Spectroscopic Analysis of Algol During Eclipse Cycle
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Binocular Universe: You're My Hero! December 2010
Binocular Universe: You're My Hero! December 2010 Phil Harrington on't you just love a happy ending? I know I do. Picture this. Princess Andromeda, a helpless damsel in distress, chained to a rock as a ferocious D sea monster loomed nearby. Just when all appeared lost, our hero -- Perseus! -- plunges out of the sky, kills the monster, and sweeps up our maiden in his arms. Together, they fly off into the sunset on his winged horse to live happily ever after. Such is the stuff of myths and legends. That story, the legend of Perseus and Andromeda, was recounted in last month's column when we visited some binocular targets within the constellation Cassiopeia. In mythology, Queen Cassiopeia was Andromeda's mother, and the cause for her peril in the first place. Left: Autumn 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 This month, we return to the scene of the rescue, to our hero, Perseus. He stands in our sky to the east of Cassiopeia and Andromeda, should the Queen's bragging get her daughter into hot water again. The constellation's brightest star, Mirfak (Alpha [α] Persei), lies about two-thirds of the way along a line that stretches from Pegasus to the bright star Capella in Auriga. Shining at magnitude +1.8, Mirfak is classified as a class F5 white supergiant. It radiates some 5,000 times the energy of our Sun and has a diameter 62 times larger. -
Wynyard Planetarium & Observatory a Autumn Observing Notes
Wynyard Planetarium & Observatory A Autumn Observing Notes Wynyard Planetarium & Observatory PUBLIC OBSERVING – Autumn Tour of the Sky with the Naked Eye CASSIOPEIA Look for the ‘W’ 4 shape 3 Polaris URSA MINOR Notice how the constellations swing around Polaris during the night Pherkad Kochab Is Kochab orange compared 2 to Polaris? Pointers Is Dubhe Dubhe yellowish compared to Merak? 1 Merak THE PLOUGH Figure 1: Sketch of the northern sky in autumn. © Rob Peeling, CaDAS, 2007 version 1.2 Wynyard Planetarium & Observatory PUBLIC OBSERVING – Autumn North 1. On leaving the planetarium, turn around and look northwards over the roof of the building. Close to the horizon is a group of stars like the outline of a saucepan with the handle stretching to your left. This is the Plough (also called the Big Dipper) and is part of the constellation Ursa Major, the Great Bear. The two right-hand stars are called the Pointers. Can you tell that the higher of the two, Dubhe is slightly yellowish compared to the lower, Merak? Check with binoculars. Not all stars are white. The colour shows that Dubhe is cooler than Merak in the same way that red-hot is cooler than white- hot. 2. Use the Pointers to guide you upwards to the next bright star. This is Polaris, the Pole (or North) Star. Note that it is not the brightest star in the sky, a common misconception. Below and to the left are two prominent but fainter stars. These are Kochab and Pherkad, the Guardians of the Pole. Look carefully and you will notice that Kochab is slightly orange when compared to Polaris. -
Keck Spectra of Brown Dwarf Candidates and a Precise
TABLE 1 Summary of Optical Imaging for Alpha Persei Telescope Area Covered Limiting Magnitude (sq.degrees) (R/I) CWRU Schmidt 3.2 21.5/20.5 MHO 1.2m 1.1 22.0/20.7 KPNO 0.9m 0.5 21.5/20.5 KPNO 4.0m 1.3 22.4/21.0 KPNO 4.0m a (2.5) ≈ 24/≈ 23 aBouvier et al. (1999) TABLE 2 Photometry of Alpha Persei Stars Star α(J2000) δ(J2000) Ic R − Ic K Ic − K AP300 3 17 27.6 49 36 53.0 17.85 2.18 14.62 3.23 AP301 3 18 09.2 49 25 19.0 17.75 2.22 14.14 3.61 AP302 3 19 08.4 48 43 48.5 17.63 2.08 ······ AP303 3 19 10.9 48 42 20.0 16.98 1.88 ······ AP304 3 19 13.2 48 31 55.0 18.83 2.40 ······ AP305 3 19 21.7 49 23 32.0 18.48 2.34 ······ AP306 3 19 41.8 50 30 42.0 18.40 2.34 14.9 3.5 AP307 3 20 20.9 48 01 05.0 17.08 2.01 ······ AP308 3 20 59.7 48 18 37.0 16.71 1.89 ······ AP309 3 22 40.6 48 00 36.0 16.57 1.88 ······ AP275 a 3 23 03.3 48 53 07.0 17.25 2.20 ······ AP310 3 23 04.7 48 16 13.0 17.80 2.33 14.55 3.25 AP311 3 23 08.4 48 04 52.5 17.70 2.12 14.30 3.40 AP312 3 23 14.8 48 11 56.0 18.60 2.41 15.21 3.39 AP313 3 24 08.1 48 48 30.0 17.55 2.13 ······ AP314 3 25 19.6 49 17 58.0 18.20 2.26 15.15 3.05 AP315 3 26 34.5 49 07 46.0 18.20 2.34 14.80 3.40 arXiv:astro-ph/9909207v2 15 Sep 1999 AP316 3 27 01.3 49 14 40.0 17.75 2.18 14.48 3.27 AP317 3 28 06.0 48 45 13.5 17.85 2.29 15.0 2.85 AP318 3 30 42.5 48 21 27.0 17.45 2.16 14.10 3.35 AP319 3 31 03.2 49 02 58.0 16.89 1.95 ······ AP320 3 31 25.3 49 02 52.0 16.79 1.90 ······ AP321 3 32 18.7 49 32 18.0 17.75 2.20 ······ AP322 3 33 08.3 49 37 56.5 17.60 2.14 14.57 3.03 AP323 3 33 20.7 48 45 51.0 17.50 2.13 14.33 3.17 AP324 3 33 48.2 48 52 30.5 18.10 2.36 14.68 3.42 AP325 3 35 47.2 49 17 43.0 17.65 2.30 14.14 3.51 AP326 3 38 55.2 48 57 31.0 18.70 2.40 15.09 3.61 aAP275 is from Prosser (1994). -
The Ages of Early-Type Stars: Str\" Omgren Photometric Methods
Draft version September 10, 2018 Preprint typeset using LATEX style emulateapj v. 5/2/11 THE AGES OF EARLY-TYPE STARS: STROMGREN¨ PHOTOMETRIC METHODS CALIBRATED, VALIDATED, TESTED, AND APPLIED TO HOSTS AND PROSPECTIVE HOSTS OF DIRECTLY IMAGED EXOPLANETS Trevor J. David1,2 and Lynne A. Hillenbrand1 1Department of Astronomy; MC 249-17; California Institute of Technology; Pasadena, CA 91125, USA; tjd,[email protected] Draft version September 10, 2018 ABSTRACT Age determination is undertaken for nearby early-type (BAF) stars, which constitute attractive targets for high-contrast debris disk and planet imaging surveys. Our analysis sequence consists of: acquisition of uvbyβ photometry from catalogs, correction for the effects of extinction, interpolation of the photometry onto model atmosphere grids from which atmospheric parameters are determined, and finally, comparison to the theoretical isochrones from pre-main sequence through post-main sequence stellar evolution models, accounting for the effects of stellar rotation. We calibrate and validate our methods at the atmospheric parameter stage by comparing our results to fundamentally determined Teff and log g values. We validate and test our methods at the evolutionary model stage by comparing our results on ages to the accepted ages of several benchmark open clusters (IC 2602, α Persei, Pleiades, Hyades). Finally, we apply our methods to estimate stellar ages for 3493 field stars, including several with directly imaged exoplanet candidates. Subject headings: stars: early-type |evolution |fundamental parameters |Hertzsprung-Russell and C-M diagrams |planetary systems |astronomical databases: catalogs 1. INTRODUCTION planet formation efficiency to stellar mass. The claim is In contrast to other fundamental stellar parameters that while 14% of A stars have one or more > 1MJupiter companions∼ at <5 AU, only 2% of M stars do (Johnson such as mass, radius, and angular momentum { that for ∼ certain well-studied stars and stellar systems can be an- et al. -
Algol As Horus in the Cairo Calendar: the Possible Means and the Motives of the Observations
Open Astron. 2018; 27: 232–263 Research Article Sebastian Porceddu*, Lauri Jetsu, Tapio Markkanen, Joonas Lyytinen, Perttu Kajatkari, Jyri Lehtinen, and Jaana Toivari-Viitala Algol as Horus in the Cairo Calendar: the possible means and the motives of the observations https://doi.org/10.1515/astro-2018-0033 Received Feb 15, 2018; accepted May 04, 2018 Abstract: An ancient Egyptian Calendar of Lucky and Unlucky Days, the Cairo Calendar (CC), assigns luck with the period of 2.850 days. Previous astronomical, astrophysical and statistical analyses of CC support the idea that this was the period of the eclipsing binary Algol three millennia ago. However, next to nothing is known about who recorded Algol’s period into CC and especially how. Here, we show that the ancient Egyptian scribes had the possible means and the motives for such astronomical observations. Their principles of describing celestial phenomena as activity of gods reveal why Algol received the title of Horus Keywords: Algol, Horus, ancient Egyptian Astronomy, variable stars, the Cairo Calendar, hemerologies 1 Introduction ies (Porceddu et al., 2008; Jetsu et al., 2013; Jetsu and Porceddu, 2015), we use only the best preserved continuous calendar which is found on pages recto III-XXX and verso The ancient Egyptian texts known as the Calendars of I-IX of papyrus Cairo 86637.The other texts and fragments Lucky and Unlucky Days, or hemerologies, are literary contained in the same papyrus are ignored from this analy- works that assign prognoses to each day of the Egyp- sis because the connection of these fragments to the main tian year (Wells, 2001a, p117-118), (Leitz, 1994, p1-2) (Bacs, calendar is not apparent and we do not know what year 1990, p41-45) (Troy, 1989, p127-147) and (Helck et al., 1975– they describe, so combining any data points from these 1992, p156). -
