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Astron. Astrophys. 322, 511-522 (1997)

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8. Summary

Our main results can be summarized as follows:

  1. The photometric period of IN Comae is 5.913 [FORMULA] 0.005 days and not 1.2 days as claimed by several earlier studies. We interpret it as the rotation period of IN Comae.
  2. The spectral classification is G5 [FORMULA] 0.5III-IV (maybe III- but not IV) in agreement with its minimum radius of 7.8 [FORMULA] 0.2 [FORMULA] and an effective temperature of 5200 [FORMULA] 60 K. An inclination of [FORMULA] is therefore most likely.
  3. Our three Doppler images from March 1994 reveal mostly low-latitude spots with a temperature of 4700 [FORMULA] 50 (rms) K. Only the Fe I -6411 line shows a small, asymmetric polar spot of similar temperature.
  4. Surprisingly, some of the cool features from the strong calcium line show up at significantly lower latitudes than in the weaker iron-line maps. We tentatively suggest that we actually map an optical-depth dependence of the flux ratio between spots and photosphere.
  5. We detect "interstellar" absorption lines in the NaD spectrum of IN Comae but suggest that their origin may be due to the planetary nebula and not to interstellar absorption since the star is located very close to the galactic north pole where no significant interstellar reddening is obvious (in agreement with a recent study of interstellar hydrogen towards the north galactic pole by Piskunov et al. 1996).
  6. From the width of the Ca II -K line, the Wilson-Bappu relation gives a distance of about 700 pc.
  7. There is no detectable Li I 6707-Å line indicating that IN Comae is an old star that had enough time to deplete its surface lithium, which in turn is in agreement with its location within the planetary nebulae LoTr-5.
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© European Southern Observatory (ESO) 1997

Online publication: June 5, 1998