Browsing by Author "Carpenter, JM"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    The formation and evolution of planetary systems (FEPS): Discovery of an unusual debris system associated with HD 12039
    (IOP Publishing, 2006-02-20) Hines, DC; Backman, DE; Bouwman, J; Hillenbrand, LA; Carpenter, JM; Meyer, MR; Kim, JS; Silverstone, MD; Rodmann, J; Wolf, S; Mamajek, EE; Brooke, TY; Padgett, DL; Henning, T; Moro-Martin, A; Stobie, E; Gordon, KD; Morrison, JE; Muzerolle, J; Su, KYL; National Aeronautics & Space Administration (NASA); Max Planck Society; California Institute of Technology; University of Arizona; Harvard University; Smithsonian Astrophysical Observatory; Smithsonian Institution; Princeton University; University of Alabama Tuscaloosa
    We report the discovery of a debris system associated with the similar to 30 Myr old G3/5V star HD 12039 using Spitzer Space Telescope observations from 3.6-160 mu m. An observed infrared excess (L-IR/L-* = 1 x 10(-4)) above the expected photosphere for lambda greater than or similar to 14 mu m is fit by thermally emitting material with a color temperature of T similar to 110 K, warmer than the majority of debris disks identified to date around Sun-like stars. The object is not detected at 70 mu m with a 3 sigma upper limit 6 times the expected photospheric flux. The spectrum of the infrared excess can be explained by warm, optically thin material comprised of blackbody-like grains of size greater than or similar to 7 mu m that reside in a belt orbiting the star at 4-6 AU. An alternate model dominated by smaller grains, near the blowout size a similar to 0.5 mu m, located at 30-40 AU is also possible but requires the dust to have been produced recently, since such small grains will be expelled from the system by radiation pressure in approximately a few times 10(2) yr.
  • Thumbnail Image
    Item
    Formation and evolution of planetary systems: Cold outer disks associated with sun-like stars
    (IOP Publishing, 2005-10-10) Kim, JS; Hines, DC; Backman, DE; Hillenbrand, LA; Meyer, MR; Rodmann, J; Moro-Martin, A; Carpenter, JM; Silverstone, MD; Bouwman, J; Mamajek, EE; Wolf, S; Malhotra, R; Pascucci, I; Najita, J; Padgett, DL; Henning, T; Brooke, TY; Cohen, M; Strom, SE; Stobie, EB; Engelbracht, CW; Gordon, KD; Misselt, K; Morrison, JE; Muzerolle, J; Su, KYL; University of Arizona; National Aeronautics & Space Administration (NASA); NASA Ames Research Center; California Institute of Technology; Max Planck Society; Princeton University; Harvard University; Smithsonian Astrophysical Observatory; Smithsonian Institution; National Optical Astronomy Observatory; University of California System; University of California Berkeley; University of Alabama Tuscaloosa
    We present the discovery of debris systems around three Sun-like stars based on observations performed with the Spitzer Space Telescope as part of a Legacy Science Program, "The Formation and Evolution of Planetary Systems'' ( FEPS). We also confirm the presence of debris around two other stars. All the stars exhibit infrared emission in excess of the expected photospheres in the 70 mu m band but are consistent with photospheric emission at <= 33 mu m. This restricts the maximum temperature of debris in equilibrium with the stellar radiation to T < 70 K. We find that these sources are relatively old in the FEPS sample, in the age range 0.7 - 3 Gyr. On the basis of models of the spectral energy distributions, we suggest that these debris systems represent materials generated by collisions of planetesimal belts. We speculate on the nature of these systems through comparisons to our own Kuiper Belt, and on the possible presence of planet( s) responsible for stirring the system and ultimately releasing dust through collisions. We further report observations of a nearby star HD 13974 ( d 11 pc) that are indistinguishable from a bare photosphere at both 24 and 70 mu m. The observations place strong upper limits on the presence of any cold dust in this nearby system (L-IR/L-* < 10 (-5.2)).
  • Thumbnail Image
    Item
    The formation and evolution of planetary systems: First results from a Spitzer Legacy Science Program
    (University of Chicago Press, 2004-09) Meyer, MR; Hillenbrand, LA; Backman, DE; Beckwith, SVW; Bouwman, J; Brooke, TY; Carpenter, JM; Cohen, M; Gorti, U; Henning, T; Hines, DC; Hollenbach, D; Kim, JS; Lunine, J; Malhotra, R; Mamajek, EE; Metchev, S; Moro-Martin, A; Morris, P; Najita, J; Padgett, DL; Rodmann, J; Silverstone, MD; Soderblom, DR; Stauffer, JR; Stobie, EB; Strom, SE; Watson, DM; Weidenschilling, SJ; Wolf, S; Young, E; Engelbracht, CW; Gordon, KD; Misselt, K; Morrison, J; Muzerolle, J; Su, K; University of Arizona; California Institute of Technology; National Aeronautics & Space Administration (NASA); NASA Ames Research Center; Space Telescope Science Institute; Johns Hopkins University; Max Planck Society; University of California System; University of California Berkeley; National Optical Astronomy Observatory; University of Rochester; University of Alabama Tuscaloosa
    We present 3-160 mum photometry obtained with the Infrared Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS) instruments for the first five targets from the Spitzer Space Telescope Legacy Science Program "Formation and Evolution of Planetary Systems'' and 4-35 mum spectrophotometry obtained with the Infrared Spectrograph (IRS) for two sources. We discuss in detail our observations of the debris disks surrounding HD 105 (G0 V, 30+/-10 Myr) and HD 150706 (G3 V, similar to700+/-300 Myr). For HD 105, possible interpretations include large bodies clearing the dust inside of 45 AU or a reservoir of gas capable of sculpting the dust distribution. The disk surrounding HD 150706 also exhibits evidence of a large inner hole in its dust distribution. Of the four survey targets without previously detected IR excess, spanning ages 30 Myr to 3 Gyr, the new detection of excess in just one system of intermediate age suggests a variety of initial conditions or divergent evolutionary paths for debris disk systems orbiting solar-type stars.