- ID:
- ivo://CDS.VizieR/J/ApJ/744/6
- Title:
- SONYC census of very low-mass objects in NGC1333
- Short Name:
- J/ApJ/744/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SONYC - Substellar Objects in Nearby Young Clusters - is a program to investigate the frequency and properties of young substellar objects with masses down to a few times that of Jupiter. In a series of papers we have obtained follow-up spectroscopy for a large number of candidate very low mass (VLM) members of the ~1Myr old cluster NGC1333 in the Perseus star forming region. For more details on the survey, see the associated paper (Scholz et al., 2012ApJ...744....6S). Here we present a census of spectroscopically confirmed very low mass objects in NGC1333. We include all objects with spectral type of M5 or later and/or effective temperature of 3200K or cooler. In total, there are now 58 objects which fulfill these criteria. In three tables we list photometric and spectroscopic properties for our own sample as well as for objects listed in the literature. In addition, we also include three tables of the objects that have been rejected as very low mass cluster members based on our spectroscopic follow-up. Finally, we attach the two photometric candidate lists from which the spectroscopic sample was extracted, see Scholz et al. (2012ApJ...756...24S) for more details on these catalogues.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/744/134
- Title:
- SONYC new brown dwarfs in {rho} Oph
- Short Name:
- J/ApJ/744/134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SONYC - Substellar Objects in Nearby Young Clusters - is a survey program to investigate the frequency and properties of substellar objects with masses down to a few times that of Jupiter in nearby star-forming regions. In two papers of the SONYC series we have obtained follow-up spectroscopy for a large number of candidate very low ma ss (VLM) members of the ~1Myr old cluster rho Ophiuchi. For more details on the survey, see the associated paper (Muzic et al., 2012ApJ...744..134M). Here we publish the two catalogues of photometric candidate members from which the spectroscopic samples were extracted (see Geers et al. 2011ApJ...726...23G and Muzic et al. 2012ApJ...744..134M for more details on these catalogues). We include a table containing all the spectroscopically confirmed VLM members of the cluster observed within the SONYC campaign. We also attach and a table with all the objects that have been rejected as VLM members based on our spectroscopic follow-up. The majority of these latter objects are expected to be background contaminants, although some of them could also be embedded cluster members with spectral types earlier than M.
- ID:
- ivo://CDS.VizieR/J/A+A/650/A39
- Title:
- SOPHIE and HARPS Young Nearby Stars - YNS
- Short Name:
- J/A+A/650/A39
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The search of close (a<~5au) giant planet (GP) companions with radial velocity (RV) around young stars and the estimate of their occurrence rates is important to constrain the migration timescales. Furthermore, this search will allow the giant planet occurrence rates to be computed at all separations via the combination with direct imaging techniques. The RV search around young stars is a challenge as they are generally faster rotators than older stars of similar spectral types and they exhibit signatures of magnetic activity (spots) or pulsation in their RV time series. Specific analyses are necessary to characterize, and possibly correct for, this activity. Our aim is to search for planets around young nearby stars and to estimate the GP occurrence rates for periods up to 1000 days. We used the SOPHIE spectrograph on the 1.93m telescope at the Haute-Provence Observatory to observe 63 A-M young (<400Myr) stars. We used our Spectroscopic data via Analysis of the Fourier Interspectrum Radial velocities (SAFIR) software to compute the RVs and other spectroscopic observables. We then combined this survey with the HARPS YNS survey to compute the companion occurrence rates on a total of 120 young A-M stars. Results. We report one new trend compatible with a planetary companion on HD 109647. We also report HD 105693 and HD 112097 as binaries, and we confirm the binarity of HD 2454, HD13531, HD 17250 A, HD 28945, HD 39587, HD 131156, HD 142229, HD 186704 A, and HD 195943. We constrained for the first time the orbital parameters of HD 195943 B. We refute the HD 13507 single brown dwarf (BD) companion solution and propose a double BD companion solution. Two GPs were previously reported from this survey in the HD 113337 system. Based on our sample of 120 young stars, we obtain a GP occurrence rate of 1^+2/2^_0/3_% for periods lower than 1000 days, and we obtain an upper limit on BD occurrence rate of 0.9^+2^_0.9_% in the same period range. We report a possible lack of close (P {in} [1; 1000] days) GPs around young FK stars compared to their older counterparts, with a confidence level of 90%.
- ID:
- ivo://CDS.VizieR/J/A+A/440/1061
- Title:
- Southern red high proper motion objects
- Short Name:
- J/A+A/440/1061
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of spectroscopic follow-up observations for a sample of 71 red objects with high proper motions in the range 0.08-1.14 arcsec/yr as detected using APM and SuperCOSMOS Sky Surveys (SSS) measurements of multi-epoch photographic Schmidt plates. Red objects were selected by combining the photographic BjRI magnitudes with 2MASS near-infrared JHKs magnitudes. Some 50 of the 71 spectroscopically classified objects turn out to be late-type (>M6) dwarfs and in more detail, the sample includes 35 ultracool dwarfs with spectral types between M8 and L2, some previously reported, as well as five M-type subdwarfs, including a cool esdM6 object, SSSPM J0500-5406. Distance estimates based on the spectral types and 2MASS J magnitudes place almost all of the late-type (>M6) dwarfs within 50pc, with 25 objects located inside the 25pc limit of the catalogue of nearby stars. Most of the early-type M dwarfs are located at larger distances of 100-200pc, suggesting halo kinematics for some of them. All objects with Halpha equivalent widths larger than 10 Angstroms have relatively small tangential velocities (<50km/s). Finally, some late-type but blue objects are candidate binaries.
