DOCSLIB.ORG

Absolute Dimensions of the Unevolved F-Type Eclipsing Binary BT Vulpeculae

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Absolute Dimensions of the Unevolved F-Type Eclipsing Binary BT Vulpeculae Accepted for publication in The Astrophysical Journal A Preprint typeset using LTEX style emulateapj v. 12/16/11 ABSOLUTE DIMENSIONS OF THE UNEVOLVED F-TYPE ECLIPSING BINARY BT VULPECULAE Guillermo Torres1, Claud H. Sandberg Lacy2, Francis C. Fekel3, and Matthew W. Muterspaugh4,5 Accepted for publication in The Astrophysical Journal ABSTRACT We report extensive differential V -band photometry and high-resolution spectroscopy for the 1.14 day, detached, double-lined eclipsing binary BT Vul (F0+F7). Our radial-velocity monitoring and light N curve analysis lead to absolute masses and radii of M1 = 1.5439 ± 0.0098 M⊙ and R1 = 1.536 ± N N N 0.018 R⊙ for the primary, and M2 = 1.2196 ± 0.0080 M⊙ and R2 = 1.151 ± 0.029 R⊙ for the secondary. The effective temperatures are 7270±150 K and 6260±180 K, respectively. Both stars are rapid rotators, and the orbit is circular. A comparison with stellar evolution models from the MIST series shows excellent agreement with these determinations, for a composition of [Fe/H] = +0.08 and an age of 350 Myr. The two components of BT Vul are very near the zero-age main sequence. 1. INTRODUCTION Table 1 The discovery of the photometric variability of Times of Minimum Light for BT Vul BT Vul (HD 340072, TYC 2164-161-1, Gaia DR2 1836032243422750464; V = 11.49, SpT F0+F7) was HJD σ O − C made by S. Beljawsky (see Guthnick & Schneller 1939), (2,400,000+) Year Epoch (days) (days) Ecl Type although the original period given (3.988 days) was in- 34740.28 1953.9912 −16421.0 0.0063 +0.004269 1 PG correct. Other than measurements of the times of eclipse 35402.18 1955.8034 −15841.0 0.0063 +0.007879 1 PG since its discovery, no detailed studies of this short-period 43351.786 1977.5682 −8875.0 0.0100 +0.009984 1 V 43779.735 1978.7399 −8500.0 0.0100 +0.008731 1 V system (P =1.14 days) have appeared in the literature. 44022.812 1979.4054 −8287.0 0.0100 +0.009988 1 V In this paper we report the first systematic photometric and spectroscopic monitoring of the binary, leading to a Note. — ‘Ecl’ is 1 for the primary and 2 for the secondary minimum; ‘Type’ is PG, V, and PE for the photographic, visual, full determination of its physical properties. and photoelectric/CCD techniques. The ‘Epoch’ is counted from Section 2 presents our observations, beginning in the reference time of primary minimum in this section. For Section 2.1 with a determination of a highly precise measurements with published uncertainties the errors reported here have been multiplied by scale factors of 3.35 and 2.75 for ephemeris based on more than six decades of timing ob- the photoelectric timings of the primary and secondary minima servations. Section 2.2 then reports our spectroscopic (see text), and scale factors of 4.35 and 1.28 for the visual observations of BT Vul, with the derivation of the radial observations. Measurements with no published errors have been velocities and spectroscopic orbital elements. Our exten- assigned values of 0.0063 days, 0.010 days, and 0.0058 days for the photographic, visual, and photoelectric techniques, respec- sive photometric V -band measurements are described in tively. Sources for the individual measurements are listed at Section 2.3. The analysis of the lightcurves is found in http://var2.astro.cz/EN/brno/eclipsing_binaries.php and Section 3, and is followed in Section 4 by a determina- https://www.bav-astro.eu/index.php/veroeffentlichungen/ tion of the absolute dimensions of the system, and in service-for-scientists/lkdb-engl. (This table is available in Section 5 with a comparison of the physical properties its entirety in machine-readable form.) with current models of stellar evolution. Final remarks tial photometric observations we describe in this paper. appear in Section 6. A linear ephemeris was derived by weighted least squares, in which the published uncertainties, when avail- 2. OBSERVATIONS able, were scaled in order to achieve reduced χ2 values 2.1. Eclipse timings near unity for each type of eclipse and each type of obser- arXiv:2004.00022v1 [astro-ph.SR] 31 Mar 2020 vation. For measurements with no reported