scholarly journals Very wide companion fraction from Gaia DR2: A weak or no enhancement for hot Jupiter hosts, and a strong enhancement for contact binaries

2020 ◽  
Vol 497 (2) ◽  
pp. 2250-2259
Author(s):  
Hsiang-Chih Hwang ◽  
Jacob H Hamer ◽  
Nadia L Zakamska ◽  
Kevin C Schlaufman
Keyword(s):  
Main Sequence ◽  
Age Dependence ◽  
Ongoing Debate ◽  
Hot Jupiters ◽  
Field Star ◽  
Random Pairing ◽  
Contact Binaries ◽  
Formation And Evolution ◽  
Gaia Dr2 ◽  
Hot Jupiter

ABSTRACT There is an ongoing debate on whether hot Jupiter hosts are more likely to be found in wide binaries with separations of ≳100 AU. In this paper, we search for comoving, very wide companions with separations of 103–104 AU for hot Jupiter hosts and main-sequence contact binaries in Gaia DR2, and compare the very wide companion fractions with their object-by-object-matched field star samples. We find that 11.9 ± 2.5 per cent of hot Jupiter hosts and 14.1 ± 1.0 per cent of contact binaries have companions at separations of 103–104 AU. While the very wide companion fraction of hot Jupiter hosts is a factor of 1.9 ± 0.5 larger than their matched field star sample, it is consistent, within ∼1σ, with that of matched field stars if the matching is only with field stars without close companions (within ∼50 AU) as is the case for hot Jupiter hosts. The very wide companion fraction of contact binaries is a factor of 3.1 ± 0.5 larger than their matched field star sample, suggesting that the formation and evolution of contact binaries are either tied to or correlated with the presence of wide companions. In contrast, the weak enhancement of very wide companion fraction for hot Jupiter hosts implies that the formation of hot Jupiters is not as sensitive to those environment properties. Our results also hint that the occurrence rates of dual hot Jupiter hosts and dual contact binaries may be higher than the expected values from random pairing of field stars, which may be due to their underlying metallicity and age dependence.

scholarly journals Stellar population of Sco OB2 revealed by Gaia DR2 data

2019 ◽  
Vol 623 ◽  
pp. A112 ◽  
Author(s):  
F. Damiani ◽  
L. Prisinzano ◽  
I. Pillitteri ◽  
G. Micela ◽  
S. Sciortino
Keyword(s):  
Stellar Population ◽  
Main Sequence ◽  
Open Cluster ◽  
Proper Motions ◽  
Lower Mass ◽  
Global Pattern ◽  
Field Star ◽  
Photometric Measurements ◽  
Stellar Masses ◽  
Gaia Dr2

Context. The Sco OB2 association is the nearest OB association, extending over approximately 2000 square degrees on the sky. Only its brightest and most massive members are already known (from HIPPARCOS) across its entire size, while studies of its lower mass population refer only to small portions of its extent. Aims. In this work we exploit the capabilities of Gaia DR2 measurements to search for Sco OB2 members across its entire size and down to the lowest stellar masses. Methods. We used both Gaia astrometric (proper motions and parallaxes) and photometric measurements (integrated photometry and colors) to select association members, using minimal assumptions derived mostly from the HIPPARCOS studies. Gaia resolves small details in both the kinematics of individual Sco OB2 subgroups and their distribution with distance from the Sun. We developed methods to explore the 3D kinematics of a stellar population covering large sky areas. Results. We find nearly 11 000 pre-main-sequence (PMS) members of Sco OB2 (with less than 3% field-star contamination), plus ∼3600 main-sequence (MS) candidate members with a larger (10–30%) field-star contamination. A higher confidence subsample of ∼9200 PMS (and ∼1340 MS) members is also selected (<1% contamination for the PMS), however this group is affected by larger (∼15%) incompleteness. We separately classify stars in compact and diffuse populations. Most members belong to one of several kinematically distinct diffuse populations, whose ensemble clearly outlines the shape of the entire association. Upper Sco is the densest region of Sco OB2. It is characterized by a complex spatial and kinematical structure and has no global pattern of motion. Other dense subclusters are found in Lower Centaurus-Crux and in Upper Centaurus-Lupus; the richest example of the latter, which has been recently identified, is coincident with the group near V1062 Sco. Most of the clustered stars appear to be younger than the diffuse PMS population, suggesting star formation in small groups that rapidly disperse and are diluted, reaching space densities lower than field stars while keeping memory of their original kinematics. We also find that the open cluster IC 2602 has a similar dynamics to Sco OB2, and its PMS members are currently evaporating and forming a diffuse (size ∼10°) halo around its double-peaked core.

