6 research outputs found
Orbital Eccentricity -- Multiplicity Correlation for Planetary Systems and Comparison to the Solar System
The orbit eccentricities of the Solar System planets are unusually low
compared to the average of known exoplanetary systems. A power law correlation
has previously been found between the multiplicity of a planetary system and
the orbital eccentricities of its components, for systems with multiplicities
above two. In this study we investigate the correlation for an expanded data
sample, by focusing on planetary systems as units (unlike previous studies that
have focused on individual planets). Our full data sample contains 1171
exoplanets, in 895 systems, and the correlation between eccentricity and
multiplicity is found to follow a clear power law for all multiplicities above
one. We discuss the correlation for several individual subsamples, and find
that all samples consistently follow the same basic trend regardless of e.g.
planet types and detection methods. We find that the eccentricities of the
Solar System fit the general trend and suggest that the Solar System might not
show uncommonly low eccentricities (as often speculated) but rather uncommonly
many planets compared to a "standard" planetary system. The only outlier from
the power law correlation is, consistently in all the samples, the one-planet
systems. It has previously been suggested that this may be due to additional
unseen exoplanets in the observed one-planet systems. Based on this assumption
and the power law correlation, we estimate that the probability of a system
having 8 planets or more is of the order of 1%, in good agreement with recent
predictions from analyses based on independent arguments.Comment: Accepted for publication in MNRAS; added acknowledgemen
OGLE-2019-BLG-0825: Constraints on the Source System and Effect on Binary-lens Parameters arising from a Five Day Xallarap Effect in a Candidate Planetary Microlensing Event
We present an analysis of microlensing event OGLE-2019-BLG-0825. This event
was identified as a planetary candidate by preliminary modeling. We find that
significant residuals from the best-fit static binary-lens model exist and a
xallarap effect can fit the residuals very well and significantly improves
values. On the other hand, by including the xallarap effect in our
models, we find that binary-lens parameters like mass-ratio, , and
separation, , cannot be constrained well. However, we also find that the
parameters for the source system like the orbital period and semi major axis
are consistent between all the models we analyzed. We therefore constrain the
properties of the source system better than the properties of the lens system.
The source system comprises a G-type main-sequence star orbited by a brown
dwarf with a period of days. This analysis is the first to demonstrate
that the xallarap effect does affect binary-lens parameters in planetary
events. It would not be common for the presence or absence of the xallarap
effect to affect lens parameters in events with long orbital periods of the
source system or events with transits to caustics, but in other cases, such as
this event, the xallarap effect can affect binary-lens parameters.Comment: 19 pages, 7 figures, 6 tables. Accepted by A
Self-assembly of caseinomacropeptide as a potential key mechanism in the formation of visible storage induced aggregates in acidic whey protein isolate dispersions
Self-assembly of caseinomacropeptide as a potential key mechanism in the formation of visible storage induced aggregates in acidic whey protein isolate dispersions
OGLE-2019-BLG-0825: Constraints on the Source System and Effect on Binary-lens Parameters Arising from a Five-day Xallarap Effect in a Candidate Planetary Microlensing Event
We present an analysis of microlensing event OGLE-2019-BLG-0825. This event was identified as a planetary candidate by preliminary modeling. We find that significant residuals from the best-fit static binary-lens model exist and a xallarap effect can fit the residuals very well and significantly improves χ ^2 values. On the other hand, by including the xallarap effect in our models, we find that binary-lens parameters such as mass ratio, q , and separation, s , cannot be constrained well. However, we also find that the parameters for the source system such as the orbital period and semimajor axis are consistent between all the models we analyzed. We therefore constrain the properties of the source system better than the properties of the lens system. The source system comprises a G-type main-sequence star orbited by a brown dwarf with a period of P ∼ 5 days. This analysis is the first to demonstrate that the xallarap effect does affect binary-lens parameters in planetary events. It would not be common for the presence or absence of the xallarap effect to affect lens parameters in events with long orbital periods of the source system or events with transits to caustics, but in other cases, such as this event, the xallarap effect can affect binary-lens parameters