TY - JOUR

T1 - An interesting episode of accretion activity in UX Orionis

AU - Natta, A.

AU - Grinin, V. P.

AU - Tambovtseva, L. V.

PY - 2000/10/10

Y1 - 2000/10/10

N2 - This paper presents observations of an episode of accretion activity in the pre-main-sequence star UX Ori. High-velocity, redshifted absorption is seen in several lines of H, Ca II, Na I, and Fe II during an interval of eight nights in the fall of 1996 with similar velocity and time evolution. A non-LTE analysis of the line optical depths shows that the infalling gas cannot be heavily hydrogen-depleted, as would be expected if it was produced by the evaporation of a solid body of chemical composition similar to solar system comets. On the contrary, the observations are consistent with gas of solar chemical composition at temperature ∼6000-7000 K.

AB - This paper presents observations of an episode of accretion activity in the pre-main-sequence star UX Ori. High-velocity, redshifted absorption is seen in several lines of H, Ca II, Na I, and Fe II during an interval of eight nights in the fall of 1996 with similar velocity and time evolution. A non-LTE analysis of the line optical depths shows that the infalling gas cannot be heavily hydrogen-depleted, as would be expected if it was produced by the evaporation of a solid body of chemical composition similar to solar system comets. On the contrary, the observations are consistent with gas of solar chemical composition at temperature ∼6000-7000 K.

KW - Circumstellar matter

KW - Stars: formation

KW - Stars: individual (UX Orionis)

KW - Stars: pre-main-sequence

UR - http://www.scopus.com/inward/record.url?scp=0034633456&partnerID=8YFLogxK

U2 - 10.1086/309526

DO - 10.1086/309526

M3 - Article

AN - SCOPUS:0034633456

VL - 542

SP - 421

EP - 427

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1 PART 1

ER -