Open AccessOptical, infrared and millimetre‐wave properties of Vega‐like systems – IV. Observations of a new sample of candidate Vega‐like sources
Author(s) -
J. Sylvester Roger,
Mannings Vincent
Publication year - 2000
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2000.03194.x
Subject(s) - physics , vega , astrophysics , stars , infrared , spectral energy distribution , circumstellar dust , wavelength , astronomy , spectral line , emission spectrum , infrared excess , optics
Photometric observations at optical and near‐infrared wavelengths are presented for members of a new sample of candidate Vega‐like systems, or main sequence stars with excess infrared emission due to circumstellar dust. The observations are combined with IRAS fluxes to define the spectral energy distributions of the sources. Most of the sources show only photospheric emission at near‐IR wavelengths, indicating a lack of hot (∼1000 K) dust. Mid‐infrared spectra are presented for four sources from the sample. One of them, HD 150193, shows strong silicate emission, while another, HD 176363, was not detected. The spectra of two stars from our previous sample of Vega‐like sources both show UIR‐band emission, attributed to hydrocarbon materials. Detailed comparisons of the optical and IRAS positions suggest that in some cases the IRAS source is not physically associated with the visible star. Alternative associations are suggested for several of these sources. Fractional excess luminosities are derived from the observed spectral energy distributions. The values found are comparable to those measured previously for other Vega‐like sources.