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1911. TKRS catalog of GOODS-North Field
ID:
ivo://CDS.VizieR/J/AJ/127/3121
Title:
TKRS catalog of GOODS-North Field
Short Name:
J/AJ/127/3121
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the results of an extensive imaging and spectroscopic survey in the Great Observatories Origins Deep Survey (GOODS)-North field completed using DEIMOS on the Keck II telescope. Observations of 2018 targets in a magnitude-limited sample of 2911 objects to R_AB_=24.4 yield secure redshifts for a sample of 1440 galaxies and active galactic nuclei (AGNs) plus 96 stars. In addition to redshifts and associated quality assessments, our catalog also includes photometric and astrometric measurements for all targets detected in our R-band imaging survey of the GOODS-North region.
1912. 2007.5 to 2010.4 HST astrometry of HD 202206
ID:
ivo://CDS.VizieR/J/AJ/153/258
Title:
2007.5 to 2010.4 HST astrometry of HD 202206
Short Name:
J/AJ/153/258
Date:
21 Oct 2021
Publisher:
CDS
Description:
Using Hubble Space Telescope Fine Guidance Sensor astrometry and previously published radial velocity measures, we explore the exoplanetary system HD202206. Our modeling results in a parallax, {pi}_abs_=21.96+/-0.12 milliseconds of arc, a mass for HD202206B of M_B_=0.089_-0.006_^+0.007M_{Sun}_, and a mass for HD202206c of M_c_=17.9_-1.8_^+2.9^M_Jup_. HD202206 is a nearly face-on G + M binary orbited by a brown dwarf. The system architecture that we determine supports past assertions that stability requires a 5:1 mean motion resonance (we find a period ratio, P_c_/P_B_=4.92+/-0.04) and coplanarity (we find a mutual inclination, {Phi}=6{deg}+/-2{deg}).
1913. Tori in AGNs through Spitzer/IRS spectra
ID:
ivo://CDS.VizieR/J/ApJ/841/37
Title:
Tori in AGNs through Spitzer/IRS spectra
Short Name:
J/ApJ/841/37
Date:
21 Oct 2021
Publisher:
CDS
Description:
Several authors have claimed that less luminous active galactic nuclei (AGNs) are not capable of sustaining a dusty torus structure. Thus, a gradual resizing of the torus is expected when the AGN luminosity decreases. Our aim is to examine mid-infrared observations of local AGNs of different luminosities for the gradual resizing and disappearance of the torus. We applied the decomposition method described by Hernan-Caballero+ (2015, J/ApJ/803/109) to a sample of ~100 Spitzer/IRS spectra of low-luminosity AGNs and powerful Seyferts in order to decontaminate the torus component from other contributors. We have also included Starburst objects to ensure secure decomposition of the Spitzer/IRS spectra. We have used the affinity propagation (AP) method to cluster the data into five groups within the sample according to torus contribution to the 5-15{mu}m range (C_torus_) and bolometric luminosity (L_bol_).
1914. TO stars metallicity estimate
ID:
ivo://CDS.VizieR/J/A+A/651/A79
Title:
TO stars metallicity estimate
Short Name:
J/A+A/651/A79
Date:
21 Oct 2021
Publisher:
CDS
Description:
The goal of the Turn-Off Primordial Stars survey (TOPoS) project is to find and analyse turn-off (TO) stars of extremely low metallicity. To select the targets for spectroscopic follow-up at high spectral resolution, we relied on low-resolution spectra from the Sloan Digital Sky Survey (SDSS). In this paper, we use the metallicity estimates we obtained from our analysis of the SDSS spectra to construct the metallicity distribution function (MDF) of the Milky Way, with special emphasis on its metal-weak tail. The goal is to provide the underlying distribution out of which the TOPoS sample was extracted. We made use of SDSS photometry, Gaia photometry, and distance estimates derived from the Gaia parallaxes to derive a metallicity estimate for a large sample of over 24 million TO stars. This sample was used to derive the metallicity bias of the sample for which SDSS spectra are available. We determined that the spectroscopic sample is strongly biased in favour of metal-poor stars, as intended. A comparison with the unbiased photometric sample allows us to correct for the selection bias. We selected a sub-sample of stars with reliable parallaxes for which we combined the SDSS radial velocities with Gaia proper motions and parallaxes to compute actions and orbital parameters in the Galactic potential. This allowed us to characterise the stars dynamically, and in particular to select a sub-sample that belongs to the Gaia-Sausage-Enceladus (GSE) accretion event. We are thus also able to provide the MDF of GSE. The metal-weak tail derived in our study is very similar to that derived in the H3 survey and in the Hamburg/ESO Survey. This allows us to average the three MDFs and provide an error bar for each metallicity bin. Inasmuch as the GSE structure is representative of the progenitor galaxy that collided with the Milky Way, that galaxy appears to be strongly deficient in metal-poor stars compared to the Milky Way, suggesting that the metal-weak tail of the latter has been largely formed by accretion of low-mass galaxies rather than massive galaxies, such as the GSE progenitor.
