- ID:
- ivo://CDS.VizieR/J/A+A/600/L11
- Title:
- GTC transit light curves of WASP-52b
- Short Name:
- J/A+A/600/L11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the first detection of sodium absorption in the atmosphere of the hot Jupiter WASP-52b. We observed one transit of WASP-52b with the low-resolution Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) at the 10.4m Gran Telescopio Canarias (GTC). The resulting transmission spectrum, covering the wavelength range from 522nm to 903nm, is flat and featureless, except for the significant narrow absorption signature at the sodium doublet, which can be explained by an atmosphere in solar composition with clouds at 1 mbar. A cloud-free atmosphere is stringently ruled out. By assessing the absorption depths of sodium in various bin widths, we find that temperature increases towards lower atmospheric pressure levels, with a positive temperature gradient of 0.88+/-0.65K/km , possibly indicative of upper atmospheric heating and a temperature inversion.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/605/A114
- Title:
- GTC transit light curves of WASP-48b
- Short Name:
- J/A+A/605/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained long-slit optical spectroscopy of one transit of WASP-48b with the Optical System for Imaging and low-Intermediate-Resolution Integrated Spectroscopy (OSIRIS) spectrograph. We report a relatively flat transmission spectrum (wavelength coverage from 530 nm to 905 nm) for WASP-48b with no statistical significant detection of atmospheric species, although the theoretical models that fit the data more closely include TiO and VO.
- ID:
- ivo://CDS.VizieR/J/ApJ/736/L25
- Title:
- Habitability of Kepler planetary candidates
- Short Name:
- J/ApJ/736/L25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This Letter outlines a simple approach to evaluate habitability of terrestrial planets by assuming different types of planetary atmospheres and using corresponding model calculations. Our approach can be applied for current and future candidates provided by the Kepler mission and other searches. The resulting uncertainties and changes in the number of planetary candidates in the habitability zone (HZ) for the Kepler 2011 February data release are discussed. To first order, the HZ depends on the effective stellar flux distribution in wavelength and time, the planet albedo, and greenhouse gas effects. We provide a simple set of parameters which can be used for evaluating future planet candidates from transit searches.
- ID:
- ivo://CDS.VizieR/J/ApJ/649/1010
- Title:
- Habitability of known exoplanetary systems
- Short Name:
- J/ApJ/649/1010
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Habitable planets are likely to be broadly Earth-like in composition, mass, and size. Masses are likely to be within a factor of a few of the Earth's mass. Currently, we do not have sufficiently sensitive techniques to detect Earth-mass planets, except in rare circumstances. It is thus necessary to model the known exoplanetary systems. In particular, we need to establish whether Earth-mass planets could be present in the classical habitable zone (HZ) or whether the giant planets that we know to be present would have gravitationally ejected Earth-mass planets or prevented their formation. We have answered this question by applying computer models to the 152 exoplanetary systems known by 2006 April 18 that are sufficiently well characterized for our analysis. For systems in which there is a giant planet, inside the HZ, which must have arrived there by migration, there are two cases: (1) where the migration of the giant planet across the HZ has not ruled out the existence of Earth-mass planets in the HZ; and (2) where the migration has ruled out existence. For each case, we have determined the proportion of the systems that could contain habitable Earth-mass planets today, and the proportion for which this has been the case for at least the past 1000Myr (excluding any early heavy bombardment). For case 1 we get 60% and 50%, respectively, and for case 2 we get 7% and 7%, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A63
- Title:
- HADES VI. GJ 3942b activity with HARPS-N
- Short Name:
- J/A+A/608/A63
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Short- to mid-term magnetic phenomena on the stellar surface of M-type stars can resemble the effects of planets in radial velocity data, and may also hide them. We analyze 145 spectroscopic HARPS-N observations of GJ 3942 taken over the past five years and additional photometry in order to disentangle stellar activity effects from genuine Doppler signals as a result of the orbital motion of the star around the common barycenter with its planet. To achieve this, we use the common methods of pre-whitening, and treat the correlated red noise by a first-order moving average term and by Gaussian-process regression following an MCMC analysis. We identify the rotational period of the star at 16.3-days and discover a new super-Earth, GJ 3942b, with an orbital period of 6.9-days and a minimum mass of 7.1M_Earth_. An additional signal in the periodogram of the residuals is present, but at this point we cannot claim with sufficient significance that it is related to a second planet. If confirmed, this planet candidate would have a minimum mass of 6.3M_Earth_ and a period of 10.4-days, which might indicate a 3:2 mean-motion resonance with the inner planet.
- ID:
- ivo://CDS.VizieR/J/ApJ/792/L31
- Title:
- HARPS and HARPS-N 55 Cnc radial velocities
- Short Name:
- J/ApJ/792/L31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Rossiter-McLaughlin observations of the transiting super-Earth 55 Cnc e collected during six transit events between 2012 January and 2013 November with HARPS and HARPS-N. We detect no radial velocity signal above 35 cm/s (3{sigma}) and confine the stellar vsini_*_ to 0.2+/-0.5 km/s. The star appears to be a very slow rotator, producing a very low amplitude Rossiter-McLaughlin effect. Given such a low amplitude, the Rossiter-McLaughlin effect of 55 Cnc e is undetected in our data, and any spin-orbit angle of the system remains possible. We also performed Doppler tomography and reach a similar conclusion. Our results offer a glimpse of the capacity of future instrumentation to study low amplitude Rossiter-McLaughlin effects produced by super-Earths.
