- ID:
- ivo://CDS.VizieR/J/A+A/493/639
- Title:
- Velocity curves of HD 40307
- Short Name:
- J/A+A/493/639
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of a planetary system with three Super-Earths orbiting HD 40307. HD 40307 is a K2 V metal-deficient star at a distance of only 13 parsec, which is part of the HARPS GTO high-precision planet-search programme. The three planets on circular orbits have very low minimum masses of 4.2, 6.9, and 9.2 Earth masses and periods of 4.3, 9.6, and 20.5 days, respectively.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/619/A2
- Title:
- Velocity curves of 3 open cluster stars
- Short Name:
- J/A+A/619/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The aim of this work is to search for planets around intermediate-mass stars in open clusters by using data from an extensive survey with more than 15 years of observations. We obtain high-precision radial velocities (RV) with the HARPS spectrograph for a sample of 142 giant stars in 17 open clusters. We fit Keplerian orbits when a significant periodic signal is detected. We also study the variation of stellar activity indicators and line-profile variations to discard stellar-induced signals. We present the discovery of a periodic RV signal compatible with the presence of a planet candidate in the 1.15Gyr open cluster IC4651 orbiting the 2.06M_{sun}_ star No. 9122. If confirmed, the planet candidate would have a minimum mass of 7.2M_J_ and a period of 747 days. However, we also find that the FWHM of the CCF varies with a period close to the RV, casting doubts on the planetary nature of the signal. We also provide refined parameters for the previously discovered planet around NGC2423 No. 3 but show evidence that the BIS of the CCF is correlated with the RV during some of the observing periods. This fact advises us that this might not be a real planet and that the RV variations could be caused by stellar activity and/or pulsations. Finally, we show that the previously reported signal by a brown dwarf around NGC4349 No. 127 is presumably produced by stellar activity modulation. The long-term monitoring of several red giants in open clusters has allowed us to find periodic RV variations in several stars. However, we also show that the follow-up of this kind of stars should last more than one orbital period to detect long-term signals of stellar origin. This work warns that although it is possible to detect planets around red giants, large-amplitude, long-period RV modulations do exist in such stars that can mimic the presence of an orbiting planetary body. Therefore, we need to better understand how such RV modulations behave as stars evolve along the Red Giant Branch and perform a detailed study of all the possible stellar-induced signals (e.g. spots, pulsations, granulation) to comprehend the origin of RV variations.
- ID:
- ivo://CDS.VizieR/J/A+A/537/A117
- Title:
- Velocity curves of SW CMa and HW CMa
- Short Name:
- J/A+A/537/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate physical properties of eclipsing stars provide important constraints on models of stellar structure and evolution, especially when combined with spectroscopic information on their chemical composition. Empirical calibrations of the data also lead to accurate mass and radius estimates for exoplanet host stars. Finally, accurate data for unusual stellar subtypes, such as Am stars, also help to unravel the cause(s) of their peculiarities. We aim to determine the masses, radii, effective temperatures, detailed chemical composition and rotational speeds for the Am-type eclipsing binaries SWCMa (A4-5m) and HWCMa (A6m) and compare them with similar normal stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/113/151
- Title:
- Velocity dispersions for elliptical galaxies
- Short Name:
- J/A+AS/113/151
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Measurements of central velocity dispersions and heliocentric radial velocities are presented for 94 field galaxies. Among these, 5 new radial velocities and 80 new central velocity dispersions are obtained. Reduction was performed independently by cross-correlation, Fourier-quotient and Fourier-correlation-quotient methods.
