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III. the Young Open Cluster NGC 1893 in the HII Region W8
MNRAS 443, 454–473 (2014) doi:10.1093/mnras/stu1170 Sejong Open Cluster Survey (SOS) – III. The young open cluster NGC 1893 in the H II region W8 Beomdu Lim,1,2‹† Hwankyung Sung,2‹ Jinyoung S. Kim,3 Michael S. Bessell4 and Byeong-Gon Park1 1Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, Daejeon 305-348, Korea 2Department of Astronomy and Space Science, Sejong University, 209 Neungdong-Ro, Gwangjin-gu, Seoul 143-747, Korea 3Steward Observatory, University of Arizona, 933 N. Cherry Ave. Tucson, AZ 85721-0065, USA 4Research School of Astronomy and Astrophysics, Australian National University, MSO, Cotter Road, Weston, ACT 2611, Australia Downloaded from Accepted 2014 June 11. Received 2014 June 10; in original form 2014 March 31 ABSTRACT http://mnras.oxfordjournals.org/ We present a UBVI and Hα photometric study of the young open cluster NGC 1893 in the H II region W8 (IC 410 or Sh 2-236). A total of 65 early-type members are selected from photometric diagrams. A mean reddening of the stars is E(B − V)=0.563 ± 0.083 mag. The published photometric data in the near- and mid-infrared passbands are used to test the reddening law towards the cluster, and we confirm that the reddening law is normal (RV = 3.1). Zero-age main-sequence fitting gives a distance modulus of V0 − MV = 12.7 ± 0.2 mag, equivalent to 3.5 ± 0.3 kpc. From Hα photometry, 125 Hα emission stars and candidates are identified as pre-main-sequence (PMS). The lists of young stellar objects and X-ray sources published by previous studies allow us to select a large number of PMS members down to at The Australian National University on September 16, 2014 1M. -
BRAS Newsletter August 2013
www.brastro.org August 2013 Next meeting Aug 12th 7:00PM at the HRPO Dark Site Observing Dates: Primary on Aug. 3rd, Secondary on Aug. 10th Photo credit: Saturn taken on 20” OGS + Orion Starshoot - Ben Toman 1 What's in this issue: PRESIDENT'S MESSAGE....................................................................................................................3 NOTES FROM THE VICE PRESIDENT ............................................................................................4 MESSAGE FROM THE HRPO …....................................................................................................5 MONTHLY OBSERVING NOTES ....................................................................................................6 OUTREACH CHAIRPERSON’S NOTES .........................................................................................13 MEMBERSHIP APPLICATION .......................................................................................................14 2 PRESIDENT'S MESSAGE Hi Everyone, I hope you’ve been having a great Summer so far and had luck beating the heat as much as possible. The weather sure hasn’t been cooperative for observing, though! First I have a pretty cool announcement. Thanks to the efforts of club member Walt Cooney, there are 5 newly named asteroids in the sky. (53256) Sinitiere - Named for former BRAS Treasurer Bob Sinitiere (74439) Brenden - Named for founding member Craig Brenden (85878) Guzik - Named for LSU professor T. Greg Guzik (101722) Pursell - Named for founding member Wally Pursell -
Discovery of a Pulsar Wind Nebula Candidate in the Cygnus Loop
Discovery of a Pulsar Wind Nebula Candidate in the Cygnus Loop 2 3 S Satoru Katsuda" Hiroshi Tsunemi , Koji Mori , Hiroyuki Uchida" Robert Petre , Shin'ya 1 Yamada , and Thru Tamagawa' ABSTRACT We report on a discovery of a diffuse nebula containing a pointlike source in the southern blowout region of the Cygnus Loop supernova remnant, based on Suzaku and XMM-Newton observations. The X-ray spectra from the nebula and the pointlike source are well represented by an absorbed power-law model with photon indices of 2.2±0.1 and 1.6±0.2, respectively. The photon indices as well as the flux ratio of F nebula/ F po;.,li" ~ 4 lead us to propose that the system is a pulsar wind nebula, although pulsations have not yet been detected. If we attribute its origin to the Cygnus Loop supernova, then the 0.5- 8 keY luminosity of the nebula is computed to be 2.1xlo"' (d/MOpc)2ergss-" where d is the distance to the Loop. This implies a spin-down loss-energy E ~ 2.6 X 1035 (d/MOpc)2ergss-'. The location of the neutron star candidate, ~2° away from the geometric center of the Loop, implies a high transverse velocity of ~ 1850(8/2D ) (d/540pc) (t/lOkyr)- ' kms-" assuming