The disk and environment of a young Vega analog: HD 169142

C. A. Grady, G. Schneider, K. Hamaguchi, M. L. Sitko, W. J. Carpenter, D. Hines, K. A. Collins, G. M. Williger, B. E. Woodgate, T. H. Henning, F. Ménard, D. Wilner, R. Petre, P. Palunas, A. Quirrenbach, J. A. Nuth, M. D. Silverstone, J. S. Kim

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

Abstract

We trace the disk of HD169142 (A8 Ve) from 0.57″ to 1.4″ (≃80-200 AU projected distance) in 1.1 μm scattered light with ASTNICMOS coronagraphy. The azimuthally symmetric disk has a peak azimuthally medianed surface brightness (SB) of ≈5 mJy arcsec-2 at 0.57″ from the star, and drops ∝r-3. This radial SB profile is consistent with the presence of spatially resolved PAH emission and a Meeus group I IR SED only if the inner disk is either substantially flatter than the outer disk or partially devoid of material. Analysis of new HSTACS FUV imagery in tandem with archival IUE data indicates Macc ≤ 10-9 Ṁ yr -1. We estimate the age of HD 169142 to be 6-3 +6 Myr by identifying 2MASS 18242929-2946559, located 9.3″ to the southwest, as a 130 mas separation weak-line T Tauri binary that is comoving with HD 169142 at the 4 σ confidence level. We find no evidence for any additional stellar companion in either the ACS or Chandra ACIS-S data at r ≤ 1″. HD 169142 has previously been interpreted as a slowly rotating, chemically peculiar star, However, by combining the disk inclination and v sin i from the literature, we find that the star has vequatorial ≈ 240 km s-1, making it a rapid rotator, similar to Altair or Vega. The UV data for HD 169142 are consistent with gravity darkening, while the X-ray luminosity and spectrum resembles early F stars at the age of the ß Pictoris moving group, rather than mid-A stars. In this context, spectral features previously interpreted as evidence for chemical peculiarity are more likely to reflect the presence of a strong photospheric latitudinal temperature gradient. With such a gradient, HD 169142 should closely resemble Vega at the epoch of central disk clearing.

Original languageEnglish (US)
Pages (from-to)1391-1406
Number of pages16
JournalAstrophysical Journal
Volume665
Issue number2 I
DOIs
StatePublished - Aug 10 2007
Externally publishedYes

Keywords

  • Binaries: Visual
  • Brown dwarfs
  • Planetary systems: Protoplanetary disks
  • Stars: Individual (2MASS 18242929-2946559 HD 22128 HD 36112 HD 142666 HD 169142 HD 220750)
  • Stars: Low-mass
  • Stars: Pre-main-sequence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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