Related papers: HDE 245059: A Weak-Lined T Tauri Binary Revealed b…

We present the results of a high-resolution imaging survey of 22 brown dwarfs and very low mass stars in the nearby (~145 pc) young (~1-2 Myr) low-density star-forming region Taurus-Auriga. We obtained images with the Advanced Camera for…

We report the discovery of HE 0430-2457, the first extremely low-mass pre-white dwarf (ELM pre-WD) in a long period binary (P = 771 +- 3 d). The spectroscopic parameters of the primary are determined to be Teff = 26200 +- 1500 K and logg =…

Using high resolution near-infrared spectroscopy with the Keck telescope, we have detected the radial velocity signatures of the cool secondary components in four optically identified pre-main-sequence, single-lined spectroscopic binaries.…

We report the results of our radial-velocity monitoring of spectroscopic binary systems in a sample of X-ray sources from the ROSAT All Sky Survey south of the Taurus-Auriga star-forming region. The original sample of approximately 120…

We study the O-type star HD 161853, which has been noted as a probable double-lined spectroscopic binary system. We secured high-resolution spectra of HD 161853 during the past nine years. We separated the two components in the system and…

We have discovered that the extremely red, low-gravity L7 dwarf 2MASS J11193254-1137466 is a 0.14" (3.6 AU) binary using Keck laser guide star adaptive optics imaging. 2MASS J11193254-1137466 has previously been identified as a likely…

We present high resolution (R $\sim$ 44,000) UVES spectra of the eclipsing pre-main sequence star KH 15D covering the wavelength range 4780 to 6810 {\AA} obtained at three phases: out of eclipse, near minimum light and during egress. The…

We present the results of our study of the long-period eclipsing binary star \Aur. The results are based on spectroscopic data obtained with the UFES \'echelle spectrograph and photometric observations from TESS. The derived radial velocity…

New multi-color light curves of the very short period K-type eclipsing binary V1799 Ori were obtained and analyzed with the W-D code. The photometric solutions reveal that the system is a W-type shallow-contact binary with a mass ratio of…

We find the star HD 34700 to be a double-lined spectroscopic binary. We also identify it as a weak-line T Tauri object The spectra of both components are very similar and both show the Li I feature at 6708 \AA. Strong arguments in favour of…

We have discovered that the Halpha emission line star Haro 5-2, located in the 3-6 Myr old Ori OB1b association, is a young quadruple system. The system has a 2+2 configuration with an outer separation of 2.6 arcseconds and with resolved…

We present high-resolution X-ray spectra of the multiple (hierarchical quadruple) weak-lined T Tauri star system HD 98800, obtained with the High Energy Transmission Gratings Spectrograph (HETGS) aboard the Chandra X-ray Observatory (CXO).…

Stellar-substellar binary systems are quite rare, and provide interesting benchmarks. They constrain the complex physics of substellar atmospheres, because several physical parameters of the substellar secondary can be fixed from the much…

Re-observations with the H.E.S.S. telescope array of the very-high-energy (VHE) source HESS J1018-589 A coincident with the Fermi-LAT $\gamma$-ray binary 1FGL J1018.6-5856 have resulted in a source detection significance of more than…

We present new Spitzer IRAC/PU/MIPS photometry from 3.6 to 24 um, and new Gemini GMOS photometry at 0.48 um, of the young brown dwarf eclipsing binary 2MASS J05352184-0546085, located in the Orion Nebula Cluster. No excess disk emission is…

As part of our continuing campaign to measure the masses of pre-main sequence stars dynamically and thus to assess the reliability of the discrepant theoretical calculations of contraction to the main sequence, we present new results for…

The young system RX J0529.3+1210 was initially identified as a single-lined spectroscopic binary. Using high-resolution infrared spectra, acquired with NIRSPEC on Keck II, we measured radial velocities for the secondary. The method of using…

The H$\alpha$ profile varies with the orbital period. The two strong shell type emission peaks are identified as from one single broad emission feature with an absorption centered around -7.5~\kms. The intensity variations are largely…

The star HII 2407 is a member of the relatively young Pleiades star cluster and was previously discovered to be a single-lined spectroscopic binary. It is newly identified here within $Kepler$/$K2$ photometric time series data as an…

IRAS~04158+2805 has long been thought to be a very low mass T-Tauri star (VLMS) surrounded by a nearly edge-on, extremely large disc. Recent observations revealed that this source hosts a binary surrounded by an extended circumbinary disc…