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Light curve of OGLE-2014-BLG-0319 from the OGLE (red
points) and MOA (black points) data. The gray dashed lines in panels represent
the best-fit single-lens model. The blue panel shows a zoom-in view
corresponding to the area surrounded by a blue chain line. Credit: Miyazaki et
al., 2021. |
A new sub-Jupiter-mass extraterrestrial world has been discovered orbiting an M-dwarf star, according to an international team of scientists. The newly discovered exoplanet, designated OGLE-2014-BLG-0319Lb, is nearly half the mass of Jupiter. An article detailing the discovery was released on the arXiv pre-print site.
The microlensing approach, which is based on the
gravitational lens effect, is mostly employed to detect planetary and
stellar-mass objects, regardless of the light they emit. As a result, this
approach is sensitive to an object's mass rather than its luminosity, allowing
astronomers to examine objects that emit little or no light.
The Optical Gravitational Lensing Experiment (OGLE)
collaboration announced the finding of the microlensing event
OGLE-2014-BLG-0319 on March 21, 2014. The Microlensing Observations in
Astrophysics (MOA) team also spotted the event, which was given the designation
MOA-2014-BLG-171.
A group of astronomers led by Shota Miyazaki of Osaka
University in Japan recently examined this microlensing event and discovered a
signal indicating the presence of a planetary object. In most microlensing
occurrences, planetary signals appear as short-lived abnormal deviations from
ordinary single-lens light curves. These deviations can sometimes lead to a
degeneracy problem, where one anomaly can have multiple model interpretations.
The researchers noted in the report, "In this publication, we evaluate a microlensing event OGLE-2014-BLG-0319 that presents three planetary interpretations with different mass ratios."
Overall, the researchers discovered that the newly
discovered planet has a mass of roughly 0.49 Jupiter masses and orbits its host
at a distance of 3.49 AU. Most likely, the progenitor star is an Mdwarf with a
mass of 0.47 solar masses. The system is approximately 25,200 light years
distant from Earth, near the Galactic bulge.
Follow-up observations with high angular resolution
could offer more insight on the features of the newly discovered extrasolar
world and its host in the future. The researchers predicted that it would take
several more years to clarify the lens position and detect the lens flux.
The authors of the report went on to say that their
research highlighted the difficulty of degeneracy when it comes to finding new
exoplanets through microlensing occurrences. They found that this problem would
be more common for events occurring on short timescales, and that it might have
a significant impact on estimates of the frequency of such planets.
"Shorter timescale events, such as those caused by low-mass objects like brown dwarfs or free-floating planets, would make this strategy difficult to succeed. As a result, for measuring the mass ratio function of companions orbiting such low-mass hosts, which only microlensing can investigate, careful treatment is required "In the paper, the astronomers noted.
References:
OGLE-2014-BLG-0319: A Sub-Jupiter-Mass Planetary Event
Encountered Degeneracy with Different Mass Ratios and Lens-Source Relative
Proper Motions, arXiv:2112.14997 [astro-ph.EP] arxiv.org/abs/2112.14997
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