STARS2016: Understanding the Roles of Rotation, Pulsation and Chemical Peculiarities in the Upper Main Sequence
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Stellar Variability in Open Clusters. I. a New Class of Variable Stars in NGC
Astronomy & Astrophysics manuscript no. ngc3766˙v3˙1b c ESO 2018 September 8, 2018 Stellar variability in open clusters I. A new class of variable stars in NGC 3766 N. Mowlavi1, F. Barblan1, S. Saesen1, and L. Eyer1 1Astronomy Department, Geneva Observatory, chemin des Maillettes, 1290 Versoix, Switzerland e-mail: [email protected] Accepted 16/04/2013 ABSTRACT Aims. We analyze the population of periodic variable stars in the open cluster NGC 3766 based on a 7-year multiband monitoring campaign conducted on the 1.2 m Swiss Euler telescope at La Silla, Chili. Methods. The data reduction, light curve cleaning, and period search procedures, combined with the long observation time line, allowed us to detect variability amplitudes down to the mmag level. The variability properties were complemented with the positions in the color-magnitude and color-color diagrams to classify periodic variable stars into distinct variability types. Results. We find a large population (36 stars) of new variable stars between the red edge of slowly pulsating B (SPB) stars and the blue edge of δ Sct stars, a region in the Hertzsprung-Russell (HR) diagram where no pulsation is predicted to occur based on standard stellar models. The bulk of their periods ranges from 0.1 to 0.7 d, with amplitudes between 1 and 4 mmag for the majority of them. About 20% of stars in that region of the HR diagram are found to be variable, but the number of members of this new group is expected to be higher, with amplitudes below our mmag detection limit. -
Isolating the Pre-Main Sequence in Collinder 34, NGC 3293, NGC 3766 and NGC 6231
MNRAS 448, 1687–1703 (2015) doi:10.1093/mnras/stv026 Isolating the pre-main sequence in Collinder 34, NGC 3293, NGC 3766 and NGC 6231 T. A. Saurin,‹ E. Bica and C. Bonatto Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, CP 15051, RS, Porto Alegre 91501-970, Brazil Accepted 2015 January 6. Received 2014 December 18; in original form 2014 July 17 Downloaded from ABSTRACT We employed field star decontaminated Two Micron All Sky Survey photometry to study four nearby optical embedded clusters – Collinder 34, NGC 3293, NGC 3766 and NGC 6231 – obtaining deep colour–magnitude diagrams and stellar radial density profiles. We found what seem to be pre-main sequences detached in different amounts from main sequences in these http://mnras.oxfordjournals.org/ diagrams. The structural analysis of each cluster revealed different radial distributions for these two sequences. We argued that the detached evolutionary sequences in our sample may be evidence of sequential star formation. Finally, we compared the sample cluster parameters with those of other young clusters in the literature and point out evidence that NGC 3766 and NGC 6231 might be evolving to OB associations. Key words: open clusters and associations: individual: Collinder 34 – open clusters and asso- ciations: individual: NGC 3293 – open clusters and associations: individual: NGC 3766 – open clusters and associations: individual: NGC 6231. at Universidade Federal do Rio Grande Sul on April 6, 2015 that may be interpreted as mass and age segregation (e.g. Hillen- 1 INTRODUCTION brand 1997). Youngstar clusters remain embedded in molecular clouds during the Using Two Micron All Sky Survey (2MASS;1 Skrutskie et al. -
Orbit of the Mercury-Manganese Binary 41 Eridani? C
A&A 600, L5 (2017) Astronomy DOI: 10.1051/0004-6361/201730414 & c ESO 2017 Astrophysics Letter to the Editor Orbit of the mercury-manganese binary 41 Eridani? C. A. Hummel1, M. Schöller1, G. Duvert2, and S. Hubrig3 1 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany e-mail: [email protected] 2 UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble, UMR 5274, 38041 Grenoble, France 3 Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany Received 10 January 2017 / Accepted 1 March 2017 ABSTRACT Context. Mercury-manganese (HgMn) stars are a class of slowly rotating chemically peculiar main-sequence late B-type stars. More than two-thirds of the HgMn stars are known to belong to spectroscopic binaries. Aims. By determining orbital solutions for binary HgMn stars, we will be able to obtain the masses for both components and the distance to the system. Consequently, we can establish the position of both components in the Hertzsprung-Russell diagram and confront the chemical peculiarities of the HgMn stars with their age and evolutionary history. Methods. We initiated a program to identify interferometric binaries in a sample of HgMn stars, using the PIONIER near-infrared interferometer at the VLTI on Cerro Paranal, Chile. For the detected systems, we intend to obtain full orbital solutions in conjunction with spectroscopic data. Results. The data obtained for the SB2 system 41 Eridani allowed the determination of the orbital elements with a period of just five days and a semi-major axis of under 2 mas. -
