A dataset provided by the European Space Agency

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


DOI 10.5270/esa-ucnmwg7
Author maness, h.
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 ┬Ám range, bridging the gap between earlier infrared space missions and groundbased facilities.
Creator Contact https://support.cosmos.esa.int/herschel/
Date Published 2012-09-20T18:21:42Z
Publisher And Registrant European Space Agency
Credit Guidelines European Space Agency, 2012-09-20T18:21:42Z, OT1_hmaness_1, SPG v14.2.0. https://doi.org/10.5270/esa-ucnmwg7