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gr8stars II : judgement day for spectroscopic parameter model systematics
Alix Violet Freckelton, Annelies Mortier, Megan Bedell +18
Many areas of astrophysics, including exoplanetary studies, rely on precise and accurate stellar parameters. This demands that uncertainties on these parameters truly reflect all b…
Stellar-activity analysis of the nearby M dwarf GJ 526. Multi-dimensional Gaussian-process modelling of RV, FWHM and S-index
A. K. Stefanov, J. I. González Hernández, A. Suárez Mascareño +17
M dwarfs are the most abundant stars in the Galaxy, and their low masses make them natural favourites for exoplanet radial-velocity (RV) searches. Nevertheless, these stars often d…
gr8stars I: A homogeneous spectroscopic study of bright FGKM dwarfs and a public library of their high-resolution spectra
Alix Violet Freckelton, Annelies Mortier, Megan Bedell +15
As the fields of stellar and exoplanetary study grow and revolutionary new detection instruments are created, it is imperative that a homogeneous, precise source of stellar paramet…
On the 12C/13C isotopic ratio at the dawn of chemical evolution
P. Molaro, D. S. Aguado, E. Caffau +21
The known Mega and Hyper Metal-Poor (MMP-HMP) stars with [Fe/H]<-6.0 and <-5.0, respectively, likely belong to the CEMP-no class, i.e. carbon-enhanced stars with low or absent seco…
The pristine nature of SMSS 16051443 revealed by ESPRESSO
D. S. Aguado, E. Caffau, P. Molaro +20
SMSS J160540.18144323.1 is the carbon-enhanced metal-poor (CEMP) star with the lowest iron abundance ever measured, [Fe/H]=-6.2, which was first reported with the SkyMapper tele…
Espresso observations of HE 01075240 and other CEMP-no stars with
D. Aguado, P. Molaro, E. Caffau +22
HE 01075240 is a hyper metal-poor star with . We performed high-res observations with the ESPRESSO spectrograph at the VLT to constrain the kinematical propert…
AlH lines in the blue spectrum of Proxima Centauri
Yakiv V. Pavlenko, Jonathan Tennyson, Sergei N. Yurchenko +4
The recently-computed ExoMol line lists for isotopologues of AlH are used to analyse the blue spectrum (4000-4500 Å) of Proxima Cen (M5.5 V). Comparison of the observed and compute…
The solar gravitational redshift from HARPS-LFC Moon spectra. A test of the General Theory of Relativity
J. I. González Hernández, R. Rebolo, L. Pasquini +15
The General Theory of Relativity predicts the redshift of spectral lines in the solar photosphere, as a consequence of the gravitational potential of the Sun. This effect can be me…
Temporal changes of the flare activity of Proxima Cen
Ya. V. Pavlenko, A. Suarez Mascareno, M. R. Zapatero Osorio +5
We study temporal variations of the emission lines of Halpha, Hepsilon, H and K Ca II, D1 and D2 Na I, 4026 and 5876 A He I in the HARPS spectra of Proxima Centauri across an exten…
HADES RV Programme with HARPS-N at TNG. X. The non-saturated regime of the stellar activity-rotation relationship for M-Dwarfs
E. González-Álvarez, G. Micela, J. Maldonado +22
Aims. We aim to extend the relationship between X-ray luminosity (Lx) and rotation period (Prot) found for main-sequence FGK stars and test whether it also holds for early-M dwarfs…
Stellar activity analysis of Barnard's Star: Very slow rotation and evidence for long-term activity cycle
B. Toledo-Padrón, J. I. González Hernández, C. Rodríguez-López +58
The search for Earth-like planets around late-type stars using ultra-stable spectrographs requires a very precise characterization of the stellar activity and the magnetic cycle of…
HADES RV Programme with HARPS-N at TNG. VII. Rotation and activity of M-Dwarfs from time-series high-resolution spectroscopy of chromospheric indicators
A. Suárez Mascareño, R. Rebolo, J. I. González Hernández +28
We aim to investigate the presence of signatures of magnetic cycles and rotation on a sample of 71 early M-dwarfs from the HADES RV programme using high-resolution time-series spec…
HADES RV Programme with HARPS-N at TNG VI. GJ 3942 b behind dominant activity signals
M. Perger, I. Ribas, M. Damasso +29
Short- to mid-term magnetic phenomena on the stellar surface of M-type stars cannot only resemble the effects of planets in radial velocity data, but also may hide them. We analyze…
Flare activity and photospheric analysis of Proxima Centauri
Ya. V. Pavlenko, A. Suarez Mascareno, R. Rebolo +3
We present the analysis of emission lines in high-resolution optical spectra of the planet-host star Proxima Centauri (Proxima) classified as a M5.5V\@. We carry out the detailed a…
The HADES RV Programme with HARPS-N@TNG. III. Flux-flux and activity-rotation relationships of early-M dwarfs
J. Maldonado, G. Scandariato, B. Stelzer +23
(Abridged) Understanding stellar activity in M dwarfs is crucial for the physics of stellar atmospheres as well as for ongoing radial velocity exoplanet programmes. Despite the inc…
The HADES RV Programme with HARPS-N@TNG IV. Time resolved analysis of the Ca ii H&K and Hα chromospheric emission of low-activity early-type M dwarfs
G. Scandariato, J. Maldonado L. Affer, K. Biazzo +22
M dwarfs are prime targets for planet search programs, particularly of those focused on the detection and characterization of rocky planets in the habitable zone. Understanding the…
Magnetic Cycles and Rotation Periods of Late Type Stars from photometric time series
A. Suárez Mascareño, R. Rebolo, J. I. González Hernández
We investigate the photometric modulation induced by magnetic activity cycles and study the relationship between rotation period and activity cycle(s) in late-type (FGKM) stars. We…
An eclipsing double-line spectroscopic binary at the stellar/substellar boundary in the Upper Scorpius OB association
N. Lodieu, R. Alonso, J. I. Gonzalez Hernandez +12
We aim at constraining evolutionary models at low mass and young ages by identifying interesting transiting system members of the nearest OB association to the Sun, Upper Scorpius,…