Debris disks surrounding main sequence stars are analoguous to the Kuiper Belt around the Sun and are signposts for exoplanetary systems according to planet formation theory. Low-mass stars (M-stars) are challenging targets for both exoplanet searches and debris disk searches. However, they are vital for understanding planet formation in complement of higher mass stars. With Herschel, we propose to confirm and characterise two M-star candidate disks while only two others are presently known among low-mass stars. The two M-stars, GJ842.2 and HD95650, have candidate disks from SCUBA and Spitzer observations. We propose to make PACS images that are deep enough to detect theirphotospheres in order to verify unambiguously position coincidence between stars and disks. This approach could not be accomplished by neither SCUBA nor Spitzer. Additionally, it is reasonable to speculate that these disks will be large enough to be resolved by PACS providing definite proof of their nature. Finally, we request SPIRE in complement to PACS to fully sample the SED of the dust emission in order to determine their fractional dust lumninosities and dust properties. One of the key question in debris disk studies today is to understand the physics responsible for the trend apparent in their detection fractions indicating fewer debris disks around lower-mass stars. Several physical clues have been suggested; for instance, observed and theorised lack of massive gaseous planets around M-stars could reduce disk stirring and so dust production. It is vital to expand the number of known disks around M-stars to tackle this key question. By resolving two new disks and modelling their images, we shall infer the scale of the planetary systems around M-stars and be able to measure the size of the inner hole hosting planets. Asymmetries in their images would be indicative of resonances with planets. The scarcity of known disks around M-stars makes these observations crucial.
Publication
Instrument
PACS_PacsPhoto_largeScan, SPIRE_SpirePhoto_small
Temporal Coverage
2012-03-04T02:35:30Z/2012-12-08T22:17:48Z
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.
European Space Agency, lestrade et al., 2013, 'Confirmation and characterisation of two debris disks around low-mass stars.', SPG v14.2.0, European Space Agency, https://doi.org/10.5270/esa-fn5v97a
