18 research outputs found
The outflow of the protostar in B335: I
The isolated globule B335 contains a single, low luminosity Class 0 protostar
associated with a bipolar nebula and outflow system seen nearly perpendicular
to its axis. We observed the innermost regions of this outflow as part of
JWST/NIRCam GTO program 1187, primarily intended for wide-field slitless
spectroscopy of background stars behind the globule. We find a system of
expanding shock fronts with kinematic ages of only a few decades emerging
symmetrically from the position of the embedded protostar, which is not
directly detected at NIRCam wavelengths. The innermost and youngest of the
shock fronts studied here shows strong emission from CO. The next older shock
front shows less CO and the third shock front shows only H_2 emission in our
data. This third and most distant of these inner shock fronts shows substantial
evolution of its shape since it was last observed with high spatial resolution
in 1996 with Keck/NIRC. This may be evidence of a faster internal shock
catching up with a slower one and of the two shocks merging.Comment: This paper is accepted by The Astronomical Journa
JWST/NIRCam Imaging of Young Stellar Objects. I. Constraints on Planets Exterior to The Spiral Disk Around MWC 758
MWC 758 is a young star hosting a spiral protoplanetary disk. The spirals are
likely companion-driven, and two previously-identified candidate companions
have been identified -- one at the end the Southern spiral arm at ~0.6 arcsec,
and one interior to the gap at ~0.1 arcsec. With JWST/NIRCam, we provide new
images of the disk and constraints on planets exterior to ~1". We detect the
two-armed spiral disk, a known background star, and a spatially resolved
background galaxy, but no clear companions. The candidates that have been
reported are at separations that are not probed by our data with sensitivity
sufficient to detect them -- nevertheless, these observations place new limits
on companions down to ~2 Jupiter-masses at ~150 au and ~0.5 Jupiter masses at
~600 au. Owing to the unprecedented sensitivity of JWST and youth of the
target, these are among the deepest mass-detection limits yet obtained through
direct imaging observations, and provide new insights into the system's
dynamical nature.Comment: Accepted for publication in A
Origins Space Telescope:From First Light to Life
The Origins Space Telescope is one of four large missions studied by by the community with NASA support in preparation for the Decadal Survey
The Science Performance of JWST as Characterized in Commissioning
This paper characterizes the actual science performance of the James Webb
Space Telescope (JWST), as determined from the six month commissioning period.
We summarize the performance of the spacecraft, telescope, science instruments,
and ground system, with an emphasis on differences from pre-launch
expectations. Commissioning has made clear that JWST is fully capable of
achieving the discoveries for which it was built. Moreover, almost across the
board, the science performance of JWST is better than expected; in most cases,
JWST will go deeper faster than expected. The telescope and instrument suite
have demonstrated the sensitivity, stability, image quality, and spectral range
that are necessary to transform our understanding of the cosmos through
observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures;
https://iopscience.iop.org/article/10.1088/1538-3873/acb29
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Origins Space Telescope: baseline mission concept
The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the Universe today? How do habitable planets form? How common are life-bearing worlds? To answer these alluring questions, Origins will operate at mid- and far-infrared (IR) wavelengths and offer powerful spectroscopic instruments and sensitivity three orders of magnitude better than that of the Herschel Space Observatory, the largest telescope flown in space to date. We describe the baseline concept for Origins recommended to the 2020 US Decadal Survey in Astronomy and Astrophysics. The baseline design includes a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. A mid-infrared instrument (Mid-Infrared Spectrometer and Camera Transit spectrometer) will measure the spectra of transiting exoplanets in the 2.8 to 20 μm wavelength range and offer unprecedented spectrophotometric precision, enabling definitive exoplanet biosignature detections. The far-IR imager polarimeter will be able to survey thousands of square degrees with broadband imaging at 50 and 250 μm. The Origins Survey Spectrometer will cover wavelengths from 25 to 588 μm, making wide-area and deep spectroscopic surveys with spectral resolving power R ∼ 300, and pointed observations at R ∼ 40,000 and 300,000 with selectable instrument modes. Origins was designed to minimize complexity. The architecture is similar to that of the Spitzer Space Telescope and requires very few deployments after launch, while the cryothermal system design leverages James Webb Space Telescope technology and experience. A combination of current-state-of-the-art cryocoolers and next-generation detector technology will enable Origins’ natural background-limited sensitivity
The Outflow of The Protostar in B335. I.
The isolated globule B335 contains a single, low-luminosity Class 0 protostar associated with a bipolar nebula and outflow system seen nearly perpendicular to its axis. We observed the innermost regions of this outflow as part of JWST/NIRCam Guaranteed Time Observations program 1187, primarily intended for wide-field slitless spectroscopy of background stars behind the globule. We find a system of expanding shock fronts with kinematic ages of only a few decades emerging symmetrically from the position of the embedded protostar, which is not directly detected at NIRCam wavelengths. The innermost and youngest of the shock fronts studied here shows strong emission from CO. The next older shock front shows less CO and the third shock front shows only H _2 emission in our data. This third and most distant of these inner shock fronts shows substantial evolution of its shape since it was last observed with high spatial resolution in 1996 with Keck/NIRC. This may be evidence of a faster internal shock catching up with a slower one and of the two shocks merging
JWST/NIRCam Imaging of Young Stellar Objects. I. Constraints on Planets Exterior to the Spiral Disk Around MWC 758
MWC 758 is a young star hosting a spiral protoplanetary disk. The spirals are likely companion-driven, and two previously identified candidate companions have been identified—one at the end the Southern spiral arm at ∼0.″6, and one interior to the gap at ∼0.″1. With JWST/NIRCam, we provide new images of the disk and constraints on planets exterior to ∼1″. We detect the two-armed spiral disk, a known background star, and a spatially resolved background galaxy, but no clear companions. The candidates that have been reported are at separations that are not probed by our data with sensitivity sufficient to detect them−nevertheless, these observations place new limits on companions down to ∼2 M _Jup at ∼150 au and ∼0.5 M _Jup at ≳600 au. Owing to the unprecedented sensitivity of JWST and youth of the target, these are among the deepest mass-detection limits yet obtained through direct imaging observations, and provide new insights into the system’s dynamical nature