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G. Maciejewski,
D. Dimitrov,
M. Seeliger,
St. Raetz,
L. Bukowiecki,
M. Kitze,
R. Errmann,
G. Nowak,
A. Niedzielski,
V. Popov, [......],
G. Corfini,
H. Takahashi,
K. Tachihara,
J. M. Benko,
K. Sarneczky,
Gy. M. Szabo,
T. N. Varga,
M. Vanko,
Y. C. Joshi,
W. P. Chen
[show abstract]
[hide abstract]
ABSTRACT: The transiting planet WASP-12 b was identified as a potential target for
transit timing studies because a departure from a linear ephemeris was reported
in the literature. Such deviations could be caused by an additional planet in
the system. We attempt to confirm the existence of claimed variations in
transit timing and interpret its origin. We organised a multi-site campaign to
observe transits by WASP-12 b in three observing seasons, using 0.5-2.6-metre
telescopes. We obtained 61 transit light curves, many of them with
sub-millimagnitude precision. The simultaneous analysis of the best-quality
datasets allowed us to obtain refined system parameters, which agree with
values reported in previous studies. The residuals versus a linear ephemeris
reveal a possible periodic signal that may be approximated by a sinusoid with
an amplitude of 0.00068+/-0.00013 d and period of 500+/-20 orbital periods of
WASP-12 b. The joint analysis of timing data and published radial velocity
measurements results in a two-planet model which better explains observations
than single-planet scenarios. We hypothesize that WASP-12 b might be not the
only planet in the system and there might be the additional 0.1 M_Jup body on a
3.6-d eccentric orbit. A dynamical analysis indicates that the proposed
two-planet system is stable over long timescales.
Astronomy and Astrophysics 01/2013; · 4.59 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: We present follow-up high-contrast imaging data of PZ Tel B, the substellar companion of a solar analogue pre-main-sequence star and member of the approximately 12-Myr-old β Pic moving group. Between 2010 October and 2011 June, we observed PZ Tel in three observing epochs with NACO/ESO-VLT, which proves the companionship of PZ Tel B on a very high significance level and shows that the photometry of the PZ Tel system is stable on the 10 per cent level. The orbital motion of PZ Tel B relative to its primary is clearly detected between all observing epochs, and we even find evidence for deceleration of its orbital motion, as expected for an object on a Keplerian orbit moving towards its apastron.
We also present new photometric measurements of PZ Tel just recently obtained by WISE, which clearly confirm that there is no excess emission in the spectral energy distribution (SED) of the star up to 24 μ m, while a prominent excess is detected at 70 μm with MIPS/Spitzer.
To quantify the orbit elements of the PZ Tel system, we applied a least-squares Monte Carlo (LSMC) fit on all astrometric measures taken with NACO. The results of the performed LSMC fit are that one cannot yet determine a single 'best'-fitting orbital solution, due to the poor astrometric coverage of the orbit. However, the obtained good LSMC solutions (χ red 2≤2) give an overview of the distributions and correlations of all orbit elements. According to our LSMC fit, PZ Tel is an eccentric binary (e ≳ 0.6), and the orbit elements degenerate with growing eccentricity.
For e < 0.95, the PZ Tel system is seen nearly edge-on (92° ≲ i ≲ 110°), has a longitude of the ascending node of 50° ≲ Ω ≲ 65°, an argument of periastron 170° ≲ ω ≲ 290° and exhibits a semimajor axis a larger than about 20 au, with the highest peak in the a-histogram located at about 25 au (or about 110 yr of orbital period), up to a few tens of au, as orbital solutions with a significantly larger semimajor axis would not be able to harbour a circumbinary disc which excites the observed excess in the SED of PZ Tel A.
