Detection of magnetic field in the B2 star rho Ophiuchi A with ESO FORS2
- Circumstantial evidence suggests that magnetism and enhanced X-ray emission are likely correlated in early B-type stars: similar fractions of them (similar to 10%) are strong and hard X-ray sources and possess strong magnetic fields. It is also known that some B-type stars have spots on their surface. Yet up to now no X-ray activity associated with spots on early-type stars was detected. In this Letter we report the detection of a magnetic field on the B2V star rho Oph A. Previously, we assessed that the X-ray activity of this star is associated with a surface spot, herewith we establish its magnetic origin. We analyze spectra of rho Oph A obtained with the FORS2 spectrograph at ESO Very Large Telescope (VLT) at two epochs, and detect a longitudinal component of the magnetic field of the order of similar to 500 G in one of the datasets. The detection of the magnetic field only at one epoch can be explained by stellar rotation which is also invoked to explain observed periodic X-ray activity. From archival HARPS ESO VLT high resolutionCircumstantial evidence suggests that magnetism and enhanced X-ray emission are likely correlated in early B-type stars: similar fractions of them (similar to 10%) are strong and hard X-ray sources and possess strong magnetic fields. It is also known that some B-type stars have spots on their surface. Yet up to now no X-ray activity associated with spots on early-type stars was detected. In this Letter we report the detection of a magnetic field on the B2V star rho Oph A. Previously, we assessed that the X-ray activity of this star is associated with a surface spot, herewith we establish its magnetic origin. We analyze spectra of rho Oph A obtained with the FORS2 spectrograph at ESO Very Large Telescope (VLT) at two epochs, and detect a longitudinal component of the magnetic field of the order of similar to 500 G in one of the datasets. The detection of the magnetic field only at one epoch can be explained by stellar rotation which is also invoked to explain observed periodic X-ray activity. From archival HARPS ESO VLT high resolution spectra we derived the fundamental stellar parameters of rho Oph A and further constrained its age. We conclude that rho Oph A provides strong evidence for the presence of active X-ray emitting regions on young magnetized early type stars.…
| Author details: | Ignazio PillitteriORCiD, Luca Fossati, N. Castro Rodriguez, Lida OskinovaORCiDGND, Scott J. Wolk |
|---|---|
| DOI: | https://doi.org/10.1051/0004-6361/201732078 |
| ISSN: | 1432-0746 |
| Title of parent work (English): | Astronomy and astrophysics : an international weekly journal |
| Publisher: | EDP Sciences |
| Place of publishing: | Les Ulis |
| Publication type: | Article |
| Language: | English |
| Date of first publication: | 2017/12/02 |
| Publication year: | 2017 |
| Release date: | 2022/01/24 |
| Tag: | pulsars: individual: rho Ophiuchi A; stars: activity; stars: early-type; stars: magnetic field |
| Volume: | 610 |
| Number of pages: | 4 |
| Funding institution: | INAFIstituto Nazionale Astrofisica; ASIItalian Space Agency; ARIEL consortium; DLRHelmholtz AssociationGerman Aerospace Centre (DLR) [50OR1302]; Russian Government Program of Competitive Growth of Kazan Federal University; NASANational Aeronautics & Space Administration (NASA) [NAS8-03060] |
| Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
| DDC classification: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
| Peer review: | Referiert |
| Publishing method: | Open Access / Bronze Open-Access |
