Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userTwo Small Transiting Planets and a Possible Third Body Orbiting HD 106315
82
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
The masses, atmospheric makeups, spin-orbit alignments, and system architectures of extrasolar planets can be best studied when the planets orbit bright stars. We report the discovery of three bodies orbiting HD 106315, a bright (V = 8.97 mag) F5 dwarf targeted by our K2 survey for transiting exoplanets. Two small, transiting planets have radii of 2.23 (+0.30/-0.25) R_Earth and 3.95 (+0.42/-0.39) R_Earth and orbital periods of 9.55 d and 21.06 d, respectively. A radial velocity (RV) trend of 0.3 +/- 0.1 m/s/d indicates the likely presence of a third body orbiting HD 106315 with period >160 d and mass >45 M_Earth. Transits of this object would have depths of >0.1% and are definitively ruled out. Though the star has v sin i = 13.2 km/s, it exhibits short-timescale RV variability of just 6.4 m/s, and so is a good target for RV measurements of the mass and density of the inner two planets and the outer objects orbit and mass. Furthermore, the combination of RV noise and moderate v sin i makes HD 106315 a valuable laboratory for studying the spin-orbit alignment of small planets through the Rossiter-McLaughlin effect. Space-based atmospheric characterization of the two transiting planets via transit and eclipse spectroscopy should also be feasible. This discovery demonstrates again the power of K2 to find compelling exoplanets worthy of future study.
rate research
Read More
We report the discovery of two super-Earth-sized planets transiting the bright (V = 8.94, K = 7.07) nearby late G-dwarf HD 3167, using data collected by the K2 mission. The inner planet, HD 3167 b, has a radius of 1.6 R_e and an ultra-short orbital period of only 0.96 days. The outer planet, HD 3167 c, has a radius of 2.9 R_e and orbits its host star every 29.85 days. At a distance of just 45.8 +/- 2.2 pc, HD 3167 is one of the closest and brightest stars hosting multiple transiting planets, making HD 3167 b and c well suited for follow-up observations. The star is chromospherically inactive with low rotational line-broadening, ideal for radial velocity observations to measure the planets masses. The outer planet is large enough that it likely has a thick gaseous envelope which could be studied via transmission spectroscopy. Planets transiting bright, nearby stars like HD 3167 are valuable objects to study leading up to the launch of the James Webb Space Telescope.
We present an atmospheric characterization study of two medium sized planets bracketing the radius of Neptune: HD 106315 c (R$_{rm{P}}$=4.98 $pm$ 0.23 R$_{oplus}$) and HD 3167 c (R$_{rm{P}}$=2.740$_{-0.100}^{+0.106}$ R$_{oplus}$). We analyse spatially scanned spectroscopic observations obtained with the G141 grism (1.125 - 1.650 $mu$m) of the Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope. We use the publicly available Iraclis pipeline and TauREx3 atmospheric retrieval code and we detect water vapor in the atmosphere of both planets with an abundance of $log_{10}[mathrm{H_2O}]=-2.1^{+0.7}_{-1.3}$ ($sim$5.68$sigma$) and $log_{10}[mathrm{H_2O}]=-4.1^{+0.9}_{-0.9}$ ($sim$3.17$sigma$) for HD 106315 c and HD 3167 c, respectively. The transmission spectrum of HD 106315 c shows also a possible evidence of ammonia absorption ($log_{10}[mathrm {NH_3}]=-4.3^{+0.7}_{-2.0}$, $sim$1.97$sigma$ -even if it is not significant-), whilst carbon dioxide absorption features may be present in the atmosphere of HD 3167 c in the $sim$1.1-1.6~$mu$m wavelength range ($log_{10}[mathrm{CO_{2}}]= -2.4^{+0.7}_{-1.0}$, $sim$3.28$sigma$). However the CO$_2$ detection appears significant, it must be considered carefully and put into perspective. Indeed, CO$_2$ presence is not explained by 1D equilibrium chemistry models, and it could be due to possible systematics. The additional contribution of clouds, CO and CH$_4$ are discussed. HD 106315 c and HD 3167 c will be interesting targets for upcoming telescopes such as the James Webb Space Telescope (JWST) and the Atmospheric Remote-Sensing Infrared Exoplanet Large-Survey (Ariel).
We report the discovery and validation of TOI 122b and TOI 237b, two warm planets transiting inactive M dwarfs observed by textit{TESS}. Our analysis shows TOI 122b has a radius of 2.72$pm$0.18 R$_rm{e}$ and receives 8.8$pm$1.0$times$ Earths bolometric insolation, and TOI 237b has a radius of 1.44$pm$0.12 R$_rm{e}$ and receives 3.7$pm$0.5$times$ Earth insolation, straddling the 6.7$times$ Earth insolation that Mercury receives from the sun. This makes these two of the cooler planets yet discovered by textit{TESS}, even on their 5.08-day and 5.43-day orbits. Together, they span the small-planet radius valley, providing useful laboratories for exploring volatile evolution around M dwarfs. Their relatively nearby distances (62.23$pm$0.21 pc and 38.11$pm$0.23 pc, respectively) make them potentially feasible targets for future radial velocity follow-up and atmospheric characterization, although such observations may require substantial investments of time on large telescopes.
The multi-planetary system HD 106315 was recently found in K2 data . The planets have periods of $P_b sim9.55$ and $P_c sim 21.06,$days, and radii of $ r_b = 2.44 pm 0.17, $ and $r_c = 4.35 pm 0.23, $ $R_{oplus}$. The brightness of the host star (V=9.0 mag) makes it an excellent target for transmission spectroscopy. However, to interpret transmission spectra it is crucial to measure the planetary masses. We obtained high precision radial velocities for HD~106315 to determine the mass of the two transiting planets discovered with Kepler K2. Our successful observation strategy was carefully tailored to mitigate the effect of stellar variability. We modelled the new radial velocity data together with the K2 transit photometry and a new ground-based partial transit of HD 106315c to derive system parameters. We estimate the mass of HD 106315b to be 12.6 $pm$ 3.2 $M_{oplus}$ and the density to be $4.7 pm 1.7, g,cm^{-3}$, while for HD 106315c we estimate a mass of 15.2 $pm$ 3.7 $M_{oplus}$ and a density of $1.01 pm 0.29, $g,cm$^{-3}$. Hence, despite planet c having a radius almost twice as large as planet b, their masses are consistent with one another. We conclude that HD 106315c has a thick hydrogen-helium gaseous envelope. A detailed investigation of HD 106315b using a planetary interior model constrains the core mass fraction to be 5-29%, and the water mass fraction to be 10-50%. An alternative, not considered by our model, is that HD 106315b is composed of a large rocky core with a thick H-He envelope. Transmission spectroscopy of these planets will give insight into their atmospheric compositions and also help constrain their core compositions.
We present the discovery of three small planets transiting K2-136 (LP 358 348, EPIC 247589423), a late K dwarf in the Hyades. The planets have orbital periods of $7.9757 pm 0.0011$, $17.30681^{+0.00034}_{-0.00036}$, and $25.5715^{+0.0038}_{-0.0040}$ days, and radii of $1.05 pm 0.16$, $3.14 pm 0.36$, and $1.55^{+0.24}_{-0.21}$ $R_oplus$, respectively. With an age of 600-800 Myr, these planets are some of the smallest and youngest transiting planets known. Due to the relatively bright (J=9.1) host star, the planets are compelling targets for future characterization via radial velocity mass measurements and transmission spectroscopy. As the first known star with multiple transiting planets in a cluster, the system should be helpful for testing theories of planet formation and migration.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
