- ID:
- ivo://CDS.VizieR/J/ApJ/770/L13
- Title:
- Detection of CH_3_COOCH_3_ in Orion
- Short Name:
- J/ApJ/770/L13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the discovery of methyl acetate, CH_3_COOCH_3_, through the detection of a large number of rotational lines from each one of the spin states of the molecule: AA species (A_1_ or A_2_), EA species (E_1_), AE species (E_2_), and EE species (E_3_ or E_4_). We also report, for the first time in space, the detection of the gauche conformer of ethyl formate, CH_3_CH_2_OCOH, in the same source. The trans conformer is also detected for the first time outside the Galactic center source SgrB2. From the derived velocity of the emission of methyl acetate, we conclude that it arises mainly from the compact ridge region with a total column density of (4.2+/-0.5)x10^15^/cm2. The derived rotational temperature is 150K. The column density for each conformer of ethyl formate, trans and gauche, is (4.5+/-1.0)x10^14^/cm2. Their abundance ratio indicates a kinetic temperature of 135K for the emitting gas and suggests that gas-phase reactions could participate efficiently in the formation of both conformers in addition to cold ice mantle reactions on the surface of dust grains.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/688/L83
- Title:
- Detection of C_5_N^-^ in IRC +10216
- Short Name:
- J/ApJ/688/L83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection in the envelope of the C-rich star IRC+10216 of four series of lines with harmonically related frequencies: B1389, B1390, B1394, and B1401. The four series must arise from linear molecules with mass and size close to those of C_6_H and C_5_N. Three of the series have half-integer rotational quantum numbers; we assign them to the ^2^{Delta} and ^2^{Sigma}^-^ vibronic states of C_6_H in its lowest ({nu}_11_) bending mode. The fourth series, B1389, has integer J with no evidence of fine or hyperfine structure; it has a rotational constant of 1388.860(2)MHz and a centrifugal distortion constant of 33(1)Hz; it is almost certainly the C_5_N^-^ anion.
- ID:
- ivo://CDS.VizieR/J/A+A/593/A30
- Title:
- Detection of fast HI outflow in Mrk231
- Short Name:
- J/A+A/593/A30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the detection, performed with the Westerbork Synthesis Radio Telescope (WSRT) and the Karl Jansky Very Large Array (VLA), of a fast HI 21-cm outflow in the ultra-luminous infrared galaxy Mrk 231. The outflow is observed as shallow HI absorption blueshifted ~1300 km/s with respect to the systemic velocity and located against the inner kpc of the radio source. The outflowing gas has an estimated column density between 5 and 15x10^18^Tspin.cm^-2^. We derive the Tspin to lie in the range 400-2000 K and the corresponding HI densities are n_HI_~10-100cm^-3^. We also obtained deeper continuum images than previously available. They confirm the complex structure of the radio continuum originating both from the AGN and star formation. At the resolution obtained with the VLA (~1-arcsec) we do not see a kpc-scale jet. Instead, we detect a plateau of emission, likely due to star formation, surrounding the bright nuclear region. We also detect a poorly collimated bridge which may represent the channel feeding the southern lobe. The unprecedented depth of the low-resolution WSRT image reveals radio emission extending 50-arcsec (43kpc) to the south and 20arcsec (17kpc) to the north.
- ID:
- ivo://CDS.VizieR/J/ApJS/158/188
- Title:
- Detection of glycolaldehyde toward Sgr B2
- Short Name:
- J/ApJS/158/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Glycolaldehyde (CHOCH_2_OH), the simplest two-carbon {alpha}-hydroxy aldehyde, has become of great interest in the field of astrochemistry due to its recent detection toward the Sagittarius B2 (N-LMH) molecular cloud. The original interstellar identification was based on an extrapolation of prior microwave rotational spectroscopy of glycolaldehyde. The millimeter and submillimeter spectra of this molecule from 128 to 354GHz were subsequently measured after the interstellar detection. We present here the millimeter spectrum of this molecule from 72 to 122.5GHz along with a combined millimeter and submillimeter pure rotational analysis of the ground and the first three vibrationally excited states of glycolaldehyde that enables a more complete molecular partition function to be determined.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/114
- Title:
- Detection of Kepler multiple M-star systems
- Short Name:
- J/ApJ/788/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have searched the Kepler light curves of ~3900 M-star targets for evidence of periodicities that indicate, by means of the effects of starspots, rapid stellar rotation. Several analysis techniques, including Fourier transforms, inspection of folded light curves, "sonograms", and phase tracking of individual modulation cycles, were applied in order to distinguish the periodicities due to rapid rotation from those due to stellar pulsations, eclipsing binaries, or transiting planets. We find 178 Kepler M-star targets with rotation periods, P_rot_<2 days, and 110 with P_rot_<1 day. Some 30 of the 178 systems exhibit two or more independent short periods within the same Kepler photometric aperture, while several have 3 or more short periods. Adaptive optics imaging and modeling of the Kepler pixel response function for a subset of our sample support the conclusion that the targets with multiple periods are highly likely to be relatively young physical binary, triple, and even quadruple M star systems. We explore in detail the one object with four incommensurate periods all less than 1.2 days, and show that two of the periods arise from one of a close pair of stars, while the other two arise from the second star, which itself is probably a visual binary. If most of these M-star systems with multiple periods turn out to be bound M-stars, this could prove a valuable way discovering young hierarchical M-star systems; the same approach may also be applicable to G and K stars. The ~5% occurrence rate of rapid rotation among the ~3900 M star targets is consistent with spin evolution models that include an initial contraction phase followed by magnetic braking, wherein a typical M star can spend several hundred Myr before spinning down to periods longer than 2 days.
