44 research outputs found
EUCLID : Dark Universe Probe and Microlensing planet Hunter
There is a remarkable synergy between requirements for Dark Energy probes by
cosmic shear measurements and planet hunting by microlensing. Employing weak
and strong gravitational lensing to trace and detect the distribution of matter
on cosmic and Galactic scales, but as well as to the very small scales of
exoplanets is a unique meeting point from cosmology to exoplanets. It will use
gravity as the tool to explore the full range of masses not accessible by any
other means. EUCLID is a 1.2m telescope with optical and IR wide field imagers
and slitless spectroscopy, proposed to ESA Cosmic Vision to probe for Dark
Energy, Baryonic acoustic oscillation, galaxy evolution, and an exoplanet hunt
via microlensing. A 3 months microlensing program will already efficiently
probe for planets down to the mass of Mars at the snow line, for free floating
terrestrial or gaseous planets and habitable super Earth. A 12+ months survey
would give a census on habitable Earth planets around solar like stars. This is
the perfect complement to the statistics that will be provided by the KEPLER
satellite, and these missions combined will provide a full census of extrasolar
planets from hot, warm, habitable, frozen to free floating.Comment: 6 pages 3 figures, invited talk in Pathways towards habitable
planets, Barcelona, Sept 200
Search for exoplanets in M31 with pixel-lensing and the PA-99-N2 event revisited
Several exoplanets have been detected towards the Galactic bulge with the
microlensing technique. We show that exoplanets in M31 may also be detected
with the pixel-lensing method, if telescopes making high cadence observations
of an ongoing microlensing event are used. Using a Monte Carlo approach we find
that the mean mass for detectable planetary systems is about .
However, even small mass exoplanets () can cause
significant deviations, which are observable with large telescopes. We
reanalysed the POINT-AGAPE microlensing event PA-99-N2. First, we test the
robustness of the binary lens conclusion for this light curve. Second, we show
that for such long duration and bright microlensing events, the efficiency for
finding planetary-like deviations is strongly enhanced with respect to that
evaluated for all planetary detectable events.Comment: 14 pages, 8 figures. Paper presented at the "II Italian-Pakistani
Workshop on Relativistic Astrophysics, Pescara, July 8-10, 2009. To be
published in a special issue of General Relativity and Gravitation (eds. F.
De Paolis, G.F.R. Ellis, A. Qadir and R. Ruffini
Limits on additional planetary companions to OGLE-2005-BLG-390L
We investigate constraints on additional planets orbiting the distant M-dwarf
star OGLE-2005-BLG-390L, around which photometric microlensing data has
revealed the existence of the sub-Neptune-mass planet OGLE-2005-BLG-390Lb. We
specifically aim to study potential Jovian companions and compare our findings
with predictions from core-accretion and disc-instability models of planet
formation. We also obtain an estimate of the detection probability for
sub-Neptune mass planets similar to OGLE-2005-BLG-390Lb using a simplified
simulation of a microlensing experiment. We compute the efficiency of our
photometric data for detecting additional planets around OGLE-2005-BLG-390L, as
a function of the microlensing model parameters and convert it into a function
of the orbital axis and planet mass by means of an adopted model of the Milky
Way. We find that more than 50 % of potential planets with a mass in excess of
1 M_J between 1.1 and 2.3 AU around OGLE-2005-BLG-390L would have revealed
their existence, whereas for gas giants above 3 M_J in orbits between 1.5 and
2.2 AU, the detection efficiency reaches 70 %; however, no such companion was
observed. Our photometric microlensing data therefore do not contradict the
existence of gas giant planets at any separation orbiting OGLE-2005-BLG-390L.
