Japan Geoscience Union Meeting 2023

Presentation information

[E] Oral

P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM11] Exoplanet

Wed. May 24, 2023 10:45 AM - 12:00 PM 102 (International Conference Hall, Makuhari Messe)

convener:Takanori Kodama(The university of Tokyo), Shota Notsu(Star and Planet Formation Laboratory, RIKEN Cluster for Pioneering Research), Yui Kawashima(RIKEN), Mayuko Mori(The University of Tokyo), Chairperson:Yuichi Ito(National Astronomical Observatory of Japan, Division of Science), Shota Notsu(Star and Planet Formation Laboratory, RIKEN Cluster for Pioneering Research)

11:30 AM - 11:45 AM

[PEM11-09] Infrared Doppler survey of late-M dwarfs with IRD-SSP: A planet detection and Recent status

*Masashi Omiya1,2 (1.Astrobiology Center, 2.National Astronomical Observatory of Japan)

Keywords:survey of exoplanets, techniques: radial velocities, stars: low-mass

We are searching for planets around late-M dwarfs in the framework of the IRD-SSP (InfraRed Doppler - Subaru Strategic Program) with the radial velocity (RV) method at the near-infrared wavelength. In this project, we have conducted a strategic 5-year RV survey of IRD-SSP original sample stars since 2019 and have looking for signs of Earth-like planets in their RV changes.
In 2022, the initial RV survey of the IRD-SSP has been almost completed to investigate the stellar properties of the sample, including stellar parameters and activities. Moreover, we have performed intensive RV monitoring concentrated on samples suitable for low-mass planet detections with low surface activities and surface temperature.
Recently, we reported a discovery of a super-Earth orbiting a M4.5 dwarf, Ross 508, with an orbital period of 10.77 days in IRD-SSP original sample. The planet has a minimum mass of 4.00 Jupiter masses and a semi-major axis of 0.05366 au because the stellar mass of Ross 508 was determined to be 0.1774 solar masses. An orbit-averaged insolation of the planet is estimated to be ~1.4 times the Earth value and the planet locates on near the inner edge of its habitable zone. In addition, the continuous RV survey allows us to discuss detectability of planets in IRD-SSP survey compared with current theoretical models, and to find some candidates of RV variations in IRD-SSP samples.