相关论文: A red giant orbiting a black hole
We examine ~10 years of photometric data and find that the black hole X-ray binary V4641 Sgr has two optical states, passive and active, during X-ray quiescence. The passive state is dominated by ellipsoidal variations and is stable in the…
We report the discovery of a new Kepler first-overtone RR Lyrae pulsator, KIC 2831097. The pulsation shows large, 0.1 d amplitude, systematic phase variations that can be interpreted as light travel-time effect caused by orbital motion in a…
We present JWST MIRI/NIRSpec observations of the extremely red quasar SDSS J165202.64+172852.3 at z~3, one of the most luminous quasars known to date, driving powerful outflows and hosting a clumpy starburst, amidst several interacting…
The star S0-2, which orbits the supermassive black hole (SMBH) in our Galaxy with a period of 16 years, provides the strongest constraint on both the mass of the SMBH and the distance to the Galactic center. S0-2 will soon provide the first…
Gl 758 B is a late-T dwarf orbiting a metal-rich Sun-like star at a projected separation of $\rho$ $\approx$ 1.6" (25 AU). We present four epochs of astrometry of this system with NIRC2 at Keck Observatory spanning 2010 to 2017 together…
The third data release of the Gaia mission (Gaia DR3) has enabled large-scale searches for dormant black hole and neutron star binaries with stellar companions at AU-scale separations. A recent study has proposed thousands of dormant black…
We report the discovery of a 16-20 Jupiter mass radial velocity companion around the very young (3 Myr) brown dwarf candidate ChaHa8. Based on high-resolution echelle spectra of ChaHa8 taken between 2000 and 2007 with UVES at the VLT, a…
Context: So far more than 60 substellar companions have been discovered around giant stars. These systems present physical and orbital properties that contrast to those detected orbiting less evolved stars. Aims: We are conducting a radial…
The recently claimed discovery of a massive ($M_\mathrm{BH}=68^{+11}_{-13}\,M_\odot$) black hole in the Galactic solar neighborhood has led to controversial discussions because it severely challenges our current view of stellar evolution. A…
We present radial-velocity (RV) measurements for the K giant $\nu$ Oph (= HIP88048, HD163917, HR6698), which reveal two brown dwarf companions with a period ratio close to 6:1. For our orbital analysis we use 150 precise RV measurements…
We have studied the future evolution of a recently discovered ULX source P13 in NGC7793. This source was shown to contain a 5-15$M_{\odot}$ black hole and a massive 18-23$M_{\odot}$ B9Ia companion on a 64 day orbit. For low black hole mass…
Lithium-rich red giants have been a long-standing mystery in stellar astrophysics. A leading theory to explain these chemically peculiar and rare objects is interactions with a close companion. To investigate their companion fraction, we…
The current theory predicts that hot subdwarf binaries are produced from evolved low-mass binaries that have undergone mass transfer and drastic mass loss during either a common envelope phase or a stable Roche lobe overflow while on the…
Context. The star-black hole (S-BH) binary known as Gaia BH3, discovered by the Gaia Collaboration is chemically and kinematically associated with the metal-poor ED-2 stream in the Milky Way halo. Aims. We explore the possibility that Gaia…
We present evidence for a new two-planet system around the giant star HD202696 (= HIP105056, BD+26 4118). The discovery is based on public HIRES radial velocity measurements taken at Keck Observatory between July 2007 and September 2014. We…
We have identified a star in the WASP archive photometry with an unusual lightcurve due to the total eclipse of a small, hot star by an apparently normal A-type star and with an orbital period of only 0.668d. From an analysis of the WASP…
The companion to the G0V star HR7672 directly imaged by Liu et al. (2002) has moved measurably along its orbit since the discovery epoch, making it possible to determine its dynamical properties. Originally targeted with adaptive optics…
Strongly irradiated giant planets are observed to have radii larger than thermal evolution models predict. Although these inflated planets have been known for over fifteen years, it is unclear whether their inflation is caused by deposition…
Several models have been proposed to explain missing red giants (RGs) near the Galactic centre. Recently, a scenario has been suggested that predicts, among other processes, a long-term ablation of the surface layers of RGs during their…
Owing to their similarities with giant exoplanets, brown dwarf companions of stars provide insights into the fundamental processes of planet formation and evolution. From their orbits, several brown dwarf companions are found to be more…