13 research outputs found
SPECULOOS Northern Observatory: Searching for Red Worlds in the Northern Skies
peer reviewedSPECULOOS is a ground-based transit survey consisting of six identical 1 m robotic telescopes. The immediate goal of the project is to detect temperate terrestrial planets transiting nearby ultracool dwarfs (late M-dwarf stars and brown dwarfs), which could be amenable for atmospheric research with the next generation of telescopes. Here, we report the developments of the northern counterpart of the project-SPECULOOS Northern Observatory, and present its performance during the first three years of operations from mid-2019 to mid-2022. Currently, the observatory consists of one telescope, which is named Artemis. The Artemis telescope demonstrates remarkable photometric precision, allowing it to be ready to detect new transiting terrestrial exoplanets around ultracool dwarfs. Over the period of the first three years after the installation, we observed 96 objects from the SPECULOOS target list for 6000 hr with a typical photometric precision of 0.5%, and reaching a precision of 0.2% for relatively bright non-variable targets with a typical exposure time of 25 s. Our weather downtime (clouds, high wind speed, high humidity, precipitation and/or high concentration of dust particles in the air) over the period of three years was 30% of overall night time. Our actual downtime is 40% because of additional time loss associated with technical problems
An M dwarf accompanied by a close-in giant orbiter with SPECULOOS
In the last decade, a dozen close-in giant planets have been discovered
orbiting stars with spectral types ranging from M0 to M4, a mystery since known
formation pathways do not predict the existence of such systems. Here, we
confirm TOI-4860 b, a Jupiter-sized planet orbiting an M4.5 host, a star at the
transition between fully and partially convective interiors. First identified
with TESS data, we validate the transiting companion's planetary nature through
multicolour photometry from the TRAPPIST-South/North, SPECULOOS, and MuSCAT3
facilities. Our analysis yields a radius of for
the planet, a mass of for the star, and an orbital period of
1.52 d. Using the newly commissioned SPIRIT InGaAs camera at the
SPECULOOS-South Observatory, we collect infrared photometry in zYJ that spans
the time of secondary eclipse. These observations do not detect a secondary
eclipse, placing an upper limit on the brightness of the companion. The
planetary nature of the companion is further confirmed through high-resolution
spectroscopy obtained with the IRD spectrograph at Subaru Telescope, from which
we measure a mass of . Based on its overall
density, TOI-4860 b appears to be rich in heavy elements, like its host star.Comment: Accepted for publication in MNRAS Letter
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in
operation since July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). Like all previous SDSS releases, DR14
is cumulative, including the most recent reductions and calibrations of all
data taken by SDSS since the first phase began operations in 2000. New in DR14
is the first public release of data from the extended Baryon Oscillation
Spectroscopic Survey (eBOSS); the first data from the second phase of the
Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2),
including stellar parameter estimates from an innovative data driven machine
learning algorithm known as "The Cannon"; and almost twice as many data cubes
from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous
release (N = 2812 in total). This paper describes the location and format of
the publicly available data from SDSS-IV surveys. We provide references to the
important technical papers describing how these data have been taken (both
targeting and observation details) and processed for scientific use. The SDSS
website (www.sdss.org) has been updated for this release, and provides links to
data downloads, as well as tutorials and examples of data use. SDSS-IV is
planning to continue to collect astronomical data until 2020, and will be
followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected
A long-period transiting substellar companion in the super-Jupiters to brown dwarfs mass regime and a prototypical warm-Jupiter detected by TESS