A High-Angular Resolution Multiplicity Survey of the Open Clusters Α Persei and Praesepe J. Patience 1, A. M. Ghez, UCLA Divisi
A High-Angular Resolution Multiplicity Survey of the Open Clusters α Persei and Praesepe J. Patience 1, A. M. Ghez, UCLA Division of Astronomy & Astrophysics, Los Angeles, CA 90095-1562 I. N. Reid 2 & K. Matthews Palomar Observatory, California Institute of Technology, Pasadena, CA 91125 1 present address: IGPP, LLNL, 7000 East Ave. L-413, Livermore, CA 94550; [email protected] 2 present address: Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 Abstract Two hundred and forty-two members of the Praesepe and α Persei clusters have been surveyed with high angular resolution 2.2 µm speckle imaging on the IRTF 3-m, the Hale 5-m, and the Keck 10-m, along with direct imaging using the near-infrared camera (NICMOS) aboard the Hubble Space Telescope (HST). The observed stars range in spectral type from B (~5 MSUN) to early-M (~0.5 MSUN), with the majority of the targets more massive than ~0.8 MSUN. The 39 binary and 1 quadruple systems detected encompass separations from 0”.053 to 7”.28; 28 of the systems are new detections and there are 9 candidate substellar companions. The results of the survey are used to test binary star formation and evolution scenarios and to investigate the effects of companion stars on X-ray emission and stellar rotation. The main results are: • Over the projected separation range of 26-581 AU and magnitude differences of ∆K<4.0 mag (comparable to α mass ratios, q=msec/mprim > 0.25), the companion star fraction (CSF) for Persei is 0.09 ± 0.03 and for Praesepe is 0.10 ± 0.03. -
How Astronomical Objects Are Named
How Astronomical Objects Are Named Jeanne E. Bishop Westlake Schools Planetarium 24525 Hilliard Road Westlake, Ohio 44145 U.S.A. bishop{at}@wlake.org Sept 2004 Introduction “What, I wonder, would the science of astrono- use of the sky by the societies of At the 1988 meeting in Rich- my be like, if we could not properly discrimi- the people that developed them. However, these different systems mond, Virginia, the Inter- nate among the stars themselves. Without the national Planetarium Society are beyond the scope of this arti- (IPS) released a statement ex- use of unique names, all observatories, both cle; the discussion will be limited plaining and opposing the sell- ancient and modern, would be useful to to the system of constellations ing of star names by private nobody, and the books describing these things used currently by astronomers in business groups. In this state- all countries. As we shall see, the ment I reviewed the official would seem to us to be more like enigmas history of the official constella- methods by which stars are rather than descriptions and explanations.” tions includes contributions and named. Later, at the IPS Exec- – Johannes Hevelius, 1611-1687 innovations of people from utive Council Meeting in 2000, many cultures and countries. there was a positive response to The IAU recognizes 88 constel- the suggestion that as continuing Chair of with the name registered in an ‘important’ lations, all originating in ancient times or the Committee for Astronomical Accuracy, I book “… is a scam. Astronomers don’t recog- during the European age of exploration and prepare a reference article that describes not nize those names. -
Fort Worth Astronomical Society December 2010 Club Calendar – 2