1915. Tracing stars of MW dwarf galaxies: Sextans
ID:
ivo://CDS.VizieR/J/A+A/609/A53
Title:
Tracing stars of MW dwarf galaxies: Sextans
Short Name:
J/A+A/609/A53
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a deep and very spatially extended CTIO/DECam g and r photometric catalogue of point-sources (reaching out to ~2 magnitudes below the oldest main-sequence turn-off and covering ~20deg^2^) around the Sextans dwarf spheroidal galaxy, together with another catalogue of literature spectroscopic measurements (Walker et al., 2009, Cat. J/AJ/137/3100 and Battaglia et al., 2011, Cat. J/MNRAS/411/1013) with updated membership probabilities.
1916. Transit depth biases & error bars for 31 planets
ID:
ivo://CDS.VizieR/J/AJ/161/174
Title:
Transit depth biases & error bars for 31 planets
Short Name:
J/AJ/161/174
Date:
20 Jan 2022
Publisher:
CDS
Description:
The occurrence of a planet transiting in front of its host star offers the opportunity to observe the planet's atmosphere filtering starlight. The fraction of occulted stellar flux is roughly proportional to the optically thick area of the planet, the extent of which depends on the opacity of the planet's gaseous envelope at the observed wavelengths. Chemical species, haze, and clouds are now routinely detected in exoplanet atmospheres through rather small features in transmission spectra, i.e., collections of planet-to-star area ratios across multiple spectral bins and/or photometric bands. Technological advances have led to a shrinking of the error bars down to a few tens of parts per million (ppm) per spectral point for the brightest targets. The upcoming James Webb Space Telescope (JWST) is anticipated to deliver transmission spectra with precision down to 10ppm. The increasing precision of measurements requires a reassessment of the approximations hitherto adopted in astrophysical models, including transit light-curve models. Recently, it has been shown that neglecting the planet's thermal emission can introduce significant biases in the transit depth measured with the JWST/Mid-InfraRed Instrument, integrated between 5 and 12{mu}m. In this paper, we take a step forward by analyzing the effects of the approximation on transmission spectra over the 0.6-12{mu}m wavelength range covered by various JWST instruments. We present open-source software to predict the spectral bias, showing that, if not corrected, it may affect the inferred molecular abundances and thermal structure of some exoplanet atmospheres.
1917. Transiting planet candidates in HATNet field 205
ID:
ivo://CDS.VizieR/J/ApJ/704/1107
Title:
Transiting planet candidates in HATNet field 205
Short Name:
J/ApJ/704/1107
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the discovery of HAT-P-8b, a transiting planet with mass M_p_=1.52^+0.18^_-0.16_M_J_, radius R_p_=1.50^+0.08^_-0.06_R_J_, and photometric period P=3.076days. HAT-P-8b has a somewhat inflated radius for its mass, and a somewhat large mass for its period. The host star is a solar-metallicity F dwarf, with mass M_*_=1.28+/-0.04M_{sun}_ and R_*_=1.58^+0.08^_-0.06R_{sun}_. HAT-P-8b was initially identified as one of the 32 transiting-planet candidates in HATNet field G205. We describe the procedures that we have used to follow up these candidates with spectroscopic and photometric observations, and we present a status report on our interpretation for 28 of the candidates. Eight are eclipsing binaries with orbital solutions whose periods are consistent with their photometric ephemerides; two of these spectroscopic orbits are single-lined and six are double-lined.
