TY - JOUR

T1 - Evaporation of star-grazing bodies in the vicinity of UX Ori-type stars

AU - Grinin, V.

AU - Natta, A.

AU - Tambovtseva, L.

PY - 1996/9/20

Y1 - 1996/9/20

N2 - This paper studies the behaviour of star-grazing planetesimal bodies in the neighbourhood of UX Ori-type stars. When approaching a star, large size bodies (diameteres of ten meters or more) disintegrate into a number of small fragments under the effect of thermal stresses. In turn, the fragments sublimate within a sphere of about ten stellar radii and form a circumstellar gas envelope. An important feature of this envelope is a strong excess of heavy elements. Our calculations show that the radiative force on the metal-enriched gas is much larger than in the case of standard chemical composition and exceeds by few times the gravity of the star. As a result, the evaporated matter is accelerated outward and is expelled from the system by radiative pressure. Thus, the evaporation of planetesimals in the vicinity of young stars leads to complex gas motions which include in-fall, quasi-keplerian rotation and the radial outflow typical of radiatively driven stellar winds.

AB - This paper studies the behaviour of star-grazing planetesimal bodies in the neighbourhood of UX Ori-type stars. When approaching a star, large size bodies (diameteres of ten meters or more) disintegrate into a number of small fragments under the effect of thermal stresses. In turn, the fragments sublimate within a sphere of about ten stellar radii and form a circumstellar gas envelope. An important feature of this envelope is a strong excess of heavy elements. Our calculations show that the radiative force on the metal-enriched gas is much larger than in the case of standard chemical composition and exceeds by few times the gravity of the star. As a result, the evaporated matter is accelerated outward and is expelled from the system by radiative pressure. Thus, the evaporation of planetesimals in the vicinity of young stars leads to complex gas motions which include in-fall, quasi-keplerian rotation and the radial outflow typical of radiatively driven stellar winds.

KW - Evaporation

KW - Star-grazing bodies

KW - Stellar wind

KW - UX Ori type stars

UR - http://www.scopus.com/inward/record.url?scp=0010702055&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0010702055

VL - 313

SP - 857

EP - 865

JO - ASTRONOMY & ASTROPHYSICS

JF - ASTRONOMY & ASTROPHYSICS

SN - 0004-6361

IS - 3

ER -