## SUMMARY OF PROPOSAL 61231

#### MS YOHKO TSUBOI TSUBOI@CR.SCPHYS.KYOTO-U.AC.JP

KYOTO UNIV.
KYOTO JAPAN 606-01
KYOTO
KITASHIRAKAWA-OIWAKE-CHO, SAKYO
Tel: 075-753-3843 Fax: 075-701-5377
Medium: 2.5GB8MM
Subject: COSMIC X-RAY BACKGROUND DEEP SURVEYS AND OTHER

#### ABSTRACT

With the ASCA PV phase, we detected Class I sources deeply embedded in the Rho-Oph dark cloud. One of the hard X-ray sources (EL29) shows a flare associated with a heat-up and cooling, while another (WL6) exhibits sinusoidal variation with no large spectral change. The later would be due to the spin rotation of the protostar. The period of the sinusoidal variation is about 1 day, which is shorter than the rotational period of T Tauri stars, or more evolved star than protostars, of \$\sim\$3--7 day. The goal of this survey project is TO DETECT THE SPIN PERIOD OF PROTOSTARS. Protostar itself cannot be detected in any other wave lengths because of the high absorption (Av\$>\$100mag), then the spin of the star can be detected only in the hard X-ray of ASCA.