uncertainties Times of minimum light have been gathered for BT Vul since 1953 using photographic, visual, and photoelec- we adopted suitable values to the same end (see Table 1). tric/CCD techniques. The available measurements are The linear ephemeris obtained is: collected in Table 1, which contains 115 timings for the Min I(HJD) = 2,453,479.931997(92)+1.141200674(50)E, primary minimum and 40 for the secondary over more than 65 years. Many of them are based on the differen- with the uncertainties indicated in parentheses. Indepen- dent periods determined from the primary and secondary 1 Center for Astrophysics | Harvard & Smithsonian, 60 Garden minima do not differ significantly. A solution allowing for Street, Cambridge, MA 02138, USA; [email protected] separate reference times of primary and secondary min- 2 Physics Department, University of Arkansas, Fayetteville, ima resulted in a phase difference of 0.49987 ± 0.00014, AR 72701, USA 3 Center of Excellence in Information Systems, Tennessee suggesting negligible eccentricity. For the rest of this State University, Nashville, TN 37209, USA work we have therefore assumed the orbit to be circular. 4 Fairborn Observatory, 1327 Duquesne Rd, Patagonia, AZ 85624 2.2. Spectroscopy 5 Current address: Division of Science, Technology, and Math- ematics, Columbia State Community College, 1665 Hampshire Spectroscopic monitoring of BT Vul was carried out Pike, Columbia, TN 38401 at two facilities. Observations at the Center for As- 2 Torres et al. Table 2 Table 3 CfA Radial Velocities for BT Vul Fairborn Radial Velocities for BT Vul HJD RV1 RV2 σ1 σ2 Orbital HJD RV1 RV2 Orbital (2,400,000+) (km s−1) (km s−1) (km s−1) (km s−1) Phase (2,400,000+) (km s−1) (km s−1) Phase 55368.9509 −139.96 136.65 4.56 4.60 0.29074 55867.7441 −115.7 97.0 0.36829 55527.5607 −142.87 135.21 3.54 3.57 0.27576 56010.9947 53.1 −122.1 0.89451 55850.5866 −129.49 121.77 2.50 2.52 0.33369 56023.9539 −151.9 136.7 0.25027 55903.5554 103.22 −177.41 3.99 4.02 0.74866 56058.9383 53.5 −107.2 0.90605 56024.0077 −143.75 133.62 1.86 1.87 0.29741 56060.8952 67.2 −129.2 0.62082 Note. — Orbital phases are counted from the reference time of Note. — Typical uncertainties for the ve- primary eclipse. (This table is available in its entirety in machine- locities are 3.0 km s−1 for the primary and readable form.) 3.4 km s−1 for the secondary. Orbital phases are counted from the reference time of primary trophysics (CfA) began in June of 2010 and contin- eclipse. (This table is available in its entirety ued until October of 2015. They were made with in machine-readable form.) the Tillinghast Reflector Echelle Spectrograph (TRES; Szentgyorgyi & F˝ur´esz 2007; F˝ur´esz 2008), a fiber-fed, the temperatures, and 70/55 kms−1 for the rotational bench-mounted instrument attached to the 1.5m Tilling- broadening. hast reflector at the Fred L. Whipple Observatory on Previous experience at CfA has shown that the raw Mount Hopkins (Arizona, USA). A total of 39 spectra radial velocities can sometimes be affected by systematic were gathered at a resolving power of R ≈ 44,000, and errors that may arise due to lines shifting in and out cover the wavelength region 3800–9100 A˚ in 51 orders. of the spectral window as a function of orbital phase, For the order centered at ∼5187 A,˚ which contains the or due to the barycentric velocity of the Earth (see Mg I b triplet, the signal-to-noise ratios range from 24 to Latham et al. 1996; Torres et al. 1997). Following these 65 per resolution element of 6.8 km s−1. The wavelength authors we applied corrections for this effect based on reference was provided by exposures of a thorium-argon simulations, the details of which may be found in those papers. In the case of the primary the adjustments are lamp before and after each science frame, and the reduc- −1 −1 tions were carried out with a dedicated pipeline. very small (< 0.4 kms ), but they can reach 2 kms For the radial velocity measurements we used the for the secondary. The resulting radial velocities in the two-dimensional cross-correlation algorithm TODCOR heliocentric frame, including corrections, are listed in Ta- (Zucker & Mazeh 1994), with separate templates for the ble 2 along with their uncertainties. The flux ratio we ± primary and secondary selected from a large library of measure using TODCOR is ℓ2/ℓ1 = 0.28 0.02, at the pre-computed synthetic spectra based on model atmo- mean wavelength of our observations (5187 A).