activity
20222026
most citedA hot mini-Neptune and a temperate, highly eccentric sub-Saturn around the bright K-dwarf TOI-2134

8 citations · 12 across the 15 of their papers we have counts for

collaborators

15 papers

astro-ph.IM2026

Connecting Granulation and Magnetic Activity in Radial Velocities: The Next Breakthrough for High-Precision Spectroscopy

Ancy Anna John, Khaled Al Moulla, Federica Rescigno +5

Stellar variability has become the dominant limitation to achieving the radial velocity (RV) precision required for the detection and characterization of Earth-like exoplanets. Whi…

astro-ph.SR2026

The Fe I 4377 Å Line as a Solar Faculae Indicator: Insights from Spectral Ratio Analysis

Katlyn L. Hobbs, Christopher A. Watson, Jean C. Costes +21

Faculae are a dominant source of stellar activity noise in radial velocity measurements, yet their low contrast and broad surface distribution make them difficult to track in disc-…

astro-ph.EP2026

Understanding eccentric temperate giants: an in-depth study of the architecture and stellar obliquity of the TOI-2134 system

Federica Rescigno, Manu Stalport, Ancy Anna John +28

We revisit the TOI-2134 planetary system with three new high-cadence TESS sectors and 98 more spectra. This new analysis confirms the two orbiting planets by simultaneously modelli…

astro-ph.EP2026★ 1 cited

Gas-depleted planet formation occurred in the four-planet system around the red dwarf LHS 1903

Thomas G. Wilson, Anna M. Simpson, Andrew Collier Cameron +173

Small exoplanet radii show two populations, referred to as super-Earths and sub-Neptunes, separated by a gap known as the radius valley. This may be produced by the removal of atmo…

astro-ph.EP2025

HARPS-N, TESS, and CHEOPS discover a transiting sub-Neptune and two outer companions around the bright solar analogue HD 85426

F. Lienhard, A. Mortier, A. Collier Cameron +96

We provide a detailed characterisation of the planetary system orbiting HD 85426 (TOI-1774). This bright G-type star (: 0.99 ; : 1.13 $\text{R…

astro-ph.SR2025★ 3 cited

A Decade of Solar High-Fidelity Spectroscopy and Precise Radial Velocities from HARPS-N

X. Dumusque, K. Al Moulla, M. Cretignier +53

We recently released 10 years of HARPS-N solar telescope and the goal of this manuscript is to present the different optimisations made to the data reduction, to describe data cura…

astro-ph.EP2025

The HD 60779 Planetary System: A Transiting Sub-Neptune on a 30-day Orbit and a More Massive Outer World

Victoria DiTomasso, David Charbonneau, Andrew Vanderburg +37

We present the discovery of the planetary system orbiting the bright (V = 7.2), nearby (35 pc), Sun-like star HD 60779, which has a mass of 1.050 +/- 0.044 solar masses and a radiu…

astro-ph.SR2025

Gaussian process regression of temperature-dependent radial velocities

Federica Rescigno, Khaled Al Moulla

Gaussian processes (GPs) described by quasi-periodic covariance functions have in recent years become a widely used tool to model the impact of stellar activity on radial velocity…

astro-ph.SR2024

The Mean Longitudinal Magnetic Field and its Uses in Radial-Velocity Surveys

F. Rescigno, A. Mortier, X. Dumusque +14

This work focuses on the analysis of the mean longitudinal magnetic field as a stellar activity tracer in the context of small exoplanet detection and characterisation in radial-ve…

astro-ph.EP2024

Investigating stellar activity through eight years of Sun-as-a-star observations

Baptiste Klein, Suzanne Aigrain, Michael Cretignier +11

Stellar magnetic activity induces both distortions and Doppler-shifts in the absorption line profiles of Sun-like stars. Those effects produce apparent radial velocity (RV) signals…

astro-ph.SR2023

The magnetically quiet solar surface dominates HARPS-N solar RVs during low activity

Ben S. Lakeland, Tim Naylor, Raphaëlle Haywood +15

Using images from the Helioseismic and Magnetic Imager aboard the \textit{Solar Dynamics Observatory} (SDO/HMI), we extract the radial-velocity (RV) signal arising from the suppres…

astro-ph.EP2023

Masses, Revised Radii, and a Third Planet Candidate in the "Inverted" Planetary System Around TOI-1266

Ryan Cloutier, Michael Greklek-McKeon, Serena Wurmser +40

Is the population of close-in planets orbiting M dwarfs sculpted by thermally driven escape or is it a direct outcome of the planet formation process? A number of recent empirical…

astro-ph.EP2023★ 8 cited

A hot mini-Neptune and a temperate, highly eccentric sub-Saturn around the bright K-dwarf TOI-2134

F. Rescigno, G. Hébrard, A. Vanderburg +64

We present the characterisation of an inner mini-Neptune in a 9.22920050.0000063 day orbit and an outer mono-transiting sub-Saturn planet in a 95.50 day orbi…

astro-ph.EP2023

Outflowing helium from a mature mini-Neptune

Michael Zhang, Fei Dai, Jacob L. Bean +2

We announce the detection of escaping helium from TOI 2134b, a mini-Neptune a few Gyr old. The average in-transit absorption spectrum shows a peak of 0.37 +- 0.05% and an equivalen…

astro-ph.SR2022

Leveraging space-based data from the nearest Solar-type star to better understand stellar activity signatures in radial velocity data

Tamar Ervin, Samuel Halverson, Abigail Burrows +8

Stellar variability is a key obstacle in reaching the sensitivity required to recover Earth-like exoplanetary signals using the radial velocity (RV) detection method. To explore ac…