Ultrahot giant exoplanets receive thousands of times Earth's insolation
. Their high-temperature atmospheres (greater than 2,000 kelvin) are ideal laboratories for studying extreme planetary climates ...and chemistry
. Daysides are predicted to be cloud-free, dominated by atomic species
and much hotter than nightsides
. Atoms are expected to recombine into molecules over the nightside
, resulting in different day and night chemistries. Although metallic elements and a large temperature contrast have been observed
, no chemical gradient has been measured across the surface of such an exoplanet. Different atmospheric chemistry between the day-to-night ('evening') and night-to-day ('morning') terminators could, however, be revealed as an asymmetric absorption signature during transit
. Here we report the detection of an asymmetric atmospheric signature in the ultrahot exoplanet WASP-76b. We spectrally and temporally resolve this signature using a combination of high-dispersion spectroscopy with a large photon-collecting area. The absorption signal, attributed to neutral iron, is blueshifted by -11 ± 0.7 kilometres per second on the trailing limb, which can be explained by a combination of planetary rotation and wind blowing from the hot dayside
. In contrast, no signal arises from the nightside close to the morning terminator, showing that atomic iron is not absorbing starlight there. We conclude that iron must therefore condense during its journey across the nightside.
Observations of metal absorption systems in the spectra of distant quasars allow one to constrain a possible variation of the fine-structure constant throughout the history of the Universe. Such a ...test poses utmost demands on the wavelength accuracy and previous studies were limited by systematics in the spectrograph wavelength calibration. A substantial advance in the field is therefore expected from the new ultra-stable high-resolution spectrograph E
SPRESSO
, which was recently installed at the VLT. In preparation of the fundamental physics related part of the E
SPRESSO
GTO program, we present a thorough assessment of the E
SPRESSO
wavelength accuracy and identify possible systematics at each of the different steps involved in the wavelength calibration process. Most importantly, we compare the default wavelength solution, which is based on the combination of Thorium-Argon arc lamp spectra and a Fabry-Pérot interferometer, to the fully independent calibration obtained from a laser frequency comb. We find wavelength-dependent discrepancies of up to 24 m s
−1
. This substantially exceeds the photon noise and highlights the presence of different sources of systematics, which we characterize in detail as part of this study. Nevertheless, our study demonstrates the outstanding accuracy of E
SPRESSO
with respect to previously used spectrographs and we show that constraints of a relative change of the fine-structure constant at the 10
−6
level can be obtained with E
SPRESSO
without being limited by wavelength calibration systematics.
Ultra-hot giant exoplanets receive thousands of times Earth’s
insolation
1
,
2
. Their high-temperature
atmospheres (>2,000 K) are ideal laboratories for studying extreme
planetary climates and ...chemistry
3
–
5
. Daysides
are predicted to be cloud-free, dominated by atomic species
6
and substantially hotter than
nightsides
5
,
7
,
8
. Atoms are expected to recombine into molecules over the
nightside
9
, resulting
in different day-night chemistry. While metallic elements and a large
temperature contrast have been observed
10
–
14
, no
chemical gradient has been measured across the surface of such an exoplanet.
Different atmospheric chemistry between the day-to-night
(“evening”) and night-to-day (“morning”) terminators
could, however, be revealed as an asymmetric absorption signature during
transit
4
,
7
,
15
. Here, we report the detection of an asymmetric
atmospheric signature in the ultra-hot exoplanet WASP-76b. We spectrally and
temporally resolve this signature thanks to the combination of high-dispersion
spectroscopy with a large photon-collecting area. The absorption signal,
attributed to neutral iron, is blueshifted by −11±0.7 km
s
-1
on the trailing limb, which can be explained by a combination
of planetary rotation and wind blowing from the hot dayside
16
. In contrast, no signal arises
from the nightside close to the morning terminator, showing that atomic iron is
not absorbing starlight there. Iron must thus condense during its journey across
the nightside.
The Son Of X-Shooter (SOXS) is a single object spectrograph, built by an international consortium for the 3.58-m ESO New Technology Telescope at the La Silla Observatory 1. It offers a simultaneous ...spectral coverage over 350-2000 nm, with two separate spectrographs. In this paper we present the status of the Near InfraRed (NIR) cryogenic echelle cross-dispersed spectrograph 1, in the range 0.80-2.00 {\mu}m with 15 orders, equipped with an 2k x 2k Hawaii H2RG IR array from Teledyne, working at 40K, that is currently assembled and tested on the SOXS instrument, in the premises of INAF in Padova. We describe the different tests and results of the cryo, vacuum, opto-mechanics and detector subsystems that finally will be part of the PAE by ESO.
