Imaging search for the unseen companion to ε Ind A - Improving the detection limits with 4 μm observations

M. Janson, Daniel Apai, M. Zechmeister, W. Brandner, M. Kürster, M. Kasper, S. Reffert, M. Endl, D. Lafrenière, K. Geißler, S. Hippler, Th Henning

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

ε Ind A is one of the nearest Sun-like stars, located only 3.6 pc away. It is known to host a binary brown dwarf companion, ε Ind Ba/Bb, at a large projected separation of 6.7 arcmin, but radial velocity measurements imply that an additional, yet unseen, component is present in the system, much closer to ε Ind A. Previously, direct imaging has excluded the presence of any stellar or high-mass brown dwarf companion at small separations, indicating that the unseen companion may be a low-mass brown dwarf or high-mass planet. We present the results of a deep high-contrast imaging search for the companion, using active angular differential imaging at 4 μm, a particularly powerful technique for planet searches around nearby and relatively old stars. We also develop an additional point spread function reference subtraction scheme based on locally optimized combination of images to further enhance the detection limits. No companion is seen in the images, although we are sensitive to significantly lower masses than previously achieved. Combining the imaging data with the known radial velocity trend, we constrain the properties of the companion to within approximately 5-20 Mjup, 10-20 au and i > 20°, unless it is an exotic stellar remnant. The results also imply that the system is probably older than the frequently assumed age of ∼1 Gyr.

Original languageEnglish (US)
Pages (from-to)377-384
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume399
Issue number1
DOIs
StatePublished - Oct 2009
Externally publishedYes

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radial velocity
planets
planet
stars
point spread functions
velocity measurement
subtraction
sun
trends
detection
trend

Keywords

  • Planetary systems
  • Stars: low-mass, brown dwarfs

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Imaging search for the unseen companion to ε Ind A - Improving the detection limits with 4 μm observations. / Janson, M.; Apai, Daniel; Zechmeister, M.; Brandner, W.; Kürster, M.; Kasper, M.; Reffert, S.; Endl, M.; Lafrenière, D.; Geißler, K.; Hippler, S.; Henning, Th.

In: Monthly Notices of the Royal Astronomical Society, Vol. 399, No. 1, 10.2009, p. 377-384.

Research output: Contribution to journalArticle

Janson, M, Apai, D, Zechmeister, M, Brandner, W, Kürster, M, Kasper, M, Reffert, S, Endl, M, Lafrenière, D, Geißler, K, Hippler, S & Henning, T 2009, 'Imaging search for the unseen companion to ε Ind A - Improving the detection limits with 4 μm observations', Monthly Notices of the Royal Astronomical Society, vol. 399, no. 1, pp. 377-384. https://doi.org/10.1111/j.1365-2966.2009.15285.x
Janson, M. ; Apai, Daniel ; Zechmeister, M. ; Brandner, W. ; Kürster, M. ; Kasper, M. ; Reffert, S. ; Endl, M. ; Lafrenière, D. ; Geißler, K. ; Hippler, S. ; Henning, Th. / Imaging search for the unseen companion to ε Ind A - Improving the detection limits with 4 μm observations. In: Monthly Notices of the Royal Astronomical Society. 2009 ; Vol. 399, No. 1. pp. 377-384.
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