scholarly journals Detection of the Irradiated Red Dwarf in WY Sge (Nova 1783)

1996 ◽  
Vol 158 ◽  
pp. 327-328
Author(s):  
M. W. Somers ◽  
K. Mukai ◽  
T. Naylor ◽  
F.A. Ringwald
Keyword(s):  
Optical Spectroscopy ◽  
White Dwarf ◽  
Type Star ◽  
Sufficient Information ◽  
Late Type ◽  
Dwarf Novae ◽  
System A ◽  
Late Type Star ◽  
The Face ◽  
Ir Photometry

AbstractWe present infrared (IR) photometry and optical spectroscopy of the eclipsing old nova WY Sge. According to hibernation theorists the disc in a system a few centuries after outburst should be significantly fainter than in other, more recent, old novae but similar to the discs of dwarf novae in quiescence. Despite the apparent faintness of the late type star we have sufficient information to infer that the face closest to the white dwarf (WD) is irradiated.

scholarly journals Evidence of a Low-Mass Companion to AB Doradus

1998 ◽  
Vol 164 ◽  
pp. 325-326
Author(s):  
J. C. Guirado ◽  
J. E. Reynolds ◽  
J.-F. Lestrade ◽  
R. A. Preston ◽  
D. L. Jauncey ◽  
...  
Keyword(s):  
Satellite Data ◽  
Main Sequence ◽  
Brown Dwarfs ◽  
Type Star ◽  
Late Type ◽  
Hydrogen Burning ◽  
Late Type Star ◽  
Low Mass

AbstractFrom the combination of VLBI phase-referenced observations and Hipparcos satellite data, we have found evidence of a low-mass object orbiting the late-type star AB Doradus. The mass of the new object is near the hydrogen burning limit and will constitute a precise point for calibrating the low end of the main sequence. This represents the first detection of a low-mass stellar companion using the VLBI technique, which could become an important tool in future searches for planets and brown dwarfs orbiting other stars.

scholarly journals A SUPER-JUPITER ORBITING A LATE-TYPE STAR: A REFINED ANALYSIS OF MICROLENSING EVENT OGLE-2012-BLG-0406

2014 ◽  
Vol 782 (1) ◽  
pp. 48 ◽  
Author(s):  
Y. Tsapras ◽  
J.-Y. Choi ◽  
R. A. Street ◽  
C. Han ◽  
V. Bozza ◽  
...  
Keyword(s):  
Type Star ◽  
Late Type ◽  
Late Type Star

scholarly journals Doppler imaging of the young late-type star LO Pegasi (BD+22°4409) in 2003 September

2008 ◽  
Vol 387 (1) ◽  
pp. 237-246 ◽  
Author(s):  
N. Piluso ◽  
A. F. Lanza ◽  
I. Pagano ◽  
A. C. Lanzafame ◽  
J.-F. Donati
Keyword(s):  
Doppler Imaging ◽  
Type Star ◽  
Late Type ◽  
Late Type Star

A Late-Type Star of Very Large Radial Velocity

1956 ◽  
Vol 68 ◽  
pp. 533 ◽  
Author(s):  
George W. Preston ◽  
William P. Bidelman
Keyword(s):  
Radial Velocity ◽  
Type Star ◽  
Late Type ◽  
Late Type Star

scholarly journals Chromospheric activity on late-type star DM UMa using high-resolution spectroscopic observations

2016 ◽  
Vol 459 (1) ◽  
pp. 854-862 ◽  
Author(s):  
LiYun Zhang ◽  
QingFeng Pi ◽  
Xianming L. Han ◽  
Liang Chang ◽  
Daimei Wang
Keyword(s):  
High Resolution ◽  
Type Star ◽  
Late Type ◽  
Spectroscopic Observations ◽  
Chromospheric Activity ◽  
Late Type Star

scholarly journals MASCARA-3b

2019 ◽  
Vol 631 ◽  
pp. A76 ◽  
Author(s):  
M. Hjorth ◽  
S. Albrecht ◽  
G. J. J. Talens ◽  
F. Grundahl ◽  
A. B. Justesen ◽  
...  
Keyword(s):  
Circular Orbit ◽  
Radial Velocities ◽  
Type Star ◽  
Late Type ◽  
Spectroscopic Measurements ◽  
Type Host ◽  
Late Type Star ◽  
Velocity Anomalies ◽  
The Mean

We report the discovery of MASCARA-3b, a hot Jupiter orbiting its bright (V = 8.33) late F-type host every 5.55149 ± 0.00001 days in an almost circular orbit (e = 0.050−0.017+0.020). This is the fourth exoplanet discovered with the Multi-site All-Sky CAmeRA (MASCARA), and the first of these that orbits a late-type star. Follow-up spectroscopic measurements were obtained in and out of transit with the Hertzsprung SONG telescope. Combining the MASCARA photometry and SONG radial velocities reveals a radius and mass of 1.36 ± 0.05 RJup and 4.2 ± 0.2 MJup. In addition, SONG spectroscopic transit observations were obtained on two separate nights. From analyzing the mean out-of-transit broadening function, we obtain v sin i⋆ = 20.4 ± 0.4 km s−1. In addition, investigating the Rossiter-McLaughlin effect, as observed in the distortion of the stellar lines directly and through velocity anomalies, we find the projected obliquity to be λ = 1.2−7.4+8.2 deg, which is consistent with alignment.

