Tsinghua PDS Workshop (2024)
| Date |
|
Wednesday, December 18 |
Location
|
|
Physics Building E100 |
Online Venue
|
|
Zoom no. 834 8945 9582 (password: 428072) |
In order to have a rough head count, please complete the registration form before 11:59am, December
16. Onsite registration/participation is
always allowed.
- Schedule:
| 1:30-2:00 |
Registration |
| 2:00-2:20 |
Round-the-room Introduction |
| 2:20-3:20 |
Title:
Dynamical Sculpting in the Outskirts of
Planetary Systems
Speaker: Sam
Hadden (University of Toronto)
Abstract: Beyond the orbit
of Neptune lie the remnants of a formerly
substantial planetesimal population. The
present-day orbital properties of these
trans-Neptunian objects (TNOs) bear the
marks of an early dynamical upheaval in the
outer solar system that may have even
ejected along-lost ice giant sibling to
Neptune and Uranus. However, decoding the
evolutionary record etched in the orbital
properties of TNOs requires rewinding
billions of years of complex dynamical
evolution. I will describe how analytical
insights into this evolution can be obtained
using a simple mapping approach. Then I will
turn my attention to exoplanetary systems
which, based on hints of a large population
of free-floating planets from ground-based
gravitational microlensing surveys, appear
to frequently experience similar dynamical
upheavals during their early
evolution. But the details of such
planet-liberating dynamical instabilities
have previously not received much attention.
I will show that in systems that lack
Jupiter-mass giant planets, instabilities
lead to prolonged bouts of planet-planet
scattering during which multiple planets are
thrown onto loosely-bound, highly eccentric
orbits. These long-lived scattering phases
can last billions of years and, since giant
planets are known to be relatively rare,
this implies that a substantial fraction of
apparently free-floating planets detected by
microlensing surveys are actually
loosely-bound planets that only appear to be
free-floating. These results have important
implications for how we interpret the
thousands of microlensing planet
discoveries, both bound and free-floating,
expected from NASA's upcoming Roman mission.
|
| 3:20-4:00 |
Coffee/Tea Break
|
4:00-5:00
|
Title: Aspects of the Rotational Evolution
of Sun-like Stars: Insights from
High-resolution Spectroscopy and Space-based
Photometry
Speaker:
Kento Masuda (Osaka University)
Abstract:
The
physical properties and orbits of planetary
systems are believed to undergo various
changes even after their formation.
Determining the ages of stars is essential for
statistically studying such evolution. A
useful method for this is gyrochronology,
which utilizes the relationship between
stellar rotation and age. While this
rotation-age relationship has been extensively
studied for relatively young low-mass stars in
open clusters through quasi-periodic
brightness variations in broad-band photometry
data, there is still limited information for
stars older than the Sun. In this talk,
I will present our recent work that provides
insights into the rotational evolution of
older Sun-like stars, focusing on (i) the
selection function of rotation periods derived
from photometric observations, and (ii) a
statistical analysis of high-resolution
spectroscopy data to derive the rotation
period distribution avoiding biases against
photometrically quiet stars.
|
| 5:00-5:30 |
Coffee/Tea & Free Discussion |
| 5:30 |
Dinner |
Contact Wei Zhu (weizhu@tsinghua.edu.cn) if there are questions
regarding this event.
|
