105 research outputs found
Very Low-Mass Stellar and Substellar Companions to Solar-Like Stars from MARVELS I: A Low Mass Ratio Stellar Companion to TYC 4110-01037-1 in a 79-day Orbit
TYC 4110-01037-1 has a low-mass stellar companion, whose small mass ratio and
short orbital period are atypical amongst solar-like (Teff ~< 6000 K) binary
systems. Our analysis of TYC 4110-01037-1 reveals it to be a moderately aged
(~<5 Gyr) solar-like star having a mass of 1.07 +/- 0.08 MSun and radius of
0.99 +/- 0.18 RSun. We analyze 32 radial velocity measurements from the
SDSS-III MARVELS survey as well as 6 supporting radial velocity measurements
from the SARG spectrograph on the 3.6m TNG telescope obtained over a period of
~2 years. The best Keplerian orbital fit parameters were found to have a period
of 78.994 +/- 0.012 days, an eccentricity of 0.1095 +/- 0.0023, and a
semi-amplitude of 4199 +/- 11 m/s. We determine the minimum companion mass (if
sin i = 1) to be 97.7 +/- 5.8 MJup. The system's companion to host star mass
ratio, >0.087 +/- 0.003, places it at the lowest end of observed values for
short period stellar companions to solar-like (Teff ~< 6000 K) stars. One
possible way to create such a system would be if a triple-component stellar
multiple broke up into a short period, low q binary during the cluster
dispersal phase of its lifetime. A candidate tertiary body has been identified
in the system via single-epoch, high contrast imagery. If this object is
confirmed to be co-moving, we estimate it would be a dM4 star. We present these
results in the context of our larger-scale effort to constrain the statistics
of low mass stellar and brown dwarf companions to FGK-type stars via the
MARVELS survey.Comment: 22 pages; accepted in A
MARVELS-1: A face-on double-lined binary star masquerading as a resonant planetary system; and consideration of rare false positives in radial velocity planet searches
We have analyzed new and previously published radial velocity observations of
MARVELS-1, known to have an ostensibly substellar companion in a ~6- day orbit.
We find significant (~100 m/s) residuals to the best-fit model for the
companion, and these residuals are naively consistent with an interior giant
planet with a P = 1.965d in a nearly perfect 3:1 period commensuribility
(|Pb/Pc - 3| < 10^{-4}). We have performed several tests for the reality of
such a companion, including a dynamical analysis, a search for photometric
variability, and a hunt for contaminating stellar spectra. We find many reasons
to be critical of a planetary interpretation, including the fact that most of
the three-body dynamical solutions are unstable. We find no evidence for
transits, and no evidence of stellar photometric variability. We have
discovered two apparent companions to MARVELS-1 with adaptive optics imaging at
Keck; both are M dwarfs, one is likely bound, and the other is likely a
foreground object. We explore false-alarm scenarios inspired by various
curiosities in the data. Ultimately, a line profile and bisector analysis lead
us to conclude that the ~100 m/s residuals are an artifact of spectral
contamination from a stellar companion contributing ~15-30% of the optical
light in the system. We conclude that origin of this contamination is the
previously detected radial velocity companion to MARVELS-1, which is not, as
previously reported, a brown dwarf, but in fact a G dwarf in a face-on orbit.Comment: ApJ 770, 119. 24 pp emulate ApJ style, 12 figures (One is very
large). v2: corrects two (important!) errors: A priori chance of this
alignment or worse is 0.1% (not 0.01%) and the primary has THREE total
companions (not four
Dark Energy Survey Year 6 Results: Intra-Cluster Light from Redshift 0.2 to 0.5
Using the full six years of imaging data from the Dark Energy Survey, we
study the surface brightness profiles of galaxy cluster central galaxies and
intra-cluster light. We apply a ``stacking'' method to over four thousand
galaxy clusters identified by the redMaPPer cluster finding algorithm in the
redshift range of 0.2 to 0.5. This yields high signal-to-noise radial profile
measurements of the central galaxy and intra-cluster light out to 1 Mpc from
the cluster center. Using redMaPPer richness as a cluster mass indicator, we
find that the intra-cluster light brightness has a strong mass dependence
throughout the 0.2 to 0.5 redshift range, and the dependence grows stronger at
a larger radius. In terms of redshift evolution, we find some evidence that the
central galaxy, as well as the diffuse light within the transition region
between the cluster central galaxy and intra-cluster light within 80 kpc from
the center, may be growing over time. At larger radii, more than 80 kpc away
from the cluster center, we do not find evidence of additional redshift
evolution beyond the cluster mass dependence, which is consistent with the
findings from the IllustrisTNG hydrodynamic simulation. We speculate that the
major driver of intra-cluster light growth, especially at large radii, is
associated with cluster mass growth. Finally, we find that the color of the
cluster central galaxy and intra-cluster light displays a radial gradient that
becomes bluer at a larger radius, which is consistent with a stellar stripping
and disruption origin of intra-cluster light as suggested by simulation
studies.Comment: Submitted to MNRA
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