Monthly Notices of the Royal Astronomical Society 08/2012; · 4.90 Impact Factor
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T. Pribulla,
M. Vaňko,
M. Ammler - von Eiff,
M. Andreev,
A. Aslantürk,
N. Awadalla,
D. Baluďanský,
A. Bonanno,
H. Božić,
G. Catanzaro, [......],
J. Schulz,
H. V. Şenavcı,
T. Szalai,
P. Székely,
D. Sudar,
C. T. Tezcan,
M. E. Törün,
V. Turcu,
O. Vince,
M. Zejda
[show abstract]
[hide abstract]
ABSTRACT: We present a new observational campaign, DWARF, aimed at detection of
circumbinary extrasolar planets using the timing of the minima of low-mass
eclipsing binaries. The observations will be performed within an extensive
network of relatively small to medium-size telescopes with apertures of ~20-200
cm. The starting sample of the objects to be monitored contains (i) low-mass
eclipsing binaries with M and K components, (ii) short-period binaries with sdB
or sdO component, and (iii) post-common-envelope systems containing a WD, which
enable to determine minima with high precision. Since the amplitude of the
timing signal increases with the orbital period of an invisible third
component, the timescale of project is long, at least 5-10 years. The paper
gives simple formulas to estimate suitability of individual eclipsing binaries
for the circumbinary planet detection. Intrinsic variability of the binaries
(photospheric spots, flares, pulsation etc.) limiting the accuracy of the
minima timing is also discussed. The manuscript also describes the best
observing strategy and methods to detect cyclic timing variability in the
minima times indicating presence of circumbinary planets. First test
observation of the selected targets are presented.
06/2012;
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[show abstract]
[hide abstract]
ABSTRACT: Analyzing exoplanets detected by radial velocity or transit observations, we
determine the multiplicity of exoplanet host stars in order to study the
influence of a stellar companion on the properties of planet candidates.
Matching the host stars of exoplanet candidates detected by radial velocity or
transit observations with online multiplicity catalogs in addition to a
literature search, 57 exoplanet host stars are identified having a stellar
companion. The resulting multiplicity rate of at least 12 percent for exoplanet
host stars is about four times smaller than the multiplicity of solar like
stars in general. The mass and the number of planets in stellar multiple
systems depend on the separation between their host star and its nearest
stellar companion, e.g. the planetary mass decreases with an increasing stellar
separation. We present an updated overview of exoplanet candidates in stellar
multiple systems, including 15 new systems (compared to the latest summary from
2009).
Astronomy and Astrophysics 04/2012; · 4.59 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The star-forming regions in Chamaeleon are one of the nearest (distance ~165
pc) and youngest (age ~2 Myrs) conglomerates of recently formed stars and the
ideal target for population studies of star formation. We investigate a total
of 16 Cha targets, which have been suggested, but not confirmed as binaries or
multiple systems in previous literature. We used the adaptive optics instrument
Naos-Conica (NACO) at the Very Large Telescope Unit Telescope 4 of the Paranal
Observatory, at 2-5 different epochs, in order to obtain relative and absolute
astrometric measurements, as well as differential photometry in the J, H, and K
band. On the basis of known proper motions and these observations, we analyse
the astrometric results in our "Proper Motion Diagram" (PMD: angular separation
/ position angle versus time), to eliminate possible (non-moving) background
stars, establish co-moving binaries and multiples, and search for curvature as
indications for orbital motion. All previously suggested close components are
co-moving and no background stars are found. The angular separations range
between 0.07 and 9 arcseconds, corresponding to projected distances between the
components of 6-845 AU. Thirteen stars are at least binaries and the remaining
three (RX J0919.4-7738, RX J0952.7-7933, VW Cha) are confirmed high-order
multiple systems with up to four components. In 13 cases, we found significant
slopes in the PMDs, which are compatible with orbital motion whose periods
range from 60 to 550 years. However, in only four cases there are indications
of a curved orbit, the ultimate proof of a gravitational bond. Massive primary
components appear to avoid the simultaneous formation of equal-mass secondary
components. (abridged)
Astronomy and Astrophysics 04/2012; · 4.59 Impact Factor
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The YETI Collaboration,
W. P. Chen,
S. C. -L. Hu,
R. Errmann,
Ch. Adam,
S. Baar,
A. Berndt,
L. Bukowiecki,
D. P. Dimitrov,
T. Eisenbeiß, [......],
C. Briceño,
R. Chini,
E. L. N. Jensen,
E. H. Nikogossian,
A. K. Pandey,
J. Sperauskas,
H. Takahashi,
F. M. Walter,
Z. -Y. Wu,
X. Zhou
[show abstract]
[hide abstract]
ABSTRACT: GM Cep in the young (~4 Myr) open cluster Trumpler 37 has been known to be an
abrupt variable and to have a circumstellar disk with very active accretion.
Our monitoring observations in 2009-2011 revealed the star to show sporadic
flare events, each with brightening of < 0.5 mag lasting for days. These
brightening events, associated with a color change toward the blue, should
originate from an increased accretion activity. Moreover, the star also
underwent a brightness drop of ~1 mag lasting for about a month, during which
the star became bluer when fainter. Such brightness drops seem to have a
recurrence time scale of a year, as evidenced in our data and the photometric
behavior of GM Cep over a century. Between consecutive drops, the star
brightened gradually by about 1 mag and became blue at peak luminosity. We
propose that the drop is caused by obscuration of the central star by an
orbiting dust concentration. The UX Orionis type of activity in GM Cep
therefore exemplifies the disk inhomogeneity process in transition between
grain coagulation and planetesimal formation in a young circumstellar disk.