scholarly journals Origins of Hot Jupiters

2018 ◽  
Vol 56 (1) ◽  
pp. 175-221 ◽  
Author(s):  
Rebekah I. Dawson ◽  
John Asher Johnson
Keyword(s):  
Solar System ◽  
Main Sequence ◽  
Planetary Systems ◽  
Main Sequence Stars ◽  
High Eccentricity ◽  
Hot Jupiters ◽  
In Situ Formation ◽  
Tidal Migration ◽  
Hot Jupiter

Hot Jupiters were the first exoplanets to be discovered around main sequence stars and astonished us with their close-in orbits. They are a prime example of how exoplanets have challenged our textbook, solar-system inspired story of how planetary systems form and evolve. More than twenty years after the discovery of the first hot Jupiter, there is no consensus on their predominant origin channel. Three classes of hot Jupiter creation hypotheses have been proposed: in situ formation, disk migration, and high-eccentricity tidal migration. Although no origin channel alone satisfactorily explains all the evidence, two major origin channels together plausibly account for properties of hot Jupiters themselves and their connections to other exoplanet populations.

scholarly journals Tidally induced stellar oscillations: converting modelled oscillations excited by hot Jupiters into observables

2020 ◽  
Vol 500 (2) ◽  
pp. 2711-2731
Author(s):  
Andrew Bunting ◽  
Caroline Terquem
Keyword(s):  
Radial Velocity ◽  
Orbital Period ◽  
Planetary Systems ◽  
Velocity Signal ◽  
Convective Flux ◽  
Hot Jupiters ◽  
Stellar Oscillations ◽  
Orbital Periods ◽  
Hot Jupiter

ABSTRACT We calculate the conversion from non-adiabatic, non-radial oscillations tidally induced by a hot Jupiter on a star to observable spectroscopic and photometric signals. Models with both frozen convection and an approximation for a perturbation to the convective flux are discussed. Observables are calculated for some real planetary systems to give specific predictions. The photometric signal is predicted to be proportional to the inverse square of the orbital period, P−2, as in the equilibrium tide approximation. However, the radial velocity signal is predicted to be proportional to P−1, and is therefore much larger at long orbital periods than the signal corresponding to the equilibrium tide approximation, which is proportional to P−3. The prospects for detecting these oscillations and the implications for the detection and characterization of planets are discussed.

scholarly journals TOI-150b and TOI-163b: two transiting hot Jupiters, one eccentric and one inflated, revealed by TESS near and at the edge of the JWST CVZ

2019 ◽  
Vol 490 (1) ◽  
pp. 1094-1110 ◽  
Author(s):  
Diana Kossakowski ◽  
Néstor Espinoza ◽  
Rafael Brahm ◽  
Andrés Jordán ◽  
Thomas Henning ◽  
...  
Keyword(s):  
High Resolution ◽  
Time Scale ◽  
High Resolution Spectroscopy ◽  
Spin Orbit ◽  
Eccentric Orbit ◽  
Hot Jupiters ◽  
Eclipse Observations ◽  
James Webb Space Telescope ◽  
Hot Jupiter

