The GAPS programme at TNG

Context. Transiting ultra-hot Jupiters are ideal candidates for studying the exoplanet atmospheres and their dynamics, particularly by means of high-resolution spectra with high signal-to-noise ratios. One such object is KELT-20b. It orbits the fast-rotating A2-type star KELT-20. Many atomic species have been found in its atmosphere, with blueshifted signals that indicate a day- to night-side wind. Aims. We observe the atmospheric Rossiter-McLaughlin effect in the ultra-hot Jupiter KELT-20b and study any variation of the atmospheric signal during the transit. For this purpose, we analysed five nights of HARPS-N spectra covering five transits of KELT-20b. Methods. We computed the mean line profiles of the spectra with a least-squares deconvolution using a stellar mask obtained from the Vienna Atomic Line Database (Teff = 10 000 K, log g = 4.3), and then we extracted the stellar radial velocities by fitting them with a rotational broadening profile in order to obtain the radial velocity time-series. We used the mean line profile residuals tomography to analyse the planetary atmospheric signal and its variations. We also used the cross-correlation method to study a previously reported double-peak feature in the FeI planetary signal. Results. We observed both the classical and the atmospheric Rossiter-McLaughlin effect in the radial velocity time-series. The latter gave us an estimate of the radius of the planetary atmosphere that correlates with the stellar mask used in our work (Rp+atmo∕Rp = 1.13 ± 0.02). We isolated the planetary atmospheric trace in the tomography, and we found radial velocity variations of the planetary atmospheric signal during transit with an overall blueshift of ≈10 km s−1, along with small variations in the signal depth, and less significant, in the full width at half maximum (FWHM). We also find a possible variation in the structure and position of the FeI signal in different transits. Conclusions. We confirm the previously detected blueshift of the atmospheric signal during the transit. The FWHM variations of the atmospheric signal, if confirmed, may be caused by more turbulent condition at the beginning of the transit, by a variable contribution of the elements present in the stellar mask to the overall planetary atmospheric signal, or by iron condensation. The FeI signal show indications of variability from one transit to the next.

[1]  M. Osorio,et al.  Atmospheric Rossiter–McLaughlin effect and transmission spectroscopy of WASP-121b with ESPRESSO , 2020, Astronomy & Astrophysics.

[2]  M. Giampapa,et al.  The GAPS programme at TNG , 2020, Astronomy & Astrophysics.

[3]  Antonino Francesco Lanza,et al.  Neutral Iron Emission Lines from the Dayside of KELT-9b: The GAPS Program with HARPS-N at TNG XX , 2020, The Astrophysical Journal.

[4]  D. Ehrenreich,et al.  High-resolution transmission spectroscopy of MASCARA-2 b with EXPRES , 2020, Astronomy & Astrophysics.

[5]  H. Kawahara,et al.  Searching for thermal inversion agents in the transmission spectrum of KELT-20b/MASCARA-2b: detection of neutral iron and ionised calcium H&K lines , 2020, Monthly Notices of the Royal Astronomical Society.

[6]  M. López‐Puertas,et al.  Detection of Fe I and Fe II in the atmosphere of MASCARA-2b using a cross-correlation method , 2020, Astronomy & Astrophysics.

[7]  J. L. Rasilla,et al.  Nightside condensation of iron in an ultra-hot giant exoplanet , 2020, Nature.

[8]  S. Cabot,et al.  Detection of neutral atomic species in the ultra-hot Jupiter WASP-121b , 2020, Monthly Notices of the Royal Astronomical Society.

[9]  D. Bayliss,et al.  Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) , 2020, Astronomy & Astrophysics.

[10]  A. Bonomo,et al.  The GAPS Programme with HARPS-N at TNG , 2019, Astronomy & Astrophysics.

[11]  M. Osorio,et al.  Atmospheric characterization of the ultra-hot Jupiter MASCARA-2b/KELT-20b , 2019, Astronomy & Astrophysics.

[12]  D. Ehrenreich,et al.  A spectral survey of an ultra-hot Jupiter , 2019, Astronomy & Astrophysics.

[13]  T. Barman,et al.  The Influence of Host Star Spectral Type on Ultra-hot Jupiter Atmospheres , 2019, The Astrophysical Journal.

[14]  A. Rest,et al.  Nebular Spectroscopy of Kepler’s Brightest Supernova , 2018, The Astrophysical Journal.

