1,718 research outputs found
A Transiting Planet of a Sun-like Star
A planet transits an 11th magnitude, G1V star in the constellation Corona
Borealis. We designate the planet XO-1b, and the star, XO-1, also known as GSC
02041-01657. XO-1 lacks a trigonometric distance; we estimate it to be 200+-20
pc. Of the ten stars currently known to host extrasolar transiting planets, the
star XO-1 is the most similar to the Sun in its physical characteristics: its
radius is 1.0+-0.08 R_Sun, its mass is 1.0+-0.03 M_Sun, V sini < 3 km/s, and
its metallicity [Fe/H] is 0.015+-0.04. The orbital period of the planet XO-1b
is 3.941534+-0.000027 days, one of the longer ones known. The planetary mass is
0.90+-0.07 M_Jupiter, which is marginally larger than that of other transiting
planets with periods between 3 and 4 days. Both the planetary radius and the
inclination are functions of the spectroscopically determined stellar radius.
If the stellar radius is 1.0+-0.08 R_Sun, then the planetary radius is
1.30+-0.11 R_Jupiter and the inclination of the orbit is 87.7+-1.2 degrees. We
have demonstrated a productive international collaboration between professional
and amateur astronomers that was important to distinguishing this planet from
many other similar candidates.Comment: 31 pages, 9 figures, accepted for part 1 of Ap
XO-5b: A Transiting Jupiter-sized Planet With A Four Day Period
The star XO-5 (GSC 02959-00729, V=12.1, G8V) hosts a Jupiter-sized,
Rp=1.15+/-0.12 Rjup, transiting extrasolar planet, XO-5b, with an orbital
period of P=4.187732+/-0.00002 days. The planet mass (Mp=1.15+/-0.08 Mjup) and
surface gravity (gp=22+/-5 m/s^2) are significantly larger than expected by
empirical Mp-P and Mp-P-[Fe/H] relationships. However, the deviation from the
Mp-P relationship for XO-5b is not large enough to suggest a distinct type of
planet as is suggested for GJ 436b, HAT-P-2b, and XO-3b. By coincidence XO-5
overlies the extreme H I plume that emanates from the interacting galaxy pair
NGC 2444/NGC 2445 (Arp 143).Comment: 10 pages, 9 Figures, Submitted to Ap
A Gyrochronology and Microvariability Survey of the Milky Way's Older Stars Using Kepler's Two-Wheels Program
Even with the diminished precision possible with only two reaction wheels,
the Kepler spacecraft can obtain mmag level, time-resolved photometry of tens
of thousands of sources. The presence of such a rich, large data set could be
transformative for stellar astronomy. In this white paper, we discuss how
rotation periods for a large ensemble of single and binary main- sequence
dwarfs can yield a quantitative understanding of the evolution of stellar
spin-down over time. This will allow us to calibrate rotation-based ages beyond
~1 Gyr, which is the oldest benchmark that exists today apart from the Sun.
Measurement of rotation periods of M dwarfs past the fully-convective boundary
will enable extension of gyrochronology to the end of the stellar
main-sequence, yielding precise ages ({\sigma} ~10%) for the vast majority of
nearby stars. It will also help set constraints on the angular momentum
evolution and magnetic field generation in these stars. Our Kepler-based study
would be supported by a suite of ongoing and future ground-based observations.
Finally, we briefly discuss two ancillary science cases, detection of
long-period low-mass eclipsing binaries and microvariability in white dwarfs
and hot subdwarf B stars that the Kepler Two-Wheels Program would facilitate.Comment: Kepler white pape
XO-2b: Transiting Hot Jupiter in a Metal-rich Common Proper Motion Binary
We report on a V=11.2 early K dwarf, XO-2 (GSC 03413-00005), that hosts a
Rp=0.98+0.03/-0.01 Rjup, Mp=0.57+/-0.06 Mjup transiting extrasolar planet,
XO-2b, with an orbital period of 2.615857+/-0.000005 days. XO-2 has high
metallicity, [Fe/H]=0.45+/-0.02, high proper motion, mu_tot=157 mas/yr, and has
a common proper motion stellar companion with 31" separation. The two stars are
nearly identical twins, with very similar spectra and apparent magnitudes. Due
to the high metallicity, these early K dwarf stars have a mass and radius close
to solar, Ms=0.98+/-0.02 Msolar and Rs=0.97+0.02/-0.01 Rsolar. The high proper
motion of XO-2 results from an eccentric orbit (Galactic pericenter, Rper<4
kpc) well confined to the Galactic disk (Zmax~100 pc). In addition, the phase
space position of XO-2 is near the Hercules dynamical stream, which points to
an origin of XO-2 in the metal-rich, inner Thin Disk and subsequent dynamical
scattering into the solar neighborhood. We describe an efficient Markov Chain
Monte Carlo algorithm for calculating the Bayesian posterior probability of the
system parameters from a transit light curve.Comment: 14 pages, 10 Figures, Accepted in ApJ. Negligible changes to XO-2
system properties. Removed Chi^2 light curve analysis section, and simplified
MCMC light curve analysis discussio
Exposing athletes to playing form activity: outcomes of a randomised control trial among community netball teams using a game-centred approach.
