292 citations · 3.4k across the 115 of their papers we have counts for
116 papers
Identification of additional young nearby runaway stars based on Gaia data release 2 observations and the lithium test
R. Bischoff, M. Mugrauer, G. Torres +4
Runaway stars are characterised by their remarkably high space velocities, and the study of their formation mechanisms has attracted considerable interest. Young, nearby runaway st…
On the nature of the candidate T-Tauri star V501 Aurigae
M. Vaňko, G. Torres, L. Hambálek +18
We report new multi-colour photometry and high-resolution spectroscopic observations of the long-period variable V501 Aur, previously considered to be a weak-lined T-Tauri star bel…
KIC011764567: An evolved object showing substantial flare-activity
M. Kitze, A. A. Akopian, V. Hambaryan +2
We intensively studied the flare activity on the stellar object KIC011764567. The star was thought to be solar type, with a temperature of K, $\log(g) =…
Tycho Brahe, Abu Mashar, and the comet beyond Venus (ninth century A.D.)
Ralph Neuhaeuser, Paul Kunitzsch, Markus Mugrauer +2
From his observations of the A.D. 1572 super-nova and the A.D. 1577 comet, Tycho Brahe concluded that such transient celestial objects are outside the Earth's atmosphere, and he qu…
Interpretation of the historic Yemeni reports of supernova SN 1006: early discovery in mid-April 1006 ?
Ralph Neuhaeuser, Dagmar Neuhaeuser, Wafiq Rada +3
The recently published Yemeni observing report about SN 1006 from al-Yamani clearly gives AD 1006 Apr (mid-Rajab 396h) as first observation date. Since this is about 1.5…
Sunspot numbers based on historic records in the 1610s - early telescopic observations by Simon Marius and others
Ralph Neuhaeuser, Dagmar L. Neuhaeuser
Hoyt & Schatten (1998) claim that Simon Marius would have observed the sun from 1617 Jun 7 to 1618 Dec 31 (Gregorian calendar) all days, except three short gaps in 1618, but would…
An Arabic report about supernova SN 1006 by Ibn Sina (Avicenna)
Ralph Neuhaeuser, Carl Ehrig-Eggert, Paul Kunitzsch
We present here an Arabic report about supernova 1006 (SN 1006) written by the famous Persian scholar Ibn Sina (Lat. Avicenna, AD 980-1037), which was not discussed in astronomical…
The rotation period distributions of 4--10 Myr T Tauri stars in Orion OB1: New constraints on pre-main-sequence angular momentum evolution
Md. Tanveer Karim, Keivan G. Stassun, Cesar Briceno +15
Most existing studies of the angular momentum evolution of young stellar populations have focused on the youngest (1-3 Myr) T Tauri stars. In contrast, the angular momentum distrib…
Search for transiting exoplanets and variable stars in the open cluster NGC 7243
Z. Garai, T. Pribulla, L. Hambálek +23
We report results of the first five observing campaigns for the open stellar cluster NGC 7243 in the frame of project Young Exoplanet Transit Initiative (YETI). The project focuses…
Presumable European aurorae in the mid AD 770s were halo displays
Dagmar Neuhaeuser, Ralph Neuhaeuser
The interpretation of the strong 14-C variation around AD 775 as one (or several) solar super-flare(s) by, e.g., Usoskin et al. (2013) is based on alleged aurora sightings in the m…
Variations of 14-C around AD 775 and AD 1795 - due to solar activity
Ralph Neuhaeuser, Dagmar Neuhaeuser
The motivation for our study is the disputed cause for the strong variation of 14-C around AD 775. Our method is to compare the 14-C variation around AD 775 with other periods of s…
A review of East Asian reports of aurorae and comets circa AD 775
Jesse Chapman, Dagmar Neuhaeuser, Ralph Neuhaeuser +1
Given that a strong 14C variation in AD 775 has recently been suggested to be due to the largest solar flare ever recorded in history, it is relevant to investigate whether celesti…
Ground-based transit observations of the HAT-P-18, HAT-P-19, HAT-P-27/WASP-40 and WASP-21 systems
M. Seeliger, M. Kitze, R. Errmann +46
As part of our ongoing effort to investigate transit timing variations (TTVs) of known exoplanets, we monitored transits of the four exoplanets HAT-P-18b, HAT-P-19b, HAT-P-27b/WASP…
Supernova SN 1006 in two historic Yemeni reports
Wafiq Rada, Ralph Neuhaeuser
We present two Arabic texts of historic observations of supernova SN 1006 from Yemen as reported by al-Yamani and Ibn al-Dayba (14th to 16th century AD). An English translation of…
Newly found sunspot observations by Peter Becker from Rostock for 1708, 1709, and 1710
Ralph Neuhaeuser, Rainer Arlt, Elvira Pfitzner +1
We present a few newly found old sunspot observations from the years AD 1708, 1709, and 1710, which were obtained by Peter Becker from Rostock, Germany. For 1709, Becker gave a det…
Discovery of an OB Runaway Star Inside SNR S147
Baha Dinçel, Ralph Neuhäuser, Sinan Kaan Yerli +4
We present first results of a long term study: Searching for OB--type runaway stars inside supernova remnants (SNRs). We identified spectral types and measured radial velocities (R…
The companion candidate near Fomalhaut - a background neutron star?
Ralph Neuhaeuser, Markus Hohle, Christian Ginski +3
The directly detected planetary mass companion candidate close to the young, nearby star Fomalhaut is a subject of intense discussion. While the detection of common proper motion l…
On the GJ 436 planetary system
G. Maciejewski, A. Niedzielski, G. Nowak +4
The GJ 436 system contains a transiting planet GJ 436 b which is a hot analogue of Neptune on an eccentric orbit. Recently, two additional transiting sub-Earth planets have been po…
A direct imaging search for close stellar and sub-stellar companions to young nearby stars
Nikolaus Vogt, Markus Mugrauer, Ralph Neuhäuser +3
A total of 28 young nearby stars (ages ,Myr) have been observed in the K-band with the adaptive optics imager Naos-Conica of the Very Large Telescope at the Para…
Determination of a temporally and spatially resolved Supernova rate from OB-stars within 5kpc
J. G. Schmidt, M. M. Hohle, R. Neuhäuser
We spatially and temporally resolve the future Supernova (SN) rate in the Solar vicinity and the whole Galaxy by comparing observational parameters of massive stars with theoretica…
Astrometric follow-up observations of directly imaged sub-stellar companions to young stars and brown dwarfs
C. Ginski, T. O. B. Schmidt, M. Mugrauer +4
The formation of massive planetary or brown dwarf companions at large projected separations from their host star is not yet well understood. In order to put constraints on formatio…
A transient event in AD 775 reported by al-Tabari: A bolide - not a nova, supernova, or kilonova
Ralph Neuhaeuser, Paul Kunitzsch
Given that the cause for the strong increase in 14C in AD 774/5 in Japanese and German trees is still a matter of debate (e.g. short Gamma-Ray Burst or solar super-flare), we have…
New Radial Velocities for 30 Candidate Runaway Stars and a Possible Binary Supernova Origin for HIP 9470 and PSR J0152-1637
N. Tetzlaff, G. Torres, A. Bieryla +1
We report new radial velocity measurements for 30 candidate runaway stars. We revise their age estimates and compute their past trajectories in the Galaxy in order to determine the…
The Vela Pulsar With an Active Fallback Disk
Gökçe Özsükan, K. Yavuz Ekşi, Valeri Hambaryan +4
Fallback disks are expected to form around young neutron stars. The presence of these disks can be revealed by their blackbody spectrum in the infrared, optical and UV bands. We pr…