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3 edition of UV spectral variability in the Herbig Ae star HR 5999 found in the catalog.

UV spectral variability in the Herbig Ae star HR 5999

M. R. PeМЃrez

UV spectral variability in the Herbig Ae star HR 5999

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Published by National Aeronautics and Space Administation in [Washington, D.C.? .
Written in English

    Subjects:
  • Accretion (Astrophysics),
  • Ultraviolet astronomy.

  • Edition Notes

    Other titlesAccretion interpretation.
    StatementM.R. Pérez, C.A. Grady, and P.S. Thé.
    SeriesNASA contractor report -- NASA CR-189313.
    ContributionsGrady, C. A., Thé, P. S., United States. National Aeronautics and Space Administration.
    The Physical Object
    FormatMicroform
    Pagination1 v.
    ID Numbers
    Open LibraryOL17681345M

    FU Orionis - The MIDI Perspective.- VLTI MIDI Observations of the Herbig Ae Star HR Disentangling the Wind and the Disk in the Close Surrounding of the Young Stellar Object MWC with AMBER/VLTI.- Interferometry of M8E-IR with MIDI - Resolving the Dust Emission.- Observing T Tauri Stars in the Mid-Infrared with MIDI   Early stars of less than 2 M ☉ are called T Tauri stars, while those with greater mass are Herbig Ae/Be stars. These newly formed stars emit jets of gas along their axis of rotation, which may reduce the angular momentum of the collapsing star and result in small patches of nebulosity known as Herbig–Haro objects. The successful launch on Novem of ESA's Infrared Space Observatory (ISO) by means of an Ariane 4 carrier, has set in motion a true revolution in quantitative infrared astronomy. For the first time since the very successful IRAS mission in , the astronomical community has.


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UV spectral variability in the Herbig Ae star HR 5999 by M. R. PeМЃrez Download PDF EPUB FB2

We report recent IUE high- and low-dispersion observations with the IUE long wavelength camera (LWP) and short wavelength camera (SWP) of the Herbig Ae star HR We have found a dramatic change in the structure of the Mg II h and k lines (, Å) along with some continuum flux excesses especially at the short end of the SWP camera.

LWP high- dispersion observations of HR Cited by: 6. UV spectral variability in the Herbig Ae star HR The accretion interpretation (LWP) and short wavelength camera (SWP) of the Herbig Ae star HR We have found a dramatic change in the structure of the Mg II h and k lines (, A) along with some continuum flux excesses especially at the short end of the SWP camera.

The variable Herbig AE star HR IX - Variability in the UV shell lines Article (PDF Available) in Astronomy and Astrophysics Supplement Series September with 11 Reads. A&A manuscript no. (will be inserted by hand later) Your thesaurus codes are: 07() ASTRONOMY AND ASTROPHYSICS.

NASA CR UV spectral variability in the Herbig Ae star HR HR has a spectral type of A7 III-IV and forms a ∼ 45′′ wide proper-motion binary system with the A star HR The Hipparcos parallax for HR corresponds to a distance of +50 −30 pc. The spectral energy distribution of HR shows a clear infrared excess at wavelengths above 1µm.

IRAS detected HR at 12, 25, and 60µm, but pro. Analysis of IUE high- and low-dispersion spectra of the young Herbig Ae star HR (HD ) covering – has revealed dramatic changes in the Mg II h and k (, Å) emission profiles, changes in the column density and distribution in radial velocity of accreting gas, and flux in the Lyα, OI and CIV emission lines, which are correlated with the UV excess : M.

Pérez, C. Grady. Spectral Type: A 7 IV e L bol = L o, A V = mag M = M o, age = Myr HR v sin i = km/sec HR 12’ x 12’ K + R + B Properties of HR (alias HDV Sco): HR SpT = A no emission lines no infrared excess Ænot a Herbig star.

Infrared excess: circumstellar mass ~ M o. Analysis of IUE high- and low-dispersion spectra of the young Herbig Ae star HR (HD ) covering has revealed dramatic changes in the Mg II h and k (, Å) emission profiles, changes in the column density and distribution in radial velocity of accreting gas, and flux in the Lyα, OI and CIV emission lines, which are correlated with the UV excess luminosity.

IUE observations are noted to indicate that HD exhibits the same UV, visible, and IR spectral properties as the Herbig Ae stars AB Aur and HR It is accordingly concluded that HD. environment surrounding Herbig Ae stars. Aims. We present new long-baseline spectro-interferometric observations of the Herbig Ae star, HRobtained in the H and K bands with the AMBER instrument at the VLTI, and aim to produce near-infrared images at the sub-AU spatial scale.

by: UV spectral variability in the Herbig Ae star HR XI, The accretion interpretation. [M R Pérez; C A Grady; P S Thé; United States. National Aeronautics and Space Administration.]. Abstract. Analysis of IUE high- and low-dispersion spectra of the young Herbig Ae star HR (HD ) covering revealed dramatic changes in the Mg II h and k (, A) emission profiles, changes in the column density and distribution in radial velocity of accreting gas, and flux in the Ly(alpha), O I, and C IV emission lines, which are correlated with the UV excess Author: M.