the currently accepted age of the Cygnus Loop. Subject headings: ISM: individual objects (Cygnus Loop) - ISM: supernova remnants - pulsars: general - stars: neutron - stars: winds, outflows - X-rays: ISM 'RlKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Sailama 351-0198 2Department of EaTth and Space Science, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Thyonaka, Osaka, 60-0043, Japan SDepartment of Applied Physics, Faculty of Engineering, University of Miyazaki, 1-1 Gakuen Klbana-dai Nishi, Miyazaki, 889-2192, Japan ' Department of PhysiCS, Kyoto University, Kitashirakawa-oiwake-clto, Sakyo, Kyoto 606-8502, J apan 'NASA Goddard Space Flight Center, Code 662, Greenbelt MD 20771 - 2 - 1. -
XMM-Newton Observation of the Northeastern Limb of the Cygnus Loop Supernova Remnant
XMM-Newton Observation of the Northeastern Limb of the Cygnus Loop Supernova Remnant Norbert Nemes Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan 04 February 2005 Osaka University Abstract We have observed the northeastern limb of the Cygnus Loop supernova remnant with the XMM-Newton observatory, as part of a 7-pointing campaign to map the remnant across its diameter. We performed medium sensitivity spatially resolved X-ray spectroscopy on the data in the 0.3-3.0 keV energy range, and for the first time we have detected C emission lines in our spectra. The background subtracted spectra were fitted with a single temperature absorbed non-equilibrium (VNEI) model. We created color maps and plotted the radial variation of the different parameters. We found that the heavy element abundances were depleted, but increase toward the edge of the remnant, exhibiting a jump structure near the northeastern edge of the field of view. The depletion suggests that the plasma in this region represents the shock heated ISM rather than the ejecta, while the radial increase of the elemental abundances seems to support the cavity explosion origin. The temperature decreases in the radial direction from 0:3keV to about 0:2keV , however, this ∼ ∼ decrease is not monotonic. There is a low temperature region in the part of the field of view closest to the center of the remnant, which is characterized by low abundances and high NH values. Another low temperature region characterized by low NH values but where the heavy element abundances suddenly jump to high values was found at the northeastern edge of the field of view. -
Winter Constellations
Winter Constellations *Orion *Canis Major *Monoceros *Canis Minor *Gemini *Auriga *Taurus *Eradinus *Lepus *Monoceros *Cancer *Lynx *Ursa Major *Ursa Minor *Draco *Camelopardalis *Cassiopeia *Cepheus *Andromeda *Perseus *Lacerta *Pegasus *Triangulum *Aries *Pisces *Cetus *Leo (rising) *Hydra (rising) *Canes Venatici (rising) Orion--Myth: Orion, the great hunter. In one myth, Orion boasted he would kill all the wild animals on the earth. But, the earth goddess Gaia, who was the protector of all animals, produced a gigantic scorpion, whose body was so heavily encased that Orion was unable to pierce through the armour, and was himself stung to death. His companion Artemis was greatly saddened and arranged for Orion to be immortalised among the stars. Scorpius, the scorpion, was placed on the opposite side of the sky so that Orion would never be hurt by it again. To this day, Orion is never seen in the sky at the same time as Scorpius. DSO’s ● ***M42 “Orion Nebula” (Neb) with Trapezium A stellar nursery where new stars are being born, perhaps a thousand stars. These are immense clouds of interstellar gas and dust collapse inward to form stars, mainly of ionized hydrogen which gives off the red glow so dominant, and also ionized greenish oxygen gas. The youngest stars may be less than 300,000 years old, even as young as 10,000 years old (compared to the Sun, 4.6 billion years old). 1300 ly. 1 ● *M43--(Neb) “De Marin’s Nebula” The star-forming “comma-shaped” region connected to the Orion Nebula. ● *M78--(Neb) Hard to see. A star-forming region connected to the Orion Nebula. -
Pos(MULTIF15)020 Al
