- ID:
- ivo://CDS.VizieR/J/AJ/142/73
- Title:
- NAO Rozhen CCD measurements of multiple stars
- Short Name:
- J/AJ/142/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the 2m telescope of the Bulgarian National Astronomical Observatory at Rozhen, observations of 145 double or multiple stars were carried out during three nights on 2010 September 7-9. This is the fifth series of measurements of CCD frames of double and multiple stars obtained at Rozhen. In this paper, we present the results for the position angle and angular separation for 202 pairs and residuals for 45 pairs with published orbital elements or linear solutions. These observations have angular separations in the range 1.150"-196.372", with a median angular separation of 57.906". Three linear solutions are presented for the first time and three orbits are recalculated (one pair has both a linear fit and an orbital solution).
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- ID:
- ivo://CDS.VizieR/J/MNRAS/457/2192
- Title:
- NCJM catalog of M dwarfs
- Short Name:
- J/MNRAS/457/2192
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We develop a method to identify the spectroscopic signature of unresolved L-dwarf ultracool companions, which compares the spectra of candidates and their associated control stars using spectral ratio differences and residual spectra. We present SpeX prism-mode spectra (0.7-2.5 micron) for a pilot sample of one hundred and eleven mid M dwarfs, including twenty-eight which were previously identified as candidates for unresolved ultracool companionship (a sub-sample from Cook et al. 2016; paper 1) and eighty-three single M dwarfs which were optically colour-similar to these candidates (which we use as `control stars'). We identify four candidates with evidence for near-infrared excess. One of these (WISE J100202.50+074136.3) shows strong evidence for an unresolved L dwarf companion in both its spectral ratio difference and its residual spectra, two most likely have a different source for the near-infrared excess, and the other may be due to spectral noise. We also establish expectations for a null result (i.e. by searching for companionship signatures around the M dwarf control stars), as well as determining the expected outcome for ubiquitous companionship (as a means of comparison with our actual results), using artificially generated unresolved M+L dwarf spectra. The results of these analyses are compared to those for the candidate sample, and reasonable consistency is found. With a full follow-up program of our candidates sample from paper 1, we might expect to confirm up to 40 such companions in the future, adding extensively to the known desert population of M3-M5 dwarfs.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/68.53
- Title:
- Nearby multiple Speckle interferometry. V.
- Short Name:
- J/other/AstBu/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of speckle interferometric observations of 194 binary stars performed at the BTA 6m telescope in 2002-2006 are presented in this paper. For speckle observations we used filters with central wavelengths from 545 to 800nm and speckle camera with the fast CCD coupled with a tree-chamber intensifier. The most part of the observed systems (80 stars) - pairs, which binarity was discovered by Hipparcos satellite fo the first time. And the other stars are visual binaries and interferometric binary systems which orbital periods estimates from several to ten of the year. The pairs with slow orbital motion are included to the observation list, also. They are used for position parameters calibrations.
- ID:
- ivo://CDS.VizieR/J/A+A/422/627
- Title:
- Nearby multiple stars speckle interferometry
- Short Name:
- J/A+A/422/627
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is a continuation of diffraction-limited speckle interferometry of binary and multiple stars carried out at the 6-m telescope of the Special Astrophysical Observatory in Zelenchuk. The program has concentrated on nearby ({pi}>10mas) close binaries discovered or measured during the Hipparcos mission. Here, we present 132 measurements of relative positions and magnitude differences for 99 pairs and 8 measurements for 6 triple systems. 54 entries in the paper are new Hipparcos binaries. New triple systems with late-type dwarf components, discovered in the course of observations, are HIP 8533 and HIP 25354.
- ID:
- ivo://CDS.VizieR/J/A+A/422/1023
- Title:
- Nearby visual double stars UBVRI photometry
- Short Name:
- J/A+A/422/1023
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present accurate CCD astrometric and photometric data for 31 nearby visual double stars in the standard filters BVRI. The observations were collected with a 1.3-m telescope in 2001-2002. The results consist of relative astrometric positions (epoch, angular separation and position angle) and differential BVRI photometry of the components. Mean errors are: 0.01" for the separation; 0.06{deg} for the position angle; and 0.015mag for the photometric data. Comparing the relative positions at different epochs, we evaluate the physical association of the systems. We additionally derive fractional masses and true separations for the most probable binary systems and, whenever orbits are available, also total and component masses.