- ID:
- ivo://CDS.VizieR/J/ApJ/791/35
- Title:
- Detection of 715 Kepler planet candidates host stars
- Short Name:
- J/ApJ/791/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Robo-AO Kepler Planetary Candidate Survey is observing every Kepler planet candidate host star with laser adaptive optics imaging to search for blended nearby stars, which may be physically associated companions and/or responsible for transit false positives. In this paper, we present the results from the 2012 observing season, searching for stars close to 715 Kepler planet candidate hosts. We find 53 companions, 43 of which are new discoveries. We detail the Robo-AO survey data reduction methods including a method of using the large ensemble of target observations as mutual point-spread-function references, along with a new automated companion-detection algorithm designed for large adaptive optics surveys. Our survey is sensitive to objects from ~ 0.15'' to 2.5'' separation, with magnitude differences up to {Delta}m ~ 6. We measure an overall nearby-star probability for Kepler planet candidates of 7.4%+/-1.0%, and calculate the effects of each detected nearby star on the Kepler-measured planetary radius. We discuss several Kepler Objects of Interest (KOIs) of particular interest, including KOI-191 and KOI-1151, which are both multi-planet systems with detected stellar companions whose unusual planetary system architecture might be best explained if they are "coincident multiple" systems, with several transiting planets shared between the two stars. Finally, we find 98% confidence evidence that short-period giant planets are two to three times more likely than longer-period planets to be found in wide stellar binaries.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A96
- Title:
- Detection of the propargyl radical at lambda 3mm
- Short Name:
- J/A+A/657/A96
- Date:
- 21 Mar 2022 09:30:15
- Publisher:
- CDS
- Description:
- We report the detection of the propargyl radical (CH_2_CCH) in the cold dark cloud TMC-1 in the lambda 3mm wavelength band. We recently discovered this species in space toward the same source at a wavelength of lambda 8mm. In those observations, various hyperfine components of the 202-101 rotational transition, at 37.5GHz, were detected using the Yebes 40m telescope. Here, we used the IRAM 30m telescope to detect ten hyperfine components of the 505-404 rotational transition, lying at 93.6GHz. The observed frequencies differ by 0.2MHz with respect to the predictions from available laboratory data. This difference is significant for a radioastronomical search for CH_2_CCH in interstellar sources with narrow lines. We thus included the measured frequencies in a new spectroscopic analysis to provide accurate frequency predictions for the interstellar search for propargyl at mm wavelengths. Moreover, we recommend that future searches for CH_2_CCH in cold interstellar clouds are carried out at lambda 3mm, rather than at lambda 8 mm. The 505-404 transition is about five times more intense than the 202-101 transition in TMC-1, which implies that detecting the former requires about seven times less telescope time than detecting the latter. We constrain the rotational temperature of CH_2_CCH in TMC-1 to 9.9+/-1.5K, which indicates that the rotational levels of this species are thermalized at the gas kinetic temperature. The revised value of the column density of CH_2_CCH (including ortho and para species) is (1.0+/-0.2)x10^14^cm^-2^, and thus the CH_2_CCH/CH_3_CCH abundance ratio is revised from slightly below one to nearly one. This study opens the door for future detections of CH_2_CCH in other cold interstellar clouds, making possible to further investigate the role of this very abundant hydrocarbon radical in the synthesis of large organic molecules such as aromatic rings.
- ID:
- ivo://CDS.VizieR/J/A+A/595/A61
- Title:
- Detection of the secondary eclipse of Qatar-1b
- Short Name:
- J/A+A/595/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Qatar-1b is a close-orbiting hot Jupiter (Rp~=1.18R_J_, Mp~=1.33M_J_) around a metal-rich K-dwarf, with orbital separation and period of 0.023AU and 1.42-days. We have observed the secondary eclipse of this exoplanet in the Ks band with the objective of deriving a brightness temperature for the planet and providing further constraints to the orbital configuration of the system. We obtained near-infrared photometric data from the ground by using the OMEGA2000 instrument at the 3.5m telescope at Calar Alto (Spain) in staring mode, with the telescope defocused. We have used principal component analysis (PCA) to identify correlated systematic trends in the data. A Markov chain Monte Carlo analysis was performed to model the correlated systematics and fit for the secondary eclipse of Qatar-1b using a previously developed occultation model. We adopted the prayer bead method to assess the effect of red noise on the derived parameters.
- ID:
- ivo://CDS.VizieR/J/A+A/373/576
- Title:
- Detection of Tycho variables stars
- Short Name:
- J/A+A/373/576
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an original way to detect variable stars in the Tycho photometric observations. A modified Kolmogorov-Smirnov statistical test has been constructed, based on a model of most of the satellite's parameters, leading to the dispersion in the measurements. This allows us to build a treatment taking into account truncated detections and censored measurements, and to search for variability in the faint part of the catalogue. The selection threshold of variable stars has been calibrated to minimize false alarm rate. Reliable results were thus obtained for stars as faint as 11 mag. One thousand and ninety-one suspected variable stars have been listed, 407 of which are already known in Hipparcos, GCVS or NSV, and 684 of which are suspected variable stars to be identified soon.
- ID:
- ivo://CDS.VizieR/J/A+A/536/L9
- Title:
- Detections of transit variations in KOI 806
- Short Name:
- J/A+A/536/L9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of transit timing variations (TTVs) well in excess of one hour in the Kepler multi-planet candidate system KOI 806. This system exhibits transits consistent with three separate planets - a Super-Earth, a Jupiter, and a Saturn - lying very nearly in a 1:2:5 resonance, respectively.