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Title: TOI-663: A newly discovered multi-planet system with three transiting mini-Neptunes orbiting an early M star
We present the detection of three exoplanets orbiting the early M dwarf TOI-663 (TIC 54962195;V= 13.7 mag,J= 10.4 mag,R★= 0.512 ± 0.015R⊙,M★= 0.514 ± 0.012M⊙,d= 64 pc). TOI-663 b, c, and d, with respective radii of 2.27 ± 0.10R⊕, 2.26 ± 0.10R⊕, and 1.92 ± 0.13R⊕and masses of 4.45 ± 0.65M⊕, 3.65 ± 0.97M⊕, and <5.2M⊕at 99%, are located just above the radius valley that separates rocky and volatile-rich exoplanets. The planet candidates are identified in two TESS sectors and are validated with ground-based photometric follow-up, precise radial-velocity measurements, and high-resolution imaging. We used the software package juliet to jointly model the photometric and radial-velocity datasets, with Gaussian processes applied to correct for systematics. The three planets discovered in the TOI-663 system are low-mass mini-Neptunes with radii significantly larger than those of rocky analogs, implying that volatiles, such as water, must predominate. In addition to this internal structure analysis, we also performed a dynamical analysis that confirmed the stability of the system. The three exoplanets in the TOI-663 system, similarly to other sub-Neptunes orbiting M dwarfs, have been found to have lower densities than planets of similar sizes orbiting stars of different spectral types.  more » « less
Award ID(s):
2108465
PAR ID:
10514038
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; « less
Publisher / Repository:
ESO
Date Published:
Journal Name:
Astronomy & Astrophysics
Volume:
685
ISSN:
0004-6361
Page Range / eLocation ID:
A19
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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