Investigation of 131 Herbig Ae/Be candidate stars AJ, 126, 2971, (2003) December |
Abstract:
We present a new catalog of 108 Herbig Ae/Be candidate stars identified in the Pico dos Dias
Survey, together with 19 previously known candidates and four objects selected from the IRAS
Faint Source Catalog. These 131 stars were observed with low- and/or medium-resolution
spectroscopy, and we complement these data with high-resolution spectra of 39 stars. The
objects present a great variety of Halpha line profiles and were separated according to them.
Our study suggests that most of the time a Herbig Ae/Be star will present a double peak Halpha
line profile. Correlations among different physical parameters, such as spectral type and
v sin i with Halpha line profiles were searched. We found no correlation among Halpha line
profiles and spectral type or v sin i except for stars with P Cyg profiles, where there
is a correlation with v sin i. We also use preliminary spectral energy distributions
to seek for any influence of the circumstellar medium in the Halpha line profiles.
The presence of [O i] and [S ii] forbidden lines is used together with the Halpha
line profiles and these preliminary spectral energy
distributions to discuss the circumstellar environment of the Herbig Ae/Be candidates.
The distribution of the detected [O i] and [S ii] forbidden lines among different
spectral types points to a significantly higher occurrence of these lines among B stars,
whereas the distribution among different Halpha profile types indicates that forbidden lines are
evenly distributed among each Halpha line-profile type. Combining the distance estimates of the
Herbig candidates with the knowledge of the interstellar medium distribution, we have found
that 84 candidates can be associated with some of the more conspicuous SFRs, being in the
right direction and at a compatible distance. As a further means of checking the properties
of the HAeBe candidates, as well as their present evolutionary status, the derived luminosities
and effective temperatures of the stars with possible association to the star-forming regions
and/or Hipparcos distances were plotted together with a set of pre main-sequence evolutionary
tracks on an HR diagram. A set of 14 stars were found out of their expected positions in the
HR diagram.
vieira03.pdf - PDF version of the paper |