Magnetic White Dwarfs in Binary Systems

1982 ◽  
Vol 4 (4) ◽  
pp. 328-334 ◽  
Author(s):  
D.T. Wickramasinghe
Keyword(s):  
Standard Model ◽  
White Dwarfs ◽  
Binary Systems ◽  
Cataclysmic Variables ◽  
Accretion Disc ◽  
Type Star ◽  
Close Binary ◽  
Late Type ◽  
The Standard Model ◽  
Late Type Star

The cataclysmic variables are close binary systems consisting of a late type star and a collapsed star, usually a white dwarf, undergoing mass exchange. According to the standard model, the late type star (the secondary) fills its Roche lobe and material escaping from the inner Lagrangian point is transferred to the primary by means of a mass transfer stream and an accretion disc. The spectroscopic and photometric properties of most cataclysmic variables can be understood in terms of radiation from the various components of such a system, with the accretion disc usually dominating in the optical region (see Warner (1976) for a review). However, recently a new class of cataclysmic variables has been discovered with distinctive optical properties that are inexplicable in terms of the standard model. These systems known as the AM Herculis type variables have provided the first direct evidence for the presence of strong magnetic fields in the white dwarfs of some cataclysmic variables. We present here a review of some of the important properties of these variables with emphasis on the unique system VV Puppis which has provided the first unequivocal evidence for high harmonic cyclotron radiation from white dwarfs.

scholarly journals The Benefit of Archival Research in Investigating Dwarf Novae

1995 ◽  
Vol 151 ◽  
pp. 282-284
Author(s):  
C. la Dous
Keyword(s):  
Accretion Disk ◽  
White Dwarf ◽  
Cataclysmic Variables ◽  
Physical Parameters ◽  
Late Type ◽  
Dwarf Novae ◽  
Interested Reader ◽  
Entire Class ◽  
Short Period ◽  
Individual Observation

Dwarf novae and nova-like stars are a sub-group of the class of cataclysmic variables. Most of these stars show high and low brightness states (maxima or outbursts and minima or quiescent states, respectively). They all are short-period interacting binaries consisting of a white dwarf primary, a late-type Roche-lobe filling secondary, and an accretion disk around the white dwarf. For details on observations of cataclysmic variables and their theoretical explanations and modelling, the interested reader is referred to recent reviews.The main problem when trying to understand these systems is the wealth of patterns presented by the whole group: no two objects are nearly identical and it is hard to say which the ‘typical’ features are. As a result of this, from an individual observation, or from observations of a few systems only, it is not possible to decide which of the observed features are characteristic of the entire class, and which are specific of individual members. The only way is to investigate many different members of the same class, arrange them according to their different physical parameters, and try to determine what the general characteristics are.

scholarly journals 86 GHz VLBI Imaging of the SiO Masers in VX Sgr

1998 ◽  
Vol 164 ◽  
pp. 363-364
Author(s):  
S. S. Doeleman ◽  
C. J. Lonsdale ◽  
L. J. Greenhill
Keyword(s):  
Spectral Line ◽  
Velocity Gradient ◽  
Linear Velocity ◽  
Rigid Rotation ◽  
Type Star ◽  
Circumstellar Envelope ◽  
Late Type ◽  
Maser Emission ◽  
Late Type Star

AbstractWe present the first 86 GHz spectral line VLBI map. Strong SiO masers in the late type star VX Sgr are mapped with a relative astrometry of 0.15 mas revealing an irregular ring of maser emission that echos structure seen at 43 GHz. A surprising feature of this map is the detection of a large (0.5 km s−1 AU−1 ) linear velocity gradient that can be interpreted as rigid rotation of the circumstellar envelope.

scholarly journals Discovery of a Reflection Dust Envelope Around IRC+10216

1988 ◽  
Vol 108 ◽  
pp. 181-182
Author(s):  
M. Tamura ◽  
T. Hasegawa ◽  
N. Ukita ◽  
I. Gatley ◽  
I. S. McLean ◽  
...  
Keyword(s):  
United Kingdom ◽  
Stray Light ◽  
Type Star ◽  
Good Measure ◽  
Degree Of Polarization ◽  
Great Care ◽  
Late Type ◽  
Dust Envelope ◽  
Infrared Telescope ◽  
Late Type Star

Infared polarimetric and photometric mapping observations at K(2.2 μm) and H(1.65 μm) have revealed an extended dust envelope around the late-type star IRC+10216. The observations were made on the 3.8-m United Kingdom Infrared Telescope on Mauna Kea, Hawaii, in 1985 December and 1987 January and February. The polarization observations were made by emplying the Kyoto polarimeter (Sato et al. 1987). Great care was taken to check the contamination by stray light in the telescope and instruments as the source on peak was extremely bright (K~0 mag). From the observations of normal stars, we found that the polarized intensity (degree of polarization times the intensity) was a good measure of the envelope, free from contamination by stray light, although the intensity and the degree of polarization suffered from the contamination separately.

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