˚ spheres by R. L. Kurucz, and a line list tuned to bet- Further spectroscopic observations of BT Vul were ob- ter match the spectra of real stars (see Nordstr¨om et al. tained from 2011 November through 2018 September at 1994; Latham et al. 2002). The synthetic spectra cover Fairborn Observatory, which is situated in southeast Ari- a limited wavelength region of about 300 A˚ centered zona near Washington Camp. The observations were around 5187 A,˚ and the velocity measurements were acquired with the Tennessee State University 2m As- tronomical Spectroscopic Telescope (AST) and a fiber- made using the central 100 A,˚ which contains most of the fed echelle spectrograph (Eaton & Williamson 2007).
Load more

Recommended publications
  • Messier Objects
    Messier Objects From the Stocker Astroscience Center at Florida International University Miami Florida The Messier Project Main contributors: • Daniel Puentes • Steven Revesz • Bobby Martinez Charles Messier • Gabriel Salazar • Riya Gandhi • Dr. James Webb – Director, Stocker Astroscience center • All images reduced and combined using MIRA image processing software. (Mirametrics) What are Messier Objects? • Messier objects are a list of astronomical sources compiled by Charles Messier, an 18th and early 19th century astronomer. He created a list of distracting objects to avoid while comet hunting. This list now contains over 110 objects, many of which are the most famous astronomical bodies known. The list contains planetary nebula, star clusters, and other galaxies. - Bobby Martinez The Telescope The telescope used to take these images is an Astronomical Consultants and Equipment (ACE) 24- inch (0.61-meter) Ritchey-Chretien reflecting telescope. It has a focal ratio of F6.2 and is supported on a structure independent of the building that houses it. It is equipped with a Finger Lakes 1kx1k CCD camera cooled to -30o C at the Cassegrain focus. It is equipped with dual filter wheels, the first containing UBVRI scientific filters and the second RGBL color filters. Messier 1 Found 6,500 light years away in the constellation of Taurus, the Crab Nebula (known as M1) is a supernova remnant. The original supernova that formed the crab nebula was observed by Chinese, Japanese and Arab astronomers in 1054 AD as an incredibly bright “Guest star” which was visible for over twenty-two months. The supernova that produced the Crab Nebula is thought to have been an evolved star roughly ten times more massive than the Sun.
    [Show full text]
  • 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.
    [Show full text]
  • CONSTELLATION VULPECULA, the (LITTLE) FOX Vulpecula Is a Faint Constellation in the Northern Sky
    CONSTELLATION VULPECULA, THE (LITTLE) FOX Vulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the northern Summer Triangle (an asterism consisting of the bright stars Deneb in Cygnus (the Swan), Vega in Lyra (the Lyre) and Altair in Aquila (the Eagle). Vulpecula was introduced by the Polish astronomer Johannes Hevelius in the late 17th century. It is not associated with any figure in mythology. Hevelius originally named the constellation Vulpecula cum ansere, or Vulpecula et Anser, which means the little fox with the goose. The constellation was depicted as a fox holding a goose in its jaws. The stars were later separated to form two constellations, Anser and Vulpecula, and then merged back together into the present-day Vulpecula constellation. The goose was left out of the constellation’s name, but instead the brightest star, Alpha Vulpeculae, carries the name Anser. It is one of the seven constellations created by Hevelius. The fox and the goose shown as ‘Vulpec. & Anser’ on the Atlas Coelestis of John Flamsteed (1729). The Fox and Goose is a traditional pub name in Britain. STARS There are no stars brighter than 4th magnitude in this constellation. The brightest star is: Alpha Vulpeculae, a magnitude 4.44m red giant at a distance of 297 light-years. The star is an optical binary (separation of 413.7") that can be split using binoculars. The star also carries the traditional name Anser, which refers to the goose the little fox holds in its jaws.
