2023MNRAS.524.5196B -
Mon. Not. R. Astron. Soc., 524, 5196-5212 (2023/October-1)
DMPP-4: candidate sub-Neptune mass planets orbiting a naked-eye star.
BARNES J.R., STANDING M.R., HASWELL C.A., STAAB D., DOHERTY J.P.J., WALLER-BRIDGE M., FOSSATI L., SOTO M., ANGLADA-ESCUDE G., LLAMA J., McCUNE C. and LEWIS F.W.
Abstract (from CDS):
We present radial velocity measurements of the very bright (V ∼ 5.7) nearby F star, DMPP-4 (HD 184960). The anomalously low Ca II H&K emission suggests mass-loss from planets orbiting a low activity host star. Periodic radial velocity variability with ∼10 m s–1 amplitude is found to persist over a >4 yr time-scale. Although the non-simultaneous photometric variability in four TESS sectors supports the view of an inactive star, we identify periodic photometric signals and also find spectroscopic evidence for stellar activity. We used a posterior sampling algorithm that includes the number of Keplerian signals, Np, as a free parameter to test and compare (1) purely Keplerian models (2) a Keplerian model with linear activity correlation and (3) Keplerian models with Gaussian processes. A preferred model, with one Keplerian and quasi-periodic Gaussian process indicates a planet with a period of $P_\textrm {b} = 3.4982^{+0.0015}_{-0.0027}$ d and corresponding minimum mass of $m_\textrm {b}\, \textrm {sin}\, i = 12.2^{+1.8}_{-1.9}$ M⊕. Without further high-time resolution observations over a longer time-scale, we cannot definitively rule out the purely Keplerian model with two candidates planets with $P_\textrm {b} = 2.4570^{+0.0026}_{-0.0462}$ d, minimum mass $m_\textrm {b}\, \textrm {sin}\, i = 8.0^{+1.1}_{-1.5}$ M⊕ and $P_\textrm {c} = 5.4196^{+0.6766}_{-0.0030}$ d and corresponding minimum mass of $m_\textrm {b}\, \textrm {sin}\, i = 12.2^{+1.4}_{-1.6}$ M⊕. The candidate planets lie in the region below the lower-envelope of the Neptune Desert. Continued mass-loss may originate from the highly irradiated planets or from an as yet undetected body in the system.
Abstract Copyright:
© 2023 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
methods: observational - techniques: photometric - techniques: radial velocities - techniques: spectroscopic - planets and satellites: detection - stars: late-type
Simbad objects:
12
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