The Astrophysical Journal 03/2012; · 6.02 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: To understand the influence of additional wide stellar companions on planet
formation, it is necessary to determine the fraction of multiple stellar
systems amongst the known extrasolar planet population. We target recently
discovered radial velocity exoplanetary systems observable from the northern
hemisphere and with sufficiently high proper motion to detect stellar
companions via direct imaging. We utilize the Calar Alto 2.2m telescope in
combination with its lucky imaging camera AstraLux. 71 planet host stars have
been observed so far, yielding one new low-mass (0.239 \pm 0.022M\odot) stellar
companion, 4.5 arcsec (227AU of projected separation) northeast of the planet
host star HD185269, detected via astrometry with AstraLux. We also present
follow-up astrometry on three previously discovered stellar companions, showing
for the first time common proper motion of the 0.5 arcsec companion to
HD126614. Additionally, we determined the achieved detection limits for all
targets, which allows us to characterize the detection space of possible
further companions of these stars.
02/2012;
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M Moualla,
T ~O ~B Schmidt,
R Neuhäuser,
V ~V Hambaryan,
R Errmann,
L Trepl,
C Broeg,
T Eisenbeiss, M Mugrauer,
C Marka, [......],
T Pribulla,
S Rätz,
J Schmidt,
A Berndt,
G Maciejewski,
T Röll,
M ~M Hohle,
N Tetzlaff,
S Fiedler,
S Baar
[show abstract]
[hide abstract]
ABSTRACT: We present a new flare star, which was discovered during our survey on a
selected field at the edge of the Pleiades cluster. The field was observed in
the period 2007 - 2010 with three different CCD-cameras at the University
Observatory Jena with telescopes from 25 to 90 cm. The flare duration is almost
one hour with an amplitude in the R-band of about 1.08 mag. The location of the
flare star in a color-magnitude diagram is consistent with age and distance of
the Pleiades. In the optical PSF of the flare star there are two 2MASS objects
(unresolved in most images in the optical Jena PSF), so it is not yet known
which one of them is responsible for this flare. The BVRIJHK colors yield
spectral types of M1 and M2 with extinction being A_V=0.231+/-0.024 mag and
A_V=0.266+/-0.020 for those two stars, consistent with the Pleiades cluster.
Astronomische Nachrichten 08/2011; 332:661. · 1.01 Impact Factor
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S Raetz, M Mugrauer,
T ~O ~B Schmidt,
T Roell,
T Eisenbeiss,
M Vav nko,
A Koeltzsch,
M ~M Hohle,
C Ginski,
C Marka,
M Moualla,
N Tetzlaff,
A Reithe,
W Rammo,
S Fiedler,
J Koppenhoefer,
R Neuhäuser
European Physical Journal Web of Conferences; 07/2011
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R. Neuhäuser,
R. Errmann,
A. Berndt,
G. Maciejewski,
H. Takahashi,
W.P. Chen,
D.P. Dimitrov,
T. Pribulla,
E.H. Nikogossian,
E.L.N. Jensen, [......],
E. Schmidt,
M.M. Hohle,
M. Kitze,
N. Chakrova,
C. Gräfe,
K. Schreyer,
V.V. Hambaryan,
C.H. Broeg,
J. Koppenhoefer,
A.K. Pandey
[show abstract]
[hide abstract]
ABSTRACT: We present the Young Exoplanet Transit Initiative (YETI), in which we use several 0.2 to 2.6-m telescopes around the world to monitor continuously young (≤100 Myr), nearby (≤1 kpc) stellar clusters mainly to detect young transiting planets (and to study other variability phenomena on time-scales from minutes to years). The telescope network enables us to observe the targets continuously for several days in order not to miss any transit. The runs are typically one to two weeks long, about three runs per year per cluster in two or three subsequent years for about ten clusters. There are thousands of stars detectable in each field with several hundred known cluster members, e.g. in the first cluster observed, Tr-37, a typical cluster for the YETI survey, there are at least 469 known young stars detected in YETI data down to R = 16.5 mag with sufficient precision of 50 millimag rms (5 mmag rms down to R = 14.5 mag) to detect transits, so that we can expect at least about one young transiting object in this cluster. If we observe ∼10 similar clusters, we can expect to detect ∼10 young transiting planets with radius determinations. The precision given above is for a typical telescope of the YETI network, namely the 60/90-cm Jena telescope (similar brightness limit, namely within ±1 mag, for the others) so that planetary transits can be detected. For targets with a periodic transit-like light curve, we obtain spectroscopy to ensure that the star is young and that the transiting object can be sub-stellar; then, we obtain Adaptive Optics infrared images and spectra, to exclude