    [Show full text]
  • Astrometric Radial Velocities
    A&A 381, 446–463 (2002) Astronomy DOI: 10.1051/0004-6361:20011458 & c ESO 2002 Astrophysics Astrometric radial velocities III. Hipparcos measurements of nearby star clusters and associations?,?? Søren Madsen, Dainis Dravins, and Lennart Lindegren Lund Observatory, Box 43, 22100 Lund, Sweden e-mail: soren, dainis, [email protected] Received 10 September 2001 / Accepted 15 October 2001 Abstract. Radial motions of stars in nearby moving clusters are determined from accurate proper motions and trigonometric parallaxes, without any use of spectroscopy. Assuming that cluster members share the same ve- locity vector (apart from a random dispersion), we apply a maximum-likelihood method on astrometric data from Hipparcos to compute radial and space velocities (and their dispersions) in the Ursa Major, Hyades, Coma Berenices, Pleiades, and Praesepe clusters, and for the Scorpius-Centaurus, α Persei, and “HIP 98321” associa- tions. The radial motion of the Hyades cluster is determined to within 0.4 km s−1 (standard error), and that of its individual stars to within 0.6 km s−1. For other clusters, Hipparcos data yield astrometric radial velocities with typical accuracies of a few km s−1. A comparison of these astrometric values with spectroscopic radial ve- locities in the literature shows a good general agreement and, in the case of the best-determined Hyades cluster, also permits searches for subtle astrophysical differences, such as evidence for enhanced convective blueshifts of F-dwarf spectra, and decreased gravitational redshifts in giants. Similar comparisons for the Scorpius OB2 com- plex indicate some expansion of its associations, albeit slower than expected from their ages.
    [Show full text]
  • Astronomical Detection of a Radioactive Molecule 26Alf in a Remnant of an Ancient Explosion
    Astronomical detection of a radioactive molecule 26AlF in a remnant of an ancient explosion Tomasz Kamiński1*, Romuald Tylenda2, Karl M. Menten3, Amanda Karakas4, 5 6 5 6 1 Jan Martin Winters , Alexander A. Breier , Ka Tat Wong , Thomas F. Giesen , Nimesh A. Patel 1Harvard-Smithsonian Center for Astrophysics, MS 78, 60 Garden Street, Cambridge, MA 02138, USA 2Department for Astrophysics, N. Copernicus Astronomical Center, Rabiańska 8, 87-100, Toruń, Poland 3Max-Planck Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany 4Monash Centre for Astrophysics, School of Physics and Astronomy, Monash University, VIC 3800, Australia 5IRAM, 300 rue de la Piscine, Domaine Universitaire de Grenoble, 38406, St. Martin d’Héres, France 6Laborastrophysik, Institut für Physik, Universität Kassel, Heinrich-Plett-Straße 40, Kassel, Germany *Correspondence to: [email protected] Decades ago, γ-ray observatories identified diffuse Galactic emission at 1.809 MeV (1-3) originating from β+ decays of an isotope of aluminium, 26Al, that has a mean-life time of 1.04 million years (4). Objects responsible for the production of this radioactive isotope have never been directly identified, owing to insufficient angular resolutions and sensitivities of the γ-ray observatories. Here, we report observations of millimetre-wave rotational lines of the isotopologue of aluminium monofluoride that contains the radioactive isotope (26AlF). The emission is observed toward CK Vul which is thought to be a remnant of a stellar merger (5-7). Our constraints on the production of 26Al combined with the estimates on the merger rate make it unlikely that objects similar to CK Vul are major producers of Galactic 26Al.
