scholarly journals A Trend Between Cold Debris Disk Temperature and Stellar Type: Implications for the Formation and Evolution of Wide-Orbit Planets

2013 ◽  
Vol 8 (S299) ◽  
pp. 326-327
Author(s):  
Nicholas P. Ballering ◽  
George H. Rieke ◽  
Kate Y. L. Su ◽  
Edward Montiel
Keyword(s):  
Planet Formation ◽  
Protoplanetary Disk ◽  
Debris Disks ◽  
Temperature Dependent ◽  
Infrared Excess ◽  
Orbital Radius ◽  
Formation And Evolution ◽  
Debris Disk ◽  
Core Accretion ◽  
Dependent Processes

AbstractCold debris disks have the potential to answer many outstanding questions in wide-orbit planet formation and evolution. We characterized the infrared excess SEDs of 174 cold debris disks with Spitzer IRS and MIPS. We found a trend between the temperature of the disks and the stellar type of the stars they orbit. This argues against the importance of strictly temperature-dependent processes (e.g. ice lines) in setting the dimensions of cold debris disks. We also found no evidence that delayed stirring causes the trend. The trend may result from outward planet migration that traces the extent of the primordial protoplanetary disk, or from planet formation that halts at an orbital radius limited by the efficiency of core accretion. For the full details of this work, see Ballering et al. (2013).

scholarly journals Comprehensive Census and Complete Characterization of Nearby Debris Disk Stars

2015 ◽  
Vol 10 (S314) ◽  
pp. 179-182
Author(s):  
Tara H. Cotten ◽  
Inseok Song
Keyword(s):  
Large Scale ◽  
Complete Characterization ◽  
High Resolution Spectroscopy ◽  
Debris Disks ◽  
Infrared Excess ◽  
History Of ◽  
Debris Disk ◽  
Host Stars ◽  
Comprehensive Study

AbstractDebris disks are intimately linked to planetary system evolution since the rocky material surrounding the host stars is believed to be due to secondary generation from the collisions of planetesimals. With the conclusion and lack of future large scale infrared excess survey missions, it is time to summarize the history of using excess emission in the infrared as a tracer of debris and exploit all available data as well as provide a comprehensive study of the parameters of these important objects. We have compiled a catalog of infrared excess stars from peer-reviewed articles and performed an extensive search for new debris disks by cross-correlating the Tycho-2 and AllWISE catalogs. This study will conclude following the thorough examination of each debris disk star's parameters obtained through high-resolution spectroscopy at various facilities which is currently ongoing. We will maintain a webpage (www.debrisdisks.org) devoted to these infrared excess sources and provide various resources related to our catalog creation, SED fitting, and data reduction.

scholarly journals Modes of Gaseous Planet Formation

2004 ◽  
Vol 202 ◽  
pp. 141-148 ◽  
Author(s):  
Alan P. Boss
Keyword(s):  
Planet Formation ◽  
Gravitational Instability ◽  
Giant Planet ◽  
Solid Core ◽  
New Era ◽  
Advantages And Disadvantages ◽  
Nearby Stars ◽  
Formation And Evolution ◽  
Gas Giant ◽  
Core Accretion

The discovery of gas giant planets around nearby stars has launched a new era in our understanding of the formation and evolution of planetary systems. However, none of the over four dozen companions detected to date strongly resembles Jupiter or Saturn: their inferred masses range from sub-Saturn-mass to 10 Jupiter-masses or more, while their orbits extend from periods of a few days to a few years. Given this situation, it seems prudent to re-examine mechanisms for gas giant planet formation. The two extreme cases are top-down or bottom-up. The latter is the core accretion mechanism, long favored for our Solar System, where a roughly 10 Earth-mass solid core forms by collisional accumulation of planetesimals, followed by hydrodynamic accretion of a gaseous envelope. The former is the long-discarded disk instability mechanism, where the protoplanetary disk forms self-gravitating, gaseous protoplanets through a gravitational instability of the gas, accompanied by settling and coagulation of dust grains to form solid cores. Both of these mechanisms have a number of advantages and disadvantages, making a purely theoretical choice between them difficult at present. Observations should be able to decide the dominant mechanism by dating the epoch of gas giant planet formation: core accretion requires more than a million years to form a Jupiter-mass planet, whereas disk instability is much more rapid.