This study evaluated whether exposing junior netball players to greater amounts of competition relevant activity (playing form activity) had an effect on game play outcomes and session involvement. A group-randomised controlled trial in one junior netball club in the Hunter Region, NSW, Australia. Ninety female athletes (mean age = 9.04 years, SD 1.53) were randomised by team (n = 11) into the intervention (n = 41) or 9-week wait-list control (n = 49) condition. The Professional Learning for Understanding Games Education into Sport (PLUNGE into Sport) programme was undertaken in the first half of nine training sessions (9 × 30 min). The intervention exposed athletes to playing form activity through a coach development programme within training sessions. Athletes' decision-making, support and skill outcomes during a small-sided invasion game, and session involvement (pedometer step/min), were measured at baseline and 9-week follow-up. Linear mixed models revealed significant group-by-time intervention effects (P < 0.05) for decision-making (d = 0.4) and support (d = 0.5) during game play, and in-session activity (d = 1.2). An intervention exposing athletes to greater levels of playing form activity, delivered via a coach education programme, was efficacious in improving athlete decision-making and support skills in game play and increasing athlete involvement during sessions
Hesitancy around low dose CT screening for lung cancer
Lung cancer is the leading cause of cancer death worldwide. The absence of symptoms in early stage (I/II) disease, when curative treatment is possible, results in greater than 70% of cases being diagnosed at late stage (III/IV), when treatment is rarely curative. This contributes greatly to lung cancer's poor prognosis which sees only 16.2% of individuals diagnosed with the disease alive at 5 years. Early detection is key to improving lung cancer survival outcomes. As a result, there has been longstanding interest in finding a reliable screening test. After little success with chest radiography and sputum cytology, in 2011 the US National Lung Screening Trial (NLST) demonstrated that annual Low Dose Computed Tomography (LDCT) screening reduced lung cancer specific mortality by 20%, when compared with annual chest radiography. In 2020, the NELSON study demonstrated an even greater reduction in lung cancer specific mortality for LDCT screening at 0, 1, 3 and 5.5 years of 24% in men, when compared to no screening. Despite these impressive results, a call to arms in the 2017 European position statement on Lung Cancer Screening (LCS), and the widespread introduction across the US, there was, until recently, no population-based European national screening programme in place. We address the potential barriers and outstanding concerns including common screening foes, such as false positive tests, overdiagnosis, and the negative psychological impact of screening, as well as others more unique to LDCT LCS, including appropriate risk stratification of potential participants, radiation exposure and incidental findings. In doing this, we conclude that whilst the evidence generated from ongoing work can be used to refine the screening process, for those risks which remain, appropriate and acceptable mitigations are available, and none should serve as barriers to the implementation of national unified LCS programmes across Europe and beyond
Scalability testing automation using multivariate characterization and detection of software performance antipatterns
XO-3b: A Massive Planet in an Eccentric Orbit Transiting an F5V Star
We report the discovery of a massive (Mpsini = 13.02 +/- 0.64 Mjup; total
mass 13.25 +/- 0.64 Mjup), large (1.95 +/- 0.16 Rjup) planet in a transiting,
eccentric orbit (e = 0.260 +/- 0.017) around a 10th magnitude F5V star in the
constellation Camelopardalis. We designate the planet XO-3b, and the star XO-3,
also known as GSC 03727-01064. The orbital period of XO-3b is 3.1915426 +/-
0.00014 days. XO-3 lacks a trigonometric distance; we estimate its distance to
be 260 +/- 23 pc. The radius of XO-3 is 2.13 +/- 0.21 Rsun, its mass is 1.41
+/- 0.08 Msun, its vsini = 18.54 +/- 0.17 km/s, and its metallicity is [Fe/H] =
-0.177 +/- 0.027. This system is unusual for a number of reasons. XO-3b is one
of the most massive planets discovered around any star for which the orbital
period is less than 10 days. The mass is near the deuterium burning limit of 13
Mjup, which is a proposed boundary between planets and brown dwarfs. Although
Burrows et al. (2001) propose that formation in a disk or formation in the
interstellar medium in a manner similar to stars is a more logical way to
differentiate planets and brown dwarfs, our current observations are not
adequate to address this distinction. XO-3b is also unusual in that its
eccentricity is large given its relatively short orbital period. Both the
planetary radius and the inclination are functions of the spectroscopically
determined stellar radius. Analysis of the transit light curve of XO-3b
suggests that the spectroscopically derived parameters may be over estimated.
Though relatively noisy, the light curves favor a smaller radius in order to
better match the steepness of the ingress and egress. The light curve fits
imply a planetary radius of 1.25 +/- 0.15 Rjup, which would correspond to a
mass of 12.03 +/- 0.46 Mjup.Comment: 26 pages, 10 figures. Accepted by ApJ. Current version has several
small corrections as a result of a bug in the fitting softwar
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