: Fort Worth Astronomical Society December 2010 Established 1949 Astronomical League Member Club Calendar – 2 “Winter Solstice” Dinner – 3 Skyportunities – 4 A Man on the Moon – 5 The Season for Giving - 6 Perseus – 7 Stargazers’ Diary – 9 1 Coconut Joe by Trista Oppermann December 2010 Sunday Monday Tuesday Wednesday Thursday Friday Saturday 1 2 3 4 . Top ten binocular deep-sky objects for December: M34, M45, Mel15, Mel20, NGC 869, NGC 884, NGC 1027, NGC 1232, St2, St23 Top ten deep-sky objects for December: M34, M45, M77, NGC 869, NGC 884, NGC 891, NGC 1023, NGC 1232, NGC 1332, NGC 1360 5 6 7 8 9 10 11 New Moon 11:36 am Will you get: The Rocking Will you get: Reindeer? The Orange Telescope? 12 13 14 15 16 17 18 RASC First Qtr Moon Observers 7:59 am Will you get: Will you get: Handbooks will be available at Geminid A Major the December meteors peak Award? Meeting at Mercardo Juarez, Moon sets to those that 1:04 am Coconut It’s fraGEEly! signed up for Tuesday it must be them, Joe? Italian! $20 / copy. 19 20 21 22 23 24 25 Total Solstice Lunar Eclipse 5:38 pm Begins @ 11:30 pm Full Moon @ 2:38 am on 21st FWAS Dinner 26 27 28 29 30 31 Last Qtr Moon 7:46 am Challenge deep-sky object for December: vdB14 (Camelopardalis) Challenge binary star for December: 48 Cassiopeiae (Cassiopeia) Notable carbon star for December: U Camelopardalis Notable variable star for December: Omicron Ceti (Mira) 2 FWAS Winter Solstice Dinner Location: Mercado Juarez Restaurant FWAS Annual Banquet Tuesday, 12/21/2010; 7:00 PM - 9:30 PM Mercado Juarez Restaurant, 1651 East Northside Drive, Fort Worth, TX 76106 Fort Worth Astronomical Society's annual dinner banquet will be held at Mercado Juarez Restaurant in Fort Worth this year. -
Eclipsing Binary Stars: the Royal Road to Stellar Astrophysics John Southworth Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK
Eclipsing Binary Stars: the Royal Road to Stellar Astrophysics John Southworth Astrophysics Group, Keele University, Staffordshire, ST5 5BG, UK Introduction Russell [1] famously described eclipses as the “royal road” to stellar astrophysics (see also [2]). From photometric and spectroscopic observations it is possible to measure the masses and radii (to 1% or better!), and thus surface gravities and mean densities, of stars in eclipsing binary systems (EBs) using nothing more than geometry. Adding an effective temperature subsequently yields luminosity and then distance (or vice versa) to high precision. This wealth of directly measurable quantities makes EBs the primary source of empirical information on the properties of stars, and therefore a cornerstone of stellar astrophysics. In this review paper I summarise the current standing of EB research, present an overview of useful analysis techniques, and conclude with a glance to the future. For a deeper discussion I recommend the peerless reviews by Popper [3] [4], Andersen [5] and Torres et al. [6], and the textbook by Ron Hilditch [7]. 1. The Ghost of Christmas Past John Goodricke (ably supported by his assistant Edward Pigott) was in 1783 the first to invoke the concept of stellar eclipses, in order to explain the variations in the light of β Persei (Algol). William Herschel [8] christened the term “binary star” in the course of his work on resolved astrometric binaries. In 1889, Edward Pickering triggered the study of close binary systems when he noticed that the star Mizar exhibited spectral lines which not only moved in wavelength but were sometimes doubled. Carl Vogel [9] proved the binary nature of β Persei by detecting spectral line shifts before and after an eclipse, giving rise to the term “spectroscopic binary”. -
The 6.7 Kev Line Emission from the Stellar Flare of Algol
Journal of High Energy Physics, Gravitation and Cosmology, 2019, 5, 1090-1097 https://www.scirp.org/journal/jhepgc ISSN Online: 2380-4335 ISSN Print: 2380-4327 The 6.7 keV Line Emission from the Stellar Flare of Algol Ambrose C. Eze1,2* , Sudum Esaenwi3, Abraham I. Chima4 1Department of Physics and Geosciences, Faculty of Natural and Applied Sciences, Godfrey Okoye University, Enugu, Nigeria 2Department of Physics and Astronomy, Faculty of Physical Sciences, University of Nigeria, Nsukka, Nigeria 3NASRDA-Centre for Basic Space Science, Nsukka, Nigeria 4Department of Industrial Physics, Enugu State University of Science and Technology, Enugu, Nigeria How to cite this paper: Eze, A.C., Esaenwi, Abstract S. and Chima, A.I. (2019) The 6.7 keV Line Emission from the Stellar Flare of Algol. We present spectral analysis of Algol stellar flare data. The 