In early mid-infrared observations (c 1970) two prominent dust emission features were discovered. ... Soon after the discovery of the silicate features another feature at about 11.3 microns was discovered in the spectra of some carbon stars, not as wide or as strong as the silicate features but still thought to be due to a solid material. ... less common features: extreme carbon stars, the AlO/silicate complex, the "unidentified infrared" features, unusual silicate features . ...

Next: Radial velocity of the Up: Optical spectrum of IRAS04296 Previous: Observations and spectra reduction . ... However, molecular emission features are only very rarely observed in the optical spectra of PPNe. ... On the other hand, it is well known that cometary nuclei spectra show prominent Swan band emission. In both spectra of IRAS04296 we have discovered strong emission in the (0;0) and (0;1) bands of the Swan system of the molecule. ... Now consider the case of IRAS04296. ...

... Absorption by neutral atomic hydrogen in luminous spiral galaxies provides an excellent tool to study the gas kinematics in their nuclear regions. ... Since the absorption lines are intrinsically narrow as a result of the low temperatures of the optically thick gas, typically 30 to 150 K (Dickey, Salpeter & Terzian 1979), it is surprising that numerous galaxies show H I absorption over a broad range of velocities (a few hundred kms -1 ); see e.g., Fig. ... range . ... NGC 253 . ... NGC 660 . ...

... Editor's note: This activity is both on the Astrocappella web site and the CD-ROM featured in this article. ... Every student can demonstrate the Doppler effect! ... splash out' ball** . ... Twist the 'splash out' ball open. ... This effect can occur with both sound and light, because both sound and light reveal wave- like behavior. ... The number of waves reaching an observer in one second is called the frequency. ... What has the Doppler shift told astronomers about the expansion of the universe? ...

CHIANTI - an atomic database for emission lines. ... K.P.Dere, E.Landi, H.E.Mason, B.C.Monsignori-Fossi, P.R.Young, 1997, A , 125, 149 . Article: Available from ADS . The Arcetri Spectral Code for thin plasmas . E.Landi M.Landini 1998, A , 133, 1 . ... E.Landi, M.Landini K.P.Dere, P.R.Young, H.E.Mason, 1999, A , 135, 339 . ... K.P.Dere, E.Landi, P.R.Young, G.Del Zanna, 2001, ApJS, 134, 331 . ... G.Del Zanna, B.J.I.Bromage, E.Landi, M.Landini, 2001, A , 379, 708 . ...

... The Sun of our solar system is a typical star of intermediate size and luminosity. ... The Sun has a very complex surface magnetic field created by convective flow of the electrically conducting solar material. ... The escaping hot coronal plasma is called the solar wind . ... See the table below for the observed features above the Sun's surface. ... Chromospheric features . Coronal features . ... dense clouds of material suspended above the surface of the Sun by magnetic field line loops . ...

CONTINUUM AND BROAD EMISSION LINE VARIABILITY OF SEYFERT GALAXIES V.T. Doroshenko 1,2 , S.G. Sergeev 2 , V.I. Pronik 2 1 Crimean Lab. of the Sternberg Astronomical Institute, Moscow University, Russia 2 Scientific­Research Institute, Crimean Astrophysical Observatory, Ukraine; p/o Nauchny, 98409, Crimea, Ukraine vdorosh@sai.crimea.ua We focused on the observed properties of some Seyfert galaxies without detailed discussion of underlying physical mechanisms. ...

... SUN MOON MERCURY VENUS MARS, JUPITER SATURN . ... Mars . ... Previously understood that magnetic fields were directly related to rotation, so when I read that Mars, like Venus, didn't have one, my understanding crumbled. What exactly causes magnetic fields in planets? ... RELATED TOPICS: MAGNETIC FIELD . Planetary magnetic fields are definitely related to rotation, but directly not so much. ... Get instant access to subscriber content on Astronomy.com! ...

To a special Solar Physics issue on the Bastille Day Event: . ... Multi-scale temporal features of the 14 July 2000 meter-wavelength dynamic radio spectrum compared with TRACE data . ... Figure 1 (100 KB). SOHO/EIT (a) and LASCO/C2 (b) images show the region of the eruptive flare event of 14 July 2000 and related halo CME. ... Figure 2 (47 KB). ... Figure 3 (115 KB). Medium-scale dynamic spectrum (a), 204 MHz metric (b) and 3000 MHz microwave (c) profiles of the "Bastille Day" event. ...

... Science . ... Science Users Information > Data Handling and Products > Data Reduction FAQ > I see unexpected boxy emission-like features in my REDL spectra - where do they come from? ... Observing with ESO Telescopes . ... ESO-MIDAS . ... ESO Data . ... The pipeline by default interpolates across the bad columns in the REDL CCD when it creates the master bias, but does not so when it processes the science data. This inconsistency can create boxy emission-like features as seen in the figure below. ...

