TY  - JOUR
A1  - Foster, Mary Grace
A1  - Poppenhäger, Katja
A1  - Alvarado-Gómez, Julián David
A1  - Schmitt, Jürgen
T1  - The corona of GJ 1151 in the context of star-planet interaction
JF  - Monthly notices of the Royal Astronomical Society
N2  - The low-mass star GJ 1151 has been reported to display variable low-frequency radio emission, which has been interpreted as a signpost of coronal star-planet interactions with an unseen exoplanet. Here we report the first X-ray detection of GJ 1151's corona based on the XMM-Newton data. We find that the star displays a small flare during the X-ray observation. Averaged over the observation, we detect the star with a low coronal temperature of 1.6 MK and an X-ray luminosity of L-X = 5.5 x 10(26) erg s(-1). During the quiescent time periods excluding the flare, the star remains undetected with an upper limit of L-X,L- qui <= 3.7 x 10(26) erg s(-1). This is compatible with the coronal assumptions used in a recently published model for a star-planet interaction origin of the observed radio signals from this star.
KW  - planet
KW  - star interactions
KW  - stars: coronae
KW  - X-rays: individual: GJ 1151
Y1  - 2020
U6  - https://doi.org/10.1093/mnras/staa1982
SN  - 0035-8711
SN  - 1365-2966
VL  - 497
IS  - 1
SP  - 1015
EP  - 1019
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Foster, Mary Grace
A1  - Poppenhäger, Katja
A1  - Ilić Petković, Nikoleta
A1  - Schwope, Axel
T1  - Exoplanet X-ray irradiation and evaporation rates with eROSITA
JF  - Astronomy and astrophysics : an international weekly journal
N2  - High-energy irradiation is a driver for atmospheric evaporation and mass loss in exoplanets. This work is based on data from eROSITA, the soft X-ray instrument on board the Spectrum Roentgen Gamma mission, as well as on archival data from other missions. We aim to characterise the high-energy environment of known exoplanets and estimate their mass-loss rates. We use X-ray source catalogues from eROSITA, XMM-Newton, Chandra, and ROSAT to derive X-ray luminosities of exoplanet host stars in the 0.2–2 keV energy band with an underlying coronal, that is, optically thin thermal spectrum. We present a catalogue of stellar X-ray and EUV luminosities, exoplanetary X-ray and EUV irradiation fluxes, and estimated mass-loss rates for a total of 287 exoplanets, 96 of which are characterised for the first time based on new eROSITA detections. We identify 14 first-time X-ray detections of transiting exoplanets that are subject to irradiation levels known to cause observable evaporation signatures in other exoplanets. This makes them suitable targets for follow-up observations.
KW  - stars: coronae
KW  - stars: activity
KW  - planet-star interactions
KW  - planets and
KW  - satellites: atmospheres
KW  - X-rays: stars
Y1  - 2022
U6  - https://doi.org/10.1051/0004-6361/202141097
SN  - 0004-6361
SN  - 1432-0746
VL  - 661
PB  - EDP Sciences
CY  - Les Ulis
ER  -