A direct image has been taken of a planet so far away from his star that
it takes twenty-seven thousand years for completing one orbit, and it
shares the system with another planet which completes its orbit in just
eleven hours.
The planet CVSO 30c seen to the left of its star.
Credit: Keck II telescope (left image) and (right image) VLT (ESO / Schmidt et al.)
An international observation campaign has allowed to photograph a planet
around CVSO 30 star which is part of a curious system: the newly found
CVSO 30c orbits the star at a extreme distance (more than twenty times
the distance between Neptune and the Sun), and contrasts with its
partner CVSO 30b, found in 2012, that is only at 1.2 million kilometers
from the star (Mercury, the planet closest to the Sun, is 58 million
kilometers away from it). It is the first system found with these
characteristics, and their weird orbits could be due to the fact that
both planets interacted to each other in the past and there was a
dispersion process.
Up to now, most of the more than two thousand found planets orbiting
other stars have been detected thanks to indirect methods, which study
the influence of the planets on their stars. Barely sixty have been
found with direct imaging, a very instrumental demanding method, but
allowing exploring remote regions of the star where indirect methods are
less effective.
The confirmation that the little dot on the images was indeed a planet
has been possible thanks to the combined use of Keck (Hawaii), VLT
(Chile) and Calar Alto Observatory telescopes. “CVSO 30c has been a
surprise as it is at 660 Astronomical Units - an Astronomical Unit, or
AU, is equivalent to hundred and fifty million kilometers, the distance
between the Earth and the Sun -. Neptune is the most external planet of
our Solar System, and it is at 30 AUs” , Jesús Aceituno, Calar Alto
Observatory (CAHA, MPG/CSIC) Deputy Director points.
A unique system
Besides, this planet shares system with another one found in 2012
through indirect methods. Although both planets have a similar mass
(between one and four times the mass of Jupiter), both of them have a
relative distance never saw in the planetary system found up to now:
while one is as close to its star that it completes its orbit in barely
eleven hours, the other takes about twenty-seven thousand years for
finishing it.
Researchers think about several possibilities in order to explain this
distance disparity, but the most probable explanation points to the fact
that both planets were formed within the internal regions of the
system, and a gravitational interaction, happened in the past, resulted
in the dispersion. This is a mechanism invoked to explain what are known
as “Hot Jupiters”, gas giants very close to its star and which its
detection constituted a surprise: in so short distances, the temperature
prevents condensation of volatile ice to form gaseous planets, so they
should have migrated to the inner regions by orbital resonances with
other bodies.
This planetary system is a suitable object for studying these planetary
dispersion theories, as well as for inquire on the first planet
development phases: CVSO 30 star is a very young one, with only 2.5
million years (our Sun has 5 million years), and researchers are
studying how it could form planets so quickly.
The German-Spanish Calar Alto Observatory is located at Sierra de los Filabres, north of Almería (Andalucía, Spain). It is jointly operated by the Instituto Max Planck de Astronomía in Heidelberg, Germany, and the Instituto de Astrofísica de Andalucía (CSIC) in Granada, Spain. Calar Alto has three telescopes with apertures of 1.23m, 2.2m and 3.5m. A 1.5m aperture telescope, also located at the mountain, is operated under control of the Observatorio de Madrid.
Reference:
T.O.B. Schmidt et al. "Direct Imaging discovery of a second planet candidate around the possibly transiting planet host CVSO 30 ⋆". Astronomy & Astrophysics. DOI: http://dx.doi.org/10.1051/0004-6361/201526326
Contact:
Instituto de Astrofísica de Andalucía (IAA-CSIC)
Unidad de Divulgación y Comunicación
Silbia López de Lacalle - sll[arroba]iaa.es - 958230532
http://www.iaa.es
http://www-divulgacion.iaa.es