- ID:
- ivo://CDS.VizieR/J/A+A/564/A6
- Title:
- Near-infrared emission from the dayside of WASP-5b
- Short Name:
- J/A+A/564/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- WASP-5b is a highly irradiated dense hot Jupiter orbiting a G4V star every 1.6 days. We observed two secondary eclipses of WASP-5b in the J, H and K bands simultaneously. Thermal emission of WASP-5b is detected in the J and K bands. The retrieved planet-to-star flux ratios in the J and K bands are 0.168 +0.050/-0.052% and 0.269+/-0.062%, corresponding to brightness temperatures of 2996 +212/-261K and 2890 +246/-269K, respectively. No thermal emission is detected in the H band, with a 3-sigma upper limit of 0.166%, corresponding to a maximum temperature of 2779K. On the whole, our J, H, K results can be explained by a roughly isothermal temperature profile of ~2700K in the deep layers of the planetary dayside atmosphere that are probed at these wavelengths. Together with Spitzer observations, which probe higher layers that are found to be at ~1900K, a temperature inversion is ruled out in the range of pressures probed by the combined data set. While an oxygen-rich model is unable to explain all the data, a carbon-rich model provides a reasonable fit but violates energy balance.
- ID:
- ivo://CDS.VizieR/J/AJ/153/25
- Title:
- Near-infrared observations of 84 KOI systems
- Short Name:
- J/AJ/153/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We determine probabilities of physical association for stars in blended Kepler Objects of Interest (KOIs), and find that 14.5%_-3.4%_^+3.8%^ of companions within ~4'' are consistent with being physically unassociated with their primary. This produces a better understanding of potential false positives in the Kepler catalog and will guide models of planet formation in binary systems. Physical association is determined through two methods of calculating multi-band photometric parallax using visible and near-infrared adaptive optics observations of 84 KOI systems with 104 contaminating companions within ~4''. We find no evidence that KOI companions with separations of less than 1'' are more likely to be physically associated than KOI companions generally. We also reinterpret transit depths for 94 planet candidates, and calculate that 2.6%+/-0.4% of transits have R>15R_{oplus}_, which is consistent with prior modeling work.
- ID:
- ivo://CDS.VizieR/J/A+A/376/982
- Title:
- Near-IR observations of young binaries
- Short Name:
- J/A+A/376/982
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using near-infrared speckle interferometry we have obtained resolved JHK-photometry for the components of 58 young binary systems.
- ID:
- ivo://CDS.VizieR/J/A+A/559/A33
- Title:
- Near-IR Spectrophotometry of GJ 3470b
- Short Name:
- J/A+A/559/A33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This work presents time-series relative photometry of the planet-hosting star GJ 3470 during the transit of its 14 Earth-mass planet. Observations were obtained with the MOSFIRE near-infrared spectrograph from 2.09-2.36 micron, both in one single band and in six smaller bands. Reduction of the observations is described in the associated paper.
- ID:
- ivo://CDS.VizieR/V/144
- Title:
- Near-IR spectroscopy of low-mass binaries and brown dwarfs
- Short Name:
- V/144
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mass of a star at formation determines its subsequent evolution and demise. Low-mass stars are the most common products of star formation and their long main-sequence lifetimes cause them to accumulate over time. Star formation also produces many substellar-mass objects known as brown dwarfs, which emerge from their natal molecular clouds and continually cool as they age, pervading the Milky Way. Low-mass stars and brown dwarfs exhibit a wide range of physical characteristics and their abundance make them ideal subjects for testing formation and evolution models. I have examined a pair of pre-main sequence spectroscopic binaries and used radial velocity variations to determine orbital solutions and mass ratios. Additionally, I have employed synthetic spectra to estimate their effective temperatures and place them on theoretical Hertzsprung-Russell diagrams. From this analysis I discuss the formation and evolution of young binary systems and place bounds on absolute masses and radii. I have also studied the late-type T dwarfs revealed by the Wide-field Infrared Survey Explorer (WISE). This includes the exemplar T8 subdwarf Wolf 1130C, which has the lowest inferred metallicity in the literature and spectroscopic traits consistent with old age. Comparison to synthetic spectra implies that the dispersion in near-infrared colors of late-type T dwarfs is a result of age and/or thin sul de clouds. With the updated census of the L, T, and Y dwarfs we can now study specific brown dwarf subpopulations. Finally, I present a number of future studies that would develop our understanding of the physical qualities of T dwarf color outliers and disentangle the tracers of age and atmospheric properties. The thesis is available at: http://www.astro.ucla.edu/~gmace/thesis.html