    [Show full text]
  • CIRCULAR No. 170 (FEBRUARY 2010)
    INTERNATIONAL ASTRONOMICAL UNION COMMISSION 26 (DOUBLE STARS) INFORMATION CIRCULAR No. 170 (FEBRUARY 2010) NEW ORBITS ADS Name P T e ­(2000) 2010 Author(s) ®2000± n a i ! Last ob. 2011 111 BU 391 AB 616y04 2095.68 0.103 81±75 259±0 100352 ZIRM 00094-2759 0±5925 100500 98±98 256±86 2006.940 258.9 1.346 - SEE3 406.00 1978.45 0.850 267.70 117.00 0.801 HARTKOPF 00098-3347 0.8871 1.119 41.7 77.6 2008.5490 117.70 0.814 & MASON - HDS 33 29.03 2018.12 0.378 177.0 132.0 0.189 CVETKOVIC 00143-2732 12.4010 0.251 59.8 73.9 2008.5432 141.6 0.199 - B 1024 1466. 1926.38 0.814 126.0 73.1 0.410 LING 00149-3209 0.2456 1.586 110.4 311.8 2008.5431 72.3 0.410 238 A1803AB 35.66 1950.70 0.002 124.10 306.00 0.179 HARTKOPF 00174+0853 10.0950 0.189 95.4 282.0 2008.7670 305.00 0.187 & MASON 281 BU1015 137.00 1961.65 0.557 291.20 103.80 0.483 HARTKOPF 00206+1219 2.6283 0.333 35.0 10.0 2008.8879 104.70 0.487 & MASON - HDS 56 28.05 1999.30 0.481 96.1 294.0 0.326 CVETKOVIC 00251+4803 12.8323 0.230 164.0 358.9 2007.8257 288.7 0.334 - B1909 11.35 1995.09 0.005 119.49 311.90 0.175 HARTKOPF 00284-2020 31.7093 0.202 69.8 99.0 2009.6710 334.80 0.109 & MASON 475 D2AB 2981.00 2007.00 0.923 266.00 42.80 0.067 HARTKOPF 00345-0433 0.1208 2.740 77.5 80.2 2009.7560 55.40 0.090 & MASON 520 BU395 25.02 1998.78 0.218 291.98 96.70 0.496 HARTKOPF 00373-2446 14.3905 0.675 78.6 318.1 2009.7560 101.00 0.596 & MASON - I440 196.00 2142.00 0.650 57.00 269.30 0.402 HARTKOPF 00427-6537 1.8350 0.274 157.0 344.0 2009.6710 268.70 0.405 & MASON 1 NEW ORBITS (continuation) ADS Name P T e ­(2000) 2010 Author(s) ®2000± n a i ! Last ob.
    [Show full text]
  • Arxiv:0908.2624V1 [Astro-Ph.SR] 18 Aug 2009
    Astronomy & Astrophysics Review manuscript No. (will be inserted by the editor) Accurate masses and radii of normal stars: Modern results and applications G. Torres · J. Andersen · A. Gim´enez Received: date / Accepted: date Abstract This paper presents and discusses a critical compilation of accurate, fun- damental determinations of stellar masses and radii. We have identified 95 detached binary systems containing 190 stars (94 eclipsing systems, and α Centauri) that satisfy our criterion that the mass and radius of both stars be known to ±3% or better. All are non-interacting systems, so the stars should have evolved as if they were single. This sample more than doubles that of the earlier similar review by Andersen (1991), extends the mass range at both ends and, for the first time, includes an extragalactic binary. In every case, we have examined the original data and recomputed the stellar parameters with a consistent set of assumptions and physical constants. To these we add interstellar reddening, effective temperature, metal abundance, rotational velocity and apsidal motion determinations when available, and we compute a number of other physical parameters, notably luminosity and distance. These accurate physical parameters reveal the effects of stellar evolution with un- precedented clarity, and we discuss the use of the data in observational tests of stellar evolution models in some detail. Earlier findings of significant structural differences between moderately fast-rotating, mildly active stars and single stars, ascribed to the presence of strong magnetic and spot activity, are confirmed beyond doubt. We also show how the best data can be used to test prescriptions for the subtle interplay be- tween convection, diffusion, and other non-classical effects in stellar models.
