اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدAnalysis of spin-orbit alignment in the WASP-32, WASP-38, and HAT-P-27/WASP-40 systems
238
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We present measurements of the spin-orbit alignment angle, lambda, for the hot Jupiter systems WASP-32, WASP-38, and HAT-P-27/WASP-40, based on data obtained using the HARPS spectrograph. We analyse the Rossiter-McLaughlin effect for all three systems, and also carry out Doppler tomography for WASP-32 and WASP-38. We find that WASP-32 (T_eff = 6140 +90 -100 K) is aligned, with an alignment angle of lambda = 10.5 +6.4 -6.5 degrees obtained through tomography, and that WASP-38 (T_eff = 6180 +40 -60 K) is also aligned, with tomographic analysis yielding lambda = 7.5 +4.7 -6.1 degrees. This latter result provides an order of magnitude improvement in the uncertainty in lambda compared to the previous analysis of Simpson et al. (2011). We are only able to loosely constrain the angle for HAT-P-27/WASP-40 (T_eff = 5190 +160 -170 K) to lambda = 24.2 +76.0 -44.5 degrees, owing to the poor signal-to-noise of our data. We consider this result a non-detection under a slightly updated version of the alignment test of Brown et al. (2012). We place our results in the context of the full sample of spin-orbit alignment measurements, finding that they provide further support for previously established trends.
قيم البحث
اقرأ أيضاً
We present observations of the Rossiter-McLaughlin effect for the transiting exoplanet systems WASP-1, WASP-24, WASP-38 and HAT-P-8, and deduce the orientations of the planetary orbits with respect to the host stars rotation axes. The planets WASP-24
b, WASP-38b and HAT-P-8b appear to move in prograde orbits and be well aligned, having sky-projected spin orbit angles consistent with zero: {lambda} = -4.7 pm 4.0{deg}, {lambda} = 15 + 33{deg}/-43{deg} and {lambda} = -9.7 +9.0{deg}/-7.7{deg}, respectively. The host stars have Teff < 6250 K and conform with the trend of cooler stars having low obliquities. WASP-38b is a massive planet on a moderately long period, eccentric orbit so may be expected to have a misaligned orbit given the high obliquities measured in similar systems. However, we find no evidence for a large spin-orbit angle. By contrast, WASP-1b joins the growing number of misaligned systems and has an almost polar orbit, {lambda} = -79 +4.5{deg}/-4.3{deg}. It is neither very massive, eccentric nor orbiting a hot host star, and therefore does not share the properties of many other misaligned systems.
We report the detection of WASP-35b, a planet transiting a metal-poor ([Fe/H] = -0.15) star in the Southern hemisphere, WASP-48b, an inflated planet which may have spun-up its slightly evolved host star of 1.75 R_sun in the Northern hemisphere, and t
he independent discovery of HAT-P-30b / WASP-51b, a new planet in the Northern hemisphere. Using WASP, RISE, FTS and TRAPPIST photometry, with CORALIE, SOPHIE and NOT spectroscopy, we determine that WASP-35b has a mass of 0.72 +/- 0.06 M_J and radius of 1.32 +/- 0.03 R_J, and orbits with a period of 3.16 days, WASP-48b has a mass of 0.98 +/- 0.09 M_J, radius of 1.67 +/- 0.08 R_J and orbits in 2.14 days, while WASP-51b, with an orbital period of 2.81 days, is found to have a mass of 0.76 +/- 0.05 M_J and radius of 1.42 +/- 0.04 R_J, agreeing with values of 0.71 +/- 0.03 M_J and 1.34 +/- 0.07 R_J reported for HAT-P-30b.
Ultra-hot Jupiters are the hottest exoplanets discovered so far. Observations begin to provide insight into the composition of their extended atmospheres and their chemical day/night asymmetries. Both are strongly affected by cloud formation. We expl
ore trends in cloud properties for a sample of five giant gas planets: WASP-43b, WASP-18b, HAT-P-7b, WASP-103b, and WASP-121b. This provides a reference frame for cloud properties for the JWST targets WASP-43b and WASP-121b. We further explore chemically inert tracers to observe geometrical asymmetries, and if the location of inner boundary of a 3D GCM matters for the clouds that form. The large day/night temperature differences of ultra-hot Jupiters cause large chemical asymmetries: cloud-free days but cloudy nights, atomic vs. molecular gases and respectively different mean molecular weights, deep thermal ionospheres vs. low-ionised atmospheres, undepleted vs enhanced C/O. WASP-18b, as the heaviest planet in the sample, has the lowest global C/O. The global climate may be considered as similar amongst ultra-hot Jupiters, but different to that of hot gas giants. The local weather, however, is individual for each planet since the local thermodynamic conditions, and hence the local cloud and gas properties, differ. The morning and the evening terminator of ultra-hot Jupiters will carry signatures of their strong chemical asymmetry such that ingress/egress asymmetries can be expected. An increased C/O ratio is a clear sign of cloud formation, making cloud modelling a necessity when utilizing C/O (or other mineral ratios) as tracer for planet formation. The changing geometrical extension of the atmosphere from the day to the nightside may be probed through chemically inert species like helium. Ultra-hot Jupiters are likely to develop deep atmospheric ionospheres which may impact the atmosphere dynamics through MHD processes.
We present photometry of 4 transits of the exoplanet WASP-4b, each with a precision of approximately 500 ppm and a time sampling of 40-60s. We have used the data to refine the estimates of the system parameters and ephemerides. During two of the tran
sits we observed a short-lived, low-amplitude anomaly that we interpret as the occultation of a starspot by the planet. We also find evidence for a pair of similar anomalies in previously published photometry. The recurrence of these anomalies suggests that the stellar rotation axis is nearly aligned with the orbital axis, or else the star spot would not have remained on the transit chord. By analyzing the timings of the anomalies we find the sky-projected stellar obliquity to be -1_{-12}^{+14} degrees. This result is consistent with (and more constraining than) a recent observation of the Rossiter-McLaughlin effect. It suggests that the planet migration mechanism preserved the initially low obliquity, or else that tidal evolution has realigned the system. Future applications of this method using data from the Corot and Kepler missions will allow spin-orbit alignment to be probed for many other exoplanets.
We present new transit light curves for planets in six extrasolar planetary systems. They were acquired with 0.4-2.2 m telescopes located in west Asia, Europe, and South America. When combined with literature data, they allowed us to redetermine syst
em parameters in a homogeneous way. Our results for individual systems are in agreement with values reported in previous studies. We refined transit ephemerides and reduced uncertainties of orbital periods by a factor between 2 and 7. No sign of any variations in transit times was detected for the planets studied.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
