- ID:
- ivo://CDS.VizieR/J/A+A/615/A175
- Title:
- Solar system analogs with HARPS
- Short Name:
- J/A+A/615/A175
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The assessment of the frequency of planetary systems reproducing the solar system's architecture is still an open problem in exoplanetary science. Detailed study of multiplicity and architecture is generally hampered by limitations in quality, temporal extension and observing strategy, causing difficulties in detecting low-mass inner planets in the presence of outer giant planets. We present the results of high-cadence and high-precision HARPS observations on 20 solar-type stars known to host a single long-period giant planet in order to search for additional inner companions and estimate the occurence rate f_p_ of scaled solar system analogues - in other words, systems featuring lower-mass inner planets in the presence of long-period giant planets. We carried out combined fits of our HARPS data with literature radial velocities using differential evolution MCMC to refine the literature orbital solutions and search for additional inner planets. We then derived the survey detection limits to provide preliminary estimates of f_p_. We generally find better constrained orbital parameters for the known planets than those found in the literature; significant updates can be especially appreciated on half of the selected planetary systems. While no additional inner planet is detected, we find evidence for previously unreported long-period massive companions in systems HD 50499 and HD 73267. We finally estimate the frequency of inner low mass (10-30M_{earth}_) planets in the presence of outer giant planets as f_p_<9.84% for P<150-days. Our preliminary estimate of f_p_ is significantly lower than the literature values for similarly defined mass and period ranges; the lack of inner candidate planets found in our sample can also be seen as evidence corroborating the inwards-migration formation model for super-Earths and mini-Neptunes. Our results also underline the need for high-cadence and high-precision followup observations as the key to precisely determine the occurence of solar system analogues.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/152/112
- Title:
- Solar-type stars from SDSS-III MARVELS. VI. HD 87646
- Short Name:
- J/AJ/152/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detections of a giant planet (MARVELS-7b) and a brown dwarf (BD) candidate (MARVELS-7c) around the primary star in the close binary system, HD87646. To the best of our knowledge, it is the first close binary system with more than one substellar circumprimary companion that has been discovered. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using the Exoplanet Tracker at the Kitt Peak National Observatory, the High Resolution Spectrograph at the Hobby Eberley telescope, the "Classic" spectrograph at the Automatic Spectroscopic Telescope at the Fairborn Observatory, and MARVELS from SDSS-III confirmed this giant planet discovery and revealed the existence of a long-period BD in this binary. HD87646 is a close binary with a separation of ~22 au between the two stars, estimated using the Hipparcos catalog and our newly acquired AO image from PALAO on the 200inch Hale Telescope at Palomar. The primary star in the binary, HD87646A, has T_eff_=5770+/-80K, logg=4.1+/-0.1, and [Fe/H]=-0.17+/-0.08. The derived minimum masses of the two substellar companions of HD87646A are 12.4+/-0.7M_Jup_ and 57.0+/-3.7M_Jup_. The periods are 13.481+/-0.001days and 674+/-4 days and the measured eccentricities are 0.05+/-0.02 and 0.50+/-0.02 respectively. Our dynamical simulations show that the system is stable if the binary orbit has a large semimajor axis and a low eccentricity, which can be verified with future astrometry observations.
- ID:
- ivo://CDS.VizieR/J/A+A/625/A17
- Title:
- SOPHIE data of Gliese 411
- Short Name:
- J/A+A/625/A17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Periodic radial velocity variations in the nearby M-dwarf star Gl 411 are reported, based on measurements with the SOPHIE spectrograph. Current data do not allow us to distinguish between a 12.95-day period and its one-day alias at 1.08-days, but favour the former slightly. The velocity variation has an amplitude of 1.6m/s, making this the lowest-amplitude signal detected with SOPHIE up to now. We have performed a detailed analysis of the significance of the signal and its origin, including extensive simulations with both uncorrelated and correlated noise, representing the signal induced by stellar activity. The signal is significantly detected, and the results from all tests point to its planetary origin. Additionally, the presence of an additional acceleration in the velocity time series is suggested by the current data. On the other hand, a previously reported signal with a period of 9.9 days, detected in HIRES velocities of this star, is not recovered in the SOPHIE data. An independent analysis of the HIRES dataset also fails to unveil the 9.9-day signal. If the 12.95-day period is the real one, the amplitude of the signal detected with SOPHIE implies the presence of a planet, called Gl 411 b, with a minimum mass of around three Earth masses, orbiting its star at a distance of 0.079AU. The planet receives about 3.5 times the insolation received by Earth, which implies an equilibrium temperature between 256 and 350K, and makes it too hot to be in the habitable zone. At a distance of only 2.5pc, Gl 411 b, is the third closest low-mass planet detected to date. Its proximity to Earth will permit probing its atmosphere with a combination of high-contrast imaging and high-dispersion spectroscopy in the next decade.
