Analysis of 70 Ophiuchi AB Including Seismic Constraints
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Catching up with Barnard's Star. Dave Eagle Within the Constellation Of
Catching Up with Barnard’s Star. Dave Eagle Within the constellation of Ophiuchus lies Barnard’s Star. It is a fairly faint red dwarf star of magnitude 9.53, six light years from Earth, so is fairly close to us. Its luminosity is 1/2,500th that of the Sun and 16% its mass. The diameter is estimated at about 140,000 miles, so it’s quite a small, faint star and well below naked eye visibility. So why is this star so well known? In 1916 Edward Barnard looked at a photographic plate of the area. When he compared this to a similar plate made in 1894, he noticed that one of the stars had moved between the time of the two plates being taken. Although all the stars in the sky in reality are all moving quite fast, from our remote vantage point on Earth most stars appear to appear virtually static during our lifetime as their apparent motion is extremely small. Barnard’s star, being so close and moving so fast, is one of the stars that bucks this trend. So fast indeed that it will subtend the apparent diameter equivalent to the Moon or Sun in about 176 years. So compared to other stars it is really shifting. The star is travelling at 103 miles per second and is approaching us at about 87 miles per second. In about 8,000 years it will become the closest star to us, at just under 4 light years and will have brightened to magnitude 8.6. Peter van de Camp caused great excitement in the 1960’s when he claimed to have discovered a planet (or more) around the star, due to wobbles superimposed on its movement. -
100 Closest Stars Designation R.A
100 closest stars Designation R.A. Dec. Mag. Common Name 1 Gliese+Jahreis 551 14h30m –62°40’ 11.09 Proxima Centauri Gliese+Jahreis 559 14h40m –60°50’ 0.01, 1.34 Alpha Centauri A,B 2 Gliese+Jahreis 699 17h58m 4°42’ 9.53 Barnard’s Star 3 Gliese+Jahreis 406 10h56m 7°01’ 13.44 Wolf 359 4 Gliese+Jahreis 411 11h03m 35°58’ 7.47 Lalande 21185 5 Gliese+Jahreis 244 6h45m –16°49’ -1.43, 8.44 Sirius A,B 6 Gliese+Jahreis 65 1h39m –17°57’ 12.54, 12.99 BL Ceti, UV Ceti 7 Gliese+Jahreis 729 18h50m –23°50’ 10.43 Ross 154 8 Gliese+Jahreis 905 23h45m 44°11’ 12.29 Ross 248 9 Gliese+Jahreis 144 3h33m –9°28’ 3.73 Epsilon Eridani 10 Gliese+Jahreis 887 23h06m –35°51’ 7.34 Lacaille 9352 11 Gliese+Jahreis 447 11h48m 0°48’ 11.13 Ross 128 12 Gliese+Jahreis 866 22h39m –15°18’ 13.33, 13.27, 14.03 EZ Aquarii A,B,C 13 Gliese+Jahreis 280 7h39m 5°14’ 10.7 Procyon A,B 14 Gliese+Jahreis 820 21h07m 38°45’ 5.21, 6.03 61 Cygni A,B 15 Gliese+Jahreis 725 18h43m 59°38’ 8.90, 9.69 16 Gliese+Jahreis 15 0h18m 44°01’ 8.08, 11.06 GX Andromedae, GQ Andromedae 17 Gliese+Jahreis 845 22h03m –56°47’ 4.69 Epsilon Indi A,B,C 18 Gliese+Jahreis 1111 8h30m 26°47’ 14.78 DX Cancri 19 Gliese+Jahreis 71 1h44m –15°56’ 3.49 Tau Ceti 20 Gliese+Jahreis 1061 3h36m –44°31’ 13.09 21 Gliese+Jahreis 54.1 1h13m –17°00’ 12.02 YZ Ceti 22 Gliese+Jahreis 273 7h27m 5°14’ 9.86 Luyten’s Star 23 SO 0253+1652 2h53m 16°53’ 15.14 24 SCR 1845-6357 18h45m –63°58’ 17.40J 25 Gliese+Jahreis 191 5h12m –45°01’ 8.84 Kapteyn’s Star 26 Gliese+Jahreis 825 21h17m –38°52’ 6.67 AX Microscopii 27 Gliese+Jahreis 860 22h28m 57°42’ 9.79, -
August 13 2016 7:00Pm at the Herrett Center for Arts & Science College of Southern Idaho
Snake River Skies The Newsletter of the Magic Valley Astronomical Society www.mvastro.org Membership Meeting President’s Message Saturday, August 13th 2016 7:00pm at the Herrett Center for Arts & Science College of Southern Idaho. Public Star Party Follows at the Colleagues, Centennial Observatory Club Officers It's that time of year: The City of Rocks Star Party. Set for Friday, Aug. 5th, and Saturday, Aug. 6th, the event is the gem of the MVAS year. As we've done every Robert Mayer, President year, we will hold solar viewing at the Smoky Mountain Campground, followed by a [email protected] potluck there at the campground. Again, MVAS will provide the main course and 208-312-1203 beverages. Paul McClain, Vice