other bright eclipsing stars in the (larger) optical PSF; we carry out other observations as needed to rule out other false positive scenarios; finally, we also perform spectroscopy to determine the mass of the transiting companion. For planets with mass and radius determinations, we can calculate the mean density and probe the internal structure. We aim to constrain planet formation models and their time-scales by discovering planets younger than ∼100 Myr and determining not only their orbital parameters, but also measuring their true masses and radii, which is possible so far only by the transit method. Here, we present an overview and first results (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Astronomische Nachrichten 06/2011; 332(6):547 - 561. · 1.01 Impact Factor
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R. Neuhäuser,
R. Errmann,
A Berndt,
G. Maciejewski,
H Takahashi,
W P Chen,
D. P. Dimitrov,
T. Pribulla,
E. H. Nikogossian,
E. L. N. Jensen, [......],
E Schmidt,
M. M. Hohle,
M. Kitze,
N. Chakrova,
C. Gräfe,
K. Schreyer,
V. V. Hambaryan,
C. H. Broeg,
J. Koppenhoefer,
A. K. Pandey
[show abstract]
[hide abstract]
ABSTRACT: We present the Young Exoplanet Transit Initiative (YETI), in which we use
several 0.2 to 2.6m telescopes around the world to monitor continuously young
(< 100 Myr), nearby (< 1 kpc) stellar clusters mainly to detect young
transiting planets (and to study other variability phenomena on time-scales
from minutes to years). The telescope network enables us to observe the targets
continuously for several days in order not to miss any transit. The runs are
typically one to two weeks long, about three runs per year per cluster in two
or three subsequent years for about ten clusters. There are thousands of stars
detectable in each field with several hundred known cluster members, e.g. in
the first cluster observed, Tr-37, a typical cluster for the YETI survey, there
are at least 469 known young stars detected in YETI data down to R=16.5 mag
with sufficient precision of 50 milli-mag rms (5 mmag rms down to R=14.5 mag)
to detect transits, so that we can expect at least about one young transiting
object in this cluster. If we observe 10 similar clusters, we can expect to
detect approximately 10 young transiting planets with radius determinations.
The precision given above is for a typical telescope of the YETI network,
namely the 60/90-cm Jena telescope (similar brightness limit, namely within
+/-1 mag, for the others) so that planetary transits can be detected. For
planets with mass and radius determinations, we can calculate the mean density
and probe the internal structure. We aim to constrain planet formation models
and their time-scales by discovering planets younger than 100 Myr and
determining not only their orbital parameters, but also measuring their true
masses and radii, which is possible so far only by the transit method. Here, we
present an overview and first results. (Abstract shortened)
06/2011;
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[show abstract]
[hide abstract]
ABSTRACT: About 4" south of the young A0-type star HR 7329, a faint companion candidate
was found by Lowrance et al. (2000). Its spectral type of M7-8 is consistent
with a young brown dwarf companion. Here, we report ten new astrometric imaging
observations of the pair HR 7329 A and B, obtained with the Hubble Space
Telescope and the Very Large Telescope, aimed at showing common proper motion
with high significance and possible orbital motion of B around A. With 11 yrs
of epoch difference between the first and our last image, we can reject by more
than 21 sigma that B would be a non-moving background object unrelated to A. We
detect no change in position angle and small or no change in separation (2.91
+/- 2.41 mas/yr), so that the orbit of HR 7329 B around A is inclined and/or
eccentric and/or the orbital motion is currently only in radial direction. If
HR 7329 B is responsible for the outer radius of the debris disk around HR 7329
A being 24 AU, and if HR 7329 B currently is at its apastron at 200 AU (4.2" at
47.7 pc), we determine its pericenter distance to be 71 AU, its semi-major axis
to be 136 AU, and its eccentricity to be e=0.47. From the magnitude differences
between HR 7329 A and B and the 2MASS magnitudes for the HR 7329 A+B system, we
can estimate the magnitudes of HR 7329 B (J=12.06+/-0.19, H=11.75+/-0.10,
Ks=11.6+/-0.1, L=11.1+/-0.2 mag) and then, with a few otherwise known
parameters, its luminosity and mass (20-50 Jupiter masses). In the deepest
images available, we did not detect any additional companion candidates up to
<=9", but determine upper limits in the planetary mass regime.
