS members. We Observer’s Log 3 will surely miss him. Notes & News 4 Reflections 8 Constellation Quiz 28 As we turn the corner to spring, we have a Reflections (Continued) 30 multitude of projects and improvements to make at the Hill. Our observatory director, Sam Benicci, has suggested using our meeting dates as daytime CVAS Officers workdays. I understand that everyone won’t be Marty Mullet President available every month, but do try to attend at least George Trimble Vice President one work session this year. Along those lines, if you Steve Fishman Treasurer Joe Maser Secretary wish to use the Hill and need training on the tele- Steve Kainec Director of scopes, please let me or Sam know. We will be Observations happy to schedule a couple of evenings to get you Sam Bennici Observatory comfortable with opening and closing the buildings Director Dan Rothstein Historian and operating the telescopes.
    [Show full text]
  • A Deep Wide-Field Optical Survey in the Young Open Cluster Collinder
    A&A 450, 147–158 (2006) Astronomy DOI: 10.1051/0004-6361:20054105 & c ESO 2006 Astrophysics A deep wide-field optical survey in the young open cluster Collinder 359, N. Lodieu1,2,, J. Bouvier3, D. J. James3,4,W.J.deWit3, F. Palla5, M. J. McCaughrean2,6, and J.-C. Cuillandre7 1 Department of Physics & Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK e-mail: [email protected] 2 Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany 3 Laboratoire d’Astrophysique, Observatoire de Grenoble, BP 53, 38041 Grenoble Cedex 9, France e-mail: [Jerome.Bouvier;Willem-Jan.DeWit]@obs.ujf-grenoble.fr 4 Physics and Astronomy Department, Vanderbilt University, 1807 Station B, Nashville, TN 37235, USA e-mail: [email protected] 5 INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Florence, Italy e-mail: [email protected] 6 University of Exeter, School of Physics, Stocker Road, Exeter EX4 4QL, UK e-mail: [email protected]; [email protected] 7 Canada-France-Hawaii Telescope Corp., Kamuela, HI 96743, USA e-mail: [email protected] Received 26 August 2005 / Accepted 30 December 2005 ABSTRACT We present the first deep, optical, wide-field imaging survey of the young open cluster Collinder 359, complemented by near-infrared follow-up observations. This study is part of a large programme aimed at examining the dependence of the mass function on environment and time. We have surveyed 1.6 square degrees in the cluster, in the I and z filters, with the CFH12K camera on the Canada-France-Hawaii 3.6-m telescope down to completeness and detection limits in both filters of 22.0 and 24.0 mag, respectively.
    [Show full text]
  • July 2019 BRAS Newsletter
    A th Monthly Meeting July 8 at 7PM at HRPO (Monthly meetings are on 2nd Mondays, Highland Road Park Observatory). Program: Viewing of NASA’s The Eagle Has Landed video, after which members can discuss and share personal memories of Apollo 11 (and other) missions. What's In This Issue? President’s Message Secretary's Summary Outreach Report Astrophotography Group Asteroid and Comet News Light Pollution Committee Report Globe at Night Member’s Corner – Conner Matherne’s Astral Visions Messages from the HRPO Science Academy Friday Night Lecture Series APOLLO EVENTS Observing Notes: OphiuchusThe Serpent Bearer or Handler & Mythology Like this newsletter? See PAST ISSUES online back to 2009 Visit us on Facebook – Baton Rouge Astronomical Society Newsletter of the Baton Rouge Astronomical Society Page 2 July 2019 © 2019 President’s Message July 20, 2019 will mark the 50th anniversary of the Apollo 11 Moon Landing, one of the great milestones of United States and World History. Our meeting on Monday, July 8th involves inviting members of B.R.A.S. to share any memories we have of this event. These memories don't necessarily have to be especially profound (though this is certainly encouraged), and they can be about any of the Apollo missions, not just Apollo 11. BRAS ZAZZLE SHOP We opened a shop on Zazzle We are working some the bugs (i.e. T- Shirt prices). The shop can be found at: https://www.zazzle.com/store/br_astronomical VOLUNTEER AT HRPO: If any of the members wish to volunteer at HRPO, please speak to Chris Kersey, BRAS Liaison for BREC, to fill out the paperwork.
