Modeling the infrared bow shock at δ Velorum: Implications for studies of debris disks and λ boötis stars

A. Gáspár, K. Y.L. Su, G. H. Rieke, Z. Balog, I. Kamp, J. R. Martínez-Galarza, K. Stapelfeldt

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


We have discovered a bow shock shaped mid-infrared excess region in front of δ Velorum using 24 μm observations obtained with the Multiband Imaging Photometer for Spitzer ( MIPS). Although the bow shock morphology was only detected in the 24 μm observations, its excess was also resolved at 70 μm. We show that the stellar heating of an ambient interstellar medium (ISM) cloud can produce the measured flux. Since δ Velorum was classified as a debris disk star previously, our discovery may call into question the same classification of other stars. We model the interaction of the star and ISM, producing images that show the same geometry and surface brightness as is observed. The modeled ISM is ∼15 times overdense relative to the average Local Bubble value, which is surprising considering the close proximity (24 pc) of δ Velorum. The abundance anomalies of λ Boötis stars have been previously explained as arising from the same type of interaction of stars with the ISM. Low-resolution optical spectra of δ Velorum show that it does not belong to this stellar class. The star therefore is an interesting testbed for the ISM accretion theory of the λ Boötis phenomenon.

Original languageEnglish (US)
Pages (from-to)974-983
Number of pages10
JournalAstrophysical Journal
Issue number2
StatePublished - Jan 10 2008


  • ISM: kinematics and dynamics
  • Infrared: ISM
  • Radiation mechanisms: thermal
  • Shock waves
  • Stars: evolution
  • Stars: imaging
  • Stars: individual (HD 74956, δ Velorum)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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