Suzaku Highlights of Supernova Remnants PoS(MULTIF15)020 Satoru Katsuda∗† Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa 252-5210, Japan E-mail: [email protected] Hiroshi Tsunemi Department of Earth and Space Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan E-mail: [email protected] Suzaku was the Japanese 5th X-ray astronomy satellite operated from 2005 July 10 to 2015 Au- gust 26. Its key features are high-sensitivity wide-band X-ray spectroscopy available with both the X-ray imaging CCD cameras and the non-imaging collimated hard X-ray detector. A number of interesting scientific discoveries have been achieved in various fields. Among them, I will focus on results on supernova remnants. The topics in this paper include (1) revealing distributions of supernova ejecta, (2) establishing over-ionized plasmas by discoveries of radiative-recombination continua, (3) constraining progenitors of Type Ia SNRs from Mn/Cr and Ni/Fe line ratios, and (4) searching for X-ray counterparts from unidentified HESS sources. These results are of high sci- entific importance in physics of supernova explosions, non-equilibrium plasmas, and cosmic-ray acceleration. XI Multifrequency Behaviour of High Energy Cosmic Sources Workshop, 25-30 May 2015 Palermo, Italy ∗Speaker. †A footnote may follow. © c CopyrightCopyright owned owned by the author(s) under the terms of the Creative Creative Commons License Attribution-NonCommercial 4.0 International. http://pos.sissa.it/ Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). -
Exploration of the Moon
Exploration of the Moon The physical exploration of the Moon began when Luna 2, a space probe launched by the Soviet Union, made an impact on the surface of the Moon on September 14, 1959. Prior to that the only available means of exploration had been observation from Earth. The invention of the optical telescope brought about the first leap in the quality of lunar observations. Galileo Galilei is generally credited as the first person to use a telescope for astronomical purposes; having made his own telescope in 1609, the mountains and craters on the lunar surface were among his first observations using it. NASA's Apollo program was the first, and to date only, mission to successfully land humans on the Moon, which it did six times. The first landing took place in 1969, when astronauts placed scientific instruments and returnedlunar samples to Earth. Apollo 12 Lunar Module Intrepid prepares to descend towards the surface of the Moon. NASA photo. Contents Early history Space race Recent exploration Plans Past and future lunar missions See also References External links Early history The ancient Greek philosopher Anaxagoras (d. 428 BC) reasoned that the Sun and Moon were both giant spherical rocks, and that the latter reflected the light of the former. His non-religious view of the heavens was one cause for his imprisonment and eventual exile.[1] In his little book On the Face in the Moon's Orb, Plutarch suggested that the Moon had deep recesses in which the light of the Sun did not reach and that the spots are nothing but the shadows of rivers or deep chasms. -
2012 年發表 53 篇 1. Chang,Chan-Kao , Lai,Shao-Yu
2012 年發表 53 篇 1. Chang,Chan-Kao , Lai,Shao-Yu , Ko,Chung-Ming, et al. , Information on the Milky Way from the 2MASS All Sky Star Count: Bimodal Color Distributions ,The Astrophysical Journal, Volume 759, Issue 2, 94, 10 p..( 2012) 2. Chen,W.P. , Hu,S.C.-L. , Errmann,R., et al. , A Possible Detection of Occultation by a Proto-planetary Clump in GM Cephei ,The Astrophysical Journal, Volume 751, Issue 2, 118, 5 p..( 2012) 3. Hwang,Chorng-Yuan , Tsai,Mengchun, Star Formation in the Central Kiloparsec of Nearby Active Galaxies ,Journal of Physics: Conference Series, Volume 372, Issue 1, id. 0120..( 2012) 4. Ip, W.-H., ENA diagnostics of auroral activity at Mars ,Planetary and Space Science, v. 63, pp. 83, (2012) 5. J.M. Nester and C.-H. Wang, Can torsion be treated as just another tensor field? ,International Journal of Modern Physics: Conference Series, v. 7, pp. 158, (2012) 6. Lee, C.-H., Riffeser, A., Koppenhoefer, J., et al., PAndromeda?First Results from the High-cadence Monitoring of M31 with Pan-STARRS 1 ,The Astronomical Journal, Volume 143, Issue 4, article id. 89, 16 pp. (2012) 7. Lin, Z.-Y., Lara, L. M., Vincent, J. B., and Ip, W.-H., Physical studies of 81P/Wild 2 from the last two apparitions ,Astronomy and Astrophysics, v. 537, pp. A101, (2012) 8. Ngeow, C.-C., On the Application of Wesenheit Function in Deriving Distance to Galactic Cepheids ,The Astrophysical Journal, v. 747, pp. 50, (2012) 9. Ngeow, C.-C., Kanbur, S. M., Bellinger, E. P., et al., Period- luminosity relations for Cepheid variables: from mid-infrared to multi- phase, Astrophysics and Space Science, v. -
Apparent and Absolute Magnitudes of Stars: a Simple Formula