- ID:
- ivo://CDS.VizieR/J/A+A/393/57
- Title:
- Velocity field in the Local Group
- Short Name:
- J/A+A/393/57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Pratton, Melott and McKee (1997ApJ...479L..15P) showed that the velocity field around clusters could generate an apparent distortion that appears as tangential structures or radial filaments. In the present paper we determine the parameters of the Peebles' model (1976ApJ...205..318P) describing infall of galaxies onto clusters with the aim of testing quantitatively the amplitude of this distortion. The distances are determined from the concept of sosie galaxies (Paturel, 1994A&A...289..711P) using 21 calibrators for which the distances were recently calculated from two independent Cepheid calibrations. We use both B and I-band magnitudes.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A108
- Title:
- Velocity field of the Lyra complex
- Short Name:
- J/A+A/633/A108
- Date:
- 02 Nov 2021 11:15:00
- Publisher:
- CDS
- Description:
- The formation of cosmic structures culminates with the assembly of galaxy clusters, a process that is quite different from cluster to cluster. We present the study of the structure and dynamics of the Lyra complex, consisting of the two clusters RXC J1825.3+3026 and CIZA J1824.1+3029, which was very recently studied by using both X-ray and radio data. This is the first analysis based on the kinematics of member galaxies. New spectroscopic data for 285 galaxies were acquired at the Italian Telescopio Nazionale Galileo and were used in combination with PanSTARRS photometry. The result of our member selection is a sample of 198 galaxies. For RXCJ1825 and CIZAJ1824 we report the redshifts, z=0.0645 and z=0.0708, the first estimates of velocity dispersion, sigma_v_=995_-125_^+131^km/s and sigma_v_=700+/-50km/s, and of dynamical mass, M_200_=1.1+/-0.4x10^15^M_[sun}_ and M_200_=4+/-0.110^14^M_{sun}_. The past assembly of RXCJ1825 is traced by the two dominant galaxies, which are both aligned with the major axis of the galaxy distribution along the east-west direction, and by a minor northeast substructure. We also detect a quite peculiar high velocity field in the southwest region of the Lyra complex. This feature is likely related to a very luminous galaxy, which is characterized by a high velocity. This galaxy is suggested to be the central galaxy of a group that is in interaction with RXCJ1825 according to very recent studies based on X-ray and radio data. The redshift of the whole Lyra complex is z=0.067. Assuming that the redshift difference between RXCJ1825 and CIZAJ1824 is due to the relative kinematics, the projected distance between the cluster centers is D~1.3Mpc and the line-of-sight velocity difference is ~1750km/s. A dynamical analysis of the system shows that the two clusters are likely to be gravitationally bound in a pre-merger phase, and that CIZAJ1824 is moving toward RXCJ1825. Our results corroborate a picture where the Lyra region is the place of a very complex scenario of cluster assembly.
- ID:
- ivo://CDS.VizieR/J/A+A/275/67
- Title:
- Velocity Field of the outer Galaxy
- Short Name:
- J/A+A/275/67
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/420/147
- Title:
- Velocity in 6 spiral galaxies
- Short Name:
- J/A+A/420/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High resolution Fabry-Perot data of six spiral galaxies are presented. Those data extend the previous sample of spiral galaxies studied with high resolution 3-D spectroscopy to earlier morphological types. All the galaxies in the sample have available HI data at 21cm from the VLA or Westerbork. Velocity fields are analyzed and H{alpha} rotation curves are computed and compared to HI curves. The kinematics of NGC 5055 central regions are looked at more closely. Its peculiar kinematics can be interpreted either as a bipolar outflow or as a counter-rotating disk, possibly hosting a 9+/-2x10^8^M_{sun}-compact object. Most of the H{alpha} rotation curves present a significantly steeper inner slope than their HI counterparts. The 21cm data thus seems affected by moderate to strong beam smearing. The beam smearing has an effect at higher scale-length/beam-width than previously thought (up to 20km/s at a ratio of 8.5).
- ID:
- ivo://CDS.VizieR/J/ApJ/733/46
- Title:
- Velocity measurements in Segue 1
- Short Name:
- J/ApJ/733/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a comprehensive Keck/DEIMOS spectroscopic survey of the ultra-faint Milky Way satellite galaxy Segue 1. We have obtained velocity measurements for 98.2% of the stars within 67pc (10', or 2.3 half-light radii) of the center of Segue 1 that have colors and magnitudes consistent with membership, down to a magnitude limit of r=21.7. Based on photometric, kinematic, and metallicity information, we identify 71 stars as probable Segue 1 members, including some as far out as 87pc. After correcting for the influence of binary stars using repeated velocity measurements, we determine a velocity dispersion of 3.7^+1.4^_-1.1_km/s. The mass within the half-light radius is 5.8^+8.2^_-3.1_x10^5^M_{sun}_. The stellar kinematics of Segue 1 require very high mass-to-light ratios unless the system is far from dynamical equilibrium, even if the period distribution of unresolved binary stars is skewed toward implausibly short periods. With a total luminosity less than that of a single bright red giant and a V-band mass-to-light ratio of 3400M_{sun}_/L_{sun}_, Segue 1 is the darkest galaxy currently known.
- ID:
- ivo://CDS.VizieR/J/A+A/551/A59
- Title:
- Velocity monitoring for 3 stars with HARPS
- Short Name:
- J/A+A/551/A59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The vast diversity of planetary systems detected to date is defying our capability of understanding their formation and evolution. Well-defined volume-limited surveys are the best tool at our disposal to tackle the problem, via the acquisition of robust statistics of the orbital elements. We are using the HARPS spectrograph to conduct our survey of 850 nearby solar-type stars, and in the course of the past nine years we have monitored the radial velocity of HD 103774, HD 109271, and BD-061339. In this work we present the detection of five planets orbiting these stars, with msini between 0.6 and 7 Neptune masses, four of which are in two multiple systems, comprising one super-Earth and one planet within the habitable zone of a late-type dwarf. Although for strategic reasons we chose efficiency over precision in this survey, we have the capability to detect planets down to the Neptune and super-Earth mass range as well as multiple systems, provided that enough data points are made available.
