Asset Details
Do you wish to reserve the book?
Inside-out evacuation of transitional protoplanetary discs by the magneto-rotational instability
Hey, we have placed the reservation for you!
By the way, why not check out events that you can attend while you pick your title.
Oops! Something went wrong.
Looks like we were not able to place the reservation. Kindly try again later.
Are you sure you want to remove the book from the shelf?
Inside-out evacuation of transitional protoplanetary discs by the magneto-rotational instability
Do you wish to request the book?
Inside-out evacuation of transitional protoplanetary discs by the magneto-rotational instability
Please be aware that the book you have requested cannot be checked out. If you would like to checkout this book, you can reserve another copy
We have requested the book for you!
Your request is successful and it will be processed during the Library working hours. Please check the status of your request in My Requests.
Oops! Something went wrong.
Looks like we were not able to place your request. Kindly try again later.
Journal Article
Inside-out evacuation of transitional protoplanetary discs by the magneto-rotational instability
2007
Overview
A newborn star is encircled by a remnant disc of gas and dust. A fraction of the disc coalesces into planets. Another fraction spirals inward and accretes onto the star
1
. Accreting gas not only produces observed ultraviolet radiation, but also drags along embedded planets, helping to explain otherwise mysterious features of observed extrasolar systems. What drives disc accretion has remained uncertain. The magneto-rotational instability (MRI), driven by coupling between magnetic fields and disc rotation, supplies a powerful means of transport
2
, but protoplanetary disc gas might be too poorly ionized to couple to magnetic fields
1
,
2
,
3
,
4
,
5
,
6
. Here we show that the MRI explains the observed accretion rates of newly discovered transitional discs
7
,
8
, which are swept clean of dust inside rim radii of ∼10
AU
. Stellar coronal X-rays ionize the disc rim, activating the MRI there. Gas flows steadily from the rim to the star, at a rate set by the depth to which X-rays ionize the rim wall. Blown out by radiation pressure, dust largely fails to accrete with gas. Our picture supplies one concrete setting for theories of how planets grow and have their orbits shaped by disc gas
9
, and when combined with photo-evaporative disc winds
10
provides a framework for understanding how discs dissipate.