Available online at www.worldscientificnews.com WSN 96 (2018) 120-133 EISSN 2392-2192 Apparent and Absolute Magnitudes of Stars: A Simple Formula Dulli Chandra Agrawal Department of Farm Engineering, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi - 221005, India E-mail address: [email protected] ABSTRACT An empirical formula for estimating the apparent and absolute magnitudes of stars in terms of the parameters radius, distance and temperature is proposed for the first time for the benefit of the students. This reproduces successfully not only the magnitudes of solo stars having spherical shape and uniform photosphere temperature but the corresponding Hertzsprung-Russell plot demonstrates the main sequence, giants, super-giants and white dwarf classification also. Keywords: Stars, apparent magnitude, absolute magnitude, empirical formula, Hertzsprung-Russell diagram 1. INTRODUCTION The visible brightness of a star is expressed in terms of its apparent magnitude [1] as well as absolute magnitude [2]; the absolute magnitude is in fact the apparent magnitude while it is observed from a distance of . The apparent magnitude of a celestial object having flux in the visible band is expressed as [1, 3, 4] ( ) (1) ( Received 14 March 2018; Accepted 31 March 2018; Date of Publication 01 April 2018 ) World Scientific News 96 (2018) 120-133 Here is the reference luminous flux per unit area in the same band such as that of star Vega having apparent magnitude almost zero. Here the flux is the magnitude of starlight the Earth intercepts in a direction normal to the incidence over an area of one square meter. The condition that the Earth intercepts in the direction normal to the incidence is normally fulfilled for stars which are far away from the Earth. -
Hubble Revisits the Veil Nebula 2 April 2021
Image: Hubble revisits the Veil Nebula 2 April 2021 this stellar violence, the shockwaves and debris from the supernova sculpted the Veil Nebula's delicate tracery of ionized gas—creating a scene of surprising astronomical beauty. The Veil Nebula is also featured in Hubble's Caldwell Catalog, a collection of astronomical objects that have been imaged by Hubble and are visible to amateur astronomers in the night sky. Provided by NASA Credit: ESA/Hubble & NASA, Z. Levay This image taken by the NASA/ESA Hubble Space Telescope revisits the Veil Nebula, which was featured in a previous Hubble image release. In this image, new processing techniques have been applied, bringing out fine details of the nebula's delicate threads and filaments of ionized gas. To create this colorful image, observations were taken by Hubble's Wide Field Camera 3 instrument using five different filters. The new post-processing methods have further enhanced details of emissions from doubly ionized oxygen (seen here in blues), ionized hydrogen, and ionized nitrogen (seen here in reds). The Veil Nebula lies around 2,100 light-years from Earth in the constellation of Cygnus (the Swan), making it a relatively close neighbor in astronomical terms. Only a small portion of the nebula was captured in this image. The Veil Nebula is the visible portion of the nearby Cygnus Loop, a supernova remnant formed roughly 10,000 years ago by the death of a massive star. That star—which was 20 times the mass of the Sun—lived fast and died young, ending its life in a cataclysmic release of energy. -
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). -
Eyes Skies Full En.Pdf
1 00:00:05,240 --> 00:00:08,800 By taking our sense of sight far beyond the realm of our forebears' 2 00:00:08,880 --> 00:00:13,200 imagination, these wonderful instruments, the telescopes, open the way to 3 00:00:13,280 --> 00:00:17,240 a deeper and more perfect understanding of nature. - René Descartes, 1637 4 00:00:17,720 --> 00:00:22,520 For millennia mankind gazed out into the mesmerising night sky 5 00:00:22,600 --> 00:00:28,320 without recognising the stars of our own Milky Way Galaxy as other suns 6 00:00:28,400 --> 00:00:33,400 or the billions of sister galaxies making up the rest of our Universe 7 00:00:35,440 --> 00:00:38,760 or that we are merely punctuation in the Universe’s 8 00:00:38,840 --> 00:00:42,480 13.7 billion year-long story. 9 00:00:42,560 --> 00:00:46,080 With only our eyes as observing tools we had no means of 10 00:00:46,160 --> 00:00:50,120 finding solar systems around other stars, or of determining 11 00:00:50,200 --> 00:00:55,000 whether life exists elsewhere in the Universe. 12 00:00:58,080 --> 00:01:00,320 Today we are well on our way to unravelling many of the 13 00:01:00,400 --> 00:01:03,520 mysteries of the Universe, living in what may be the most remarkable 14 00:01:03,600 --> 00:01:05,920 age of astronomical discovery.