    [Show full text]
  • GEORGE HERBIG and Early Stellar Evolution
    GEORGE HERBIG and Early Stellar Evolution Bo Reipurth Institute for Astronomy Special Publications No. 1 George Herbig in 1960 —————————————————————– GEORGE HERBIG and Early Stellar Evolution —————————————————————– Bo Reipurth Institute for Astronomy University of Hawaii at Manoa 640 North Aohoku Place Hilo, HI 96720 USA . Dedicated to Hannelore Herbig c 2016 by Bo Reipurth Version 1.0 – April 19, 2016 Cover Image: The HH 24 complex in the Lynds 1630 cloud in Orion was discov- ered by Herbig and Kuhi in 1963. This near-infrared HST image shows several collimated Herbig-Haro jets emanating from an embedded multiple system of T Tauri stars. Courtesy Space Telescope Science Institute. This book can be referenced as follows: Reipurth, B. 2016, http://ifa.hawaii.edu/SP1 i FOREWORD I first learned about George Herbig’s work when I was a teenager. I grew up in Denmark in the 1950s, a time when Europe was healing the wounds after the ravages of the Second World War. Already at the age of 7 I had fallen in love with astronomy, but information was very hard to come by in those days, so I scraped together what I could, mainly relying on the local library. At some point I was introduced to the magazine Sky and Telescope, and soon invested my pocket money in a subscription. Every month I would sit at our dining room table with a dictionary and work my way through the latest issue. In one issue I read about Herbig-Haro objects, and I was completely mesmerized that these objects could be signposts of the formation of stars, and I dreamt about some day being able to contribute to this field of study.
    [Show full text]
  • A History of Star Catalogues
    A History of Star Catalogues © Rick Thurmond 2003 Abstract Throughout the history of astronomy there have been a large number of catalogues of stars. The different catalogues reflect different interests in the sky throughout history, as well as changes in technology. A star catalogue is a major undertaking, and likely needs strong justification as well as the latest instrumentation. In this paper I will describe a representative sample of star catalogues through history and try to explain the reasons for conducting them and the technology used. Along the way I explain some relevent terms in italicized sections. While the story of any one catalogue can be the subject of a whole book (and several are) it is interesting to survey the history and note the trends in star catalogues. 1 Contents Abstract 1 1. Origin of Star Names 4 2. Hipparchus 4 • Precession 4 3. Almagest 5 4. Ulugh Beg 6 5. Brahe and Kepler 8 6. Bayer 9 7. Hevelius 9 • Coordinate Systems 14 8. Flamsteed 15 • Mural Arc 17 9. Lacaille 18 10. Piazzi 18 11. Baily 19 12. Fundamental Catalogues 19 12.1. FK3-FK5 20 13. Berliner Durchmusterung 20 • Meridian Telescopes 21 13.1. Sudlich Durchmusterung 21 13.2. Cordoba Durchmusterung 22 13.3. Cape Photographic Durchmusterung 22 14. Carte du Ciel 23 2 15. Greenwich Catalogues 24 16. AGK 25 16.1. AGK3 26 17. Yale Bright Star Catalog 27 18. Preliminary General Catalogue 28 18.1. Albany Zone Catalogues 30 18.2. San Luis Catalogue 31 18.3. Albany Catalogue 33 19. Henry Draper Catalogue 33 19.1.