Abstract We present the discovery of TYC9191-519-1b (TOI-150b, TIC 271893367) and HD271181b (TOI-163b, TIC 179317684), two hot Jupiters initially detected using 30-min cadence Transiting Exoplanet Survey Satellite (TESS) photometry from Sector 1 and thoroughly characterized through follow-up photometry (CHAT, Hazelwood, LCO/CTIO, El Sauce, TRAPPIST-S), high-resolution spectroscopy (FEROS, CORALIE), and speckle imaging (Gemini/DSSI), confirming the planetary nature of the two signals. A simultaneous joint fit of photometry and radial velocity using a new fitting package juliet reveals that TOI-150b is a $1.254\pm 0.016\ \rm {R}_ \rm{J}$, massive ($2.61^{+0.19}_{-0.12}\ \rm {M}_ \rm{J}$) hot Jupiter in a 5.857-d orbit, while TOI-163b is an inflated ($R_ \rm{P}$ = $1.478^{+0.022}_{-0.029} \,\mathrm{ R}_ \rm{J}$, $M_ \rm{P}$ = $1.219\pm 0.11 \, \rm{M}_ \rm{J}$) hot Jupiter on a P = 4.231-d orbit; both planets orbit F-type stars. A particularly interesting result is that TOI-150b shows an eccentric orbit ($e=0.262^{+0.045}_{-0.037}$), which is quite uncommon among hot Jupiters. We estimate that this is consistent, however, with the circularization time-scale, which is slightly larger than the age of the system. These two hot Jupiters are both prime candidates for further characterization – in particular, both are excellent candidates for determining spin-orbit alignments via the Rossiter–McLaughlin (RM) effect and for characterizing atmospheric thermal structures using secondary eclipse observations considering they are both located closely to the James Webb Space Telescope (JWST) Continuous Viewing Zone (CVZ).

scholarly journals TESS Giants Transiting Giants. I.: A Noninflated Hot Jupiter Orbiting a Massive Subgiant

2022 ◽  
Vol 163 (2) ◽  
pp. 53
Author(s):  
Nicholas Saunders ◽  
Samuel K. Grunblatt ◽  
Daniel Huber ◽  
Karen A. Collins ◽  
Eric L. N. Jensen ◽  
...  
Keyword(s):  
Main Sequence ◽  
Planetary System ◽  
Scattered Light ◽  
Image Data ◽  
Velocity Measurements ◽  
Main Sequence Stars ◽  
Transiting Planets ◽  
Depth Difference ◽  
Evolved Stars ◽  
Hot Jupiter

Abstract While the population of confirmed exoplanets continues to grow, the sample of confirmed transiting planets around evolved stars is still limited. We present the discovery and confirmation of a hot Jupiter orbiting TOI-2184 (TIC 176956893), a massive evolved subgiant (M ⋆ = 1.53 ± 0.12 M ⊙, R ⋆ = 2.90 ± 0.14 R ⊙) in the Transiting Exoplanet Survey Satellite (TESS) Southern Continuous Viewing Zone. The planet was flagged as a false positive by the TESS Quick-Look Pipeline due to periodic systematics introducing a spurious depth difference between even and odd transits. Using a new pipeline to remove background scattered light in TESS Full Frame Image data, we combine space-based TESS photometry, ground-based photometry, and ground-based radial velocity measurements to report a planet radius of R p = 1.017 ± 0.051 R J and mass of M p = 0.65 ± 0.16 M J . For a planet so close to its star, the mass and radius of TOI-2184b are unusually well matched to those of Jupiter. We find that the radius of TOI-2184b is smaller than theoretically predicted based on its mass and incident flux, providing a valuable new constraint on the timescale of post-main-sequence planet inflation. The discovery of TOI-2184b demonstrates the feasibility of detecting planets around faint (TESS magnitude > 12) post-main-sequence stars and suggests that many more similar systems are waiting to be detected in the TESS FFIs, whose confirmation may elucidate the final stages of planetary system evolution.