- ID:
- ivo://CDS.VizieR/J/A+A/651/A11
- Title:
- SOPHIE radial velocities of 27 F/G stars
- Short Name:
- J/A+A/651/A11
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Distinguishing classes within substellar objects and understanding their formation and evolution need larger samples of substellar companions such as exoplanets, brown dwarfs, and low-mass stars. In this paper, we look for substellar companions using radial velocity surveys of FGK stars with the SOPHIE spectrograph at the Observatoire de Haute-Provence. We assign here the radial velocity variations of 27 stars to their orbital motion induced by low-mass companions. We also constrained their plane-of-the-sky motion using HIPPARCOS and Gaia Data Release 1 measurements, which constrain the true masses of some of these companions. We report the detection and characterization of six cool Jupiters, three brown dwarf candidates, and 16 low-mass stellar companions. We additionally update the orbital parameters of the low-mass star HD 8291 B, and we conclude that the radial velocity variations of HD 204277 are likely due to stellar activity despite resembling the signal of a giant planet. One of the new giant planets, BD+631405 b, adds to the population of highly eccentric cool Jupiters, and it is presently the most massive member. Two of the cool Jupiter systems also exhibit signatures of an additional outer companion. The orbital periods of the new companions span 30 days to 11.5 years, their masses 0.72M_Jup_ to 0.61M_{sun}_, and their eccentricities 0.04 to 0.88. These discoveries probe the diversity of substellar objects and low-mass stars, which will help constrain the models of their formation and evolution.
- ID:
- ivo://CDS.VizieR/J/ApJ/785/47
- Title:
- Sources around target stars in Upper Scorpius
- Short Name:
- J/ApJ/785/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a multiplicity survey of 91 stars spanning masses of ~0.2-10 M_{sun}_ in the Upper Scorpius star-forming region, based on adaptive optics imaging with the Gemini North telescope. Our observations identified 29 binaries, 5 triples, and no higher order multiples. The corresponding raw multiplicity frequency is 0.37+/-0.05. In the regime where our observations are complete - companion separations of 0.1''-5'' (~15-800 AU) with magnitude limits ranging from K <9.3 at 0.1'' to K<15.8 at 5'' - the multiplicity frequency is 0.27_0.04_^+0.05^. For similar separations, the multiplicity frequency in Upper Scorpius is comparable to that in other dispersed star-forming regions, but is a factor of two to three higher than in denser star-forming regions or in the field. Our sample displays a constant multiplicity frequency as a function of stellar mass. Among our sample of binaries, we find that both wider (>100 AU) and higher-mass systems tend to have companions with lower companion-to-primary mass ratios. Three of the companions identified in our survey are unambiguously substellar and have estimated masses below 0.04 M_{sun}_ (two of them are new discoveries from this survey - 1RXS J160929.1-210524b and HIP 78530B - although we have reported them separately in earlier papers). These three companions have projected orbital separations of 300-900 AU. Based on a statistical analysis factoring in sensitivity limits, we calculate an occurrence rate of 5-40 M_Jup_ companions of ~4.0% for orbital separations of 250-1000 AU, compared to <1.8% at smaller separations, suggesting that such companions are more frequent on wider orbits.
