SUMMARY OF PROPOSAL 42011
DR. EDWARD F. GUINAN
VILLANOVA UNIVERSITY
PENNSYLVANIA USA 19085
VILLANOVA
LANCASTER AVE.

  E-mail: GUINAN@UCIS.VILL.EDU	Tel: (610) 519 4823	Fax: (610) 519 6132
  Medium: 4GBDAT

Subject: STARS                                                       
  Title: THE YOUNG F0 V STAR 47 CAS: PROBING THE MAGNETIC DYNAMO IN A STAR WITH A SHALLOW CONVECTIVE ZONE


Abstract:
 The target 47 Cas was identified in the ROSAT All-Sky Survey as one of the strongest
 single stellar X-ray sources, and at a distance of 38 pc, as one of the most
 luminous main-sequence stars known (log LX=30.5). Its spectral type of F0V locates
 the star in a regime where it should have a very shallow convective zone and where
 acoustic heating is thought to be the dominant source of coronal heating. However,
 X-ray rotational modulation(P=0.97d), strong X-ray flares, giant radio flares, and a
 strong CIV 1550A emission line argue for a magnetic, solar-like corona. The proposed
 ASCA observations will be ideal to study structuring and variability of this corona.
 A significant fraction of the rotation period will be covered. Supporting observations at other wavelengths will be arranged.

 Co-Is:
   1  MANUEL GUEDEL       	PSI                           SWITZ     
      GUEDEL@ASTRO.PHYS.ETHZ.CH	0041 - 1 - 632 71 29


Target Name           PRI RA        Dec        Time TC  Off GIS SIS_Cts  Obs
-------------------   --- --------  --------   ---- --  --- --- -------  ---
47 CAS                 0   31.2792   77.2814    40   N   Y   P  5.00000   1