President After the potluck, the party moves over to the corral by the bunkhouse over at [email protected] Castle Rocks, with deep sky viewing beginning sometime after 9 p.m. This is a chance to dig into some of the darkest skies in the west. Gary Leavitt, Secretary [email protected] Some members have already reserved campsites, but for those who are thinking of 208-731-7476 dropping by at the last minute, we have room for you at the bunkhouse, and would love to have to come by. Jim Tubbs, Treasurer / ALCOR [email protected] The following Saturday will be the regular MVAS meeting. Please check E-mail or 208-404-2999 Facebook for updates on our guest speaker that day. David Olsen, Newsletter Editor Until then, clear views, [email protected] Robert Mayer Rick Widmer, Webmaster [email protected] Magic Valley Astronomical Society is a member of the Astronomical League M-51 imaged by Rick Widmer & Ken Thomason Herrett Telescope Shotwell Camera https://herrett.csi.edu/astronomy/observatory/City_of_Rocks_Star_Party_2016.asp Calendars for August Sun Mon Tue Wed Thu Fri Sat 1 2 3 4 5 6 New Moon City Rocks City Rocks Lunation 1158 Castle Rocks Castle Rocks Star Party Star Party Almo, ID Almo, ID 7 8 9 10 11 12 13 MVAS General Mtg. -
The Denver Observer July 2018
The Denver JULY 2018 OBSERVER The globular cluster, Messier 19, one of this month’s targets in “July Skies,” in a Hubble Space Telescope image. Credit: NASA, ESA, STScI and I. King (Univer- sity of California – Berkeley) JULY SKIES by Zachary Singer The Solar System ’scopes towards the planets when they’re Sky Calendar The big news for July is that Mars comes highest in the sky on a given night, to get the 6 Last-Quarter Moon to opposition on the 27th, meaning that it sharpest image—but Mars is worth viewing 12 New Moon will be at its highest in the south on that date naked-eye when it’s rising. Surprised? The 19 First-Quarter Moon around 1 AM, and also more or less at its red (well, orange) planet appears even redder 27 Full Moon largest as seen from Earth. Now, don’t let that when rising, making for much deeper color. fool you—Mars is already very good as July It’s a guilty pleasure on an aesthetic level, if begins, showing a disk 21” across, which is not a scientific one. If you want to indulge better than we got two years ago, and only yourself, Mars rises around 10:30 PM at In the Observer slightly smaller than the 24” expected at the beginning of July, an hour earlier mid- the end of the month. (Observations in my month, and about 8:20 PM at month’s end. President’s Message . .2 6-inch reflector at the end of June showed an Meanwhile, Mercury is an evening Society Directory. -
The Future of Space Imaging
The FutureofSpaceImaging The Future of Space Imaging Report of a Community-Based Study of an Advanced Camera for the Hubble Space Telescope hen Lyman Spitzer first proposed a great, W earth-orbiting telescope in , the nuclear energy source of stars had been known for just six years. Knowledge of galaxies beyond our own and the understanding that our universe is expanding were only about twenty years of age in the human consciousness. The planet Pluto was seventeen. Quasars, black holes, gravitational lenses, and detection of the Big Bang were still in the future—together with much of what constitutes our current understanding of the solar system and the cos- mos beyond it. In , forty-seven years after it was conceived in a for- gotten milieu of thought, the Hubble Space Telescope is a reality. Today, the science of the Hubble attests to the forward momentum of astronomical exploration from ancient times. The qualities of motion and drive for knowledge it exemplifies are not fixed in an epoch or a gen- eration: most of the astronomers using Hubble today were not born when the idea of it was first advanced, and many were in the early stages of their education when the glass for its mirror was cast. The commitments we make today to the fu- ture of the Hubble observatory will equip a new generation of young men and women to explore the astronomical frontier at the start of the st century. 1 2 3 4 5 6 7 8 9 FRONT & BACK COVER 1.Globular clusters containing young stars at the core of elliptical galaxy NGC 1275. -
