The Barbara A. Mikulski Archive for Space Telescopes (MAST) hosts science-ready data products from over 20 NASA missions plus community-contributed data collections and other select surveys. The data support forefront research in the ultraviolet, optical, and near-infrared wavelength bands. We have constructed bibliographies for each mission from publications in nearly 40 professional journals and identified more than 37,000 refereed articles where investigators made a science usage of data hosted in MAST. The publication rate over the last 50 yr shows that most MAST missions have had very high productivity during their in-service lifetimes and have remained so for years or decades afterward. Annual citations of these publications, a measure of impact on research, are robust for most missions, with citations that grow over more than a decade. Most of the citations come from about 10% of the articles within each mission. We examined the bibliographies of the active missions Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) in greater detail. For HST, the rate of archival publications exceeded those authored by the original observing teams within a decade of launch and is now more than 3 times higher. Early indications hint that JWST archival articles could dominate the publication rate even sooner. The production of articles resulting from any given observing program can extend for decades. Programs with small and very large allocations of observing time tend to be particularly productive per unit of observing time. For HST in general, a first publication appears within 1.5 yr for 50% of observing programs and within 3.8 yr for 80% of programs. We discuss various external factors that affect publication metrics, their strengths and limitations for measuring scientific impact, and the challenges of making meaningful comparisons of publication metrics across missions.

Specifically selected to leverage the unique ultraviolet capabilities of the Hubble Space Telescope, the Hubble Ultraviolet Legacy Library of Young Stars as Essential Standards (ULLYSES) is a Director’s Discretionary program of approximately 1000 orbits—the largest ever executed—that produced a UV spectroscopic library of O and B stars in nearby low-metallicity galaxies and accreting low-mass stars in the Milky Way. Observations from ULLYSES combined with archival spectra uniformly sample the fundamental astrophysical parameter space for each mass regime, including spectral type, luminosity class, and metallicity for massive stars, and the mass, age, and disk accretion rate for low-mass stars. The ULLYSES spectral library of massive stars will be critical to characterize how massive stars evolve at different metallicities; to advance our understanding of the production of ionizing photons, and thus of galaxy evolution and the re-ionization of the Universe; and to provide the templates necessary for the synthesis of integrated stellar populations. The massive-star spectra are also transforming our understanding of the interstellar and circumgalactic media of low-metallicity galaxies. On the low-mass end, UV spectra of T Tauri stars contain a plethora of diagnostics of accretion, winds, and the warm disk surface. These diagnostics are crucial for evaluating disk evolution and provide important input to assess atmospheric escape of planets and to interpret powerful probes of disk chemistry, as observed with the Atacama Large Millimeter Array and the James Webb Space Telescope. In this paper, we motivate the design of the program, describe the observing strategy and target selection, and present initial results.

We report the characterization of 28 low-mass (0.02 M ⊙ ≤ M 2 ≤ 0.25 M ⊙ ) companions to Kepler objects of interest (KOIs), eight of which were previously designated confirmed planets. These objects were detected as transiting companions to Sunlike stars (G and F dwarfs) by the Kepler mission and are confirmed as single-lined spectroscopic binaries in the current work using the northern multiplexed Apache Point Observatory Galactic Evolution Experiment near-infrared spectrograph (APOGEE-N) as part of the third and fourth Sloan Digital Sky Surveys. We have observed hundreds of KOIs using APOGEE-N and collected a total of 43,175 spectra with a median of 19 visits and a median baseline of ∼1.9 yr per target. We jointly model the Kepler photometry and APOGEE-N radial velocities to derive fundamental parameters for this subset of 28 transiting companions. The radii for most of these low-mass companions are overinflated (by ∼10%) when compared to theoretical models. Tidally locked M dwarfs on short-period orbits show the largest amount of inflation, but inflation is also evident for companions that are well separated from the host star. We demonstrate that APOGEE-N data provide reliable radial velocities when compared to precise high-resolution spectrographs that enable detailed characterization of individual systems and the inference of orbital elements for faint ( H > 12) KOIs. The data from the entire APOGEE-KOI program are public and present an opportunity to characterize an extensive subset of the binary population observed by Kepler.

Contemporary studies of exoplanet habitability use white-light measurements to calculate the ultraviolet (UV) effects of stellar flares, often by assuming a 9000K blackbody for the bolometric flare spectrum. We have combined TESS and archival GALEX photometry to test the UV predictions of white-light flare rates using the 9000K model. We have found that the UV predictions of white-light flare rates do not accurately reflect the NUV or FUV flaring activity of low-mass stars and are working to quantify the scale of this disconnect. UV Flares and Exoplanet Habitability Their intense optical and UV irradiation has given flares a pivotal role in the habitability of planets around low-mass stars. Flare UV emission can alter atmospheric chemistry [1], but may also provide the UV flux required for abiogenesis [2]. In order to fully assess the habitability of exoplanets around low-mass stars, accurate knowledge of the UV energies and occurrence rates of their flares is essential. Current habitability studies often use white-light flare rates from TESS to anchor or predict UV activity, often assuming a 9000K blackbody flare model [3]. This model lacks UV emission lines and underestimates the peak flare temperature, causing discrepancies between the UV predictions of white-light flare rates and the true UV flare activity. However, the scale of this disconnect is not yet fully understood and tests of the UV predictions of white-light rates are needed.

