scholarly journals Spin-orbit alignment of exoplanet systems: how can Asteroseismology help us?

2015 ◽  
Vol 11 (A29A) ◽  
pp. 71-76
Author(s):  
Tiago L. Campante
Keyword(s):  
Signal To Noise Ratio ◽  
Spin Orbit ◽  
Hot Jupiters ◽  
Long Period ◽  
Oscillation Modes ◽  
And Migration ◽  
Stellar Properties ◽  
Orbit Geometry ◽  
Exoplanet Systems ◽  
Host Stars

AbstractMeasuring the obliquities of exoplanet-host stars provides invaluable diagnostic information for theories of planetary formation and migration. Most of these results have so far been obtained by measuring the Rossiter--McLaughlin effect, clearly favoring systems that harbor hot Jupiters. While it would be extremely helpful to extend these measurements to long-period and multiple-planet systems, it is also true that the latter systems tend to involve smaller planets, making it ever so difficult to apply such techniques. Asteroseismology provides a powerful method of determining the inclination of the stellar spin axis from an analysis of the rotationally-induced splittings of the oscillation modes. This provides an estimate of the obliquity independently of other methods. The applicability of the asteroseismic method is determined by the stellar properties and not by the signal-to-noise ratio of the transit data. Here we present a recap of the spin-orbit geometry, explain how the asteroseismic method works, and review previous applications of the method to exoplanet-host stars.

scholarly journals Spin-orbit alignment of exoplanet systems: analysis of an ensemble of asteroseismic observations

2015 ◽  
Vol 11 (A29B) ◽  
pp. 636-641
Author(s):  
Tiago L. Campante
Keyword(s):  
Signal To Noise Ratio ◽  
Spin Orbit ◽  
Planetary Formation ◽  
Hot Jupiters ◽  
Transiting Planets ◽  
Oscillation Modes ◽  
Solar Type ◽  
And Migration ◽  
Exoplanet Systems ◽  
Host Stars

AbstractMeasuring the obliquities of exoplanet-host stars provides invaluable diagnostic information for theories of planetary formation and migration. Most of these results have so far been obtained by measuring the Rossiter–McLaughlin effect, clearly favoring systems that harbor hot Jupiters. While it would be extremely helpful to extend these measurements to long-period and multiple-planet systems, it is also true that the latter systems tend to involve smaller planets, making it ever so difficult to apply such techniques. Asteroseismology provides a powerful method of determining the inclination of the stellar spin axis — from an analysis of the rotationally-induced splittings of the oscillation modes — whose applicability is ultimately determined by the stellar parameters and not by the signal-to-noise ratio of the transit data. Here we present the first statistical analysis of an ensemble of asteroseismic obliquity measurements obtained for solar-type stars with transiting planets. The sample consists of 25 Kepler planet-candidate host stars, 14 of which are multi-transiting systems. We seek empirical constraints on the spin-orbit alignment of exoplanet systems and discuss the implications for theories of planetary formation and migration.

scholarly journals Transmission spectroscopy and Rossiter-McLaughlin measurements of the young Neptune orbiting AU Mic

2020 ◽  
Vol 643 ◽  
pp. A25
Author(s):  
E. Palle ◽  
M. Oshagh ◽  
N. Casasayas-Barris ◽  
T. Hirano ◽  
M. Stangret ◽  
...  
Keyword(s):  
Time Series ◽  
Signal To Noise Ratio ◽  
Dynamical Evolution ◽  
Spin Orbit ◽  
Large Signal ◽  
Atmospheric Transmission ◽  
Transmission Spectroscopy ◽  
Very Large Telescope ◽  
Rotation Plane ◽  
And Migration

AU Mic b is a Neptune-sized planet on an 8.47-day orbit around the nearest pre-main sequence (~20 Myr) star to the Sun, the bright (V = 8.81) M dwarf AU Mic. The planet was preliminary detected in Doppler radial velocity time series and recently confirmed to be transiting with data from the TESS mission. AU Mic b is likely to be cooling and contracting and might be accompanied by a second, more massive planet, in an outer orbit. Here, we present the observations of the transit of AU Mic b using ESPRESSO on the Very Large Telescope. We obtained a high-resolution time series of spectra to measure the Rossiter-McLaughlin effect, to constrain the spin-orbit alignment of the star and planet, and to simultaneously attempt to retrieve the planet’s atmospheric transmission spectrum. These observations allowed us to study, for the first time, the early phases of the dynamical evolution of young systems. We applied different methodologies to derive the spin-orbit angle of AU Mic b, and all of them retrieve values consistent with the planet being aligned with the rotation plane of the star. We determined a conservative spin-orbit angle λ value of −2.96−10.30+10.44 degrees, indicative that the formation and migration of the planets of the AU Mic system occurred within the disc. Unfortunately, and despite the large signal-to-noise ratio of our measurements, the degree of stellar activity prevented us from detecting any features from the planetary atmosphere. In fact, our results suggest that transmission spectroscopy for recently formed planets around active young stars is going to remain very challenging, if at all possible, for the near future.