The Interstellar Medium --- HW060227
Introduction to Astronomy HW150312 due in one week 1. (a) Estimate how many kilograms of hydrogen the Sun has consumed over the past 4.56 billion years, and estimate the amount of mass that the Sun has lost as a result. Assume that the Sun’s luminosity has remained the same during the time. (b) In fact, however, the Sun’s luminosity when it first formed was only about 70% of its present value (the “faint young sun paradox”). With this in mind, explain whether your answers are an overestimate or an underestimate. 2. How far away is a star that has a proper motion of 0.08 arcseconds per year and a tangential velocity (proper motion) of 40 km/s? For a star at this distance, what would its tangential velocity have to be in order for it to exhibit the same proper motion as Barnard’s star? 3. The visual binary 70 Ophiuchi has a period of 87.7 years. The parallax of 70 Ophiuchi is 0.2 arcseconds, and the apparent length of the semimajor axis as seen through a telescope is 4.5 arcsec. (a) What is the distance to 70 Ophiuchi in parsecs? (b) What is the actual length of the semimajor axis in AU? (c) What is the sum of the masses of the two stars in solar masses? 4. Search the World Wide Web for information about Gaia, a European Space Agency (ESA) spacecraft meant to extend the work carried out by Hipparcos. What is the status of Gaia? What is the main mission of Gaia? How does it compare to Hipparcos in terms of performance? What other types of research is it supposed to carry out? 5. -
Cycle 20 Abstract Catalog (Based on Phase I Submissions)
Cycle 20 Abstract Catalog (Based on Phase I Submissions) Proposal Category: AR Scientific Category: STAR FORMATION ID: 12814 Program Title: Signatures of turbulence in directly imaged protoplanetary disks Principal Investigator: Philip Armitage PI Institution: University of Colorado at Boulder HST imaging of the edge-on protoplanetary disk in the HH 30 system has shown that substantial changes to the morphology of the disk occur on time scales much shorter than the local dynamical time. This may be due to time- variable obscuration of starlight by the turbulent inner disk. More recently, mid-infrared variability of protoplanetary disks has been attributed to a similar physical origin. We propose a theoretical investigation that will establish whether the optical and infrared variability is due to turbulent variations in the scale height of dust in the inner disk, and determine what observations of that variability can tell us of the nature of disk turbulence. We will use a new generation of global magnetohydrodynamic simulations to directly model the turbulence in an annulus of the inner disk, extending from the dust destruction radius out to the radius where turbulence is quenched by poor coupling of the gas to magnetic fields. We will use the output of the MHD simulations as input to Monte Carlo radiative transfer calculations of stellar irradiation of the outer disk. We will use these calculations to produce light curves that show how time variable shadowing from the inner disk affects the outer disk observables: scattered light images and the infrared spectral energy distribution. Proposal Category: GO Scientific Category: COOL STARS ID: 12815 Program Title: Photometry of the Coldest Benchmark Brown Dwarf Principal Investigator: Kevin Luhman PI Institution: The Pennsylvania State University In 2011, we used images from the Spitzer Space Telescope to discover the coldest directly imaged companion to a nearby star (300-345 K). -
Astronomy 2009 Index
