IRAS 08159-3543: Optical Detection of the Dusty, Neutral Bipolar Wind of a Luminous Young Stellar Object

Abstract

view Abstract Citations (12) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS IRAS 08159-3543: Optical Detection of the Dusty, Neutral Bipolar Wind of a Luminous Young Stellar Object Neckel, Th. ; Staude, H. J. Abstract We have detected by optical means the neutral bipolar wind from IRAS 08159-3543, a deeply embedded, luminous young stellar object (YSO) (L ∼2.4 × 104 Lsun, AV ≳ 43 mag). The wind is observable, because it carries huge amounts of dust flowing outward in the bright lobes at υf 570 km s-1. The velocity field of the neutral flow was determined by long-slit spectroscopy of the broad Hα line emitted by the ionized envelope near the unseen YSO and scattered by the moving dust. The velocity of the neutral flow far out in the lobes is nearly the same as the outflow velocity reached in the ionized envelope. Therefore, most of the outflowing material in the lobes must have been accelerated by the primary mechanism at work near the YSO. The ionized envelope is bisected in its equatorial plane by an optically thick layer; also, in the scattered spectrum of the YSO several chromospheric Fe II emission lines are observed. These findings can be taken as evidence for an active accretion disk surrounding the YSO and driving the wind seen in the ionized envelope. The outflowing dust observed in the lobes may be carried along by a neutral wind leaving the outer (cooler) parts of the disk. We estimate the spectral type of the YSO (F-K) from the brightness and color of the scattered continuum: in the H-R diagram the YSO is located far above the zero-age main sequence and the theoretical stellar birth- line. The total mass loss in the wind is Mṡ 6 × 10-5 -2 × 10-4 Msun yr-1. The corresponding ratio Mṡ/L lies within the range derived from CO outflows (Levreault 1988). Thus, relative to the luminosity of the source, the wind carries as much momentum as is observed in molecular outflows driven by YSOs of low and intermediate luminosity. Within a volume whose total extent is about 0.5 pc, the neutral outflow in the lobes is interspersed with shock-ionized material (filling factor ∼0.04), which moves outward at about one-fourth of the speed of the neutral flow. Publication: The Astrophysical Journal Pub Date: August 1995 DOI: 10.1086/176011 Bibcode: 1995ApJ...448..832N Keywords: ACCRETION; ACCRETION DISKS; STARS: CIRCUMSTELLAR MATTER; ISM: DUST; EXTINCTION; STARS: MASS LOSS; STARS: PRE-MAIN-SEQUENCE full text sources ADS | data products SIMBAD (10)