A Spitzer/IRAC Search for Substellar Companions of the Debris Disk Star epsilon Eridani

Abstract

We have used the InfraRed Array Camera (IRAC) onboard the Spitzer Space telescope to search for low mass companions of the nearby debris disk star epsilon Eridani. The star was observed in two epochs 39 days apart, with different focal plane rotation to allow the subtraction of the instrumental Point Spread Function, achieving a maximum sensitivity of 0.01 MJy/sr at 3.6 and 4.5 um, and 0.05 MJy/sr at 5.8 and 8.0 um. This sensitivity is not sufficient to directly detect scattered or thermal radiation from the epsilon Eridani debris disk. It is however sufficient to allow the detection of Jovian planets with mass as low as 1 MJ in the IRAC 4.5 um band. In this band, we detected over 460 sources within the 5.70 arcmin field of view of our images. To test if any of these sources could be a low mass companion to epsilon Eridani, we have compared their colors and magnitudes with models and photometry of low mass objects. Of the sources detected in at least two IRAC bands, none fall into the range of mid-IR color and luminosity expected for cool, 1 Gyr substellar and planetary mass companions of epsilon Eridani, as determined by both models and observations of field M, L and T dwarf. We identify three new sources which have detections at 4.5 um only, the lower limit placed on their [3.6]-[4.5] color consistent with models of planetary mass objects. Their nature cannot be established with the currently available data and a new observation at a later epoch will be needed to measure their proper motion, in order to determine if they are physically associated to epsilon Eridani.

arXiv comment36 pages, to be published on The Astrophysical Journal, vol. 647, August 2006

References in corpus (23)

• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• The Spitzer Space Telescope Mission
• The Infrared Spectrograph on the Spitzer Space Telescope
• A Non-Gray Theory of Extrasolar Giant Planets and Brown Dwarfs
• Detection of Thermal Emission from an Extrasolar Planet
• Infrared radiation from an extrasolar planet
• A dust ring around Epsilon Eridani: analogue to the young Solar System
• Beyond the T Dwarfs: Theoretical Spectra, Colors, and Detectability of the Coolest Brown Dwarfs
• Number Counts At 3 < lambda < 10 um From the Spitzer Space Telescope
• Evidence for a Long-period Planet Orbiting Epsilon Eridani
• Strong Infrared Emission from the Extrasolar Planet HD189733b
• Dynamical Instabilities in Extrasolar Planetary Systems Containing Two Giant Planets
• Spectral Irradiance Calibration in the Infrared. XIII. "Supertemplates" and On-Orbit Calibrators for SIRTF's Infrared Array Camera (IRAC)
• The Vega Debris Disk -- A Surprise from Spitzer
• Structure in the Epislon Eridani dusty disk caused by mean motion resonances with a 0.3 eccentricity planet at periastron
• The NGC 7129 Young Stellar Cluster: A Combined Spitzer, MMT, and 2MASS Census of Disks, Protostars, and Outflows
• Sub-mm observations and modelling of Vega type stars
• IRAC Imaging of Lockman Hole
• Deep Keck adaptive optics searches for extrasolar planets in the dust of Epsilon Eridani and Vega
• Deep mid-infrared observations of Lyman-break galaxies
• The Dynamical Influence of a Planet at Semimajor Axis 3.4 AU on the Dust Around Epsilon Eridani
• Modeling the Infrared Emission from the Epsilon Eridani Disk
• Limits on the Optical Brightness of the Epsilon Eridani Dust Ring

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• Imaging Extrasolar Giant Planets
• Discovery of Two T Dwarf Companions with the Spitzer Space Telescope
• Debris Disks: Seeing Dust, Thinking of Planetesimals and Planets
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• Debris disc stirring by secular perturbations from giant planets
• Epsilon Eridani's Planetary Debris Disk: Structure and Dynamics based on Spitzer and CSO Observations
• Discovery of a Wide Binary Brown Dwarf Born in Isolation
• The cold origin of the warm dust around epsilon Eridani
• A temperate super-Jupiter imaged with JWST in the mid-infrared
• Spitzer/IRAC Limits to Planetary Companions of Fomalhaut and epsilon Eridani
• The Northern Arc of $\epsilon$ Eridani's Debris Ring as Seen by ALMA
• The circumstellar envelopes of the Cepheids L Car and RS Pup - Comparative study in the infrared with Spitzer, VLT/VISIR and VLTI/MIDI
• High-contrast Imaging with Spitzer: Deep Observations of Vega, Fomalhaut, and epsilon Eridani
• A comprehensive examination of the Eps Eri system -- Verification of a 4 micron narrow-band high-contrast imaging approach for planet searches
• Galactic Cepheids with Spitzer: II. Search for Extended Infrared Emission
• Spitzer detection of PAH and silicate features in post-AGB stars and young Planetary Nebulae
• NACO-SDI direct imaging search for the exoplanet Eps Eri b
• High Contrast Imaging with Spitzer : Constraining the Frequency of Giant Planets out to 1000 AU separations
• Imaging the Cool Hypergiant NML Cygni's Dusty Circumstellar Envelope with Adaptive Optics
• A Mid-Infrared Study of Directly-Imaged Planetary-Mass Companions using Archival Spitzer/IRAC Images
• Spectroscopy of Putative Brown Dwarfs in Taurus
• Astrophysics in 2006
• A coronagraphic search for wide sub-stellar companions among members of the Ursa Major moving group
• Searching for Wide Companions and Identifying Circum(sub)stellar Disks through PSF-Fitting of Spitzer/IRAC Archival Images
• A Mid-Infrared Search for Substellar Companions of Nearby Planet-Host Stars
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