    [Show full text]
  • Variations of the RS Cvn Type Binary ER Vulpeculae
    A&A 400, 257–264 (2003) Astronomy DOI: 10.1051/0004-6361:20021885 & c ESO 2003 Astrophysics Hα variations of the RS CVn type binary ER Vulpeculae O.¨ Cakırlı ¸ 1,C.Ibanoˇ˙ glu1, A. Frasca2, and S. Catalano2 1 Ege University Observatory, Bornova, Izmir,˙ Turkey e-mail: [email protected] 2 INAF - Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania, Italy e-mail: [email protected]; [email protected] Received 9 September 2002 / Accepted 17 December 2002 Abstract. We present the results of spectroscopic observations of the active eclipsing binary ER Vul in the 5860–6700 Å spec- tral range carried out at the Catania Astrophysical Observatory. Accurate measurements of radial velocities by using the cross- correlation technique have been made and a new orbital solution is given. All spectra display chromospheric emission which fills in the Hα absorption lines of both components. The equivalent width (EW)oftheHα emission has been measured by subtraction of a synthetic spectrum built up with spectra of inactive standard stars. The EW of total Hα emission, arisen from both components, shows a phase-dependent variation. It reaches its maximum value just before the primary eclipse. We were able to separate the contributions to the Hα emission from the individual components at phases far from the eclipses. We have found that the secondary, cooler component is the most active and its Hα residual emission shows the same trend as the total Hα emission, along orbital phase. This Hα equivalent width variation can be due to plage-like structures on the chromosphere of secondary star.
    [Show full text]
  • Aerodynamic Phenomena in Stellar Atmospheres, a Bibliography
    - PB 151389 knical rlote 91c. 30 Moulder laboratories AERODYNAMIC PHENOMENA STELLAR ATMOSPHERES -A BIBLIOGRAPHY U. S. DEPARTMENT OF COMMERCE NATIONAL BUREAU OF STANDARDS ^M THE NATIONAL BUREAU OF STANDARDS Functions and Activities The functions of the National Bureau of Standards are set forth in the Act of Congress, March 3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent with these standards; the determination of physical constants and properties of materials; the development of methods and instruments for testing materials, devices, and structures; advisory services to government agencies on scientific and technical problems; in- vention and development of devices to serve special needs of the Government; and the development of standard practices, codes, and specifications. The work includes basic and applied research, development, engineering, instrumentation, testing, evaluation, calibration services, and various consultation and information services. Research projects are also performed for other government agencies when the work relates to and supplements the basic program of the Bureau or when the Bureau's unique competence is required. The scope of activities is suggested by the listing of divisions and sections on the inside of the back cover. Publications The results of the Bureau's work take the form of either actual equipment and devices or pub- lished papers.
    [Show full text]
  • Molecular Remnant of Nova 1670 (CK Vulpeculae). II. a Three-Dimensional
    Astronomy & Astrophysics manuscript no. CKVulMoleculesALMA_v0 ©ESO 2020 October 13, 2020 Molecular remnant of Nova 1670 (CK Vulpeculae) II. A three-dimensional view on the gas distribution and velocity field T. Kaminski´ 1; 2, W. Steffen3, V. Bujarrabal4, R. Tylenda1, K. M. Menten5, and M. Hajduk6 1 Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, ul. Rabianska´ 8, 87-100 Torun,´ Poland, e-mail: [email protected] 2 Center for Astrophysics j Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USA 3 Instituto de Astronomía, OAN, UNAM, Ensenada, Mexico 4 Observatorio Astronomico Nacional (OAN, IGN), Campus Universitario, Ctra. NII km 33 600, Apartado 112, E-28803 Alcala de Henares, Spain 5 Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany 6 University of Warmia and Mazury, Faculty of Geoengineering, ul. Prawochenskiego 15, 10-720 Olsztyn, Poland October 13, 2020 ABSTRACT CK Vul is the remnant of an energetic eruption known as Nova 1670 that is thought to be caused by a stellar merger. The remnant is composed of (1) a large hourglass nebula of recombining gas (of 7100size), very similar to some classical planetary and pre-planetary nebulae (PPNe), and (2) of a much smaller and cooler inner remnant prominent in millimeter-wave emission from molecules. We investigate the three-dimensional spatio-kinematic structure of both components. The analysis of the hourglass structure yields a revised distance to the object of >2.6 kpc, at least 3.7 times greater than so far assumed. At this distance, the stellar remnant has a bolometric luminosity >12 L and is surrounded by molecular material of total mass >0.8 M (the latter value has a large systematic uncertainty).
    [Show full text]