06/2011;
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St. Raetz,
G. Maciejewski, M. Mugrauer,
T. O. B. Schmidt,
T. Roell,
T. Eisenbeiss,
A Berndt,
M. M. Hohle,
Ch. Ginski,
R. Errmann,
M. Seeliger,
Ch. Adam,
T. Pribulla,
N. Tetzlaff,
M. Vaňko,
J. Koppenhoefer,
M. Raetz,
R. Neuhäuser
[show abstract]
[hide abstract]
ABSTRACT: We report on our ongoing search for timing, duration, and depth variations in the exoplanet TrES-2. In Raetz et al. (2009) we already presented ten different transits obtained at the University Observatory Jena. Between November 2008 and August 2010 twelve additional transits could be observed. The timing, depth and duration of each individual event was analyzed and is presented here.
EPJ Web of Conferences. 01/2011;
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T. Pribulla,
A. Merand,
P. Kervella,
M. Vaňko,
I. R. Stevens,
R. Chini,
V. Hoffmeister,
O. Stahl,
A Berndt, M. Mugrauer,
M. Ammler-von Eiff
[show abstract]
[hide abstract]
ABSTRACT: Context. The nearby multiple system delta Velorum contains a widely detached
eclipsing binary and a third component.
Aims. We take advantage of this system offering the opportunity to determine
the set of fundamental parameters (masses, luminosities, and radii) of three
coeval stars with sufficient precision to test models of stellar evolution.
Methods. Extensive high-resolution spectroscopy is analyzed by the broadening
function technique to provide the first spectroscopic orbit of the eclipsing
pair. Simultaneous analysis of the spectroscopic data and the SMEI satellite
light curve is performed to provide astrophysical parameters for the
components. We use a modified Roche model assuming an eccentric orbit and
asynchronous rotation.
Results. The observations show that components of the eclipsing pair rotate
at about two-thirds of the break-up velocity, which excludes any chemical
peculiarity and results in a non-uniform surface brightness. Although the inner
orbit is eccentric, no apsidal motion is seen during the SMEI photometric
observations. For the inner orbit, the orbital parameters are eccentricity e =
0.29, longitude of the periastron passage omega = 109 degrees, and inclination
89.0 degrees.
Conclusions. Component's masses MAa = 2.53+/-0.11 Msun, MAb = 2.37+/-0.10
Msun and MB = 1.5 Msun combined with inferred radii of Aa and Ab components
indicate that the eclipsing pair has already left the Main sequence and the
estimated age of the system is about 400 Myr.
12/2010;
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G. Maciejewski,
R. Neuhaeuser,
R. Errmann, M. Mugrauer,
Ch. Adam,
A Berndt,
T. Eisenbeiss,
S. Fiedler,
Ch. Ginski,
M. Hohle, [......],
C. Marka,
M. Moualla,
T. Pribulla,
St. Raetz,
T. Roell,
T. O. B. Schmidt,
M. Seeliger,
I. Spaleniak,
N. Tetzlaff,
L. Trepl
[show abstract]
[hide abstract]
ABSTRACT: Transiting exoplanets (TEPs) observed just about 10 Myrs after formation of their host systems may serve as the Rosetta Stone for planet formation theories. They would give strong constraints on several aspects of planet formation, e.g. time-scales (planet formation would then be possible within 10 Myrs), the radius of the planet could indicate whether planets form by gravitational collapse (being larger when young) or accretion growth (being smaller when young). We present a survey, the main goal of which is to find and then characterise TEPs in very young open clusters. Comment: Poster contribution to Detection and Dynamics of Transiting Exoplanets (Haute Provence Observatory Colloquium, 23-27 August 2010)
10/2010;
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G. Maciejewski,
D Dimitrov,
R. Neuhaeuser,
N. Tetzlaff,
A. Niedzielski,
St. Raetz,
W P Chen,
F. Walter,
C. Marka,
S. Baar,
T. Krejcova,
J. Budaj,
V. Krushevska,
K. Tachihara,
H Takahashi, M. Mugrauer
[show abstract]
[hide abstract]
ABSTRACT: Transit timing analysis may be an effective method of discovering additional bodies in extrasolar systems which harbour transiting exoplanets. The deviations from the Keplerian motion, caused by mutual gravitational interactions between planets, are expected to generate transit timing variations of transiting exoplanets. In 2009 we collected 9 light curves of 8 transits of the exoplanet WASP-10b. Combining these data with published ones, we found that transit timing cannot be explained by a constant period but by a periodic variation. Simplified three-body models which reproduce the observed variations of timing residuals were identified by numerical simulations. We found that the configuration with an additional planet of mass of $\sim$0.1 $M_{\rm{J}}$ and orbital period of $\sim$5.23 d, located close to the outer 5:3 mean motion resonance, is the most likely scenario. If the second planet is a transiter, the estimated flux drop will be $\sim$0.3 per cent and can be observable with a ground-based telescope. Moreover, we present evidence that the spots on the stellar surface and rotation of the star affect the radial velocity curve giving rise to spurious eccentricity of the orbit of the first planet. We argue that the orbit of WASP-10b is essentially circular. Using the gyrochronology method, the host star was found to be $270 \pm 80$ Myr old. This young age can explain the large radius reported for WASP-10b. Comment: MNRAS accepted
