K2-HERMES II. Planet-candidate properties from K2 Campaigns 1-13
Robert A. Wittenmyer, Jake T. Clark, Sanjib Sharma, Dennis Stello, Jonathan Horner, Stephen R. Kane, Catherine P. Stevens, Duncan J. Wright, Lorenzo Spina, Klem… 展开作者
Robert A. Wittenmyer, Jake T. Clark, Sanjib Sharma, Dennis Stello, Jonathan Horner, Stephen R. Kane, Catherine P. Stevens, Duncan J. Wright, Lorenzo Spina, Klemen Cotar, Martin Asplund, Joss Bland-Hawthorn, Sven Buder, Andrew R. Casey, Gayandhi M. De Silva, Valentina D'Orazi, Ken Freeman, Janez Kos, Geraint Lewis, Jane Lin, Karin Lind, Sarah L. Martell, Jeffrey D. Simpson, Daniel B. Zucker, Tomaz Zwitter
备注：
Accepted for publication in MNRAS. Full versions of online-only Tables 2 and 3 available on request. Same for Table 4, in exchange for the trick to make MNRAS style break long tables across pages
Accurate and precise radius estimates of transiting exoplanets are critical for understanding their compositions and formation mechanisms. To know the planet, we must know the host star in as much detail as possible. We present complete results for planet-candidate hosts from the K2-HERMES survey, which uses the HERMES multi-object spectrograph on the Anglo-Australian Telescope to obtain R$\sim$28,000 spectra for more than 30,000 K2 stars. We present complete host-star parameters and planet-candidate radii for 224 K2 candidate planets from C1-C13. Our results cast severe doubt on 30 K2 candidates, as we derive unphysically large radii, larger than 2 $R_{Jup}$. This work highlights the importance of obtaining accurate, precise, and self-consistent stellar parameters for ongoing large planet search programs - something that will only become more important in the coming years, as TESS begins to deliver its own harvest of exoplanets.
Using our K2 Campaign 5 fully automated planet detection data set (43 planets), which has corresponding measures of completeness and reliability, we infer an underlying planet population model for the FGK dwarfs sample (9,257 stars). Implementing a broken power-law for both the period and radius distribution, we find an overall planet occurrence of $1.00^{+1.07}_{-0.51}$ planets per star within a period range of 0.5-38 days. Making similar cuts and running a comparable analysis on the Kepler sample (2,318 planets; 94,222 stars), we find an overall occurrence of $1.10\pm0.05$ planets per star. …
The Gemini NICI Planet-Finding Campaign: The Frequency of Giant Planets Around Debris Disk Stars
作为双子座NICI行星发现活动的一部分，我们已经完成了对57颗碎片盘星周围巨行星的高对比度直接成像调查。我们实现了0.5”处12.4 mag和1”处14.1 mag的中值H带对比度。对66个预测间隔< 500 AU的候选天体的跟踪观测表明，它们都是背景天体。为了根据我们的成像数据对潜在的巨行星种群建立统计约束，我们开发了一种新的贝叶斯形式主义，该形式主义包括（1）未检测，（2）单历元候选者，（3）天体测量和（4）光度信息，以及（5）每个恒星有多颗行星的可能性来约束行星种群。我们的形式主义使我们能够在我们的分析中包括以前已知的Beta Picture和HR 8799行星。我们的研究结果显示，在95%的置信度，<13% of debris disk stars have a >5 MJup行星超过80 AU，<21% of debris disk stars have a >3 MJup行星40 AU以外，基于热启动进化模型。我们将直接成像的行星数量建模为d^2N/dMda ~ m^alpha a^beta，其中m是行星质量，a是轨道半长轴（最大值为amax）。我们发现beta < -0.8和/或alpha > 1.7。同样，我们发现beta < -0.8和/或amax < 200 AU。如果我们忽略Beta Pic和HR 8799行星（如果它们属于一个罕见而独…
Constraining Orbital Periods from Nonconsecutive Observations: Period Estimates for Long-Period Planets in Six Systems Observed by K2 During Multiple Campaigns
We analyzed the photometry of 20038 cool stars from campaigns 12, 13, 14 and 15 of the K2 mission in order to detect, characterize and validate new planetary candidates transiting low-mass stars. We present a catalogue of 25 new periodic transit-like signals in 22 stars, of which we computed the parameters of the stellar host for 19 stars and the planetary parameters for 21 signals. We acquired speckle and AO images, and also inspected archival Pan-STARRS1 images and Gaia DR2 to discard the presence of close stellar companions and to check possible transit dilutions due to nearby stars. False …
We present the first short-duration candidate microlensing events from the Kepler K2 mission. From late April to early July 2016, Campaign 9 of K2 obtained high temporal cadence observations over a 3.7 square degree region of the Galactic bulge. Its primary objectives were to look for evidence of a free-floating planet (FFP) population using microlensing, and demonstrate the feasibility of space-based planetary microlensing surveys. Though Kepler K2 is far from optimal for microlensing, the recently developed MCPM photometric pipeline enables us to identify and model microlensing events. We de…
We analysed 68 candidate planetary systems first identified during Campaigns 5 and 6 (C5 and C6) of the NASA \textit{K2} mission. We set out to validate these systems by using a suite of follow-up observations, including adaptive optics, speckle imaging, and reconnaissance spectroscopy. The overlap between C5 with C16 and C18, and C6 with C17, yields lightcurves with long baselines that allow us to measure the transit ephemeris very precisely, revisit single transit candidates identified in earlier campaigns, and search for additional transiting planets with longer periods not detectable in pr…