scholarly journals A multiplicity study of transiting exoplanet host stars

2020 ◽  
Vol 635 ◽  
pp. A73 ◽  
Author(s):  
A. J. Bohn ◽  
J. Southworth ◽  
C. Ginski ◽  
M. A. Kenworthy ◽  
P. F. L. Maxted ◽  
...  
Keyword(s):  
Proper Motion ◽  
Angular Separation ◽  
Current Data ◽  
Formation Mechanisms ◽  
Multiple Systems ◽  
Hot Jupiters ◽  
Data Release ◽  
And Migration ◽  
Almost All ◽  
Host Stars

Context. Many main-sequence stars are part of multiple systems. The effect of stellar multiplicity on planet formation and migration, however, is poorly understood. Aims. We study the multiplicity of stars hosting known transiting extra-solar planets to test competing theories on the formation mechanisms of hot Jupiters. Methods. We observed 45 exoplanet host stars using the infrared dual imaging spectrograph of the Spectro-Polarimetric High-Contrast Exoplanet Research (SPHERE) instrument at the Very Large Telescope to search for potential companions. For each identified candidate companion we determined the probability that it is gravitationally bound to its host by performing common proper motion checks and modelling of synthetic stellar populations around the host. In addition, we derived contrast limits as a function of angular separation to set upper limits on further companions in these systems. We converted the derived contrast into mass thresholds using AMES-Cond, AMES-Dusty, and BT-Settl models. Results. We detected new candidate companions around K2-38, WASP-72, WASP-80, WASP-87, WASP-88, WASP-108, WASP-118, WASP-120, WASP-122, WASP123, WASP-130, WASP-131, and WASP-137. The closest candidates were detected at separations of 0.′′124±0.′′007 and 0.′′189±0.′′003 around WASP-108 and WASP-131; the measured K-band contrasts indicate that these are stellar companions of 0.35 ± 0.02 M⊙ and 0.62−0.04+0.05 M⊙, respectively. Including the re-detection and confirmation of previously known companions in 13 other systems, we derived a multiplicity fraction of 55.4−9.4+5.9%. For the representative sub-sample of 40 hot Jupiter host stars among our targets, the derived multiplicity rate is 54.8−9.9+6.3%. Our data do not confirm any trend that systems with eccentric planetary companions are preferably part of multiple systems. On average, we reached a magnitude contrast of 8.5 ± 0.9 mag at an angular separation of 0.′′5. This allows us to exclude additional stellar companions with masses higher than 0.08M⊙ for almost all observed systems; around the closest and youngest systems, this sensitivity is achieved at physical separations as small as 10 au. Conclusions. Our study shows that SPHERE is an ideal instrument for detecting and characterising close companions to exoplanetary host stars. Although the second data release of the Gaia mission also provides useful constraints for some of the systems, the achieved sensitivity provided by the current data release of this mission is not good enough to measure parallaxes and proper motions for all detected candidates. For 14 identified companion candidates further astrometric epochs are required to confirm their common proper motion at 5σ significance.

scholarly journals Estimation of singly transiting K2 planet periods with Gaia parallaxes

2019 ◽  
Vol 489 (3) ◽  
pp. 3149-3161 ◽  
Author(s):  
Emily Sandford ◽  
Néstor Espinoza ◽  
Rafael Brahm ◽  
Andrés Jordán
Keyword(s):  
Direct Measurement ◽  
Free Parameter ◽  
Broad Band ◽  
Long Period ◽  
Period Distribution ◽  
Typical Period ◽  
Stellar Models ◽  
Host Stars ◽  
Stellar Density ◽  
As If

ABSTRACT When a planet is only observed to transit once, direct measurement of its period is impossible. It is possible, however, to constrain the periods of single transiters, and this is desirable as they are likely to represent the cold and far extremes of the planet population observed by any particular survey. Improving the accuracy with which the period of single transiters can be constrained is therefore critical to enhance the long-period planet yield of surveys. Here, we combine Gaia parallaxes with stellar models and broad-band photometry to estimate the stellar densities of K2 planet host stars, then use that stellar density information to model individual planet transits and infer the posterior period distribution. We show that the densities we infer are reliable by comparing with densities derived through asteroseismology, and apply our method to 27 validation planets of known (directly measured) period, treating each transit as if it were the only one, as well as to 12 true single transiters. When we treat eccentricity as a free parameter, we achieve a fractional period uncertainty over the true single transits of $94^{+87}_{-58}{{\ \rm per\ cent}}$, and when we fix e = 0, we achieve fractional period uncertainty $15^{+30}_{-6}{{\ \rm per\ cent}}$, a roughly threefold improvement over typical period uncertainties of previous studies.