- ID:
- ivo://CDS.VizieR/J/MNRAS/439/354
- Title:
- Sources around Tycho's Supernova 1572
- Short Name:
- J/MNRAS/439/354
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With archival and new Hubble Space Telescope observations, we have refined the space-velocity measurements of the stars in the central region of the remnant of Tycho's supernova (SN) 1572, one of the historical Galactic Type Ia supernova remnants (SNRs). We derived a proper motion for Tycho-G of (pmRAcosDE;pmDE) J2000.0 =(-2.63;,-3.98)+/-(0.06;,0.04)[formal errors] +/-(0.18;0.10)[expected errors]mas/yr. If the star were at the distance of the SNR (taken here to be 2.83kpc), its velocity would be V_b_=-51+/-1.5km/s. We also reconstruct the binary orbit that Tycho-G should have followed if it were the surviving companion of SN 1572. We redetermine the Ni abundance of this star and compare it with new abundance data from stars of the Galactic disc, finding that [Ni/Fe] is about 1.7{sigma} above the Galactic trend. From the high velocity of Tycho-G perpendicular to the Galactic plane (-90+/-3km/s<=V_b_<=-45+/-1km/s, for the allowed range of distances to the star), its metallicity and its Ni excess, we find the probability of it being a chance interloper to be P<~0.00037 at most. The projected rotational velocity of the star should be below current observational limits. The projected position of Tycho-G is, within the uncertainties, consistent with the centroid of the X-ray emission of Tycho's SNR; moreover, its brightness is generally consistent with the post-explosion evolution of the luminosity of an SN companion. Among the other 23 stars having V<22mag and located within 42-arcsec from the X-ray centroid, only 4 are at distances compatible with that of the SNR, and none of them shows any peculiarity. Therefore, if even Tycho-G is not the surviving companion of SN 1572, the absence of other viable candidates does favour the merging of two white dwarfs as the producer of the SN.
- ID:
- ivo://CDS.VizieR/J/AJ/160/9
- Title:
- Speckle holography of binary systems with OAN-SPM
- Short Name:
- J/AJ/160/9
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We present our first results of multiband Speckle Holography of components of visual double stars. The observations were performed during 2019-April at the 2.1m telescope at the Observatorio Astronomico Nacional at Sierra de San Pedro Martir (Mexico). We have observed 190 double stars with separation between 3" and 5". The position angle, separation and magnitude difference in three broadband optical filters (VRI) for these systems are provided. For 15 systems we found different interesting features, we have identified a close component for 9 of those systems; 5 of them are newly discovered. In the remaining 6 systems, although unresolved, we found elongations that we have been able to derive astrometric parameters if proven to be a (newly discovered) close component. This corresponds to about 8% of the sample presenting a certain feature in one of the components and about 5% of the sample having a confirmed close component.
- ID:
- ivo://CDS.VizieR/J/AJ/138/813
- Title:
- Speckle interferometry at Mount Wilson Obs.
- Short Name:
- J/AJ/138/813
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results are presented for 607 speckle interferometric observations of double stars, as well as 222 measures of single stars or unresolved pairs. All data were obtained in 2006 and 2007 at the Mount Wilson Observatory, using the 2.5 m Hooker telescope. Separations range from 0.06" to 6.31", with a median of 0.34". These three observing runs concentrated on binaries in need of confirmation (mainly Hipparcos and Tycho pairs), as well as systems in need of improved orbital elements. New orbital solutions have been determined for 35 systems as a result.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/47.211
- Title:
- Speckle interferometry at OAN. III.
- Short Name:
- J/other/RMxAA/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present speckle interferometric measurements of binary stars performed during August of 2010 with the 1.5m telescope and during November of 2010 with the 2.1m telescope of the Observatorio Astronomico Nacional at SPM (Mexico). We report here the results of 238 measurements of 225 pairs with a primary limiting magnitude of V=12.2; 211 of them have separations less than 1". The mean error in separation is 0.03" and 1.5{deg} in position angle. Some of the position angles were determined with the usual 180{deg} ambiguity.
- ID:
- ivo://CDS.VizieR/J/AJ/162/41
- Title:
- Speckle interferometry at SOAR in 2020
- Short Name:
- J/AJ/162/41
- Date:
- 14 Mar 2022 06:54:42
- Publisher:
- CDS
- Description:
- The results of speckle interferometric observations at the 4.1m Southern Astrophysical Research Telescope in 2020, as well as earlier unpublished data, are given, totaling 1735 measurements of 1288 resolved pairs and nonresolutions of 1177 targets. We resolved for the first time 59 new pairs or subsystems in known binaries, mostly among nearby dwarf stars. This work continues our long-term speckle program. Its main goal is to monitor orbital motion of close binaries, including members of high-order hierarchies and Hipparcos pairs in the solar neighborhood. We also report observations of 892 members of young moving groups and associations, where we resolved 103 new pairs.
