Search Publications
The Gaia-ESO survey: A spectroscopic study of the young open cluster NGC 3293
Gilmore, G.; Gosset, E.; Herrero, A. +24 more
We present a spectroscopic analysis of the GIRAFFE and UVES data collected by the Gaia-ESO survey for the young open cluster NGC 3293. Archive spectra from the same instruments obtained in the framework of the `VLT-FLAMES survey of massive stars' are also analysed. Atmospheric parameters, non-local thermodynamic equilibrium (LTE) chemical abundanc…
Hubble Space Telescope Observations of Active Asteroid P/2020 O1 (Lemmon-PANSTARRS)
Mutchler, Max; Jewitt, David; Agarwal, Jessica +3 more
We present Hubble Space Telescope observations of active asteroid P/2020 O1 taken to examine its development for a year after perihelion. We find that the mass loss peaks at ≲1 kg s-1 in 2020 August and then declines to nearly zero over four months. Long-duration mass loss (~180 days) is consistent with a sublimation origin, indicating …
Albedo variegation on Comet 67P/Churyumov-Gerasimenko
Buratti, Bonnie J.; Hicks, Michael D.; Davidsson, Björn J. R.
We here study the level of albedo variegation on the nucleus of Comet 67P/Churyumov-Gerasimenko. This is done by fitting the parameters of a standard photometric phase function model to disc-average radiance factor data in images acquired by the Rosetta/OSIRIS Narrow Angle Camera in the orange filter. Local discrepancies between the observed radia…
Impact of bar resonances in the velocity-space distribution of the solar neighbourhood stars in a self-consistent N-body Galactic disc simulation
Fujii, Michiko S.; Portegies Zwart, Simon; Baba, Junichi +3 more
The velocity-space distribution of the solar neighbourhood stars shows complex substructures. Most of the previous studies use static potentials to investigate their origins. Instead we use a self-consistent N-body model of the Milky Way, whose potential is asymmetric and evolves with time. In this paper, we quantitatively evaluate the similaritie…
An X-ray fading, UV brightening QSO at z ≈ 6
Bauer, F. E.; Brandt, W. N.; Vignali, C. +13 more
Explaining the existence of super massive black holes (SMBHs) with MBH ≳ 108 M⊙ at z ≳ 6 is a persistent challenge to modern astrophysics. Multiwavelength observations of z ≳ 6 quasi-stellar objects (QSOs) reveal that, on average, their accretion physics is similar to that of their counterparts at lower redshift. H…
Redshift space three-point correlation function of IGM at z < 0.48
Srianand, Raghunathan; Gaikwad, Prakash; Maitra, Soumak +1 more
Ly α forest decomposed into Voigt profile components allows us to study clustering properties of the intergalactic-medium and its dependence on various physical quantities. Here, we report the first detections of probability excess of low-z (i.e z < 0.48) Ly α absorber triplets over redshift-space scale of r∥ ≤ 8 pMpc (Mpc in physica…
An old warm Jupiter orbiting the metal-poor G-dwarf TOI-5542
Jordán, Andrés; Stassun, Keivan G.; Worters, Hannah L. +30 more
We report the discovery of a 1.32−0.10+0.10 MJup planet orbiting on a 75.12 day period around the G3V 10.8−3.6+2.1 Gyr old star TOI-5542 (TIC 466206508; TYC 9086-1210-1). The planet was first detected by the Transiting Exoplanet Survey Satellite (TESS) as a single transit event in TESS Sector …
Chemical Properties of the Local Disk and Halo. II. Abundances of 3745 M Dwarfs and Subdwarfs from Improved Model Fitting of Low-resolution Spectra
Nordlander, Thomas; Lépine, Sébastien; Hejazi, Neda
We present a model-fit pipeline to determine the stellar parameters of M-type dwarfs, which is an improvement on our previous work described in Hejazi et al. We apply this pipeline to analyze the low-resolution (R ~ 2000) spectra of 3745 M dwarfs/subdwarfs, collected at the MDM Observatory, Lick Observatory, Kitt Peak National Observatory, and Cer…
No swan song for Sun-as-a-star helioseismology: Performances of the Solar-SONG prototype for individual mode characterisation
Christensen-Dalsgaard, J.; García, R. A.; Grundahl, F. +5 more
The GOLF instrument on board SoHO has been in operation for almost 25 years, but the ageing of the instrument has now strongly affected its performance, especially in the low-frequency pressure-mode (p-mode) region. At the end of the SoHO mission, the ground-based network BiSON will remain the only facility able to perform Sun-integrated helioseis…
New CCD Astrometric Observations of Himalia Using Gaia DR2 in 2015-2021
Chen, Y.; Vienne, A.; Lin, F. R. +4 more
The long arc and high-quality astrometric measurements of outer irregular satellites are prerequisites for improving their orbital theories and increasing the precision of their ephemerides. In order to obtain good astrometric positions of Himalia, the largest irregular satellite of Jupiter, we have processed and reduced 911 ground-based CCD frame…