    [Show full text]
  • Updated Parameters of 1743 Open Clusters Based on Gaia DR2
    MNRAS 000,1–17 (2015) Preprint 25 March 2021 Compiled using MNRAS LATEX style file v3.0 Updated parameters of 1743 open clusters based on Gaia DR2 W. S. Dias,1¢ H. Monteiro,1, A. Moitinho2, J. R. D. Lépine3, G., Carraro,4, E. Paunzen5, B. Alessi6 and L. Villela1,7 1Instituto de Física e Química, Universidade Federal de Itajubá, Av. BPS 1303 Pinheirinho, 37500-903 Itajubá, MG, Brazil 2CENTRA, Faculdade de Ciências, Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa, Portugal 3Universidade de São Paulo, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, São Paulo, SP, Brazil 4Department of Physics and Astronomy, University of Padova, Vicolo dell’Osservatorio 3, I-35122 Padova, Italy 0000-0002-0155-9434 5Departament of Theoretical Physics and Astrophysics. Marsaryk University. Brno, Czech Republic 6 Av. Eng. Antônio Heitor Eiras Garcia 1236, apto 142. Bairro Jardim Esmeralda CEP 05588001 São Paulo, SP, Brazil 7 Departamento de Engenharia Elétrica, Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 514, Campus Universitário de Goiabeiras, 29075-710 Vitória, ES, Brazil Accepted Received ABSTRACT In this study we follow up our recent paper (Monteiro et al. 2020) and present a homogeneous sample of fundamental parameters of open clusters in our Galaxy, entirely based on Gaia DR2 data. We used published membership probability of the stars derived from Gaia DR2 data and applied our isochrone fitting code, updated as in Monteiro et al.(2020), to 퐺 퐵% and 퐺 '% Gaia DR2 data for member stars. In doing this we take into account the nominal errors in the data and derive distance, age, and extinction of each cluster.
    [Show full text]
  • Binocular Astronomy
    Stephen Tonkin Binocular Astronomy Second Edition The Patrick Moore The Patrick Moore Practical Astronomy Series For further volumes: http://www.springer.com/series/3192 Binocular Astronomy Stephen Tonkin Second Edition Stephen Tonkin Fordingbridge Hampshire , UK ISSN 1431-9756 ISBN 978-1-4614-7466-1 ISBN 978-1-4614-7467-8 (eBook) DOI 10.1007/978-1-4614-7467-8 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2013941879 © Springer Science+Business Media New York 2007, 2014 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, speci fi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on micro fi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied speci fi cally for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc.
    [Show full text]
  • A Deep Wide-Field Optical Survey in the Young Open Cluster Collinder
    Astronomy & Astrophysics manuscript no. 4105file April 25, 2018 (DOI: will be inserted by hand later) A deep wide-field optical survey in the young open cluster Collinder 359 ⋆ ⋆⋆ N. Lodieu1,2 ⋆⋆⋆, J. Bouvier3, D. J. James3,4, W. J. de Wit3, F. Palla5, M. J. McCaughrean2,6, and J.–C. Cuillandre7 1 Department of Physics & Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK e-mail: [email protected] 2 Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany 3 Laboratoire d’Astrophysique, Observatoire de Grenoble, BP 53, 38041 Grenoble C´edex 9, France e-mail: [email protected], [email protected] 4 Physics and Astronomy Department, Vanderbilt University, 1807 Station B, Nashville, TN 37235, USA e-mail: [email protected] 5 INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Florence, Italy e-mail: [email protected] 6 University of Exeter, School of Physics, Stocker Road, Exeter EX4 4QL, UK e-mail: [email protected], [email protected] 7 Canada-France-Hawaii Telescope Corp., Kamuela, HI 96743, USA e-mail: [email protected] Received April 25, 2018 /Accepted Abstract. We present the first deep, optical, wide-field imaging survey of the young open cluster Collinder 359, complemented by near-infrared follow-up observations. This study is part of a large programme aimed at examining the dependence of the mass function on environment and time. We have surveyed 1.6 square degrees in the cluster, in the I and z filters, with the CFH12K camera on the Canada-France-Hawaii 3.6-m telescope down to completeness and detection limits in both filters of 22.0 and 24.0 mag, respectively.