We present the preliminary design of Cerberus, a new scientific instrument for the alt-az, 80cm OARPAF telescope in the Ligurian mountains above Genoa, Italy. Cerberus will provide three focal ...stations at the Nasmyth focus, allowing: imaging and photometry with standard Johnson-Cousins UBVRI+Ha+Free filters, an on-axis guiding camera, and a tip-tilt lens for image stabilization up to 10Hz; long slit spectroscopy at R 5900 thanks to a LHIRES III spectrograph provided with a 1200l/mm grism; échelle spectroscopy at R 9300 using a FLECHAS spectrograph with optical fiber.
We present the advancements in the development of the scheduler for the Son Of X-shooter instrument at the ESO-NTT 3.58-m telescope in La Silla, Chile. SOXS is designed as a single-object ...spectroscopic facility and features a high-efficiency spectrograph with two arms covering the spectral range of 350-2000 nm and a mean resolving power of approximately R=4500. It will conduct UV-visible and near-infrared follow-up observations of astrophysical transients, drawing from a broad pool of targets accessible through the streaming services of wide-field telescopes, both current and future, as well as high-energy satellites. The instrument will cater to various scientific objectives within the astrophysical community, each entailing specific requirements for observation planning. SOXS will operate at the European Southern Observatory (ESO) in La Silla, without the presence of astronomers on the mountain. This poses a unique challenge for the scheduling process, demanding a fully automated algorithm that is autonomously interacting with the appropriate databases and the La Silla Weather API, and is capable of presenting the operator not only with an ordered list of optimal targets (in terms of observing constraints) but also with optimal backups in the event of changing weather conditions. This imposes the necessity for a scheduler with rapid-response capabilities without compromising the optimization process, ensuring the high quality of observations and best use of the time at the telescope. We thus developed a new highly available and scalable architecture, implementing API Restful applications like Docker Containers, API Gateway, and Python-based Flask frameworks. We provide an overview of the current state of the scheduler, which is now ready for the approaching on-site testing during Commissioning phase, along with insights into its web interface and preliminary performance tests.
SOXS (Son Of X-Shooter) is the new single object spectrograph for the ESO New Technology Telescope (NTT) at the La Silla Observatory, able to cover simultaneously both the UV-VIS and NIR bands ...(350-2000 nm). The instrument is currently in the integration and test phase, approaching the Preliminary Acceptance in Europe (PAE) before shipment to Chile for commissioning. After the assembly and preliminary test of the control electronics at INAF - Astronomical Observatory of Capodimonte (Napoli), the two main control cabinets of SOXS are now hosted in Padova, connected to the real hardware. This contribution describes the final electronic cabinets layout, the control strategy and the different integration phases, waiting for the Preliminary Acceptance in Europe and the installation of the instrument in Chile.
The Instrument Control Software of SOXS (Son Of X-Shooter), the forthcoming spectrograph for the ESO New Technology Telescope at the La Silla Observatory, has reached a mature state of development ...and is approaching the crucial Preliminary Acceptance in Europe phase. Now that all the subsystems have been integrated in the laboratories of the Padova Astronomical Observatory, the team operates for testing purposes with the whole instrument at both engineering and scientific level. These activities will make use of a set of software peculiarities that will be discussed in this contribution. In particular, we focus on the synoptic panel, the co-rotator system special device, on the Active Flexure Compensation system which controls two separate piezo tip-tilt devices.
The Son Of X-Shooter (SOXS) will be the specialized facility to observe any transient event with a flexible scheduler at the ESO New Technology Telescope (NTT) at La Silla, Chile. SOXS is a single ...object spectrograph offering simultaneous spectral coverage in UV-VIS (350-850 nm) and NIR (800-2000 nm) wavelength regimes with an average of R~4500 for a 1arcsec slit. SOXS also has imaging capabilities in the visible wavelength regime. Currently, SOXS is being integrated at the INAF-Astronomical Observatory of Padova. Subsystem- and system-level tests and verification are ongoing to ensure and confirm that every requirement and performance are met. In this paper, we report on the integration and verification of SOXS as the team and the instrument prepare for the Preliminary Acceptance Europe (PAE).
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