1918. Transition circumstellar disks in Ophiuchus
ID:
ivo://CDS.VizieR/J/ApJ/712/925
Title:
Transition circumstellar disks in Ophiuchus
Short Name:
J/ApJ/712/925
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained millimeter-wavelength photometry, high-resolution optical spectroscopy, and adaptive optics near-infrared imaging for a sample of 26 Spitzer-selected transition circumstellar disks. All of our targets are located in the Ophiuchus molecular cloud (d~125pc) and have spectral energy distributions (SEDs) suggesting the presence of inner opacity holes. We use these ground-based data to estimate the disk mass, multiplicity, and accretion rate for each object in our sample in order to investigate the mechanisms potentially responsible for their inner holes. We find that transition disks are a heterogeneous group of objects, with disk masses ranging from <0.6 to 40M_JUP_ and accretion rates ranging from <10^-11^ to 10^-7^M_{sun}_/yr, but most tend to have much lower masses and accretion rates than "full disks" (i.e., disks without opacity holes). Eight of our targets have stellar companions: six of them are binaries and the other two are triple systems. In four cases, the stellar companions are close enough to suspect they are responsible for the inferred inner holes. We find that nine of our 26 targets have low disk mass (<2.5M_JUP_) and negligible accretion (<10^-11^M_{sun}_/yr), and are thus consistent with photoevaporating (or photoevaporated) disks. Four of these nine non-accreting objects have fractional disk luminosities <10^-3^ and could already be in a debris disk stage. Seventeen of our transition disks are accreting. Thirteen of these accreting objects are consistent with grain growth. The remaining four accreting objects have SEDs suggesting the presence of sharp inner holes, and thus are excellent candidates for harboring giant planets.
1919. Transition disks. II. Southern MoC
ID:
ivo://CDS.VizieR/J/ApJ/749/79
Title:
Transition disks. II. Southern MoC
Short Name:
J/ApJ/749/79
Date:
21 Oct 2021
Publisher:
CDS
Description:
Transition disk objects are pre-main-sequence stars with little or no near-IR excess and significant far-IR excess, implying inner opacity holes in their disks. Here we present a multifrequency study of transition disk candidates located in Lupus I, III, IV, V, VI, Corona Australis, and Scorpius. Complementing the information provided by Spitzer with adaptive optics (AO) imaging (NaCo, VLT), submillimeter photometry (APEX), and echelle spectroscopy (Magellan, Du Pont Telescopes), we estimate the multiplicity, disk mass, and accretion rate for each object in our sample in order to identify the mechanism potentially responsible for its inner hole. We find that our transition disks show a rich diversity in their spectral energy distribution morphology, have disk masses ranging from <~1 to 10M_JUP_, and accretion rates ranging from <~10^-11^ to 10^-7.7^M_{sun}_/yr. Of the 17 bona fide transition disks in our sample, three, nine, three, and two objects are consistent with giant planet formation, grain growth, photoevaporation, and debris disks, respectively. Two disks could be circumbinary, which offers tidal truncation as an alternative origin of the inner hole.
1920. Transit light curves of TRAPPIST-1 planets
ID:
ivo://CDS.VizieR/J/AJ/156/218
Title:
Transit light curves of TRAPPIST-1 planets
Short Name:
J/AJ/156/218
Date:
21 Oct 2021
Publisher:
CDS
Description:
The TRAPPIST-1 planetary system provides an exceptional opportunity for the atmospheric characterization of temperate terrestrial exoplanets with the upcoming James Webb Space Telescope (JWST). Assessing the potential impact of stellar contamination on the planets' transit transmission spectra is an essential precursor to this characterization. Planetary transits themselves can be used to scan the stellar photosphere and to constrain its heterogeneity through transit depth variations in time and wavelength. In this context, we present our analysis of 169 transits observed in the optical from space with K2 and from the ground with the SPECULOOS and Liverpool telescopes. Combining our measured transit depths with literature results gathered in the mid-/near-IR with Spitzer/IRAC and HST/WFC3, we construct the broadband transmission spectra of the TRAPPIST-1 planets over the 0.8-4.5 {mu}m spectral range. While planet b, d, and f spectra show some structures at the 200-300 ppm level, the four others are globally flat. Even if we cannot discard their instrumental origins, two scenarios seem to be favored by the data: a stellar photosphere dominated by a few high-latitude giant (cold) spots, or, alternatively, by a few small and hot (3500-4000 K) faculae. In both cases, the stellar contamination of the transit transmission spectra is expected to be less dramatic than predicted in recent papers. Nevertheless, based on our results, stellar contamination can still be of comparable or greater order than planetary atmospheric signals at certain wavelengths. Understanding and correcting the effects of stellar heterogeneity therefore appears essential for preparing for the exploration of TRAPPIST-1 with JWST.