Astronomy Magazine 2009 Index Subject Index 1RXS J160929.1-210524 (star), 1:24 4C 60.07 (galaxy pair), 2:24 6dFGS (Six Degree Field Galaxy Survey), 8:18 21-centimeter (neutral hydrogen) tomography, 12:10 93 Minerva (asteroid), 12:18 2008 TC3 (asteroid), 1:24 2009 FH (asteroid), 7:19 A Abell 21 (Medusa Nebula), 3:70 Abell 1656 (Coma galaxy cluster), 3:8–9, 6:16 Allen Telescope Array (ATA) radio telescope, 12:10 ALMA (Atacama Large Millimeter/sub-millimeter Array), 4:21, 9:19 Alpha (α) Canis Majoris (Sirius) (star), 2:68, 10:77 Alpha (α) Orionis (star). See Betelgeuse (Alpha [α] Orionis) (star) Alpha Centauri (star), 2:78 amateur astronomy, 10:18, 11:48–53, 12:19, 56 Andromeda Galaxy (M31) merging with Milky Way, 3:51 midpoint between Milky Way Galaxy and, 1:62–63 ultraviolet images of, 12:22 Antarctic Neumayer Station III, 6:19 Anthe (moon of Saturn), 1:21 Aperture Spherical Telescope (FAST), 4:24 APEX (Atacama Pathfinder Experiment) radio telescope, 3:19 Apollo missions, 8:19 AR11005 (sunspot group), 11:79 Arches Cluster, 10:22 Ares launch system, 1:37, 3:19, 9:19 Ariane 5 rocket, 4:21 Arianespace SA, 4:21 Armstrong, Neil A., 2:20 Arp 147 (galaxy pair), 2:20 Arp 194 (galaxy group), 8:21 art, cosmology-inspired, 5:10 ASPERA (Astroparticle European Research Area), 1:26 asteroids. See also names of specific asteroids binary, 1:32–33 close approach to Earth, 6:22, 7:19 collision with Jupiter, 11:20 collisions with Earth, 1:24 composition of, 10:55 discovery of, 5:21 effect of environment on surface of, 8:22 measuring distant, 6:23 moons orbiting, -
The Detectability of Nightside City Lights on Exoplanets
Draft version September 6, 2021 Typeset using LATEX twocolumn style in AASTeX63 The Detectability of Nightside City Lights on Exoplanets Thomas G. Beatty1 1Department of Astronomy and Steward Observatory, University of Arizona, Tucson, AZ 85721; [email protected] ABSTRACT Next-generation missions designed to detect biosignatures on exoplanets will also be capable of plac- ing constraints on the presence of technosignatures (evidence for technological life) on these same worlds. Here, I estimate the detectability of nightside city lights on habitable, Earth-like, exoplan- ets around nearby stars using direct-imaging observations from the proposed LUVOIR and HabEx observatories. I use data from the Soumi National Polar-orbiting Partnership satellite to determine the surface flux from city lights at the top of Earth's atmosphere, and the spectra of commercially available high-power lamps to model the spectral energy distribution of the city lights. I consider how the detectability scales with urbanization fraction: from Earth's value of 0.05%, up to the limiting case of an ecumenopolis { or planet-wide city. I then calculate the minimum detectable urbanization fraction using 300 hours of observing time for generic Earth-analogs around stars within 8 pc of the Sun, and for nearby known potentially habitable planets. Though Earth itself would not be detectable by LUVOIR or HabEx, planets around M-dwarfs close to the Sun would show detectable signals from city lights for urbanization levels of 0.4% to 3%, while city lights on planets around nearby Sun-like stars would be detectable at urbanization levels of & 10%. The known planet Proxima b is a particu- larly compelling target for LUVOIR A observations, which would be able to detect city lights twelve times that of Earth in 300 hours, an urbanization level that is expected to occur on Earth around the mid-22nd-century. -
Meeting Abstracts
228th AAS San Diego, CA – June, 2016 Meeting Abstracts Session Table of Contents 100 – Welcome Address by AAS President Photoionized Plasmas, Tim Kallman (NASA 301 – The Polarization of the Cosmic Meg Urry GSFC) Microwave Background: Current Status and 101 – Kavli Foundation Lecture: Observation 201 – Extrasolar Planets: Atmospheres Future Prospects of Gravitational Waves, Gabriela Gonzalez 202 – Evolution of Galaxies 302 – Bridging Laboratory & Astrophysics: (LIGO) 203 – Bridging Laboratory & Astrophysics: Atomic Physics in X-rays 102 – The NASA K2 Mission Molecules in the mm II 303 – The Limits of Scientific Cosmology: 103 – Galaxies Big and Small 204 – The Limits of Scientific Cosmology: Town Hall 104 – Bridging Laboratory & Astrophysics: Setting the Stage 304 – Star Formation in a Range of Dust & Ices in the mm and X-rays 205 – Small Telescope Research Environments 105 – College Astronomy Education: Communities of Practice: Research Areas 305 – Plenary Talk: From the First Stars and Research, Resources, and Getting Involved Suitable for Small Telescopes Galaxies to the Epoch of Reionization: 20 106 – Small Telescope Research 206 – Plenary Talk: APOGEE: The New View Years of Computational Progress, Michael Communities of Practice: Pro-Am of the Milky Way -- Large Scale Galactic Norman (UC San Diego) Communities of Practice Structure, Jo Bovy (University of Toronto) 308 – Star Formation, Associations, and 107 – Plenary Talk: From Space Archeology 208 – Classification and Properties of Young Stellar Objects in the Milky Way to Serving -