scholarly journals The HIP 79977 debris disk in polarized light

2017 ◽  
Vol 607 ◽  
pp. A90 ◽  
Author(s):  
N. Engler ◽  
H. M. Schmid ◽  
Ch. Thalmann ◽  
A. Boccaletti ◽  
A. Bazzon ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Rayleigh Scattering ◽  
Broad Band ◽  
Contrast Ratio ◽  
Asymmetry Factor ◽  
Debris Disks ◽  
Infrared Excess ◽  
Model Calculations ◽  
Diagnostic Potential ◽  
Debris Disk

Context. Debris disks are observed around 10 to 20% of FGK main-sequence stars as infrared excess emission. They are important signposts for the presence of colliding planetesimals and therefore provide important information about the evolution of planetary systems. Direct imaging of such disks reveals their geometric structure and constrains their dust-particle properties. Aims. We present observations of the known edge-on debris disk around HIP 79977 (HD 146897) taken with the ZIMPOL differential polarimeter of the SPHERE instrument. We measure the observed polarization signal and investigate the diagnostic potential of such data with model simulations. Methods. SPHERE-ZIMPOL polarimetric data of the 15 Myr-old F star HIP 79977 (Upper Sco, 123 pc) were taken in the Very Broad Band (VBB) filter (λc = 735 nm, Δλ = 290 nm) with a spatial resolution of about 25 mas. Imaging polarimetry efficiently suppresses the residual speckle noise from the AO system and provides a differential signal with relatively small systematic measuring uncertainties. We measure the polarization flux along and perpendicular to the disk spine of the highly inclined disk for projected separations between 0.2′′ (25 AU) and 1.6′′ (200 AU). We perform model calculations for the polarized flux of an optically thin debris disk which are used to determine or constrain the disk parameters of HIP 79977. Results. We measure a polarized flux contrast ratio for the disk of (Fpol)disk/F∗ = (5.5 ± 0.9) × 10-4 in the VBB filter. The surface brightness of the polarized flux reaches a maximum of SBmax = 16.2 mag arcsec-2 at a separation of 0.2′′–0.5′′ along the disk spine with a maximum surface brightness contrast of 7.64 mag arcsec-2. The polarized flux has a minimum near the star <0.2′′ because no or only little polarization is produced by forward or backward scattering in the disk section lying in front of or behind the star. The width of the disk perpendicular to the spine shows a systematic increase in FWHM from 0.1′′ (12 AU) to 0.3′′−0.5′′, when going from a separation of 0.2′′ to >1′′. This can be explained by a radial blow-out of small grains. The data are modelled as a circular dust belt with a well defined disk inclination i = 85( ± 1.5)° and a radius between r0 = 60 and 90 AU. The radial density dependence is described by (r/r0)α with a steep (positive) power law index α = 5 inside r0 and a more shallow (negative) index α = −2.5 outside r0. The scattering asymmetry factor lies between g = 0.2 and 0.6 (forward scattering) adopting a scattering-angle dependence for the fractional polarization such as that for Rayleigh scattering. Conclusions. Polarimetric imaging with SPHERE-ZIMPOL of the edge-on debris disk around HIP 79977 provides accurate profiles for the polarized flux. Our data are qualitatively very similar to the case of AU Mic and they confirm that edge-on debris disks have a polarization minimum at a position near the star and a maximum near the projected separation of the main debris belt. The comparison of the polarized flux contrast ratio (Fpol)disk/F∗ with the fractional infrared excess provides strong constraints on the scattering albedo of the dust.

Interaction of solid bodies with atmospheres of protoplanets

2018 ◽  
Vol 14 (S345) ◽  
pp. 351-352
Author(s):  
Ernst A. Dorfi ◽  
Florian Ragossnig
Keyword(s):  
Kinetic Energy ◽  
Physical Properties ◽  
Planet Formation ◽  
Frictional Heating ◽  
Protoplanetary Disk ◽  
Small Bodies ◽  
Early Stages ◽  
Break Up ◽  
Solid Bodies ◽  
Stellar Source

AbstractDuring the early stages of planet formation accretion of small bodies add mass to the planet and deposit their energy kinetic energy. Caused by frictional heating and/or large stagnation pressures within the dense and extended atmospheres most of the in-falling bodies get destroyed by melting or break-up before they impact on the planet’s surface. The energy is added to the atmospheric layers rather than heating the planet directly. These processes can significantly alter the physical properties of protoplanets before they are exposed with their primordial atmospheres to the early stellar source when the protoplanetary disk becomes evaporated.

