We present a revised mass measurement for HD 119130 b (aka K2-292 b), a transiting planet (
The early K-type T-Tauri star, V1298 Tau (
- Award ID(s):
- 2108465
- PAR ID:
- 10415592
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astronomical Journal
- Volume:
- 165
- Issue:
- 6
- ISSN:
- 0004-6256
- Format(s):
- Medium: X Size: Article No. 250
- Size(s):
- Article No. 250
- Sponsoring Org:
- National Science Foundation
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Abstract P = 17 days,R p=R ⊕) orbiting a chromospherically inactive G dwarf, previously thought to be one of the densest sub-Neptunes known. Our follow-up Doppler observations with HARPS, HARPS-N, and HIRES reveal that HD 119130 b is, in fact, nearly one-third as massive as originally suggested by its initial confirmation paper. Our revised analysis findsM p= 8.8 ± 3.2M ⊕(M p< 15.4M ⊕at 98% confidence) compared to the previously reportedM p= 24.5 ± 4.4M ⊕. While the true cause of the original mass measurement’s inaccuracy remains uncertain, we present the plausible explanation that the planet’s radial velocity (RV) semiamplitude was inflated due to constructive interference with a second, untreated sinusoidal signal in the data (possibly rotational modulation from the star). HD 119130 b illustrates the complexities of interpreting the RV orbits of small transiting planets. While RV mass measurements of such planets may be precise, they are not necessarily guaranteed to be accurate. This system serves as a cautionary tale as observers and theorists alike look to the exoplanet mass–radius diagram for insights into the physics of small-planet formation. -
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