We report on the confirmation and follow-up characterization of two long-period transiting substellar companions on low-eccentricity orbits around TIC 4672985 and TOI-2529, whose transit events were detected by the TESS space mission. Ground-based photometric and spectroscopic follow up from different facilities, confirmed the substellar nature of TIC 4672985 b, a massive gas giant, in the transition between the super-Jupiters and brown-dwarfs mass regime. From the joint analysis we derived the following orbital parameters: P = 69.0480+0.0004−0.0005 d, Mp = 12.74+1.01−1.01 MJ, Rp =1.026+0.065−0.067 RJ and e = 0.018+0.004−0.004 . In addition, the RV time series revealed a significant trend at the ∼ 350 m s−1 yr−1level, which is indicative of the presence of a massive outer companion in the system. TIC 4672985 b is a unique example of a transiting substellar companion with a mass above the deuterium-burning limit, located beyond 0.1 AU and in a nearly circular orbit. These planetary properties are difficult to reproduce from canonical planet formation and evolution models. For TOI-2529 b, we obtained the following orbital parameters: P = 64.5949+0.0003−0.0003 d, Mp =2.340+0.197−0.195 MJ, Rp = 1.030+0.050−0.050 RJ and e = 0.021+0.024−0.015 , making this object a new example of a growing population of transiting warm giant planets
TOI-2084 b and TOI-4184 b: two new sub-Neptunes around M dwarf stars
We present the discovery and validation of two TESS exoplanets orbiting
nearby M dwarfs: TOI-2084b, and TOI-4184b. We characterized the host stars by
combining spectra from Shane/Kast and Magellan/FIRE, SED (Spectral Energy
Distribution) analysis, and stellar evolutionary models. In addition, we used
Gemini-South/Zorro & -North/Alopeke high-resolution imaging, archival science
images, and statistical validation packages to support the planetary
interpretation. We performed a global analysis of multi-colour photometric data
from TESS and ground-based facilities in order to derive the stellar and
planetary physical parameters for each system. We find that TOI-2084b and
TOI-4184b are sub-Neptune-sized planets with radii of Rp = 2.47 +/- 0.13R_Earth
and Rp = 2.43 +/- 0.21R_Earth, respectively. TOI-2084b completes an orbit
around its host star every 6.08 days, has an equilibrium temperature of T_eq =
527 +/- 8K and an irradiation of S_p = 12.8 +/- 0.8 S_Earth. Its host star is a
dwarf of spectral M2.0 +/- 0.5 at a distance of 114pc with an effective
temperature of T_eff = 3550 +/- 50 K, and has a wide, co-moving M8 companion at
a projected separation of 1400 au. TOI-4184b orbits around an M5.0 +/- 0.5 type
dwarf star (Kmag = 11.87) each 4.9 days, and has an equilibrium temperature of
T_eq = 412 +/- 8 K and an irradiation of S_p = 4.8 +/- 0.4 S_Earth. TOI-4184 is
a metal poor star ([Fe/H] = -0.27 +/- 0.09 dex) at a distance of 69 pc with an
effective temperature of T_eff = 3225 +/- 75 K. Both planets are located at the
edge of the sub-Jovian desert in the radius-period plane. The combination of
the small size and the large infrared brightness of their host stars make these
new planets promising targets for future atmospheric exploration with JWST.Comment: Accepted for publication in A&
TOI-2084 b and TOI-4184 b:two new sub-Neptunes around M dwarf stars
Funding: The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. This research is in part funded by the European Union’s Horizon 2020 research and innovation program (grants agreements n◦ 803193/BEBOP), and from the Science and Technology Facilities Council (STFC; grant n◦ ST/S00193X/1). U.G.J. gratefully acknowledges support from tthe European Union H2020-MSCA-ITN-2019 under grant No. 860470 (CHAMELEON). We acknowledge funding from the European Research Council under the ERC Grant Agreement n. 337591-ExTrA.We present the discovery and validation of two TESS exoplanets orbiting nearby M dwarfs: TOI-2084 b, and TOI-4184b. We characterized the host stars by combining spectra from Shane/Kast and Magellan/FIRE, spectral energy distribution analysis, and stellar evolutionary models. In addition, we used Gemini-South/Zorro & -North/Alopeke high-resolution imaging, archival science images, and statistical validation packages to support the planetary interpretation. We performed a global analysis of multi-colour photometric data from TESS and ground-based facilities in order to derive the stellar and planetary physical parameters for each system. We find that TOI-2084 band TOI-4184 bare sub-Neptune-sized planets with radii of Rp = 2.47 ± 0.13R⊕ and Rp = 2.43 ± 0.21 R⊕, respectively. TOI-2084 b completes an orbit around its host star every 6.08 days, has an equilibrium temperature of Teq = 527 ± 8 K and an irradiation of Sp = 12.8 ± 0.8 S⊕. Its host star is a dwarf of spectral M2.0 ± 0.5 at a distance of 114 pc with an effective temperature of Teff = 3550 ± 50 K, and has a wide, co-moving M8 companion at a projected separation of 1400 au. TOI-4184 b orbits around an M5.0 ± 0.5 type dwarf star (Kmag = 11.87) each 4.9 days, and has an equilibrium temperature of Teq = 412 ± 8 K and an irradiation of Sp = 4.8 ± 0.4 S⊕. TOI-4184 is a metal poor star ([Fe/H] = −0.27 ± 0.09 dex) at a distance of 69 pc with an effective temperature of Teff = 3225 ± 75 K. Both planets are located at the edge of the sub-Jovian desert in the radius-period plane. The combination of the small size and the large infrared brightness of their host stars make these new planets promising targets for future atmospheric exploration with JWST.Publisher PDFPeer reviewe
