- ID:
- ivo://CDS.VizieR/J/ApJ/809/77
- Title:
- Transiting Exoplanet Survey Satellite (TESS)
- Short Name:
- J/ApJ/809/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Transiting Exoplanet Survey Satellite (TESS) is a NASA-sponsored Explorer mission that will perform a wide-field survey for planets that transit bright host stars. Here, we predict the properties of the transiting planets that TESS will detect along with the EB stars that produce false-positive photometric signals. The predictions are based on Monte Carlo simulations of the nearby population of stars, occurrence rates of planets derived from Kepler, and models for the photometric performance and sky coverage of the TESS cameras. We expect that TESS will find approximately 1700 transiting planets from 2x10^5^ pre-selected target stars. This includes 556 planets smaller than twice the size of Earth, of which 419 are hosted by M dwarf stars and 137 are hosted by FGK dwarfs. Approximately 130 of the R<2R_{Earth}_ planets will have host stars brighter than Ks=9. Approximately 48 of the planets with R<2R_{Earth}_ lie within or near the habitable zone (0.2<S/S_{Earth}_<2); between 2 and 7 such planets have host stars brighter than Ks=9. We also expect approximately 1100 detections of planets with radii 2-4R_{Earth}_, and 67 planets larger than 4R_{Earth}_. Additional planets larger than 2R_{Earth}_ can be detected around stars that are not among the pre-selected target stars, because TESS will also deliver full-frame images at a 30-minute cadence. The planet detections are accompanied by over 1000 astrophysical false positives. We discuss how TESS data and ground-based observations can be used to distinguish the false positives from genuine planets. We also discuss the prospects for follow-up observations to measure the masses and atmospheres of the TESS planets.
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- ID:
- ivo://CDS.VizieR/J/AJ/157/218
- Title:
- Transiting planets near the snow line from Kepler
- Short Name:
- J/AJ/157/218
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive catalog of cool (period P>~2 yr) transiting planet candidates in the 4 yr light curves from the prime Kepler mission. Most of the candidates show only one or two transits and have largely been missed in the original Kepler Object of Interest catalog. Our catalog is based on all known such candidates in the literature, as well as new candidates from the search in this paper, and provides a resource to explore the planet population near the snow line of Sun-like stars. We homogeneously performed pixel-level vetting, stellar characterization with Gaia parallax and archival/Subaru spectroscopy, and light-curve modeling to derive planet parameters and to eliminate stellar binaries. The resulting clean sample consists of 67 planet candidates whose radii are typically constrained to 5%, in which 23 are newly reported. The number of Jupiter-sized candidates (29 with radius r>8 R_{Earth}_) in the sample is consistent with the Doppler occurrence. The smaller candidates are more prevalent (23 with 4<r/R_{Earth}_<8, 15 with r/R_{Earth}_<4) and suggest that long-period Neptune-sized planets are at least as common as the Jupiter-sized ones, although our sample is yet to be corrected for detection completeness. If the sample is assumed to be complete, these numbers imply the occurrence rate of 0.39+/-0.07 planets with 4<r/R_{Earth}_<14 and 2<P/yr<20 per FGK dwarf. The stars hosting candidates with r>4 R_{Earth}_ have systematically higher [Fe/H] than do the Kepler field stars, providing evidence that giant planet-metallicity correlation extends to P>2 yr.
- ID:
- ivo://CDS.VizieR/J/AJ/157/149
- Title:
- Transit parameters for planets around subgiants
- Short Name:
- J/AJ/157/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of seven new planets and eight planet candidates around subgiant stars, as additions to the known sample of planets around "retired A stars". Among these are the possible first three-planet systems around subgiant stars, HD 163607 and HD 4917. Additionally, we present calculations of possible transit times, durations, depths, and probabilities for all known planets around subgiant (3<logg<4) stars, focused on possible transits during the TESS mission. While most have transit probabilities of 1%-2%, we find that there are three planets with transit probabilities >9%.