Perez, C. Grady and P. The. Herbig Ae/Be stars are intermediate-mass pre-main sequence stars surrounded by circumstellar dust disks. Some are observed to produce jets, whose appearance as a sequence of shock fronts (knots) suggests a past episodic outflow by: A Statistical SpectropolarimetricStudy of Herbig Ae/Be Stars troscopic variability that a Herbig Ae star is currently undergo- Fairlamb et al.

() found that the UV-excess of Herbig Ae stars can be explained by magnetospheric accretion, but that the earliest Herbig Be stars have too large UV. Of the more evolved Group 1, only HRAB Aur, and to some extent HDhave been extensively monitored at high dispersion for UV spectral variability and mass accretion from the disk.

Evidence suggests HR is a close binary. test Halesowen Chronicle Newspaper Mk News Newspaper Harlow Star Newspaper Kidderminster Chronicle Newspaper Books by Language Additional Collections. Featured movies All video latest This Just In Prelinger Archives Democracy.

In Kurtz & Marang (MNRAS) discovered delta Scuti pulsation with a period of hours in the well-studied pre-main sequence Herbig Ae star HR (spectral type A7 III-IVe), which is embedded in an obscured region of Scorpius with many T Tauri stars in the associated dark cloud.

Mundt R., and Ray, T. (), Optical Outflows from Herbig Ae/Be Stars and Other High Luminosity Young Stellar Objects, in The Nature and Evolutionary Status of Herbig Ae/Be Stars, eds.

by P.S. Thé, M.R. Pérez, and P.J. van den Heuvel, PA – Google ScholarAuthor: V. Grinin. Herbig Ae stars. If this also happened with BN Ori, it be-comes of interest to compare its spectral features with those of a Herbig A6 −7e star as such a star might be similar to BN Ori before the FUOR outburst.

We made a detailed comparison with the spectrum of HR (V Sco), a bright and strongly variable Herbig A5 −Cited by: 6. investigations of a sample of 56 Herbig Ae/Be stars are provided. The results show that the detection rate of the line effect is very high (75 %), implying that most of Herbig Ae/Be stars possess a disk.

The statistical results might suggest that Herbig Ae stars form in the same manner as T Tauri stars via magnetospheric accretion while Herbig. Malfait et al.: An ultraviolet, optical and infrared study of Herbig Ae/Be stars Table 1.

Identi cation of program stars No identi cation IRAS IRAS b sp.t. hms ’ " deg 1 HD 02 41 04 10 B7 V. Herbig () firstly performed a systematic study of 26 stars with the certain select criteria that we called Herbig Ae/Be (HAeBe) stars. The selection criteria for HAeBe stars he gave are as follows: (a) the spectral type is A or earlier, with emission lines; (b) the star lies in an obscured region of space; (c)Cited by: 7.

The formation of low-mass (M ★ ≲ 2 M ⊙) stars in molecular clouds involves accretion disks and jets, which are of broad astrophysical interest. Accreting stars represent the closest examples of these phenomena. Star and planet formation are also intimately connected, setting the starting point for planetary systems like our own.

The ultraviolet (UV) spectral range is particularly Author: P. Christian Schneider, H. Moritz Günther. Rapid line profile variability of H[alpha] in two A0e Herbig stars of the P-Cyg-subgroup and a model for their circumstellar envelope p.

Profile variability of H[alpha] in the B3e Herbig star HD as indication of matter infall and inhomogeneous stellar wind p.

Dust and gas in shells around Herbig Ae/Be stars p. Cyclical Variability in Stellar Winds by Lex Kaper,available at Book Depository with free delivery worldwide. Fig. UV photometric variability in HR of the observed fluxes as a function of the derived visual magnitude V(FES).

Continuum variability at A (filled circles), A (open circles), A (triangles) is shown. Net observed emission fluxes for C IV (filled squares) and O I. Variable Star is a science fiction novel by American author Spider Robinson, based on the surviving seven pages of an eight-page novel outline by the late Robert A.

