Redshifted Absorption at He I 10830 as a Probe of the Accretion Geometry of T Tauri Stars

Details Redshifted Absorption at He I 10830 as a Probe of the Accretion Geometry of T Tauri Stars Redshifted Absorption at He I 10830 as a Probe of the Accretion Geometry of T Tauri Stars

2008-07-16

arxiv.org/abs/0807.2483v1

Astronomy and Astrophysics

Astrophysics

26 pages, emulateapj format, Accepted by ApJ, to appear 2008 November 10

Scientific paper

10.1086/591902

We probe the geometry of magnetospheric accretion in classical T Tauri stars by modeling red absorption at He I 10830 via scattering of the stellar and veiling continua. Under the assumptions that the accretion flow is an azimuthally symmetric dipole and helium is sufficiently optically thick that all incident 1-micron radiation is scattered, we illustrate the sensitivity of He I 10830 red absorption to both the size of the magnetosphere and the filling factor of the hot accretion shock. We compare model profiles to those observed in 21 CTTS with subcontinuum redshifted absorption at He I 10830 and find that about half of the stars have red absorptions and 1-micron veilings that are consistent with dipole flows of moderate width with accretion shock filling factors matching the size of the magnetospheric footpoints. However, the remaining 50% of the profiles, with a combination of broad, deep absorption and low 1-micron veiling, require very wide flows where magnetic footpoints are distributed over 10-20% of the stellar surface but accretion shock filling factors are < 1%. We model these profiles by invoking large magnetospheres dilutely filled with accreting gas, leaving the disk over a range of radii in many narrow "streamlets" that fill only a small fraction of the entire infall region. In some cases accreting streamlets need to originate in the disk between several stellar radii and at least the corotation radius. A few stars have such deep absorption at velocities greater than half the stellar escape velocity that flows near the star with less curvature than a dipole trajectory seem to be required.

Affiliated with

Also associated with

No associations

Rating

Redshifted Absorption at He I 10830 as a Probe of the Accretion Geometry of T Tauri Stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Redshifted Absorption at He I 10830 as a Probe of the Accretion Geometry of T Tauri Stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Redshifted Absorption at He I 10830 as a Probe of the Accretion Geometry of T Tauri Stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-660148