Astron. Astrophys. 343, 163-174 (1999)

Spectroscopic, photometric, and polarimetric study of the Herbig Ae candidate HD 36112

N.G. Beskrovnaya ¹, M.A. Pogodin ¹, A.S. Miroshnichenko ¹, P.S. Thé ², I.S. Savanov ³, N.M. Shakhovskoy ³, A.N. Rostopchina ³, O.V. Kozlova ³ and K.S. Kuratov <sup>4

1</sup> Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, 196140 Saint-Petersburg, Russia (e-mail: beskr@pulkovo.spb.su)
² Universiteit van Amsterdam, Astronomical Institute, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands
³ Crimean Astrophysical Observatory, 334413 Nauchnyi, Crimea, Ukraine
⁴ Fesenkov Astrophysical Institute of the Kazakhstan National Academy of Sciences, 480068 Almaty, Kazakhstan

Received 5 January 1998 / Accepted 9 October 1998

Abstract

We describe observations of the Herbig Ae candidate HD 36112 including high-resolution spectroscopy of photospheric and circumstellar lines, multi-colour photometry and polarimetry. These observations reveal that many features of the observational appearance of HD 36112 are similar to those of `classical' Herbig Ae stars. Among these are: the far IR excess, manifestations of the high-temperature zone in the inner envelope, distinctive types of the H profile variations, and variable multi-component polarization and brightness parameters.

The fundamental characteristics of the star have been determined. In particular, HD 36112 proves to be an unreddened A8 V of age years. This means, that the star is still at the PMS phase of evolution, but close to the ZAMS. The anomalous abundances of barium and silicon discovered in HD 36112 allow to suggest that chemical anomalies can arise already at the early stages of stellar evolution.

The totality of observed properties of HD 36112 give evidence of complicated structure of the gaseous-dusty envelope around this object, including the variable stellar wind with an extended acceleration zone, as well as large and small-grained dust, located in the orthogonal planes.

Key words: stars: individual: HD 36112 line: profiles polarization stars: circumstellar matter stars: mass-loss stars: pre-main sequence

Send offprint requests to: N.G. Beskrovnaya

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observational programme
  • 2.1. Spectroscopy in the regions containing photospheric lines
  • 2.2. Investigation of the rapid variability of the lines forming in the gaseous envelope
  • 2.3. Multicolour photometry and polarimetry
• 3. Data acquisition and reduction
  • 3.1. Spectroscopic observations
  • 3.2. Polarimetric observations
  • 3.3. Photometric observations
• 4. Results
  • 4.1. Photometry
  • 4.2. Spectral type estimates
  • 4.3. Binarity checking
  • 4.4. Projected rotational velocity
  • 4.5. Chemical anomalies
  • 4.6. Circumstellar lines
  • 4.7. Rapid variability of circumstellar lines in different runs
  • 4.8. Polarization features
• 5. Discussion
  • 5.1. Chemical anomalies and evolutionary status of HD 36112
  • 5.2. Circumstellar envelope of HD 36112
  • 5.3. Azimuthal inhomogeneity of the circumstellar envelope
    • 5.3.1. Spectroscopic evidences
    • 5.3.2. Polarimetric evidences
• 6. Conclusions
• Acknowledgements
• References

List of Objects `HD 36112' on page 3 `MWC 758' on page 3 `AB Aur' on page 3 `CQ Tau' on page 3 `RR Tau' on page 3 `HD 32509' on page 3 `HD 35187' on page 3 `HD 31648' on page 3 `HD 163296' on page 47

© European Southern Observatory (ESO) 1999

Online publication: March 1, 1999
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