A dataset provided by the European Space Agency

Name OT1_hmaness_1
Title Planets, Debris Disks, and the Lambda Bootis Stars


DOI https://doi.org/10.5270/esa-ucnmwg7
Author European Space Agency
Description We propose to explore the link between lambda Bootis stars, debris
disks, and planetesimal formation and evolution. The lambda Boo stars
are a rare type of peculiar A star (2%), which are Population 1 and
metal poor. Planet bearing systems and debris disk stars appear
unusually well represented in the lambda Boo class: for example, beta
Pic, Vega, and HR 8799 are all lambda Boo candidates.

A small sample of 14 lambda Boo stars observed by Spitzer suggests an
occurrence of infrared excess approaching 100%. Only two lambda Boo
stars are included in the DEBRIS/DUNES Herschel key program debris
disk surveys. We will use PACS/Herschel to make sensitive,
high-resolution maps of 27 new lambda Boo stars. Like DEBRIS/DUNES,
we will reach the stellar photosphere for all targets, enabling a
measurement of the true rate of excess infrared emission among lambda
Boo stars compared to normal A stars.

The depletion pattern of heavy elements in the atmospheres of lambda
Boo stars suggests they may have accreted gas from which dust grains
have condensed and been removed: this gas may be circumstellar gas
that has formed planetesimals or dusty interstellar gas. While the
circumstellar disk scenario predicts sizes of a few hundred AU, the
cloud accretion scenario predicts 1000-2000 AU bow structures oriented
in the direction of the relative motion of the cloud and star. With
target distances of < 140 pc, these bow structures are expected to be
resolved for all targets. These will be the first mid-infrared
observations of lambda Boo stars outside of the low density Local
Bubble: if interstellar medium interactions dominate the lambda Boo
phenomenon then systematic variations in excess strength and
morphology may occur with distance.
Publication IR excesses around nearby Lambda Boo stars are caused by debris discs rather than ISM bow waves . Draper Z. H. et al. . Monthly Notices of the Royal Astronomical Society, Volume 456, Issue 1, p.459-476 . 456 . 10.1093\/mnras\/stv2696 . 2016MNRAS.456..459D ,
Instrument PACS_PacsPhoto_largeScan
Temporal Coverage 2011-07-11T23:46:31Z/2012-03-20T19:22:42Z
Version SPG v14.2.0
Mission Description Herschel was launched on 14 May 2009! It is the fourth 'cornerstone' mission in the ESA science programme. With a 3.5 m Cassegrain telescope it is the largest space telescope ever launched. It is performing photometry and spectroscopy in approximately the 55-671 µm range, bridging the gap between earlier infrared space missions and groundbased facilities.
Creator Contact https://support.cosmos.esa.int/h®erschel/
Date Published 2012-09-20T18:21:42Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, 2012, Planets Comma Debris Disks Comma And The Lambda Bootis Stars, SPG v14.2.0, European Space Agency, https://doi.org/10.5270/esa-ucnmwg7