2004A&A...428L...1H


Query : 2004A&A...428L...1H

2004A&A...428L...1H - Astronomy and Astrophysics, volume 428, L1-4 (2004/12-2)

Magnetic fields in Herbig Ae stars.

HUBRIG S., SCHOELLER M. and YUDIN R.V.

Abstract (from CDS):

Herbig Ae stars are young A-type stars in the pre-main sequence evolutionary phase with masses of ∼1.5-3M. They show rather intense surface activity (Dunkin et al., 1997MNRAS.290..165D) and infrared excess related to the presence of circumstellar disks. Because of their youth, primordial magnetic fields inherited from the parent molecular cloud may be expected, but no direct evidence for the presence of magnetic fields on their surface, except in one case (Donati et al., 1997MNRAS.291..658D), has been found until now. Here we report observations of optical circular polarization with FORS 1 at the VLT in the three Herbig Ae stars HD 139614, HD 144432 and HD 144668. A definite longitudinal magnetic field at 4.8σ level, <Bz≥-450±93G, has been detected in the Herbig Ae star HD 139614. This is the largest magnetic field ever diagnosed for a Herbig Ae star. A hint of a weak magnetic field is found in the other two Herbig Ae stars, HD 144432 and HD 144668, for which magnetic fields are measured at the ∼1.6σ and ∼2.5σ level respectively. Further, we report the presence of circular polarization signatures in the CaII K line in the V Stokes spectra of HD 139614 and HD 144432, which appear unresolved at the low spectral resolution achievable with FORS 1. We suggest that models involving accretion of matter from the disk to the star along a global stellar magnetic field of a specific geometry can account for the observed Zeeman signatures.

Abstract Copyright:

Journal keyword(s): stars: pre-main-sequence - stars: polarization - stars: magnetic fields - stars: individual: HD 139614 - stars: individual: HD 144432 - stars: individual: HD 144668

Simbad objects: 5

goto Full paper

goto View the references in ADS

Number of rows : 5
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 V* DX Cha Ae* 12 00 05.0868602544 -78 11 34.565724312   6.81 6.60     A0_sh 323 0
2 HD 139614 Ae? 15 40 46.3820275416 -42 29 53.538761832   8.47 8.24     A9VekA5mA5(_lB) 186 0
3 HD 144432 Ae* 16 06 57.9533126832 -27 43 09.760564056 8.47 8.53 8.19 7.82 7.53 A9/F0V 229 1
4 V* V856 Sco Ae* 16 08 34.2870044544 -39 06 18.325711332 7.66 7.41 7.05 6.92   A7IIIne_sh 372 0
5 HD 163296 Ae* 17 56 21.2881851168 -21 57 21.871819008 7.00 6.93 6.85 6.86 6.67 A1Vep 977 0

To bookmark this query, right click on this link: simbad:objects in 2004A&A...428L...1H and select 'bookmark this link' or equivalent in the popup menu


2022.10.01-14:26:28

© Université de Strasbourg/CNRS

    • Contact