Heinlein († ). The book is set in a divergent offshoot of Heinlein's Future History and contains many references to works by Heinlein and other authors. It describes Author: Robert A. Heinlein & Spider Robinson. IV CONTENTS T Tauri stars: Not one but two transition regions C BeAtouut 89 Far UV line widths in RU Lupi M 1/?zvu>tovi & M T 1/ T logo 95 On the Mgll and Fell resonance lines in Herbig Ae stars: Preliminary analysis A JaZavvia star HR VII.

The extended atmosphere of a Herbig Ae star. Type of Variability, and its Correlation with Spectral Type and Spectroscopic Variations ' 70LO JD-2LL 4!. w~~4y-~~~-~vf-T~ TY CrA:. p!i The first purpose of the long-term photometry of Herbig Ae/Be stars is the determination of the shape of the light.

tional Herbig Ae/Be star HD Aiming to gain insight into the physical origin of the line in possible relation to accretion processes, we carried out Br γ spectro-interferometry using AMBER/VLTI from three different baselines achieving spatial and spectral resolutions.

It is well known that stellar winds are variable, and the fluctuations are often cyclical in nature. This property seems to be shared by the winds of cool and hot stars, even though their outflows are driven by fundamentally different physical mechanisms.

Since very similar models have been Price: $ Understanding A-Type Supergiants: Visible and Ultraviolet Spectral Variability. Pages Anisotropic Outflows from Herbig Ae/Be Stars. Cyclical Variability in Stellar Winds Book Subtitle Proceedings of the ESO Workshop Held at Garching, Germany, 14 – 17 October Herbig Ae/Be stars are intermediate-mass pre-main sequence stars surrounded by circumstellar dust disks.

Some are observed to produce jets, whose appearance as a sequence of shock fronts (knots) suggests a past episodic outflow variability. This “jet fossil record” can Cited by: Grants = 16 totaling over $k and observing time on 5 satellite observatories Editer 2 books: Blazar Continuum Variability, () ed.

H.R. Miller, J. Webb, J.C. Noble A.S.P. Conference series Vol.Blazar Continuum Variability II: Entering the GLAST Era, () ed. Book Contributor = Entries on Cosmology and particle Physics for Philips Encyclopedia of Astronomy and Astrophysics. Study of the properties and spectral energy distributions of the Herbig AeBe stars HD and HDThe β Pictoris Phenomenon in the Herbig Ae Star HR Coordinated ISO SWS and IUE Observations.

The β Pictoris Phenomenon among Herbig Ae/Be stars. UV. Mario van den Ancker European Southern Observatory Karl-Schwarzschild-Strasse 2 B.

McCollum, M.W. Castelaz, ``The Beta Pictoris phenomenon among Herbig Ae/Be stars: UV and Optical High Dispersion Spectra'', A&AS N.V. Voshchinnikov, M.E. van den Ancker, ``The variable Herbig Ae star HR XII. Its circumstellar. The distribution of spectral types among PAH-dominated and silicate emission Herbig stars are similar, thus the reason might be related to, e.g., intrinsically low PAH abundance in the disk atmosphere, the destruction of PAHs in the disk atmosphere by strong UV flux, or shadowing or softening of the stellar irradiation by the puffed-up inner Cited by: ‘classical’ Herbig Ae stars.

Among these are: the far IR excess, which can be a cause of its spectral variability. Investigation of the rapid variability of the lines forming A&A,Spectroscopic, photometric, and polarimetric study of the \rHerbig Ae candidate HD \r\ Made available courtesy of EDP Sciences.

Rapid irregular variables of the early spectral types, B-A or Ae. UX Orionis (ISA in the GCVS) is the prototype of a subgroup of Herbig Ae/Be stars knows as UXOR that show irregular variations with a wide range of amplitudes from barely detectable to more than 4 mag.

in V. Large-amplitude variability is confined to stars with spectral types. Herbig Ae/Be stars are intermediate mass (2–8 M)pre-main sequence and zero age-main sequence stars whose spectral energy distribution reveals an infrared excess (Her-big ; Waters and Waelkens ; Vieira et al.

They are the precursors to main sequence A-stars many of which have debris disks (Su et al.). As the higher. Variable stars are generally analysed using photometry, spectrophotometry and ements of their changes in brightness can be plotted to produce light regular variables, the period of variation and its amplitude can be very well established; for many variable stars, though, these quantities may vary slowly over time, or even from one period to the next.star is not resolved.

Depolarisation: Hot extended disk, Herbig Be stars. Line polarisation: Rotating disk accretion, Herbig Ae stars. The schematic is taken from Vink et al. 4. CONCLUSIONS Hα shows a McLean line effect across the absorption in HBe stars, depolarisation in HBe stars and line polarisation in HAe stars.Journal Article: Profile of He I lambda in the P-Cygni-type of star HD Title: Profile of He I lambda in the P-Cygni-type of star HD Full Record.