archive: SETI FW: AC Club News

# SETI FW: AC Club News

Larry Klaes ( lklaes@zoomtel.com )
Wed, 9 Sep 1998 10:01:06 -0400

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From: DaveRMoore@aol.com
Sent: Tuesday, September 08, 1998 5:55 PM
To: gc015@energex.com.au; lklaes@zoomtel.com; frank@bnkl01.astro.ucla.edu; hiffinho@gte.net; GDNordley@aol.com; lepage@bur.visidyne.com; skingsle@magnus.acs.ohio-state.edu; Fractenna@aol.com; anselmi@iride.iride.it
Subject: AC Club News

I picked up this little item which I though might be of interest.

Imaging a Circumstellar Disk around a Star with a Radial-Velocity Planetary
Companion

D. E. Trilling, R. H. Brown (LPL)

Radial-velocity searches have indirectly detected that a planet with minimum
mass 0.84 times that of Jupiter ({\rm MJ}) orbits the star 55~Cancri, a 3~ billion year old G8 star, with a period of 14.65~days and an orbital separation of 0.11~AU (Butler et al. 1997). Furthermore, the detection of excess far infrared emission from 55~Cancri is suggestive of circumstellar dust in that system (Dominik et al. 1998).

We have reported results of an infrared coronagraphic search for a mature
planetary system around 55~Cancri (Trilling and Brown 1998). We have
found a circumstellar disk of material whose inferred mass is approximately 10~times that estimated for our Solar System's Kuiper Belt. The observed
disk around 55~Cancri extends to at least 40~AU, consistent with the expected extent of our Solar System's Kuiper Belt (Weissman 1995). Our observations show that 55~Cancri's dust disk is relatively dark at
2.3~microns, consistent with absorption due to methane ice.

Assuming that 55~Cancri's disk is coplanar with the radial-velocity planet's orbit, we measure the inclination of the system and find the planet's
mass to be {1.9+1.1-0.4} {\rm MJ}. All the available evidence (a definite
radial velocity companion; the suggestion of a second radial velocity companion in the system (Butler et al. 1997); the far infrared excess
reported by Dominik et al.; and our imaging and characterization of a disk
out to at least 40~AU) is suggestive of a mature planetary system around 55~Cancri.

Dave R. Moore