Modeling the Infrared Bow Shock at δ Velorum: Implications for Studies of Debris Disks and λ Bootis Stars
Open Access
- 10 January 2008
- journal article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 672 (2), 974-983
- https://doi.org/10.1086/523299
Abstract
We have discovered a bow shock shaped mid-infrared excess region in front of delta Velorum using 24 micron observations obtained with the Multiband Imaging Photometer for Spitzer (MIPS). The excess has been classified as a debris disk from previous infrared observations. Although the bow shock morphology was only detected in the 24 micron observations, its excess was also resolved at 70 micron. We show that the stellar heating of an ambient interstellar medium (ISM) cloud can produce the measured flux. Since delta 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 delta Velorum. The abundance anomalies of lambda Bootis stars have been previously explained as arising from the same type of interaction of stars with the ISM. Low resolution optical spectra of delta 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 lambda Bootis phenomenon.Comment: 11 pages, 1 table and 13 figures, emulateapj; Accepted for publication in The Astrophysical JournaThis publication has 39 references indexed in Scilit:
- Spitzer IRS Spectroscopy of IRAS ‐discovered Debris DisksThe Astrophysical Journal Supplement Series, 2006
- Round Table Summary: Problems in Modelling Stellar AtmospheresSymposium - International Astronomical Union, 2003
- Orbits for five southern visual binariesAstronomy & Astrophysics, 2002
- Additional ultra-high-resolution observations of Ca+ ions in the local interstellar mediumMonthly Notices of the Royal Astronomical Society, 1998
- Dust around Main‐Sequence Stars: Nature or Nurture by the Interstellar Medium?The Astrophysical Journal, 1997
- A simple accretion/diffusion model for Lambda Bootis starsThe Astrophysical Journal, 1991
- Spectral class distribution of circumstellar material in main-sequence starsThe Astronomical Journal, 1988
- IRAS observations of matter around nearby starsPublications of the Astronomical Society of the Pacific, 1985
- Radiation forces on small particles in the solar systemIcarus, 1979
- On the Mechanism of Accretion by StarsMonthly Notices of the Royal Astronomical Society, 1944