Naming the Extrasolar Planets
Naming the extrasolar planets W. Lyra Max Planck Institute for Astronomy, K¨onigstuhl 17, 69177, Heidelberg, Germany [email protected] Abstract and OGLE-TR-182 b, which does not help educators convey the message that these planets are quite similar to Jupiter. Extrasolar planets are not named and are referred to only In stark contrast, the sentence“planet Apollo is a gas giant by their assigned scientific designation. The reason given like Jupiter” is heavily - yet invisibly - coated with Coper- by the IAU to not name the planets is that it is consid- nicanism. ered impractical as planets are expected to be common. I One reason given by the IAU for not considering naming advance some reasons as to why this logic is flawed, and sug- the extrasolar planets is that it is a task deemed impractical. gest names for the 403 extrasolar planet candidates known One source is quoted as having said “if planets are found to as of Oct 2009. The names follow a scheme of association occur very frequently in the Universe, a system of individual with the constellation that the host star pertains to, and names for planets might well rapidly be found equally im- therefore are mostly drawn from Roman-Greek mythology. practicable as it is for stars, as planet discoveries progress.” Other mythologies may also be used given that a suitable 1. This leads to a second argument. It is indeed impractical association is established. to name all stars. But some stars are named nonetheless. In fact, all other classes of astronomical bodies are named. -
N O T I C E This Document Has Been Reproduced From
N O T I C E THIS DOCUMENT HAS BEEN REPRODUCED FROM MICROFICHE. ALTHOUGH IT IS RECOGNIZED THAT CERTAIN PORTIONS ARE ILLEGIBLE, IT IS BEING RELEASED IN THE INTEREST OF MAKING AVAILABLE AS MUCH INFORMATION AS POSSIBLE P993-198422 International Collogium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas (4th) Held at the National institute of Standards and Technology Gaithersburg, Maryland on September 14-17, 1992 (U.S.) National inst. of Standards and Technology (PL) Gaithersburg, MD Apr 93 US. DEPARTMENT OF COMMERCE Ndioul Techcical IMermeNON Service B•11G 2-10i1A2 2 MIST-1 /4 U.S. VZPARTMENT OF COMMERCE (REV. NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY M GONTSOLw1N^BENN O4" COMM 4M /. MANUSCRIPT REVIEW AND APPROVAL "KIST/ p-850 ^' THIS NSTRUCTWNS: ATTACH ORIGINAL OF FORM TO ONE (1) COPY OF MANUSCIIN IT AND SEINE TO: PUBLICATIOM OATS NUMBER PRINTED PAGES April 1993 199 HE SECRETAIIY, APPROPRIATE EDITO RIAL REVIEW BOARD. ITLE AND SUBTITLE (CITE NN PULL) 4rh International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas -- POSTER PAPERS :ONTIEACT OR GRANT NUMBER TYPE OF REPORT AND/OR PERIOD COMM UTHOR(S) (LAST %,TAME, POST NNITIAL, SECOND INITIAL) PERFORM" ORGANIZATION (CHECK (IQ ONE SOX) EDITORS XXX MIST/GAITHERSBUIIG Sugar, Jack and Leckrone, B:;vid INST/BODUM JILA BOIRDE11 "ORATORY AND DIVISION NAMES (FIRST MOST AUTHOR ONLY) Physics Laboratory/Atomic Physics Division 'PONSORING ORGANIZATION NAME AND COMPLETE ADDRESS TREET, CITY. STATE. ZNh ^y((S/ ,T AiL7A - -ASO IECOMMENDsO FOR MIST PUBLICATION JOVIAMAL OF RESEMICM (MIST JRES) CIONOGRAPK (MIST MN) LETTER CIRCULAR J. PHYS. A CHEM. -
Progress Report 1985 - 1986
PROGRESS REPORT 1985 - 1986 Instituto de Física Universidade Federal do Rio Grande do Sul Ptril Mtffi • Imi mi FOREWORD Despite difficulties arising fro» uncertainties in the scientific policy and economic situation of the country, the scientific activity and production of the Institute regained at the level of previous years. During the present period the Institute of Physics Moved to the new University Campus thereby having access to ample new installations and waking possible the expansion of its activities. Although expected to be beneficial in the long range, numerous difficulties had to be «et particularly by experimental groups, slowing down temporarily their production, until all the equip- ments were again operational. A new COBRA 1400 computer (equivalent to a Eclipse Data General MV 8000 II one'; has been acquired. This acquisition nade possible for the first tine in many years, an adequate level of computational support for our work. During this period discussions were started on the need