Characterization of starspots on a young M-dwarf K2-25: multiband observations of stellar photometric variability and planetary transits-Reference-Cited by-同舟云学术

Characterization of starspots on a young M-dwarf K2-25: multiband observations of stellar photometric variability and planetary transits

Published:2024-03-22 Issue:1 Volume:530 Page:167-189
ISSN:0035-8711
Container-title:Monthly Notices of the Royal Astronomical Society
language:en
Short-container-title:

Author:

Mori Mayuko¹^ORCID,Ikuta Kai¹^ORCID,Fukui Akihiko²³^ORCID,Narita Norio²³⁴^ORCID,de Leon Jerome P¹^ORCID,Livingston John H⁴⁵⁶^ORCID,Ikoma Masahiro⁷^ORCID,Kawai Yugo¹^ORCID,Kawauchi Kiyoe⁸^ORCID,Murgas Felipe³⁹^ORCID,Palle Enric³⁹^ORCID,Parviainen Hannu³⁹^ORCID,Rodríguez Gareb Fernández³⁹^ORCID,Terada Yuka¹⁰¹¹^ORCID,Watanabe Noriharu¹^ORCID,Tamura Motohide⁴⁵¹²^ORCID

Affiliation:

1. Department of Multi-Disciplinary Sciences, Graduate School of Arts and Sciences, The University of Tokyo , 3-8-1 Komaba, Meguro, Tokyo 153-8902 , Japan

2. Komaba Institute for Science, The University of Tokyo , 3-8-1 Komaba, Meguro, Tokyo 153-8902 , Japan

3. Instituto de Astrofísica de Canarias (IAC) , E-38205 La Laguna, Tenerife , Spain

4. Astrobiology Center , 2-21-1 Osawa, Mitaka, Tokyo 181-8588 , Japan

5. National Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588 , Japan

6. Department of Astronomy, School of Science, The Graduate University for Advanced Studies (SOKENDAI) , 2-21-1 Osawa, Mitaka, Tokyo , Japan

7. Division of Science, National Astronomical Observatory of Japan , 2-21-1 Osawa, Mitaka, Tokyo 181-8588 , Japan

8. Department of Physical Sciences, Ritsumeikan University , Kusatsu, Shiga 525-8577 , Japan

9. Departamento de Astrofísica, Universidad de La Laguna (ULL) , E-38206 La Laguna, Tenerife , Spain

10. Institute of Astronomy and Astrophysics, Academia Sinica , P.O. Box 23-141, Taipei 10617 , Taiwan, R.O.C.

11. Department of Astrophysics, National Taiwan University , Taipei 10617 , Taiwan, R.O.C.

12. Department of Astronomy, Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 , Japan

Abstract

ABSTRACT Detailed atmospheric characterization of exoplanets by transmission spectroscopy requires careful consideration of stellar surface inhomogeneities induced by star-spots. This effect is particularly problematic for planetary systems around M-dwarfs, and their spot properties are not fully understood. We investigated the stellar activity of the young M-dwarf K2-25 and its effect on transit observations of the sub-Neptune K2-25 b. From multiband monitoring observations of stellar brightness variability using ground-based telescopes and Transiting Exoplanets Survey Satellite, we found that the temperature difference between the spots and photosphere is <190 K and the spot covering fraction is <61 per cent (2σ). We also investigated the effect of starspot activity using multiepoch, multiband transit observations. We rule out cases with extremely low spot temperatures and large spot covering fractions. The results suggest that spots could distort the transmission spectrum of K2-25 b by as much as ∼100 ppm amplitude, corresponding to the precision of JWST/NIRSPEC of the target. Our study demonstrates that simultaneous multiband observations with current instruments can constrain the spot properties of M-dwarfs with good enough precision to support atmospheric studies of young M-dwarf planets via transmission spectroscopy.

Funder

National Aeronautics and Space Administration

National Science Foundation

JSPS

JST

Publisher

Oxford University Press (OUP)

Link

https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stae841/57067900/stae841.pdf

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