Kepler uydusu, esas gorevinin yaninda, orten ciftlerin de yuksek duyarlilikta isik egrilerini elde etmistir. Orten ciftlerin isik egrisi ve tayflarinin birlikte analizinden elde edilen dinamik kutle ve yaricaplarin duyarli ve dogru degerler olmasi, yildizlara iliskin teorik calismalarda kritik oneme sahiptir. Literaturde %2-3'ten daha duyarli dinamik kutle ve yaricapa sahip yildiz sayisi 250 kadardir. HET ve SDSS teleskoplarinda devam eden bir proje ile, dinamik kutle ve yaricaplari yuksek duyarlilik ile belirlenmis yeni sistemler literature kazandirilacaktir. Ozellikle K-M turu yildizlarin yuksek duyarlilikli kutle ve yaricap degerleri literaturde cok azdir. Bu nedenle, projeye alinan sistemler, ozellikle K-M turu bilesenlere sahip olan (olabilecek) sistemler arasindan secilmistir.

The Maunakea Spectroscopic Explorer (MSE) is a planned 11.25-m aperture facility with a 1.5 square degree field of view that will be fully dedicated to multi-object spectroscopy. A rebirth of the 3.6m Canada-France-Hawaii Telescope on Maunakea, MSE will use 4332 fibers operating at three different resolving powers (R ~ 2500, 6000, 40000) across a wavelength range of 0.36-1.8mum, with dynamical fiber positioning that allows fibers to match the exposure times of individual objects. MSE will enable spectroscopic surveys with unprecedented scale and sensitivity by collecting millions of spectra per year down to limiting magnitudes of g ~ 20-24 mag, with a nominal velocity precision of ~100 m/s in high-resolution mode. This white paper describes science cases for stellar astrophysics and exoplanet science using MSE, including the discovery and atmospheric characterization of exoplanets and substellar objects, stellar physics with star clusters, asteroseismology of solar-like oscillators and opacity-driven pulsators, studies of stellar rotation, activity, and multiplicity, as well as the chemical characterization of AGB and extremely metal-poor stars.

The Transiting Exoplanet Survey Satellite (TESS), launched in April 2018, is a planet finding mission much like the Kepler mission. Like Kepler, the TESS data pipeline returns a variety of data products, from light curves and target pixel files to large full frame images. Unlike Kepler, which took full frame images relatively infrequently, TESS takes them at a 30 minute cadence, making the TESS full frame images a large and incredibly valuable scientific dataset. As part of the Mikulski Archive for Space Telescope's (MAST) mission to provide high quality access to astronomical datasets, MAST has built an image cutout service for TESS full frame images. Users can request image cutouts in a variety of ways, and the returned target pixel files are TESS pipeline compatible. We present the use and design of this software, including both the technical considerations and user experience.

The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three year observing campaign on the Sloan 2.5-m Telescope, APOGEE has collected a half million high resolution (R 22,500), high S/N (>100), infrared (1.51-1.70 microns) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design—hardware, field placement, target selection, operations—and gives an overview of these aspects as well as the data reduction, analysis and products. An index is also given to the complement of technical papers that describe various critical survey components in detail. Finally, we discuss the achieved survey performance and illustrate the variety of potential uses of the data products by way of a number of science demonstrations, which span from time series analysis of stellar spectral variations and radial velocity variations from stellar companions, to spatial maps of kinematics, metallicity and abundance patterns across the Galaxy and as a function of age, to new views of the interstellar medium, the chemistry of star clusters, and the discovery of rare stellar species. As part of SDSS-III Data Release 12, all of the APOGEE data products are now publicly available.

We have used high-resolution spectroscopy to observe the Kepler-16 eclipsing binary as a double-lined system and measure precise radial velocities for both stellar components. These velocities yield a dynamical mass ratio of q = 0.2994 +/- 0.0031. When combined with the inclination, i = 90.degrees 3401(-0.0019)(+0.0016), measured from the Kepler photometric data by Doyle et al. (D11), we derive dynamical masses for the Kepler-16 components of M-A = 0.654 +/- 0.017 M-circle dot and M-B = 0.1959 +/- 0.0031 M-circle dot, a precision of 2.5% and 1.5%, respectively. Our results confirm at the similar to 2% level the mass-ratio derived by D11 with their photometric-dynamical model (PDM), q = 0.2937 +/- 0.0006. These are among the most precise spectroscopic dynamical masses ever measured for low-mass stars and provide an important direct test of the results from the PDM technique.