A super-Earth and a mini-Neptune near the 2:1 MMR straddling the radius valley around the nearby mid-M dwarf TOI-2096
Context. Several planetary formation models have been proposed to explain the observed abundance and variety of compositions of super-Earths and mini-Neptunes. In this context, multitransiting systems orbiting low-mass stars whose planets are close to the radius valley are benchmark systems, which help to elucidate which formation model dominates.Aims. We report the discovery, validation, and initial characterization of one such system, TOI-2096 (TIC 142748283), a two-planet system composed of a super-Earth and a mini-Neptune hosted by a mid-type M dwarf located 48 pc away.Methods. We characterized the host star by combining optical spectra, analyzing its broadband spectral energy distribution, and using evolutionary models for low-mass stars. Then, we derived the planetary properties by modeling the photometric data from TESS and ground-based facilities. In addition, we used archival data, high-resolution imaging, and statistical validation to support our planetary interpretation.Results. We found that the stellar properties of TOI-2096 correspond to a dwarf star of spectral type M4±0.5. It harbors a super-Earth (R = 1.24 ± 0.07 R⊕) and a mini-Neptune (R = 1.90 ± 0.09 R⊕) in likely slightly eccentric orbits with orbital periods of 3.12 d and 6.39 d, respectively. These orbital periods are close to the first-order 2:1 mean-motion resonance (MMR), a configuration that may lead to measurable transit timing variations (TTVs). We computed the expected TTVs amplitude for each planet and found that they might be measurable with high-precision photometry delivering mid-transit times with accuracies of ≲2 min. Moreover, we conclude that measuring the planetary masses via radial velocities (RVs) could also be possible. Lastly, we found that these planets are among the best in their class to conduct atmospheric studies using the NIRSpec/Prism onboard the James Webb Space Telescope (JWST).Conclusions. The properties of this system make it a suitable candidate for further studies, particularly for mass determination using RVs and/or TTVs, decreasing the scarcity of systems that can be used to test planetary formation models around low-mass stars
A 1.55 R habitable-zone planet hosted by TOI-715, an M4 star near the ecliptic South Pole
A new generation of observatories is enabling detailed study of exoplanetary
atmospheres and the diversity of alien climates, allowing us to seek evidence
for extraterrestrial biological and geological processes. Now is therefore the
time to identify the most unique planets to be characterised with these
instruments. In this context, we report on the discovery and validation of
TOI-715 b, a planet orbiting its nearby
( pc) M4 host (TOI-715/TIC 271971130) with a period days. TOI-715 b was first identified by TESS
and validated using ground-based photometry, high-resolution imaging and
statistical validation. The planet's orbital period combined with the stellar
effective temperature give this planet an
instellation , placing it within
the most conservative definitions of the habitable zone for rocky planets.
TOI-715 b's radius falls exactly between two measured locations of the M-dwarf
radius valley; characterising its mass and composition will help understand the
true nature of the radius valley for low-mass stars. We demonstrate TOI-715 b
is amenable for characterisation using precise radial velocities and
transmission spectroscopy. Additionally, we reveal a second candidate planet in
the system, TIC 271971130.02, with a potential orbital period of days and a radius of , just inside the outer boundary of the habitable
zone, and near a 4:3 orbital period commensurability. Should this second planet
be confirmed, it would represent the smallest habitable zone planet discovered
by TESS to date.Comment: Accepted for publication in MNRA
Bringing the New Adaptive Optics Module for Interferometry (NAOMI) into Operation
published in the ESO Messenge