scholarly journals Metallicity effect and planet mass function in pebble-based planet formation models

2018 ◽  
Vol 619 ◽  
pp. A174 ◽  
Author(s):  
N. Brügger ◽  
Y. Alibert ◽  
S. Ataiee ◽  
W. Benz
Keyword(s):  
Internal Structure ◽  
Planet Formation ◽  
Large Fraction ◽  
Mass Function ◽  
Planetary Atmosphere ◽  
Population Synthesis ◽  
Core Accretion ◽  
Mass Functions ◽  
Synthesis Approach ◽  
Gaseous Envelope

Context. One of the main scenarios of planet formation is the core accretion model where a massive core forms first and then accretes a gaseous envelope. This core forms by accreting solids, either planetesimals or pebbles. A key constraint in this model is that the accretion of gas must proceed before the dissipation of the gas disc. Classical planetesimal accretion scenarios predict that the time needed to form a giant planet’s core is much longer than the time needed to dissipate the disc. This difficulty led to the development of another accretion scenario, in which cores grow by accretion of pebbles, which are much smaller and thus more easily accreted, leading to more rapid formation. Aims. The aim of this paper is to compare our updated pebble-based planet formation model with observations, in particular the well-studied metallicity effect. Methods. We adopt the Bitsch et al. (2015a, A&A, 575, A28) disc model and the Bitsch et al. (2015b, A&A, 582, A112) pebble model and use a population synthesis approach to compare the formed planets with observations. Results. We find that keeping the same parameters as in Bitsch et al. (2015b, A&A, 582, A112) leads to no planet growth due to a computation mistake in the pebble flux (2018b). Indeed a large fraction of the heavy elements should be put into pebbles (Zpeb∕Ztot = 0.9) in order to form massive planets using this approach. The resulting mass functions show a huge amount of giants and a lack of Neptune-mass planets, which are abundant according to observations. To overcome this issue we include the computation of the internal structure for the planetary atmosphere in our model. This leads to the formation of Neptune-mass planets but no observable giants. Furthermore, reducing the opacity of the planetary envelope more closely matches observations. Conclusions. We conclude that modelling the internal structure for the planetary atmosphere is necessary to reproduce observations.

Silicon and Nickel Enrichment in Planet Host Stars: Observations and Implications for the Core Accretion Theory of Planet Formation

2006 ◽  
Vol 643 (1) ◽  
pp. 484-500 ◽  
Author(s):  
Sarah E. Robinson ◽  
Gregory Laughlin ◽  
Peter Bodenheimer ◽  
Debra Fischer
Keyword(s):  
Planet Formation ◽  
The Core ◽  
Core Accretion ◽  
Host Stars ◽  
Nickel Enrichment

scholarly journals The Complete Census of 70 μm–Bright Debris Disks within “The Formation and Evolution of Planetary Systems”SpitzerLegacy Survey of Sun‐like Stars

2008 ◽  
Vol 677 (1) ◽  
pp. 630-656 ◽  
Author(s):  
Lynne A. Hillenbrand ◽  
John M. Carpenter ◽  
Jinyoung Serena Kim ◽  
Michael R. Meyer ◽  
Dana E. Backman ◽  
...  
Keyword(s):  
Planetary Systems ◽  
Debris Disks ◽  
Formation And Evolution

β Pictoris and other star spectra, in connection with planet formation

2004 ◽  
Vol 202 ◽  
pp. 300-307
Author(s):  
Anne. M. Lagrange ◽  
Herve Beust
Keyword(s):  
Planet Formation ◽  
Planetary System ◽  
Present Knowledge ◽  
Debris Disks ◽  
System Activity ◽  
Pms Stars

We review here the present knowledge on the gaseous phases of debris disks found around MS and old PMS stars, and make an attempt to connect them with planetary system activity.

scholarly journals The Debris Disk Explorer: a balloon-borne coronagraph for observing debris disks

2013 ◽  
Author(s):  
Lewis C. Roberts ◽  
Geoffrey Bryden ◽  
Wesley Traub ◽  
Stephen Unwin ◽  
John Trauger ◽  
...  
Keyword(s):  
Debris Disks ◽  
Debris Disk
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