Kinematic interpretation in the prestack depth‐migrated domain

Geophysics ◽  
1997 ◽  
Vol 62 (4) ◽  
pp. 1226-1237 ◽  
Author(s):  
Irina Apostoiu‐Marin ◽  
Andreas Ehinger
Keyword(s):  
Signal To Noise Ratio ◽  
Velocity Model ◽  
Point Of View ◽  
Prestack Depth Migration ◽  
Depth Migration ◽  
Velocity Models ◽  
Time Domain Data ◽  
And Migration ◽  
Point To Point ◽  
Homogeneous Media

Prestack depth migration can be used in the velocity model estimation process if one succeeds in interpreting depth events obtained with erroneous velocity models. The interpretational difficulty arises from the fact that migration with erroneous velocity does not yield the geologically correct reflector geometries and that individual migrated images suffer from poor signal‐to‐noise ratio. Moreover, migrated events may be of considerable complexity and thus hard to identify. In this paper, we examine the influence of wrong velocity models on the output of prestack depth migration in the case of straight reflector and point diffractor data in homogeneous media. To avoid obscuring migration results by artifacts (“smiles”), we use a geometrical technique for modeling and migration yielding a point‐to‐point map from time‐domain data to depth‐domain data. We discover that strong deformation of migrated events may occur even in situations of simple structures and small velocity errors. From a kinematical point of view, we compare the results of common‐shot and common‐offset migration. and we find that common‐offset migration with erroneous velocity models yields less severe image distortion than common‐shot migration. However, for any kind of migration, it is important to use the entire cube of migrated data to consistently interpret in the prestack depth‐migrated domain.

Gravity meter observation of free modes excited by the August 19, 1977 Indonesia earthquake

1979 ◽  
Vol 69 (5) ◽  
pp. 1445-1454
Author(s):  
John A. Linton ◽  
D. E. Smylie ◽  
O. G. Jensen
Keyword(s):  
Signal To Noise Ratio ◽  
Quartz Fiber ◽  
Large Signal ◽  
Signal To Noise ◽  
Definitive Evidence ◽  
Long Period ◽  
Noise Ratio

abstract Free modes with signal-to-noise ratio in the range of 40 to 55 dB were observed in the record taken by a vertical broadband quartz fiber gravimeter system opeating in Montreal following the event of August 19, 1977 in Indonesia. The large signal-to-noise ratio has permitted very stable Q estimates to be made for a number of the fundamental spheroidal modes. The very long-period band shows no definitive evidence of signal other than the expected tidal lines.

scholarly journals A search for transiting planets in the β Pictoris system

2018 ◽  
Vol 615 ◽  
pp. A145 ◽  
Author(s):  
M. Mol Lous ◽  
E. Weenk ◽  
M. A. Kenworthy ◽  
K. Zwintz ◽  
R. Kuschnig
Keyword(s):  
Signal To Noise Ratio ◽  
Large Fraction ◽  
Young Star ◽  
High Signal ◽  
Data Set ◽  
Transiting Planets ◽  
Using Data ◽  
Exoplanet Systems ◽  
Transit Signals

Context. Transiting exoplanets provide an opportunity for the characterization of their atmospheres, and finding the brightest star in the sky with a transiting planet enables high signal-to-noise ratio observations. The Kepler satellite has detected over 365 multiple transiting exoplanet systems, a large fraction of which have nearly coplanar orbits. If one planet is seen to transit the star, then it is likely that other planets in the system will transit the star too. The bright (V = 3.86) star β Pictoris is a nearby young star with a debris disk and gas giant exoplanet, β Pictoris b, in a multi-decade orbit around it. Both the planet’s orbit and disk are almost edge-on to our line of sight. Aims. We carry out a search for any transiting planets in the β Pictoris system with orbits of less than 30 days that are coplanar with the planet β Pictoris b. Methods. We search for a planetary transit using data from the BRITE-Constellation nanosatellite BRITE-Heweliusz, analyzing the photometry using the Box-Fitting Least Squares Algorithm (BLS). The sensitivity of the method is verified by injection of artificial planetary transit signals using the Bad-Ass Transit Model cAlculatioN (BATMAN) code. Results. No planet was found in the BRITE-Constellation data set. We rule out planets larger than 0.6 RJ for periods of less than 5 days, larger than 0.75 RJ for periods of less than 10 days, and larger than 1.05 RJ for periods of less than 20 days.

scholarly journals Stellar Obliquities and Planetary Alignments (SOPA). I. Spin–Orbit Measurements of Three Transiting Hot Jupiters: WASP-72b, WASP-100b, and WASP-109b

2018 ◽  
Vol 156 (5) ◽  
pp. 197 ◽  
Author(s):  
B. C. Addison ◽  
Songhu Wang ◽  
M. C. Johnson ◽  
C. G. Tinney ◽  
D. J. Wright ◽  
...  
Keyword(s):  
Spin Orbit ◽  
Hot Jupiters

scholarly journals On the alignment of debris discs and their host stars’ rotation axis - implications for spin-orbit misalignment in exoplanetary systems

2011 ◽  
Vol 413 (1) ◽  
pp. L71-L75 ◽  
Author(s):  
C. A. Watson ◽  
S. P. Littlefair ◽  
C. Diamond ◽  
A. Collier Cameron ◽  
A. Fitzsimmons ◽  
...  
Keyword(s):  
Rotation Axis ◽  
Spin Orbit ◽  
Exoplanetary Systems ◽  
Host Stars

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).

Sign in / Sign up

Export Citation Format

Share Document