sdOB star Feige 46 spectrum Virtual Observatory Resource

Authors
  1. Latour M.
  2. Green E.M.
  3. Fontaine G.
  4. Published by
    CDS
Abstract

We present the discovery of long-period, low-amplitude, g-mode pulsations in the intermediate He-rich hot subdwarf (sdOB) star Feige 46. So far, only one other He-enriched sdOB star (LS IV -14116) was known to exhibit such pulsations. From our ground-based light curves of Feige 46, we extracted five independent periodicities ranging from 2294s to 3400s. We fit our optical spectrum of the star with our grid of non-local thermodynamic equilibrium (NLTE) model atmospheres and derived the following atmospheric parameters: Teff=36120+/-230K, logg=5.93+/-0.04, and log N(He)/N(H)=-0.32+/-0.03 (formal fitting errors only). These parameters are very similar to those of LS IV -14116 and place Feige 46 well outside of the instability strip where the hydrogen-rich g-mode sdB pulsators are found. We used the Gaia parallax and proper motion of Feige 46 to perform a kinematic analysis of this star and found that it likely belongs to the Galactic halo population. This is most certainly an intriguing and interesting result given that LS IV -14116 is also a halo object.The mechanism responsible for the pulsations in these two peculiar objects remains unclear, but a possible scenario involves the epsilon-mechanism. Although they are the only two members in their class of variable stars, these pulsators appear to have more in common than just their pulsation properties.

Keywords
  1. Subdwarf stars
  2. Spectroscopy
Bibliographic source Bibcode
2019A&A...623L..12L
See also HTML
https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/623/L12
IVOA Identifier IVOID
ivo://CDS.VizieR/J/A+A/623/L12
Document Object Identifer DOI
doi:10.26093/cds/vizier.36239012

Access

Web browser access HTML
http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/623/L12
https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/623/L12
http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/623/L12
IVOA Table Access TAP
http://tapvizier.cds.unistra.fr/TAPVizieR/tap
Run SQL-like queries with TAP-enabled clients (e.g., TOPCAT).
Web browser access HTML
https://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/623/L12

History

2019-03-25T14:44:16Z
Resource record created
2019-03-25T14:44:16Z
Created
2019-04-16T06:21:48Z
Updated

Contact

Name
CDS support team
Postal Address
CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France
E-Mail
cds-question@unistra.fr