Abstract
K2-136 is a late-K dwarf (0.742 ± 0.039
M
⊙
) in the Hyades open cluster with three known, transiting planets and an age of 650 ± 70 Myr. Analyzing K2 photometry, we found that planets ...K2-136b, c, and d have periods of 8.0, 17.3, and 25.6 days and radii of 1.014 ± 0.050
R
⊕
, 3.00 ± 0.13
R
⊕
, and 1.565 ± 0.077
R
⊕
, respectively. We collected 93 radial velocity (RV) measurements with the High-Accuracy Radial-velocity Planet Searcher for the Northern hemisphere (HARPS-N) spectrograph (Telescopio Nazionale Galileo) and 22 RVs with the Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) spectrograph (Very Large Telescope). Analyzing HARPS-N and ESPRESSO data jointly, we found that K2-136c induced a semi-amplitude of 5.49 ± 0.53 m s
−1
, corresponding to a mass of 18.1 ± 1.9
M
⊕
. We also placed 95% upper mass limits on K2-136b and d of 4.3 and 3.0
M
⊕
, respectively. Further, we analyzed Hubble Space Telescope and XMM-Newton observations to establish the planetary high-energy environment and investigate possible atmospheric loss. K2-136c is now the smallest planet to have a measured mass in an open cluster and one of the youngest planets ever with a mass measurement. K2-136c has ∼75% the radius of Neptune but is similar in mass, yielding a density of
3.69
−
0.56
+
0.67
g cm
−3
(∼2–3 times denser than Neptune). Mass estimates for K2-136b (and possibly d) may be feasible with more RV observations, and insights into all three planets’ atmospheres through transmission spectroscopy would be challenging but potentially fruitful. This research and future mass measurements of young planets are critical for investigating the compositions and characteristics of small exoplanets at very early stages of their lives and providing insights into how exoplanets evolve with time.
Before reaching the intermediate level, a student begins their study with material found in methods books. Jane Magrath grades this as level 10 in her book Pianists Guide to Standard Teaching and ...Performance Literature (1995, 330). Because of CowelPs historical significance as one of the earliest recognized composers who championed extended techniques and his resulting strong influence on the works of Bela Bartok and John Cage, it is important for students to be exposed to his music. In this book, her piece "Duet for Piano and Tape" can be found along with 11 other pieces that present use of the modes, strumming techniques, clusters, experimental harmonies, polytonality, multimetric writing and whole tone writing. Because this piece is based very much in tonality, it would be a nice introduction to the idea of extended techniques without completely leaving the familiarity of standard literature behind. Annie Rose Tindall- Gibson, DMA, has taught at the University of Illinois Urbana-Champaign, the Orpheus Academy of Music and South Carolina State University.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Measuring periodic changes in the line-of-sight velocities of stars via spectroscopy (the “radial velocity technique”) is a well-established method to detect planets orbiting stars other than the ...Sun. As those distant stars orbit their system’s center of mass the radial velocity technique confirms that companions exist and allows for the measurement of fundamental parameters: companion masses, orbital characteristics, and, in some cases, aspects of atmospheric chemistry. Until recently Doppler spectrometers have been limited to detecting radial velocity signals of larger than one meter-per-second, a constraint that significantly hinders our discovery and characterization of small rocky worlds similar to our own. This is the motivation for developing instruments sensitive to extremely precise radial velocities (EPRVs, < 1ms−1). This dissertation describes critical aspects of the development of one such spectrometer: the Palomar Radial Velocity Instrument (PARVI).Chapter 2 presents the characterization of the fine-guiding camera used in the fiber injection unit that couples light from Palomar’s extreme adaptive optics to the spectrograph’s single-mode fiber feed.Chapter 3 describes the data acquisition and data reduction pipelines for PARVI. It includes the methodology for acquiring data with a Teledyne H2RG array, the description of the wavelength calibration using a laser frequency comb, and the process for reducing the 2D echellogram down to a 1D spectrum.Chapter 4 reveals the discovery of a new and significant, polarization-dependent, instrument noise and a warning for those considering using single-mode fibers for high resolution spectroscopy. Chapter 5 contains the first results from PARVI commissioning data. This includes the detection of the Rossiter-Mclaughlin signal of the transiting planet HD 189733 b, and presence of water and carbon monoxide in the atmosphere of HD 189733 b via transmission spectroscopy.
Abstract
Efforts to discover and characterize habitable zone planets have primarily focused on Sun-like stars and M dwarfs. K stars, however, provide an appealing compromise between these two ...alternatives that has been relatively unexplored. Understanding the ultraviolet (UV) environment around such stars is critical to our understanding of their planets, as the UV can drastically alter the photochemistry of a planet’s atmosphere. Here we present near-UV and far-UV Hubble Space Telescope's Cosmic Origins Spectrograph observations of 39 K stars at three distinct ages: 40 Myr, 650 Myr, and ≈5 Gyr. We find that the K star (0.6–0.8
M
⊙
) UV flux remains constant beyond 650 Myr before falling off by an order of magnitude by field age. This is distinct from early M stars (0.3–0.6
M
⊙
), which begin to decline after only a few hundred megayears. However, the rotation–UV activity relation for K stars is nearly identical to that of early M stars. These results may be a consequence of the spin-down stalling effect recently reported for K dwarfs, in which the spin-down of K stars halts for over a gigayear when their rotation periods reach ≈10 days, rather than the continuous spin-down that G stars experience. These results imply that exoplanets orbiting K dwarfs may experience a stronger UV environment than thought, weakening the case for K stars as hosts of potential “super-habitable” planets.
Notes that subdividing the age group 65 and over into finer age groups unmasks race differentials in mortality and morbidity that often favor blacks in the older age groups. Describes the unusual ...phenomena; proposes systematic research program to explain them; and discusses existing data sets for their analysis. (Author/NB)
This project is to help strengthen the spiritual life of the members of RPCC following thedisintegration of their church. Members met weekly for ten weeks at a community park.Selected Psalms dealing ...with issues of grief (Psalm 31), Anger (Psalm 37), Abandonment(Psalm 13), Hope (Psalm 18) and trust (Psalm 91) were studied. The study assistedmembers in effectively strengthen their spiritual walk. Five participants completed theBrief RCOPE Questionnaire, a 14 items spirituality inventory before and after the study.Results indicated improvement in the spiritual well-being of members as a result of theirparticipation in the study.
This project is to help strengthen the spiritual life of the members of RPCC following the disintegration of their church. Members met weekly for ten weeks at a community park. Selected Psalms ...dealing with issues of grief (Psalm 31), Anger (Psalm 37), Abandonment (Psalm 13), Hope (Psalm 18) and trust (Psalm 91) were studied. The study assisted members in effectively strengthen their spiritual walk. Five participants completed the Brief RCOPE Questionnaire, a 14 items spirituality inventory before and after the study. Results indicated improvement in the spiritual well-being of members as a result of their participation in the study.
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