[15]  M. Line,et al.  Retrieving Temperatures and Abundances of Exoplanet Atmospheres with High-resolution Cross-correlation Spectroscopy , 2018, The Astronomical Journal.

[16]  D. Ehrenreich,et al.  Atomic iron and titanium in the atmosphere of the exoplanet KELT-9b , 2018, Nature.

[17]  R. Rebolo,et al.  Na I and Hα absorption features in the atmosphere of MASCARA-2b/KELT-20b , 2018, Astronomy & Astrophysics.

[18]  M. Deleuil,et al.  From thermal dissociation to condensation in the atmospheres of ultra hot Jupiters: WASP-121b in context , 2018, Astronomy & Astrophysics.

[19]  N. Cowan,et al.  Increased Heat Transport in Ultra-hot Jupiter Atmospheres through H2 Dissociation and Recombination , 2018, 1802.07725.

[20]  D. Ehrenreich,et al.  Combining low- to high-resolution transit spectroscopy of HD 189733b , 2017, 1709.09678.

[21]  Keivan G. Stassun,et al.  KELT-20b: A Giant Planet with a Period of P ∼ 3.5 days Transiting the V ∼ 7.6 Early A Star HD 185603 , 2017, 1707.01518.

[22]  M. F. Andersen,et al.  MASCARA-2 b: A hot Jupiter transiting a $m_V=7.6$ A-star , 2017, 1707.01500.

[23]  M. R. Panzera,et al.  THE SPACEINN–SISMA DATABASE: CHARACTERIZATION OF A LARGE SAMPLE OF VARIABLE AND ACTIVE STARS BY MEANS OF HARPS SPECTRA , 2016, 1611.02715.

[24]  F. Pepe,et al.  The Rossiter-McLaughlin effect reloaded: Probing the 3D spin-orbit geometry, differential stellar rotation, and the spatially-resolved stellar spectrum of star-planet systems , 2016, 1602.00322.

[25]  A. Santerne,et al.  WASP-121 b: a hot Jupiter close to tidal disruption transiting an active F star , 2015, 1506.02471.

[26]  H. C. Stempels,et al.  A major upgrade of the VALD database , 2015 .

[27]  K. Heng,et al.  Atmospheric Dynamics of Hot Exoplanets , 2014, 1407.4150.

[28]  U. Munari,et al.  The GAPS programme with HARPS-N at TNG - I. Observations of the Rossiter-McLaughlin effect and characterisation of the transiting system Qatar-1 , 2013, 1304.0005.

[29]  E. Oliva,et al.  The GIANO spectrometer: towards its first light at the TNG , 2012, Other Conferences.

[30]  Nicolas Buchschacher,et al.  Harps-N: the new planet hunter at TNG , 2012, Other Conferences.

[31]  Daniel Foreman-Mackey,et al.  emcee: The MCMC Hammer , 2012, 1202.3665.

[32]  L. Arnold,et al.  Transmission spectrum of Venus as a transiting exoplanet , 2011, 1112.0572.

[33]  M. Asplund,et al.  The chemical composition of the Sun , 2009, 0909.0948.

[34]  Astrophysics,et al.  FUSE spectroscopy of the sdOB primary of the post common-envelope binary LB 3459 ( AA Doradus ) , 2008, 0809.2746.

[35]  D. Ehrenreich,et al.  The transmission spectrum of Earth-size transiting planets , 2005, astro-ph/0510215.

[36]  Yasuhiro Ohta,et al.  The Rossiter-McLaughlin Effect and Analytic Radial Velocity Curves for Transiting Extrasolar Planetary Systems , 2004, astro-ph/0410499.

[37]  A. Reiners,et al.  On the feasibility of the detection of differential rotation in stellar absorption profiles , 2002 .

[38]  Andrew Collier Cameron,et al.  Spectropolarimetric observations of active stars , 1997 .

[39]  D. F. Gray,et al.  FOURIER ANALYSIS OF SPECTRAL LINE PROFILES: A NEW TOOL FOR AN OLD ART. , 1976 .

[40]  Jean. Steinier,et al.  Smoothing and differentiation of data by simplified least square procedure. , 1964, Analytical chemistry.

[41]  D. B. McLaughlin.  Some results of a spectrographic study of the Algol system. , 1924 .

[42]  R. A. Rossiter.  On the detection of an effect of rotation during eclipse in the velocity of the brigher component of beta Lyrae, and on the constancy of velocity of this system. , 1924 .

[43]  Jan Swevers,et al.  Ground-based and airborne instrumentation for astronomy , 2010 .