scholarly journals Secondary eclipse of the hot Jupiter WASP-121b at 2 μm

2019 ◽  
Vol 625 ◽  
pp. A80 ◽  
Author(s):  
Géza Kovács ◽  
Tamás Kovács
Keyword(s):  
Near Infrared ◽  
Infrared Emission ◽  
Current Data ◽  
Emission Analysis ◽  
Hot Jupiters ◽  
Occultation Data ◽  
The One ◽  
Near Infrared Emission ◽  
Absorption Features ◽  
Hot Jupiter

Ground-based observations of the secondary eclipse in the 2MASS K band are presented for the hot Jupiter WASP-121b. These are the first occultation observations of an extrasolar planet that were carried out with an instrument attached to a 1 m class telescope (the SMARTS 1.3 m). We find a highly significant eclipse depth of (0.228 ± 0.023)%. Together with other planet atmosphere measurements, including the Hubble Space Telescope near-infrared emission spectrum, current data support more involved atmosphere models with species producing emission and absorption features, rather than simple smooth blackbody emission. Analysis of the time difference between the primary and secondary eclipses and the durations of these events yields an eccentricity of e = 0.0207 ± 0.0153, which is consistent with the earlier estimates of low or zero eccentricity, but with a smaller error. Comparing the observed occultation depth in the K band with the one derived under the assumption of zero Bond albedo and full heat redistribution, we find that WASP-121b has a deeper observed occultation depth than predicted. Together with the sample of 31 systems with K-band occultation data, this observation lends further support to the idea of inefficient heat transport between the day and night sides for most of the hot Jupiters.

Influence of the magnetic field of stellar wind on hot jupiter’s envelopes

2019 ◽  
Vol 15 (S354) ◽  
pp. 268-279
Author(s):  
Dmitry V. Bisikalo ◽  
Andrey G. Zhilkin
Keyword(s):  
Magnetic Field ◽  
Plasma Flow ◽  
Coronal Mass Ejections ◽  
Stellar Wind ◽  
Roche Lobe ◽  
Bow Shock ◽  
Hot Jupiters ◽  
The Magnetic Field ◽  
Alfven Velocity ◽  
Hot Jupiter

AbstractHot Jupiters have extended gaseous (ionospheric) envelopes, which extend far beyond the Roche lobe. The envelopes are loosely bound to the planet and, therefore, are strongly influenced by fluctuations of the stellar wind. We show that, since hot Jupiters are close to the parent stars, magnetic field of the stellar wind is an important factor defining the structure of their magnetospheres. For a typical hot Jupiter, velocity of the stellar wind plasma flow around the atmosphere is close to the Alfvén velocity. As a result stellar wind fluctuations, such as coronal mass ejections, can affect the conditions for the formation of a bow shock around a hot Jupiter. This effect can affect observational manifestations of hot Jupiters.

Ages for large samples of stars - caveats and uncertainties

2017 ◽  
Vol 13 (S334) ◽  
pp. 147-152
Author(s):  
Arlette Noels-Grötsch
Keyword(s):  
Main Sequence ◽  
Planetary Systems ◽  
Foreseeable Future ◽  
Time Line ◽  
Giant Stars ◽  
Large Samples ◽  
Formation And Evolution ◽  
Stellar Models ◽  
Red Giant ◽  
Age Determinations

AbstractAlthough a stellar age accuracy of about 10 % seems to be a reasonable requirement to draw a time line in the evolution of our Galaxy as well as in the formation and evolution of exo-planetary systems, theoretical stellar models are at present still too imperfect to really achieve this goal. Asteroseismic observations are definitely of invaluable assistance, especially if individual pulsation frequencies are available, which is still far from common. Large stellar samples are now in the spotlight with two different lines of attack, spectroscopic and photometric surveys as well as asteroseismic missions. I shall review the problems arising from stellar physics in the context of large stellar samples of main sequence and red giant stars, and I shall raise some alarm bells but also highlight some positive news for a drastic improvement in stellar age determinations below the limit of 10 % in a foreseeable future.

