Absolute Flux Distributions of Solar Analogs from the UV to the Near-IR (original) (raw)
NASA/ADS
Abstract
The 0.225-2.695mu m absolute flux distributions of the solar analogs P041C, P177D, and P330E are presented. The ultraviolet and optical wavelength range from 0.225mu m to 0.825mu m is based on high signal-to-noise spectra obtained with the HST Faint Object Spectrograph (FOS). The spectra in the near-infrared longward of 0.825mu m are scaled versions of the absolute flux calibrated reference spectrum of the Sun from Colina, Bohlin, & Castelli (1996). In the 0.400mu m to 0.825mu m range, the spectral energy distribution of P041C is slightly hotter than the Sun, 5900K vs. 5777K, and agrees with the shape of the solar spectrum to 5% in the optical. P177D shows evidence for interstellar absorption from the dust that corresponds to A_V=0.03 magnitudes in the visual. The spectral energy distribution of P330E is the same as the reference spectrum within 2%-3%. At wavelengths shortward of 0.4mu m, the differences in the spectral energy distribution between the Sun and the solar analogs are larger, and not well understood. When normalized to the same V flux, P041C and P330E are brighter than the Sun by up to 50% below 0.25mu m, whereas P177D is as much as 10% fainter. The synthesized visual magnitudes and B-V colors of the FOS absolute fluxes of P041C, P177D, and P330E agree with ground-based broad-band photometry to 0.02 magnitudes. The flux distributions of our new solar analogs will help establish the absolute calibration of NICMOS, the HST near-infrared camera and multi-object spectrograph. The spectra are available via the WWW.
Publication:
The Astronomical Journal
Pub Date:
March 1997
DOI:
Bibcode: