uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Discovery of very low amplitude 9-minute multiperiodic pulsations in the magnetic Ap star HD75445
Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
2009 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 493, no 3, L45-L48 p.Article in journal (Refereed) Published
Abstract [en]

We present our discovery of pulsational radial-velocity variations in the cool Ap star HD75445, an object spectroscopically similar to the bright, rapidly-oscillating Ap (roAp) star gamma Equ. Based on high-resolution time-series spectroscopy obtained with the HARPS spectrometer at the European Southern Observatory 3.6-m telescope, we detected oscillations in Nd II and Nd III lines with a period close to 9 min and amplitudes of 20-30 m s(-1). Substantial variation in the pulsational amplitude during our 3.8 h observing run reveals the presence of at least three excited non-radial modes. The detection of extremely low amplitude pulsations in HD75445 indicates that the roAp excitation mechanism produces variability in the radial velocity amplitude of between a few tens ms(-1) and several km s(-1). This supports the idea that many, if not all, cool Ap stars occupying the roAp instability strip may harbour non-radial pulsations, which currently remain undetected due to their small photometric and radial-velocity amplitudes.

Place, publisher, year, edition, pages
2009. Vol. 493, no 3, L45-L48 p.
Keyword [en]
stars: atmospheres, stars: chemically peculiar, stars: oscillations, stars: individual: HD75445
National Category
Physical Sciences
URN: urn:nbn:se:uu:diva-137351DOI: 10.1051/0004-6361:200811419ISI: 000262641100002OAI: oai:DiVA.org:uu-137351DiVA: diva2:378214
Available from: 2010-12-15 Created: 2010-12-15 Last updated: 2010-12-15Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text
By organisation
Department of Physics and Astronomy
In the same journal
Astronomy and Astrophysics
Physical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 151 hits
ReferencesLink to record
Permanent link

Direct link