for new research and technological facilities for our Institute, in particular laboratories for thin films and electronic microscopy, and expansion of the existing ones, like the ion implantation. The scientific achievements of the Institute were made possible by the financial support of FINEP (Financiadora de Estudos e Projetos), CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), CAPES (Coordenação de Aperfeiçoamento de Pessoal de NTvel Superior) anó the University Administration. The continuous support of the University Administration to secure outside funding is also acknowledged. The effort in editing this report,due to Professor Walter K. Iheumann with the expert assistance of Mrs. Ivone H. -
The Hot Gamma-Doradus and Maia Stars
Mon. Not. R. Astron. Soc. 000, 000–000 (0000) Printed 16 April 2018 (MN LaTEX style file v2.2) The hot γ Doradus and Maia stars L. A. Balona1, C. A. Engelbrecht2, Y. C. Joshi3, S. Joshi3, K. Sharma4, E. Semenko5, G. Pandey6, N. K. Chakradhari7, David Mkrtichian8, B. P. Hema6, J. M. Nemec9 1South African Astronomical Observatory, P.O. Box 9, Observatory 7935, South Africa, [email protected] 2Department of Physics, University of Johannesburg, PO Box 524, Auckland Park, Johannesburg 2006, South Africa 3Aryabhatta Research Institute of Observational Sciences (ARIES), Manora peak, Nainital, India 4Department of Physics and Astrophysics, University of Delhi, Delhi - 110007, India 5Special Astrophysical Observatory, Russian Academy of Sciences, Nizhny Arkhyz, 369167, Russia [email protected] 6Indian Institute of Astrophysics, Bengaluru, Karnataka 560034, India 7School of Studies in Physics and Astrophysics, Pt Ravishankar Shukla University, Raipur 492 010, India 8National Astronomical Research Institute of Thailand, 191 Huay Kaew Road, Muang, 50200, Chiangmai, Thailand 9Department of Physics & Astronomy, Camosun College, Victoria, British Columbia, V8P 5J2, Canada ABSTRACT The hot γ Doradus stars have multiple low frequencies characteristic of γ Dor or SPB variables, but are located between the red edge of the SPB and the blue edge of the γ Dor instability strips where all low-frequency modes are stable in current models of these stars. Though δ Sct stars also have low frequencies, there is no sign of high frequencies in hot γ Dor stars. We obtained spectra to refine the locations of some of these stars in the H-R diagram and conclude that these are, indeed, anomalous pulsating stars. -
Chandra X-Ray Study Confirms That the Magnetic Standard Ap Star KQ Vel
A&A 641, L8 (2020) Astronomy https://doi.org/10.1051/0004-6361/202038214 & c ESO 2020 Astrophysics LETTER TO THE EDITOR Chandra X-ray study confirms that the magnetic standard Ap star KQ Vel hosts a neutron star companion? Lidia M. Oskinova1,2, Richard Ignace3, Paolo Leto4, and Konstantin A. Postnov5,2 1 Institute for Physics and Astronomy, University Potsdam, 14476 Potsdam, Germany e-mail: [email protected] 2 Department of Astronomy, Kazan Federal University, Kremlevskaya Str 18, Kazan, Russia 3 Department of Physics & Astronomy, East Tennessee State University, Johnson City, TN 37614, USA 4 NAF – Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania, Italy 5 Sternberg Astronomical Institute, M.V. Lomonosov Moscow University, Universitetskij pr. 13, 119234 Moscow, Russia Received 20 April 2020 / Accepted 20 July 2020 ABSTRACT Context. KQ Vel is a peculiar A0p star with a strong surface magnetic field of about 7.5 kG. It has a slow rotational period of nearly 8 years. Bailey et al. (A&A, 575, A115) detected a binary companion of uncertain nature and suggested that it might be a neutron star or a black hole. Aims. We analyze X-ray data obtained by the Chandra telescope to ascertain information about the stellar magnetic field and/or interaction between the star and its companion. Methods. We confirm previous X-ray detections of KQ Vel with a relatively high X-ray luminosity of 2 × 1030 erg s−1. The X-ray spectra suggest the presence of hot gas at >20 MK and, possibly, of a nonthermal component. -
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). -
19 6 6Apj. . .14 6. .743D the VARIABILITY of RHO PUPPIS* I. J