09/2010;
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[show abstract]
[hide abstract]
ABSTRACT: Aims: We study the formation of substellar objects (exoplanets and brown dwarfs) as companions to young nearby stars. Methods: With high contrast AO imaging obtained with NACO at ESO's VLT we search for faint companion-candidates around our targets, whose companionship can be confirmed with astrometry. Results: In the course of our imaging campaign we found a faint substellar companion of the nearby pre-main sequence star PZ Tel, a member of the beta Pic moving group. The companion is 5-6 mag fainter than its host star in JHK and is located at a separation of only 0.3 arcsec (or 15 AU of projected separation) north-east of PZ Tel. Within three NACO observing epochs we could confirm common proper motion (>39 sigma) and detected orbital motion of PZ Tel B around its primary (>37 sigma). The photometry of the newly found companion is consistent with a brown dwarf with a mass of 24 to 40 MJup, at the distance (50 pc) and age (8-20 Myr) of PZ Tel. The effective temperature of the companion, derived from its photometry, ranges between 2500 and 2700 K, which corresponds to a spectral type between M6 and M8. After beta Pic b, PZ Tel B is the second closest substellar companion imaged directly around a young star. Comment: accepted for publication in A&A Letters
08/2010;
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[show abstract]
[hide abstract]
ABSTRACT: Photometric follow-ups of transiting exoplanets may lead to discoveries of additional, less massive bodies in extrasolar systems. This is possible by detecting and then analysing variations in transit timing of transiting exoplanets. We present photometric observations gathered in 2009 and 2010 for exoplanet WASP-3b during the dedicated transit-timing-variation campaign. The observed transit timing cannot be explained by a constant period but by a periodic variation in the observations minus calculations diagram. Simplified models assuming the existence of a perturbing planet in the system and reproducing the observed variations of timing residuals were identified by three-body simulations. We found that the configuration with the hypothetical second planet of the mass of about 15 Earth masses, located close to the outer 2:1 mean motion resonance is the most likely scenario reproducing observed transit timing. We emphasize, however, that more observations are required to constrain better the parameters of the hypothetical second planet in WASP-3 system. For final interpretation not only transit timing but also photometric observations of the transit of the predicted second planet and the high precision radial-velocity data are needed. Comment: MNRAS accepted
06/2010;
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[show abstract]
[hide abstract]
ABSTRACT: We present recent results of our ongoing multiplicity study of exoplanet host stars. Comment: 3 pages, 3 figures
04/2010;
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[show abstract]
[hide abstract]
ABSTRACT: In this work we present detailed photometric results of the trapezium like galactic nearby OB clusters NGC 1502 and NGC 2169 carried out at the University Observatory Jena. We determined absolute BVRI magnitudes of the mostly resolved components using Landolt standard stars. This multi colour photometry enables us to estimate spectral type and absorption as well as the masses of the components, which were not available for most of the cluster members in the literature so far, using models of stellar evolution. Furthermore, we investigated the optical spectrum of the components ADS 2984A and SZ Cam of the sextuple system in NGC 1502. Our spectra clearly confirm the multiplicity of these components, which is the first investigation of this kind at the University Observatory Jena (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Astronomische Nachrichten 05/2009; 330(5):511 - 517. · 1.01 Impact Factor