- ID:
- ivo://CDS.VizieR/J/AJ/154/64
- Title:
- Transit times of Kepler-448b and Kepler-693b
- Short Name:
- J/AJ/154/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- I report the discovery of non-transiting close companions to two transiting warm Jupiters (WJs), Kepler-448/KOI-12b (orbital period P=17.9days, radius R_p_=1.23_-0.05_^+0.06^R_Jup_) and Kepler-693/KOI-824b (P=15.4days, R_p_=0.91+/-0.05R_Jup_), via dynamical modeling of their transit timing and duration variations (TTVs and TDVs). The companions have masses of 22_-5_^+7^M_Jup_ (Kepler-448c) and 150_-40_^+60^M_Jup_ (Kepler-693c), and both are on eccentric orbits (e=0.65_-0.09_^+0.13^ for Kepler-448c and e=0.47_-0.06_^+0.11^ for Kepler-693c) with periastron distances of 1.5au. Moderate eccentricities are detected for the inner orbits as well (e=0.34_-0.07_^+0.08^ for Kepler-448b and e=0.2_-0.1_^+0.2^ for Kepler-693b). In the Kepler-693 system, a large mutual inclination between the inner and outer orbits (53_-9_^+7^deg or 134_-10_^+11^deg) is also revealed by the TDVs. This is likely to induce a secular oscillation in the eccentricity of the inner WJ that brings its periastron close enough to the host star for tidal star-planet interactions to be significant. In the Kepler-448 system, the mutual inclination is weakly constrained, and such an eccentricity oscillation is possible for a fraction of the solutions. Thus these WJs may be undergoing tidal migration to become hot Jupiters (HJs), although the migration via this process from beyond the snow line is disfavored by the close-in and massive nature of the companions. This may indicate that WJs can be formed in situ and could even evolve into HJs via high-eccentricity migration inside the snow line.
- ID:
- ivo://CDS.VizieR/J/AJ/159/239
- Title:
- Transmission Spectroscopy Metric of exoplanets
- Short Name:
- J/AJ/159/239
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent years have seen increasing interest in the characterization of sub-Neptune-sized planets because of their prevalence in the Galaxy, contrasted with their absence in our solar system. HD97658 is one of the brightest stars hosting a planet of this kind, and we present the transmission spectrum of this planet by combining four Hubble Space Telescope transits, 12 Spitzer/IRAC transits, and eight Microvariability and Oscillations of Stars Telescope (MOST) transits of this system. Our transmission spectrum has a higher signal-to-noise ratio than those from previous works, and the result suggests that the slight increase in transit depth from wavelength 1.1-1.7{mu}m reported in previous works on the transmission spectrum of this planet is likely systematic. Nonetheless, our atmospheric modeling results are inconclusive, as no model provides an excellent match to our data. Nonetheless, we find that atmospheres with high C/O ratios (C/O~>0.8) and metallicities of ~>100 solar metallicity are favored. We combine the mid-transit times from all of the new Spitzer and MOST observations and obtain an updated orbital period of P=9.489295{+/-}0.000005, with a best-fit transit time center at T0=2456361.80690{+/-}0.00038(BJD). No transit timing variations are found in this system. We also present new measurements of the stellar rotation period (34{+/-}2days) and stellar activity cycle (9.6yr) of the host star HD97658. Finally, we calculate and rank the Transmission Spectroscopy Metric of all confirmed planets cooler than 1000K and with sizes between 1R_{Earth}_ and 4R_{Earth}_. We find that at least a third of small planets cooler than 1000K can be well characterized using James Webb Space Telescope, and of those, HD97658b is ranked fifth, meaning that it remains a high-priority target for atmospheric characterization.
- ID:
- ivo://CDS.VizieR/J/AJ/157/211
- Title:
- Unresolved binaries in TESS with speckle imaging
- Short Name:
- J/AJ/157/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Transiting Exoplanet Survey Satellite (TESS) is conducting a two-year wide-field survey searching for transiting exoplanets around nearby bright stars that will be ideal for follow-up characterization. To facilitate studies of planet compositions and atmospheric properties, accurate and precise planetary radii need to be derived from the transit light curves. Since 40%-50% of exoplanet host stars are in multiple star systems, however, the observed transit depth may be diluted by the flux of a companion star, causing the radius of the planet to be underestimated. High angular resolution imaging can detect companion stars that are not resolved in the TESS Input Catalog, or by seeing-limited photometry, to validate exoplanet candidates and derive accurate planetary radii. We examine the population of stellar companions that will be detectable around TESS planet candidate host stars, and those that will remain undetected, by applying the detection limits of speckle imaging to the simulated host star populations of Sullivan et al. (2015, J/ApJ/809/77) and Barclay et al. (2018, J/ApJS/239/2). By detecting companions with contrasts of {Delta}m~<7-9 and separations of ~0.02"-1.2", speckle imaging can detect companion stars as faint as early M stars around A-F stars and stars as faint as mid-M around G-M stars, as well as up to 99% of the expected binary star distribution for systems located within a few hundred parsecs.
