TY - JOUR

T1 - On the nature of the unique eclipsing system H 187 (HMW 15)

AU - Grinin, V. P.

AU - Barsunova, O. Yu

AU - Sergeev, S. G.

AU - Sotnikova, N. Ya

AU - Demidova, T. V.

PY - 2006/12/1

Y1 - 2006/12/1

N2 - We present our photometric observations of the T Tauri star H 187. They confirm our conclusion that a new extended eclipse has begun in this young object. By the end of 2005, H 187 reached its minimum light following which its brightness began to slowly increase. Comparison with the previous ∼ 3.5-yr-long eclipse observed by Cohen et al. shows that the new eclipse follows the previous eclipse fairly closely and, hence, it was caused by a second passage of the same extended dust or gas-dust cloud around the object. We have estimated the period between these events to be 4.7 yr. The object reddened during the eclipse, suggesting that the extinction was produced by small grains ∼ 0.1μm in size. Possible mechanisms of such unusual eclipses are discussed. We draw an analogy between these eclipses and the cycles of photometric activity observed in UX Ori stars. Light curves similar to those observed for H 187 are shown to be obtained in the model of a young binary system with a low-mass companion accreting matter from the remnants of a protostellar cloud at a rate of ∼ 10-9 M Ȯ yr-1.

AB - We present our photometric observations of the T Tauri star H 187. They confirm our conclusion that a new extended eclipse has begun in this young object. By the end of 2005, H 187 reached its minimum light following which its brightness began to slowly increase. Comparison with the previous ∼ 3.5-yr-long eclipse observed by Cohen et al. shows that the new eclipse follows the previous eclipse fairly closely and, hence, it was caused by a second passage of the same extended dust or gas-dust cloud around the object. We have estimated the period between these events to be 4.7 yr. The object reddened during the eclipse, suggesting that the extinction was produced by small grains ∼ 0.1μm in size. Possible mechanisms of such unusual eclipses are discussed. We draw an analogy between these eclipses and the cycles of photometric activity observed in UX Ori stars. Light curves similar to those observed for H 187 are shown to be obtained in the model of a young binary system with a low-mass companion accreting matter from the remnants of a protostellar cloud at a rate of ∼ 10-9 M Ȯ yr-1.

KW - Accretion

KW - Photometry

KW - UX Ori stars

KW - Young eclipsing systems

UR - http://www.scopus.com/inward/record.url?scp=33845296613&partnerID=8YFLogxK

U2 - 10.1134/S1063773706120048

DO - 10.1134/S1063773706120048

M3 - Article

AN - SCOPUS:33845296613

VL - 32

SP - 827

EP - 831

JO - Astronomy Letters

JF - Astronomy Letters

SN - 1063-7737

IS - 12

ER -