scholarly journals Sparkling nights and very hot days on WASP-18b: the formation of clouds and the emergence of an ionosphere

2019 ◽  
Vol 626 ◽  
pp. A133 ◽  
Author(s):  
Ch. Helling ◽  
P. Gourbin ◽  
P. Woitke ◽  
V. Parmentier
Keyword(s):  
Gas Phase ◽  
Cloud Formation ◽  
Hot Jupiters ◽  
Gas Phase Chemistry ◽  
Formation And Evolution ◽  
Heterogeneous Clouds ◽  
Phase Chemistry ◽  
Equilibrium Calculations ◽  
Very High ◽  
Substantial Degree

Context. WASP-18b is an ultra-hot Jupiter with a temperature difference of up to 2500 K between day and night. Such giant planets begin to emerge as a planetary laboratory for understanding cloud formation and gas chemistry in well-tested parameter regimes in order to better understand planetary mass loss and for linking observed element ratios to planet formation and evolution. Aims. We aim to understand where clouds form, their interaction with the gas-phase chemistry through depletion and enrichment, the ionisation of the atmospheric gas, and the possible emergence of an ionosphere on ultra-hot Jupiters. Methods. We used 1D profiles from a 3D atmosphere simulation for WASP-18b as input for kinetic cloud formation and gas-phase chemical equilibrium calculations. We solved our kinetic cloud formation model for these 1D profiles, which sample the atmosphere of WASP-18b at 16 different locations along the equator and in the mid-latitudes. We derived the gas-phase composition consistently. Results. The dayside of WASP-18b emerges as completely cloud-free as a result of the very high atmospheric temperatures. In contrast, the nightside is covered in geometrically extended and chemically heterogeneous clouds with dispersed particle size distributions. The atmospheric C/O ratio increases to >0.7 and the enrichment of the atmospheric gas with cloud particles is ρd/ρgas > 10−3. The clouds that form at the limbs appear located farther inside the atmosphere, and they are the least extended. Not all day- to nightside terminator regions form clouds. The gas phase is dominated by H2, CO, SiO, H2O, H2S, CH4, and SiS. In addition, the dayside has a substantial degree of ionisation that is due to ions such as Na+, K+, Ca+, and Fe+. Al+ and Ti+ are the most abundant of their element classes. We find that WASP-18b, as one example for ultra-hot Jupiters, develops an ionosphere on the dayside.

scholarly journals Which stars can see Earth as a transiting exoplanet?

2020 ◽  
Vol 499 (1) ◽  
pp. L111-L115
Author(s):  
L Kaltenegger ◽  
J Pepper
Keyword(s):  
Main Sequence ◽  
Line Of Sight ◽  
Main Sequence Stars ◽  
Target List ◽  
Distant Observer ◽  
Spectroscopic Observations ◽  
Transiting Planets ◽  
Vantage Points ◽  
Life On Earth ◽  
Gaia Dr2

ABSTRACT Transit observations have found the majority of exoplanets to date. Also spectroscopic observations of transits and eclipses are the most commonly used tool to characterize exoplanet atmospheres and will be used in the search for life. However, an exoplanet’s orbit must be aligned with our line of sight to observe a transit. Here, we ask, from which stellar vantage points would a distant observer be able to search for life on Earth in the same way? We use the TESS Input Catalog and data from Gaia DR2 to identify the closest stars that could see Earth as a transiting exoplanet: We identify 1004 main-sequence stars within 100 parsecs, of which 508 guarantee a minimum 10-h long observation of Earth’s transit. Our star list consists of about 77 percent M-type, 12 percent K-type, 6 percent G-type, 4 percent F-type stars, and 1 percent A-type stars close to the ecliptic. SETI searches like the Breakthrough Listen Initiative are already focusing on this part of the sky. Our catalogue now provides a target list for this search. As part of the extended mission, NASA’s TESS will also search for transiting planets in the ecliptic to find planets that could already have found life on our transiting Earth .

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