... 11 Yellow-Green (78% transmission): Contrasts well with the red and blue characteristics of surface features on Jupiter and Saturn. ... 82A Light Blue (73% transmission): Useful on the Moon, Mars, Jupiter, and Saturn, this subtle pale blue filter enhances areas of low contrast while avoiding significant reduction of overall image brightness. ... Meade Series 4000 Photo-Visual Color Filters may be ordered individually or in the following sets: . ... Meade Series 4000 Broadband Nebular Filters . ...

A Survey of Hidden Molecular Clouds in the Milky Way J.M. Hughes ad S.J. Gibson Western Kentucky University Star formation, a critical process within galaxies, occurs in the coldest, densest interstellar clouds, whose gas and dust content are observed primarily at radio and infrared wavelengths. ... Through a comparative study, we find substantial dark molecular hydrogen that is not detected in CO emission. ... Identify cold atomic hydrogen emission clouds 21cm 2. ...

... Gas in Thermodynamic Equilibrium Conditions. Stellar Spectrums. Physical Basis of Spectral Classification of Stars. ... The Sun. General Stellar Feature of the Sun. ... Distribution of Brightness in Solar Disc. ... Chromosphere - Observations on Limb and Disc of the Sun, Basic Elements of Structure, Spectrum, Physical State. ... Solar Corona - Observation, Structure, Spectrum, Polarization, Dynamics, Rotation, Physical Condition. ... Interstellar Dust. ... Two Groups of Big Planets. ...

These are very prominent absorption lines is most all galaxies. ... These pair of absorption lines will appear in all the spectra and they should be your principle source for determining the redshift. ... When this applet opens you will see an iconic representation of galaxies in the left hand side of the applet and a target area in the right side of the applet. ... Note: What you are doing in this excercise is identical to what Hubble did in the 1920's and you are using the same galaxies. ...

... Mindful of these biases, I can now explore the relations between the measured rotation periods and various other observables. The hypothesis behind monitoring stellar variability is that active stars have asymmetric spot distributions on their photospheres. ... They found that only stars with rotation periods greater than seven days show variations greater than 0.4 magnitudes at I. Bouvier et al . ... 1993a) demonstrated a relation between X--ray flux and spectral type in ZAMS stars. ...

... Laboratory and theoretical modelling of the UV bump on the interstellar extinction curve is a very popular topic in dusty investigations. ... feature is illustrated by Fig. 10 where the profiles were calculated using the model of graphite spheres. Figure 10: Normalized extinction efficiencies for graphite spheres. ... The lower panel shows the summary extinction of two graphite spheres with radii and (from upper panel) taken in equal proportions. ...

RELATIVE SUNSPOT NUMBERS Description of Data from SGD Explanation of Data Reports: Relative Sunspot Numbers -- The relative sunspot number is an index of the activity of the entire visible disk of the Sun. ... The provisional daily Zurich relative sunspot numbers, Rz, were based upon observations made at Zurich and its two branch stations in Arosa and Locarno and communicated by M. Waldmeier of the Swiss Federal Observatory. ... This indicates the uncertainty above and below the predicted number. ...

The UV spectral lines formed at transition region temperatures in the solar atmosphere, shows a prevailing redshifted emission. Using the Solar Ultraviolet Measurements of Emitted Radiation spectrometer flown on the Solar and Heliospheric Observatory spacecraft, we measure the amount of line shift as a function of the temperature for several spectral lines formed in the range between 10^{4} and 10^{6} K. We analyze spectrograms relative to the quiet Sun and to the active region NOAA 7946. ...

... They are concerned with Attitude Control System of the spacecraft, satellite visibility from tracking stations, limits on the satellite autonomous operations during the orbit, and needs for auxiliary operations with the spacecraft. ... Among the operational constraints the most important one is the number of programmed slews per orbit, which determines the maximum number of radio sources to be observed during one orbit. ... System temperature (K) . ... Progress of the RadioAstron Project in Pictures...

... With McMath, Robert R.; Mohler, Orren C. Telluric Bands of CH 4 in the Solar Spectrum. 1949 v.109 p.28 . With Mohler, Orren C.; McMath, Robert R. New Solar Lines in the Spectral Region 1.52-1.75 . ... With Mohler, Orren C.; Pierce, A. Keith; McMath, Robert R. New Solar Lines in the Spectral Region 1.97-2.49 . ... With Mohler, Orren C.; Pierce, A. Keith; McMath, Robert R. Table of Infrared Solar Lines, 1.4-2.5 . ... With McMath, Robert R.; Mohler, Orren C.; Pierce, A. Keith . ...