2-day observation Journal of High Energy Physics, Gravita- of Algol in our Galaxy was done by Suzaku Satellite. Algol binary system con- tion and Cosmology, 5, 1090-1097. sists of two component stars that eclipse one another periodically. The stellar https://doi.org/10.4236/jhepgc.2019.54061 magnetic field activities and Roche Lobe overflow/mass transfer mechanisms Received: June 13, 2019 during rapid rotation of the component stars generate an X-ray emission. The Accepted: September 15, 2019 variation in brightness of the stellar flare from epoch to epoch provides useful Published: September 18, 2019 information of stellar properties of the component stars. The atomic physics Copyright © 2019 by author(s) and of the Kα line emission process in the vicinities of chromospherically active Scientific Research Publishing Inc. -
The Initial Conditions and Evolution of Open Clusters by Joseph Mitchell
The Initial Conditions and Evolution of Open Clusters by Joseph Mitchell Converse A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Astrophysics in the Graduate Division of the University of California, Berkeley Committee in charge: Doctor Steven Stahler, Co-chair Professor Chris McKee, Co-chair Professor James Graham Professor Michael Manga Fall 2010 The Initial Conditions and Evolution of Open Clusters Copyright 2010 by Joseph Mitchell Converse 1 Abstract The Initial Conditions and Evolution of Open Clusters by Joseph Mitchell Converse Doctor of Philosophy in Astrophysics University of California, Berkeley Doctor Steven Stahler, Co-chair Professor Chris McKee, Co-chair Despite being some of the most familiar objects observed in the sky, much remains unknown about open clusters. The theory of their formation admits many unanswered questions, and the complex dynamics of their evolution remains an extremely difficult problem to address. In this thesis, I present results that both help to constrain formation theories, as well as to shed new understanding on the many physical processes that drive their evolution. Starting with a photometric catalog of a cluster, I employ a maximum likelihood tech- nique to determine the mass distribution of its members, including single stars and both components of binary systems. This method allows me to determine not just the fraction of systems which are binary, but also the typical degree of correlation between the masses of their components. I also examine the spatial distribution of the cluster members. The issue of mass segregation is also addressed, introducing a new method for quantifying it. -
Southeastern Iowa Astronomy Club the Sidereal Times
SOUTHEASTERN IOWA ASTRONOMY CLUB THE SIDEREAL TIMES SEPTEMBER 2013 A M EMBER SOCIETY OF THE ASTRONOMICAL LEAGUE CLUB OFFICERS : MINUTES AUGUST 16, 2013 Executive Committee President Jim Hilkin called the meeng the club sent for her mother's fu- to order at 7:07pm with the following neral. Karen said that she will be President Jim Hilkin Vice President Libby Snipes members in aendance: Judy Smith- updang the look of the newsleer Treasurer Vicki Philabaum son, Karen & Larry Johnson, Libby in the near future. Dave reported Secretary David Philabaum Snipes, Jim Wilt, Ray Reineke, Dave & that a boy scout group camping at Chief Observer David Philabaum Vicki Philabaum, John Toney, and guest Big Hollow will be coming to the Members-at-Large Claus Benninghoven observatory later tonight. The next Duane Gerling Mike Tripodi. Vicki moved to approve Blake Stumpf the minutes as published, seconded by group scheduled is Great River Board of Directors Chrisan School on September 20 th . Judy, moon passed. Vicki gave the Chair Judy Hilkin Treasurer's report. Checks were wrien Jim Hilkin reported on the following Vice Chair Ray Reineke for: Astronomical League dues, liability maintenance items: some dirt has Secretary David Philabaum insurance, the phone bill, and paint for been obtained to extend the berm Members-at-Large David Martin the parking lot and doors. The club bal- on the south side of the observatory Blake Stumpf Jim Wilt ance is $1,601.05 and the grant balance farther to the east to block head- Audit Committee is $1,630.98 for a total of $3,232.03 in lights on cars coming from Area E the checking account.