2002ApJ...570L..29S

We propose a method that uses near-infrared plus uvby photometry to identify potentially extensive circumstellar dusty environments around F and A stars. The method has been applied to a sample of ∼900 metal-rich reddened F stars with 2 Micron All Sky Survey and uvby data, suggesting the presence of circumstellar dust emitting in the near-infrared for ∼70 stars. The logT_e-M_V diagram suggests that most, if not all, are likely pre-main-sequence (PMS) stars. They seem to be a continuation of the class of Herbig Ae/Be PMS stars in the spectral type F. Their number drops sharply downward of logT_e∼3.84 (spectral types later than ∼F5), which may provide new clues to the PMS evolution of 1-2 M_☉ stars. We present a list of 21 of the most conspicuous candidate stars with circumstellar dust. About half of them are associated with the extended star-forming region around ρ Ophiuchi. The brightest of these 21 stars, with V≲7.5, turn out to be IRAS sources, suggesting the presence of heated dust emitting in the far-infrared. Also in this list, HD 81270 is reported as a very unusual star moving away from the Galactic plane at a projected speed of 70 km.s^–1.