Portal:Radiation astronomy/Resource/22
Violets[edit | edit source]
"The aluminium abundance was derived from the resonance line at 394.4nm, and Al is underabundant by ∼ −0.7 dex with respect to iron."[1] "These abundances are the LTE values; no NLTE corrections, as prescribed by Baum ̈uller and Gehren (1997) and Baumüller et al. (1998), have been applied. The prescribed NLTE corrections for Teff = 6500K, log g = 4.0, [Fe/H] = –3.0 are –0.11 ... for ... Al .... If we assume these values to apply for our lower-gravity star [CS 29497-030], then Al follows iron"[1]. The elemental abundance ratios for CS 29497-030 of aluminum are [Al/H] = -3.37, [Al/Fe] = -0.67.[1]
A discovery in violet astronomy is that "carbon stars are enormously fainter in the violet region than expected from appropriate blackbody spectra."[2]
Violet photographs of the planet Venus taken in 1927 “recorded two nebulous bright streaks, or bands, running ... approximately at right angles to the terminator” that may be from the upper atmosphere.[3]
"The “Purple Haze” is a diffuse blueish/purple glow within a few arcseconds of the central star in HST images of the Homunculus (Morse et al. 1998; Smith et al. 2000, 2004). This emission is seen in excess of violet starlight scattered by dust, and the strength of the excess increases into the far UV (Smith et al. 2004; hereafter Paper I)."[4]
References[edit | edit source]
- ↑ 1.0 1.1 1.2 T. Sivarani, P. Bonifacio, P. Molaro, R. Cayrel, M. Spite, F. Spite, B. Plez, J. Andersen, B. Barbuy, T. C. Beers, E. Depagne, V. Hill, P. François, B. Nordström, and F. Primas (January 2004). "First stars IV. CS 29497-030: Evidence for operation of the s-process at very low metallicity". Astronomy and Astrophysics 413 (1): 1073-85. doi:10.1051/0004-6361:20031590. http://arxiv.org/pdf/astro-ph/0310291.pdf. Retrieved 2012-06-02.
- ↑ Jesse D. Bregman and Joel N. Bregman (May 15, 1978). "The violet opacity of carbon stars". The Astrophysical Journal 222 (5): L41-3. doi:10.1086/182688.
- ↑ W. H. Wright (August 1927). "Photographs of Venus made by Infra-red and by Violet Light". Publications of the Astronomical Society of the Pacific 39 (230): 220-1. doi:10.1086/123718.
- ↑ Nathan Smith, Jon A. Morse, Nicholas R. Collins, and Theodore R. Gull (August 2004). "The Purple Haze of η Carinae: Binary-induced Variability?". The Astrophysical Journal 610 (2): L105-8. doi:10.1086/423341.