- ID:
- ivo://CDS.VizieR/J/AJ/152/204
- Title:
- HARPS-N radial velocities of HD 179070
- Short Name:
- J/AJ/152/204
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- HD 179070, aka Kepler-21, is a V=8.25 F6IV star and the brightest exoplanet host discovered by Kepler. An early detailed analysis by Howell et al. of the first 13 months (Q0-Q5) of Kepler light curves revealed transits of a planetary companion, Kepler-21b, with a radius of about 1.60+/-0.04R_{Earth}_ and an orbital period of about 2.7857days. However, they could not determine the mass of the planet from the initial radial velocity (RV) observations with Keck-HIRES, and were only able to impose a 2{sigma} upper limit of 10M_{Earth}_. Here, we present results from the analysis of 82 new RV observations of this system obtained with HARPS-N, together with the existing 14 HIRES data points. We detect the Doppler signal of Kepler-21b with a RV semiamplitude K=2.00+/-0.65ms^-1^, which corresponds to a planetary mass of 5.1+/-1.7M_{Earth}_. We also measure an improved radius for the planet of 1.639 +0.019/-0.015R_{Earth}_, in agreement with the radius reported by Howell et al. We conclude that Kepler-21b, with a density of 6.4+/-2.1gcm^-3^, belongs to the population of small, <~6M_{Earth}_ planets with iron and magnesium silicate interiors, which have lost the majority of their envelope volatiles via stellar winds or gravitational escape. The RV analysis presented in this paper serves as an example of the type of analysis that will be necessary to confirm the masses of TESS small planet candidates.
- ID:
- ivo://CDS.VizieR/J/ApJ/800/135
- Title:
- HARPS-N radial velocities of KOI-69
- Short Name:
- J/ApJ/800/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kepler-93b is a 1.478+/-0.019R_{Earth}_ planet with a 4.7day period around a bright (V=10.2), astroseismically characterized host star with a mass of 0.911+/-0.033M_{sun}_ and a radius of 0.919+/-0.011R_{sun}_. Based on 86 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 32 archival Keck/HIRES observations, we present a precise mass estimate of 4.02+/-0.68M_{Earth}_. The corresponding high density of 6.88+/-1.18g/cm3 is consistent with a rocky composition of primarily iron and magnesium silicate. We compare Kepler-93b to other dense planets with well-constrained parameters and find that between 1 and 6M_{Earth}_, all dense planets including the Earth and Venus are well-described by the same fixed ratio of iron to magnesium silicate. There are as of yet no examples of such planets with masses >6M_{Earth}_. All known planets in this mass regime have lower densities requiring significant fractions of volatiles or H/He gas. We also constrain the mass and period of the outer companion in the Kepler-93 system from the long-term radial velocity trend and archival adaptive optics images. As the sample of dense planets with well-constrained masses and radii continues to grow, we will be able to test whether the fixed compositional model found for the seven dense planets considered in this paper extends to the full population of 1-6M_{Earth}_ planets.
- ID:
- ivo://CDS.VizieR/J/AJ/152/160
- Title:
- HARPS-N radial velocities of KOI-70
- Short Name:
- J/AJ/152/160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kepler-20 is a solar-type star (V=12.5) hosting a compact system of five transiting planets, all packed within the orbital distance of Mercury in our own solar system. A transition from rocky to gaseous planets with a planetary transition radius of ~1.6R_{Earth}_ has recently been proposed by several articles in the literature. Kepler-20b (R_p_~1.9R_{Earth}_) has a size beyond this transition radius; however, previous mass measurements were not sufficiently precise to allow definite conclusions to be drawn regarding its composition. We present new mass measurements of three of the planets in the Kepler-20 system that are facilitated by 104 radial velocity measurements from the HARPS-N spectrograph and 30 archival Keck/HIRES observations, as well as an updated photometric analysis of the Kepler data and an asteroseismic analysis of the host star (M_*_=0.948+/-0.051M_{Sun}_ and R_*_=0.964+/-0.018R_{Sun}_). Kepler-20b is a 1.868_-0.034_^+0.066^R_{Earth}_ planet in a 3.7day period with a mass of 9.70_-1.44_^+1.41^M_{Earth}_, resulting in a mean density of 8.2_-1.3_^+1.5^g/cm^3^, indicating a rocky composition with an iron-to-silicate ratio consistent with that of the Earth. This makes Kepler-20b the most massive planet with a rocky composition found to date. Furthermore, we report the discovery of an additional non-transiting planet with a minimum mass of 19.96_-3.61_^+3.08^M_{Earth}_ and an orbital period of ~34days in the gap between Kepler-20f (P~11days) and Kepler-20d (P~78days).
- ID:
- ivo://CDS.VizieR/J/A+A/556/A110
- Title:
- HARPS radial velocities of GJ 163
- Short Name:
- J/A+A/556/A110
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The meter-per-second precision achieved by today velocimeters enables the search for 1-10M_{earth}_ planets in the habitable zone of cool stars. This paper reports on the detection of 3 planets orbiting GJ 163 (HIP19394), a M3 dwarf monitored by our ESO/HARPS search for planets. We made use of the HARPS spectrograph to collect 150 radial velocities of GJ 163 over a period of 8 years. We searched the RV time series for coherent signals and found 5 distinct periodic variabilities.We investigated the stellar activity and casted doubts on the planetary interpretation for 2 signals. Before more data can be acquired we concluded that at least 3 planets are orbiting GJ 163. They have orbital periods of Pb=8.632+/-0.002, Pc=25:63+/-0.03 and Pd=604+/-8 days and minimum masses msini=10.6+/-0.6, 6.8+/-0.9, and 29+/-3, respectively. We hold our interpretations for the 2 additional signals with periods P(e)=19.4 and P(f)=108 days.