With observational efforts moving from the discovery into the characterisation mode, systematic campaigns that cover large ranges of global stellar and planetary parameters will be needed. We aim to uncover cloud formation trends and globally changing chemical regimes due to the host star's effect on the thermodynamic structure of their atmospheres. We aim to provide input for exoplanet missions like JWST, PLATO, and Ariel, as well as potential UV missions ARAGO, PolStar or POLLUX. Pre-calculated 3D GCMs for M, K, G, F host stars are the input for our kinetic cloud model. Gaseous exoplanets fa…
The wavelet-based detrending and denoising method \texttt{TFAW} is applied for the first time to \texttt{EVEREST 2.0}-corrected light curves to further improve the photometric precision of almost all K2 observing campaigns (C1-C8, C12-C18). The performance of both methods is evaluated in terms of 6 hr combined differential photometric precision (CDPP), simulated transit detection efficiency, and planet characterization in different SNR regimes. On average, \texttt{TFAW} median 6hr CDPP is $\sim$30$\%$ better than the one achieved by \texttt{EVEREST 2.0} for all observing campaigns. Using the \…
Using the EVEREST photometry pipeline, we have identified 74 candidate ultra-short-period planets (orbital period P<1 d) in the first half of the K2 data (Campaigns 0-8 and 10). Of these, 33 candidates have not previously been reported. A systematic search for additional transiting planets found 13 new multi-planet systems, doubling the number known and representing a third (32%) of USPs. We also identified 30 companions, which have periods from 1.4 to 31 days (median 5.5 d). A third (36 of 104) of the candidate USPs and companions have been statistically validated or confirmed, 10 for the fir…
We provide the first full K2 transiting exoplanet sample, using photometry from Campaigns 1-8 and 10-18, derived through an entirely automated procedure. This homogeneous planet candidate catalog is a crucial to perform a robust demographic analysis of transiting exoplanets with K2. We identify 747 unique planet candidates and 57 multi-planet systems. Of these candidates, 366 have not been previously identified, including one resonant multi-planet system and one system with two short-period gas giants. By automating the construction of this list, measurements of sample biases (completeness and…
We present K2-2016-BLG-0005Lb, a densely sampled, planetary binary caustic-crossing microlensing event found from a blind search of data gathered from Campaign 9 of the Kepler K2 mission (K2C9). K2-2016-BLG-0005Lb is the first bound microlensing exoplanet discovered from space-based data. The event has caustic entry and exit points that are resolved in the K2C9 data, enabling the lens--source relative proper motion to be measured. We have fitted a binary microlens model to the Kepler data, and to simultaneous observations from multiple ground-based surveys. Whilst the ground-based data only sp…
We present the first results of K2-OjOS, a collaborative project between professional and amateur astronomers primarily aimed to detect, characterize, and validate new extrasolar planets. For this work, 10 amateur astronomers looked for planetary signals by visually inspecting the 20 427 light curves of K2 campaign 18 (C18). They found 42 planet candidates, of which 18 are new detections and 24 had been detected in the overlapping C5 by previous works. We used archival photometric and spectroscopic observations, as well as new high-spatial resolution images in order to carry out a complete ana…
The NASA K2 mission, salvaged from the hardware failures of the Kepler telescope, has continued Kepler's planet-hunting success. It has revealed nearly 500 transiting planets around the ecliptic plane, many of which are the subject of further study, and over 1000 additional candidates. Here we present the results of an ongoing project to follow-up and statistically validate new K2 planets, in particular to identify promising new targets for further characterization. By analyzing the reconnaissance spectra, high-resolution imaging, centroid variations, and statistical likelihood of the signals …
The Origins of Planets for ArieL (OPAL) Key Science Project: the end-to-end planet formation campaign for the ESA space mission Ariel
INAF - Osservatorio Astrofisico di Torino（意大利国家天体物理研究所都灵天文台）；Centro Nazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing（高性能计算、大数据与量子计算国家研究中心）；INAF - Istituto di Astrofisica e Planetologia Spaziali（意大利国家天体物理研究所天体物理学与行星科学研究所）；INAF - Osservatorio Astronomico di Trieste（意大利国家天体物理研究所的里雅斯特天文台）