    [Show full text]
  • Limiting Magnitude
    APPENDIX A Double Stars for Indicating Resolution The following list of double stars can be used, in addition to those given in the observing lists, as an aid for comparing binocular performance and indicating resolution. Separation (arcsec) Star 31 ι Can 20 24 Com 15 ζ UMa 14.4 94 Aqr 11 ε Equ 10 γ Del 7.5 γ Ari 6.5 54 Leo 6 ζ Can 247 248 Binocular Astronomy Appendix A 249 250 Binocular Astronomy Appendix A 251 252 Binocular Astronomy APPENDIX B Limiting Magnitude Limiting magnitude may be determined by finding the magnitude of the faintest star observable or by counting the stars in a known region of sky. In addition to the optical quality of the instrument, the limiting magnitude will depend upon sky conditions, the experience of the observer, and the altitude of the objects being observed. 253 254 Binocular Astronomy M45: The Pleiades The region to be counted is that bounded by (but not including) Alcyone, Maia, Electra, and Merope. Number of Stars Limiting Magnitude 6 9.0 7 9.5 9 10.0 12 10.5 15 11.0 18 11.5 22 12.0 25 12.5 31 13.0 Appendix B 255 IC 2602 (the Southern Pleiades) The region to be counted is a triangle bounded by (but not including) θ Carinae and two 5th magnitude stars. Number of Stars Limiting Magnitude 2 9.5 4 10.0 7 10.5 12 11.0 13 11.5 17 12.0 28 12.5 36 13.0 256 Binocular Astronomy Delphinus The region to be counted is the “kite” bounded by (but not including) α, β, γ,and δ Delphini.
    [Show full text]
  • FY12 High-Level Deliverables
    National Optical Astronomy Observatory Fiscal Year Annual Report for FY 2012 (1 October 2011 – 30 September 2012) Submitted to the National Science Foundation Pursuant to Cooperative Support Agreement No. AST-0950945 21 December 2012 NOAO is operated by the Association of Universities for Research in Astronomy under cooperative agreement with the National Science Foundation Contents NOAO MISSION PROFILE ................................................................................................. IV 1 EXECUTIVE SUMMARY ................................................................................................ 1 2 NOAO ACCOMPLISHMENTS ....................................................................................... 3 2.1 Achievements ..................................................................................................... 3 2.2 Status of Vision and Goals ................................................................................. 4 2.2.1 Status of FY12 High-Level Deliverables ............................................ 5 2.2.2 FY12 Planned vs. Actual Spending and Revenues .............................. 7 2.3 Challenges and Their Impacts .......................................................................... 10 3 SCIENTIFIC ACTIVITIES AND FINDINGS .............................................................. 12 3.1 Cerro Tololo Inter-American Observatory ....................................................... 12 3.2 Kitt Peak National Observatory ......................................................................
    [Show full text]
  • Star Clusters (And Other Neat Stuff) in Ophiuchus
    Star clusters (and other neat stuff) in Ophiuchus Michael L Allen [email protected] Palouse Divide Lodge Star Party 2016 Michael L Allen Ophiuchus PDLSP '16 1 / 19 Quick facts 11th-largest constellation at 950 sq deg (2% of the sky) 5 stars brighter than 3 mag 62 Flamsteed stars (down to about 7 mag) hosts the radiant point of four meteor showers variously called Ophiuchids (May-June) location of Kepler's Supernova (1604) is the \13th member" of the zodiac (Nov 29 { Dec 17) Michael L Allen Ophiuchus PDLSP '16 2 / 19 Mythological associations Ophuichus, \to handle the serpent", associated with Aesculapius, a son of Apollo and a god of medicine learned his healing from Chiron, the centaur he passed his knowledge to his descendents, eventually reaching Hippocrates (b. 460 BCE) Aesculapius's claim: snake venom could either kill or cure he brought back from the dead Glaucus, son of Minos King of Crete, who had died from a snake bite Pluto felt that Aesculapius had overstepped his bounds and complained to Jupiter Jupiter sent an eagle, Aquila, to strike down Aesculapius Jupiter perserved Aesculapius in the sky from where he could be recalled if his healing skills should be needed Michael L Allen Ophiuchus PDLSP '16 3 / 19 Hevelius's atlas (Danzig, 1687) Michael L Allen Ophiuchus PDLSP '16 4 / 19 Binocular and easy telescope clusters All three of these clusters can be found using β Oph and γ Oph as guide stars. From very easy to moderately easy, these are Melotte 186, IC 4665, and Collinder 350.
    [Show full text]