Arxiv:2103.10894V1 [Astro-Ph.GA] 19 Mar 2021 Astronomical Distances Since It Represents the first Rung of the Extragalactic Distance Ladder
Draft version March 22, 2021 Typeset using LATEX twocolumn style in AASTeX63 The influence of metallicity on the Leavitt Law from geometrical distances of Milky Way and Magellanic Clouds Cepheids Louise Breuval,1 Pierre Kervella,1 Piotr Wielgorski´ ,2 Wolfgang Gieren,3 Dariusz Graczyk,4 Boris Trahin,1 Grzegorz Pietrzynski´ ,2 Fred´ eric´ Arenou,5 Behnam Javanmardi,1 and Bart lomiejZgirski2 1LESIA, Observatoire de Paris, Universit´ePSL, CNRS, Sorbonne Universit´e,Universit´ede Paris, 5 place Jules Janssen, 92195 Meudon, France 2Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, Bartycka 18, 00-716 Warszawa, Poland 3Universidad de Concepci´on,Departamento de Astronom´ıa,Casilla 160-C, Concepci´on,Chile 4Centrum Astronomiczne im. Mikolaja Kopernika, Polish Academy of Sciences, Rabia´nska8, 87-100, Toru´n,Poland 5GEPI, Observatoire de Paris, Universit´ePSL, CNRS, 5 place Jules Janssen, 92190 Meudon, France (Received 29 January 2021; Revised 12 March 2021; Accepted 18 March 2021) Submitted to ApJ ABSTRACT The Cepheid Period-Luminosity (PL) relation is the key tool for measuring astronomical distances and for establishing the extragalactic distance scale. In particular, the local value of the Hubble constant (H0) strongly depends on Cepheid distance measurements. The recent Gaia Data Releases and other parallax measurements from the Hubble Space Telescope (HST) already enabled to improve the accuracy of the slope (α) and intercept (β) of the PL relation. However, the dependence of this law on metallicity is still largely debated. In this paper, we combine three samples of Cepheids in the Milky Way (MW), the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC) in order to derive the metallicity term (hereafter γ) of the PL relation. -
70 Ophiuchi – Realm of Orange Suns
STAR OF THE MONTH 70 Ophiuchi – Realm of Orange Suns by Steven C. Raine here is darkness of a perfect night sky all around be a separate constellation by the Arabians, judging by a except for an orange glow coming from twin spheres 13th century globe “now resting in the Borgian museum at T of light like sun-sized mandarins. The effect is Villetri.” (Motz & Nathanson, 1991.) almost like streetlights hidden in the dark and blurred to The nearness to our Sun is however only a small part of roundness by thick fog. Yet from here stars are visible this star’s renown, for 70 Ophiuchi is best known as a binary everywhere and not the stars of home although surprisingly star system. As you can see from Figure 2, the two stars similar. A clue to the location is the way the stars nearest orbit their shared centre of gravity—the barycentre—in 88 our own Sun have shifted, Sirius, Procyon and Alpha years. An orbital period which Dole notes is “almost identi- Centauri the most notably displaced and altered in radiance. cal with … Alpha Centauri A and Alpha Centauri B.” The Towards Orion is an unfamiliar star of third magnitude primary star 70 Ophiuchi A is a K1 type main sequence which happens to be a G2 type star—the Sun of humanity star with an absolute magnitude of +5.8 and the secondary (Dole, 1964). This is the environs near 70 Ophiuchi, a binary star 70 Ophiuchi B is another orange dwarf but somewhat star located amongst the closest of our celestial neighbours fainter with an absolute magnitude of +7.3 and a spectral a meagre 16.5 light years away.