The CARMENES search for exoplanets around M dwarfs. A long-period planet around GJ 1151 measured with CARMENES and HARPS-N data

Blanco-Pozo, J.; Perger, M.; Damasso, M.; Anglada Escudé, G.; Ribas, I.; Baroch, D.; Caballero, J. A.; Cifuentes, C.; Jeffers, S. V.; Lafarga, M.; Kaminski, A.; Kaur, S.; Nagel, E.; Perdelwitz, V.; Pérez-Torres, M.; Sozzetti, A.; Viganò, D.; Amado, P. J.; Andreuzzi, G.; Béjar, V. J. S.; Brown, E. L.; Del Sordo, F.; Dreizler, S.; Galadí-Enríquez, D.; Hatzes, A. P.; Kürster, M.; Lanza, A. F.; Melis, A.; Molinari, E.; Montes, D.; Murgia, M.; Pallé, E.; Peña-Moñino, L.; Perrodin, D.; Pilia, M.; Poretti, E.; Quirrenbach, A.; Reiners, A.; Schweitzer, A.; Zapatero Osorio, M. R.; Zechmeister, M.
Bibliographical reference

Astronomy and Astrophysics

Advertised on:
3
2023
Number of authors
41
IAC number of authors
2
Citations
15
Refereed citations
12
Description
Context. Detecting a planetary companion in a short-period orbit through radio emission from the interaction with its host star is a new prospect in exoplanet science. Recently, a tantalising signal was found close to the low-mass stellar system GJ 1151 using LOFAR observations.
Aims: We studied spectroscopic time-series data of GJ 1151 in order to search for planetary companions, investigate possible signatures of stellar magnetic activity, and to find possible explanations for the radio signal.
Methods: We used the combined radial velocities measured from spectra acquired with the CARMENES, HARPS-N, and HPF instruments, extracted activity indices from those spectra in order to mitigate the impact of stellar magnetic activity on the data, and performed a detailed analysis of Gaia astrometry and all available photometric time series coming from the MEarth and ASAS-SN surveys.
Results: We found a M > 10.6 M⊕ companion to GJ 1151 in a 390d orbit at a separation of 0.57 au. Evidence for a second modulation is also present; this could be due to long-term magnetic variability or a second (substellar) companion. The star shows episodes of elevated magnetic activity, one of which could be linked to the observed LOFAR radio emission. We show that it is highly unlikely that the detected GJ 1151 c, or any additional outer companion is the source of the detected signal. We cannot firmly rule out the suggested explanation of an undetected short-period planet that could be related to the radio emission, as we establish an upper limit of 1.2 M⊕ for the minimum mass.

Tables C.1 and C.2 are only available in electronic form at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (ftp://130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/671/A50

Related projects
Projects' name image
Exoplanets and Astrobiology
The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable
Enric
Pallé Bago
Discovery of a system of super-Earths orbiting the star HD 176986 with about 5.7 and 9.2 Earth masses.
Very Low Mass Stars, Brown Dwarfs and Planets
Our goal is to study the processes that lead to the formation of low mass stars, brown dwarfs and planets and to characterize the physical properties of these objects in various evolutionary stages. Low mass stars and brown dwarfs are likely the most numerous type of objects in our Galaxy but due to their low intrinsic luminosity they are not so
Rafael
Rebolo López