Furthermore we find a detection probability for an OGLE-2005-BLG-390Lb-like
planet of around 2-5 %. In agreement with current planet formation theories,
this quantitatively supports the prediction that sub-Neptune mass planets are
common around low-mass stars.Comment: 10 pages, 4 figures, accepted by A&
A Sub-Saturn Mass Planet, MOA-2009-BLG-319Lb
We report the gravitational microlensing discovery of a sub-Saturn mass planet, MOA-2009-BLG-319Lb, orbiting a K- or M-dwarf star in the inner Galactic disk or Galactic bulge. The high-cadence observations of the MOA-II survey discovered this microlensing event and enabled its identification as a high-magnification event approximately 24 hr prior to peak magnification. As a result, the planetary signal at the peak of this light curve was observed by 20 different telescopes, which is the largest number of telescopes to contribute to a planetary discovery to date. The microlensing model for this event indicates a planet-star mass ratio of q = (3.95 ± 0.02) × 10^(–4) and a separation of d = 0.97537 ± 0.00007 in units of the Einstein radius. A Bayesian analysis based on the measured Einstein radius crossing time, t_E, and angular Einstein radius, θ_E, along with a standard Galactic model indicates a host star mass of M_L = 0.38^(+0.34)_(–0.18) M_☉ and a planet mass of M_p = 50^(+44)_(–24) M_⊕, which is half the mass of Saturn. This analysis also yields a planet-star three-dimensional separation of a = 2.4^(+1.2)_(–0.6) AU and a distance to the planetary system of D_L = 6.1^(+1.1)_(–1.2) kpc. This separation is ~2 times the distance of the snow line, a separation similar to most of the other planets discovered by microlensing
Euclid-Roman joint microlensing survey: early mass measurement, free floating planets and exomoons
Funding: EB gratefully acknowledge support from NASA grant 80NSSC19K0291. The work of DS is funded by a UK Science and Technology Facilities Council (STFC) PhD studentship. EK also acknowledges support from the STFC. EB, JPB and CR’s work was carried out within the framework of the ANR project COLD-WORLDS supported by the French National Agency for Research with the reference ANR-18-CE31-0002. JPB was supported by the University of Tasmania through the UTAS Foundation, ARC grant DP200101909 and the endowed Warren Chair in Astronomy. JR was supported by NASA ROSES grant 12-EUCLID12-0004, the Nancy Grace Roman Telescope, and JPL, which is run by Caltech under a contract for NASA. RP was supported by the Polish National Agency for Academic Exchange via Polish Returns 2019 grant. DM acknowledges support by the European Research Council (ERC) under the European Union’s FP7 Programme, Grant No. 833031.As the Kepler mission has done for hot exoplanets, the ESA Euclid and NASA Roman missions have the potential to create a breakthrough in our understanding of the demographics of cool exoplanets, including unbound, or "free-floating", planets (FFPs). In this study, we demonstrate the complementarity of the two missions and propose two joint-surveys to better constrain the mass and distance of microlensing events. We first demonstrate that an early brief Euclid survey (7 h) of the Roman microlensing fields will allow the measurement of a large fraction of events relative proper motions and lens magnitudes. Then, we study the potential of simultaneous observations by Roman and Euclid to enable the measurement of the microlensing parallax for the shortest microlensing events. Using detailed simulations of the joint detection yield we show that within one year Roman-Euclid observations will be at least an order of magnitude more sensitive than current ground-based measurements. Depending on the exact distribution of FFP, a joint Roman-Euclid campaign should detect around 130 FFP events within a year, including 110 with measured parallax that strongly constrain the FFP mass, and around 30 FFP events with direct mass and distance measurements. The ability of the joint survey to completely break the microlens mass-distance-velocity degeneracy for a significant subset of events provides a unique opportunity to verify unambiguously the FFP hypothesis or else place abundance limits for FFPs between Earth and Jupiter masses that are up to two orders of magnitude stronger than provided by ground-based surveys. Finally, we study the capabilities of the joint survey to enhance the detection and charcterization of exomoons, and found that it could lead to the detection of the first exomoon.PostprintPeer reviewe