- ID:
- ivo://CDS.VizieR/J/AJ/156/78
- Title:
- 44 validated planets from K2 Campaign 10
- Short Name:
- J/AJ/156/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 44 validated planets from the 10th observing campaign of the NASA K2 mission, as well as high-resolution spectroscopy and speckle imaging follow-up observations. These 44 planets come from an initial set of 72 vetted candidates, which we subjected to a validation process incorporating pixel-level analyses, light curve analyses, observational constraints, and statistical false positive probabilities. Our validated planet sample has median values of R_p_=2.2 R_{Earth}_, P_orb_=6.9 days, T_eq_=890 K, and J=11.2 mag. Of particular interest are four ultra-short period planets (P_orb_~<1 day), 16 planets smaller than 2 R_{Earth}_, and two planets with large predicted amplitude atmospheric transmission features orbiting infrared-bright stars. We also present 27 planet candidates, most of which are likely to be real and worthy of further observations. Our validated planet sample includes 24 new discoveries and has enhanced the number of currently known super-Earths (R_p_~1-2 R_{Earth}_), sub-Neptunes (R_p_~2-4 R_{Earth}_), and sub-Saturns (R_p_~4-8 R_{Earth}_) orbiting bright stars (J=8-10 mag) by ~4%, ~17%, and ~11%, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/890/130
- Title:
- VANDAM survey of Orion protostars. II.
- Short Name:
- J/ApJ/890/130
- Date:
- 07 Mar 2022 13:26:15
- Publisher:
- CDS
- Description:
- We have conducted a survey of 328 protostars in the Orion molecular clouds with the Atacama Large Millimeter/submillimeter Array at 0.87mm at a resolution of ~0.1" (40au), including observations with the Very Large Array at 9mm toward 148 protostars at a resolution of ~0.08" (32au). This is the largest multiwavelength survey of protostars at this resolution by an order of magnitude. We use the dust continuum emission at 0.87 and 9mm to measure the dust disk radii and masses toward the Class 0, Class I, and flat-spectrum protostars, characterizing the evolution of these disk properties in the protostellar phase. The mean dust disk radii for the Class 0, Class I, and flat-spectrum protostars are 44.9_-3.4_^+5.8^, 37.0_-3.0_^+4.9^, and 28.5_-2.3_^+3.7^au, respectively, and the mean protostellar dust disk masses are 25.9_-4.0_^+7.7^, 14.9_-2.2_^+3.8^, 11.6_-1.9_^+3.5^M_{Earth}_, respectively. The decrease in dust disk masses is expected from disk evolution and accretion, but the decrease in disk radii may point to the initial conditions of star formation not leading to the systematic growth of disk radii or that radial drift is keeping the dust disk sizes small. At least 146 protostellar disks (35% of 379 detected 0.87mm continuum sources plus 42 nondetections) have disk radii greater than 50au in our sample. These properties are not found to vary significantly between different regions within Orion. The protostellar dust disk mass distributions are systematically larger than those of Class II disks by a factor of >4, providing evidence that the cores of giant planets may need to at least begin their formation during the protostellar phase.
- ID:
- ivo://CDS.VizieR/J/ApJS/239/5
- Title:
- Variable stars and cand. planets from K2
- Short Name:
- J/ApJS/239/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We produce light curves for all ~34000 targets observed with K2 in Campaign 17 (C17), identifying 34 planet candidates, 184 eclipsing binaries, and 222 other periodic variables. The forward-facing direction of the C17 field means follow-up can begin immediately now that the campaign has concluded and interesting targets have been identified. The C17 field has a large overlap with C6, so this latest campaign also offers an infrequent opportunity to study a large number of targets already observed in a previous K2 campaign. The timing of the C17 data release, shortly before science operations begin with the Transiting Exoplanet Survey Satellite (TESS), also lets us exercise some of the tools and methods developed for identification and dissemination of planet candidates from TESS. We find excellent agreement between these results and those identified using only K2-based tools. Among our planet candidates are several planet candidates with sizes <4R_{Earth}_ and orbiting stars with Kp<~10 (indicating good RV targets of the sort TESS hopes to find) and a Jupiter-sized single-transit event around a star already hosting a 6 day planet candidate.
- ID:
- ivo://CDS.VizieR/J/BaltA/11/417
- Title:
- Vilnius photometry in Serpens cauda. II.
- Short Name:
- J/BaltA/11/417
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of spectral types, color excesses, interstellar extinctions and distances of 402 stars located in the Serpens Cauda dark cloud complex and the new results of photoelectric photometry in the Vilnius system of 56 fainter stars in the same area are presented.