.743D 6. .14 THE VARIABILITY OF RHO PUPPIS* . I. J. Danziger and L. V. Kumf 6ApJ. Mount Wilson and Palomar Observatories 6 19 Carnegie Institution of Washington, California Institute of Technology Received April 30, 1966 ABSTRACT The results of simultaneous spectrophotometric and spectral observations of the short-period variable star, p Puppis, are reported. The amplitudes of radial-velocity, light, and temperature variations are 11 km/sec, 0.15 mag., and 280° K, respectively. The relative phases differ from those observed in cluster- type c variables. Estimates of the absolute luminosity and mass from the observed gravity and the Py/(p/po) — Q relationship indicate that either p Puppis is pulsating in a higher-order harmonic mode than the first or the theory of its pulsation is not understood. I. INTRODUCTION The bright star p Puppis, classified in the MKK system as type F6II, was first shown to be variable in light (period 0.141 days) by Eggen (1956) who measured a total ampli- tude of 0.15 mag. Struve, Sahade, and Zebergs (1956) showed that there is an associated variation in radial velocity with a total amplitude of 10 km/sec and that maximum brightness occurs approximately 0.02 days later than minimum radial velocity. Bappu (1959) reported that two-color measurements indicate a variation in temperature of 300° K. An intrinsic luminosity of p Puppis, MPg = +2.4, was obtained by Kinman (1959). He assumed it fitted the observed period-luminosity relation of cluster-type c variables in order to use an observed period-luminosity relation. Strömgren’s c-l sys- tem indices were measured by McNamara and Augason (1962) to derive Mpg = +1.7 and a mass 9J£ = 3.2 $)îo from the period-density law with the pulsation constant Q ~ 0-041* It is of interest to note that, although p Puppis has been classified as a ô Scuti star, none of the multiple-period characteristics associated with such stars has been found to apply to it. -
Ioptron CEM40 Center-Balanced Equatorial Mount
iOptron®CEM40 Center-Balanced Equatorial Mount Instruction Manual Product CEM40 (#7400A series) and CEM40EC (#7400ECA series, as shown) Please read the included CEM40 Quick Setup Guide (QSG) BEFORE taking the mount out of the case! This product is a precision instrument. Please read the included QSG before assembling the mount. Please read the entire Instruction Manual before operating the mount. You must hold the mount firmly when disengaging the gear switches. Otherwise personal injury and/or equipment damage may occur. Any worm system damage due to improper operation will not be covered by iOptron’s limited warranty. If you have any questions please contact us at [email protected] WARNING! NEVER USE A TELESCOPE TO LOOK AT THE SUN WITHOUT A PROPER FILTER! Looking at or near the Sun will cause instant and irreversible damage to your eye. Children should always have adult supervision while using a telescope. 2 Table of Contents Table of Contents ........................................................................................................................................ 3 1. CEM40 Introduction ............................................................................................................................... 5 2. CEM40 Overview ................................................................................................................................... 6 2.1. Parts List ......................................................................................................................................... -
UNSC Science and Technology Command
UNSC Science and Technology Command Earth Survey Catalogue: Official Name/(Common) Star System Distance Coordinates Remarks/Status 18 Scorpii {TCP:p351} 18 Scorpii {Fact} 45.7 LY 16h 15m 37s Diameter: 1,654,100km (1.02R*) {Fact} -08° 22' 06" {Fact} Spectral Class: G2 Va {Fact} Surface Temp.: 5,800K {Fact} 18 Scorpii ?? (Falaknuma) 18 Scorpii {Fact} 45.7 LY 16h 15m 37s UNSC HQ base on world. UNSC {TCP:p351} {Fact} -08° 22' 06" recruitment center in the city of Halkia. {TCP:p355} Constellation: Scorpio 111 Tauri 111 Tauri {Fact} 47.8 LY 05h:24m:25.46s Diameter: 1,654,100km (1.19R*) {Fact} +17° 23' 00.72" {Fact} Spectral Class: F8 V {Fact} Surface Temp.: 6,200K {Fact} Constellation: Taurus 111 Tauri ?? (Victoria) 111 Tauri {Fact} 47.8 LY 05:24:25.4634 UNSC colony. {GoO:p31} {Fact} +17° 23' 00.72" Constellation: Taurus Location of a rebel cell at Camp New Hope in 2531. {GoO:p31} 51 Pegasi {Fact} 51 Pegasi {Fact} 50.1 LY 22h:57m:28s Diameter: 1,668,000km (1.2R*) {Fact} +20° 46' 7.8" {Fact} Spectral Class: G4 (yellow- orange) {Fact} Surface Temp.: Constellation: Pegasus 51 Pegasi-B (Bellerophon) 51 Pegasi 50.1 LY 22h:57m:28s Gas giant planet in the 51 Pegasi {Fact} +20° 46' 7.8" system informally named Bellerophon. Diameter: 196,000km. {Fact} Located on the edge of UNSC territory. {GoO:p15} Its moon, Pegasi Delta, contained a Covenant deuterium/tritium refinery destroyed by covert UNSC forces in 2545. {GoO:p13} Constellation: Pegasus 51 Pegasi-B-1 (Pegasi 51 Pegasi 50.1 LY 22h:57m:28s Moon of the gas giant planet 51 Delta) {GoO:p13} +20° 46' 7.8" Pegasi-B in the 51 Pegasi star Constellation: Pegasus system; a Covenant stronghold on the edge of UNSC territory.