Ground-based detection of an extended helium atmosphere in the Saturn-mass exoplanet WASP-69b. (arXiv:1812.03119v1 [astro-ph.EP])
<a href="http://arxiv.org/find/astro-ph/1/au:+Nortmann_L/0/1/0/all/0/1">Lisa Nortmann</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Palle_E/0/1/0/all/0/1">Enric Pallé</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Salz_M/0/1/0/all/0/1">Michael Salz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sanz_Forcada_J/0/1/0/all/0/1">Jorge Sanz-Forcada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nagel_E/0/1/0/all/0/1">Evangelos Nagel</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Alonso_Floriano_F/0/1/0/all/0/1">F. Javier Alonso-Floriano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Czesla_S/0/1/0/all/0/1">Stefan Czesla</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Yan_F/0/1/0/all/0/1">Fei Yan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_G/0/1/0/all/0/1">Guo Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Snellen_I/0/1/0/all/0/1">Ignas A. G. Snellen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zechmeister_M/0/1/0/all/0/1">Mathias Zechmeister</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schmitt_J/0/1/0/all/0/1">Jürgen H. M. M. Schmitt</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lopez_Puertas_M/0/1/0/all/0/1">Manuel López-Puertas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Casasayas_Barris_N/0/1/0/all/0/1">Núria Casasayas-Barris</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bauer_F/0/1/0/all/0/1">Florian F. Bauer</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Amado_P/0/1/0/all/0/1">Pedro J. Amado</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Caballero_J/0/1/0/all/0/1">José A. Caballero</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dreizler_S/0/1/0/all/0/1">Stefan Dreizler</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Henning_T/0/1/0/all/0/1">Thomas Henning</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lampon_M/0/1/0/all/0/1">Manuel Lampón</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Montes_D/0/1/0/all/0/1">David Montes</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Molaverdikhani_K/0/1/0/all/0/1">Karan Molaverdikhani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Quirrenbach_A/0/1/0/all/0/1">Andreas Quirrenbach</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Reiners_A/0/1/0/all/0/1">Ansgar Reiners</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Ribas_I/0/1/0/all/0/1">Ignasi Ribas</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sanchez_Lopez_A/0/1/0/all/0/1">Alejandro Sánchez-López</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Schneider_P/0/1/0/all/0/1">P. Christian Schneider</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Osorio_M/0/1/0/all/0/1">María R. Zapatero Osorio</a>
Hot gas giant exoplanets can lose part of their atmosphere due to strong
stellar irradiation, affecting their physical and chemical evolution. Studies
of atmospheric escape from exoplanets have mostly relied on space-based
observations of the hydrogen Lyman-{alpha} line in the far ultraviolet which
is strongly affected by interstellar absorption. Using ground-based
high-resolution spectroscopy we detect excess absorption in the helium triplet
at 1083 nm during the transit of the Saturn-mass exoplanet WASP-69b, at a
signal-to-noise ratio of 18. We measure line blue shifts of several km/s and
post transit absorption, which we interpret as the escape of part of the
atmosphere trailing behind the planet in comet-like form.
[Additional notes by authors: Furthermore, we provide upper limits for helium
signals in the atmospheres of the exoplanets HD 209458b, KELT-9b, and GJ 436b.
We investigate the host stars of all planets with detected helium signals and
those of the three planets we derive upper limits for. In each case we
calculate the X-ray and extreme ultraviolet flux received by these planets. We
find that helium is detected in the atmospheres of planets (orbiting the more
active stars and) receiving the larger amount of irradiation from their host
stars.]
Hot gas giant exoplanets can lose part of their atmosphere due to strong
stellar irradiation, affecting their physical and chemical evolution. Studies
of atmospheric escape from exoplanets have mostly relied on space-based
observations of the hydrogen Lyman-{alpha} line in the far ultraviolet which
is strongly affected by interstellar absorption. Using ground-based
high-resolution spectroscopy we detect excess absorption in the helium triplet
at 1083 nm during the transit of the Saturn-mass exoplanet WASP-69b, at a
signal-to-noise ratio of 18. We measure line blue shifts of several km/s and
post transit absorption, which we interpret as the escape of part of the
atmosphere trailing behind the planet in comet-like form.
[Additional notes by authors: Furthermore, we provide upper limits for helium
signals in the atmospheres of the exoplanets HD 209458b, KELT-9b, and GJ 436b.
We investigate the host stars of all planets with detected helium signals and
those of the three planets we derive upper limits for. In each case we
calculate the X-ray and extreme ultraviolet flux received by these planets. We
find that helium is detected in the atmospheres of planets (orbiting the more
active stars and) receiving the larger amount of irradiation from their host
stars.]
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