- ID:
- ivo://CDS.VizieR/J/MNRAS/402/575
- Title:
- Southern ultracool dwarfs in young moving groups
- Short Name:
- J/MNRAS/402/575
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We associate 132 low-mass ultracool dwarfs in the southern hemisphere as candidate members of five moving groups (MGs) using photometric and astrometric selection techniques. Of these objects, we present high-resolution spectroscopy for seven candidates and combine these with previous measurements from the literature to determine spectral types and radial velocities. We thus constrain distance and space motion spectroscopically, allowing the kinematic membership of the MGs to be assessed. Possible membership of MGs has allowed ages and metallicities to be constrained for these objects and evolutionary models have been used to estimate their mass. We estimate that up to ~75 of our candidate MG members should be genuine, and discuss future work that will confirm and exploit this major new sample.
- ID:
- ivo://CDS.VizieR/J/A+A/543/A125
- Title:
- Spectral types of CoRoT stars
- Short Name:
- J/A+A/543/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In here we study the stellar content of the CoRoT-fields IRa01, LRa01 (=LRa06), and LRa02 by determining the spectral types of 11466 stars. Nine planet host stars have already been identified in these fields. The determination of the spectral types of thousands of stars of which CoRoT obtained high-precision light-curves also opens up a large variety of other research projects. For our study, we used spectra obtained with the multi-object spectrograph AAOmega and derived the spectral types by using template spectra with well known parameters. We find that 34.8+/-0.7% of the stars observed by CoRoT in these fields are F-dwarfs, 15.1+/-0.5% G-dwarfs, and 5.0+/-0.3% K-dwarfs. We conclude that the apparent lack of exoplanets of K- and M-stars is explained by the relatively small number of these stars in the observed sample. We also show that the apparently large number of planets orbiting F-stars is also explained by the large number of such stars in these fields. Given the number of F-stars, we would have expected to find even more planet orbiting F-stars. Our study also shows that the difference between the sample of stars that CoRoT observes and a sample of randomly selected stars is relatively small, and that the yield of CoRoT is the detection one hot Jupiter amongst 2100+/-700 stars. We finally conclude that transit search programs can be used in order to study the relation between the frequency of planets and the mass of the host stars, and that the results obtained so far are in general agreement with those of radial velocity programs.
- ID:
- ivo://CDS.VizieR/III/114
- Title:
- Spectra of Late-Type Standards, 2.0-2.5 Microns
- Short Name:
- III/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains a collection of K-band spectra for 26 stars with near-solar abundances, ranging in spectral class from F8 to M7 and in luminosity from dwarfs to supergiants. The spectra cover the wavelength region from 4150 to 4950 /cm and generally exhibit a signal to noise ratio above 400. Five stars here are supergiants, 15 are giants, and six are dwarfs. Data included: observation date, starting wavenumber, wavenumber increment, scale factor of relative intensity, and offset of relative intensity.
- ID:
- ivo://CDS.VizieR/J/A+A/527/A24
- Title:
- Spectra of low-mass stars in Upper Sco
- Short Name:
- J/A+A/527/A24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained multi-fibre intermediate-resolution optical spectroscopy of 94 photometric and proper motion selected low-mass star and brown dwarf candidates in Upper Sco with the AAOmega spectrograph on the Anglo-Australian Telescope. We have estimated the spectral types and measured the equivalent widths of youth and gravity diagnostic features to confirm the spectroscopic membership of about 95% of the photometric and proper motion candidates extracted from 6.5 square degrees surveyed in Upper Sco by the UKIRT Infrared Deep Sky Survey (UKIDSS) Galactic Clusters Survey (GCS). We have estimated the effective temperatures and masses for each new spectroscopic member using the latest evolutionary models available for low-mass stars and brown dwarfs. Combining the current optical spectroscopy presented here with near-infrared spectroscopy obtained for the faintest photometric candidates, we confirm the shape and slope of our earlier photometric mass function. The luminosity function drawn from the spectroscopic sample of 113 USco members peaks at around M6 and is flat at later spectral type. The mass function may peak at 0.2M_{sun}_ and is quite flat in the substellar regime. We observe a possible excess of cool low-mass brown dwarfs compared to IC 348 and the extrapolation of the field mass functions, supporting the original hypothesis that Upper Sco may possess an excess of brown dwarfs compared.
- ID:
- ivo://CDS.VizieR/J/ApJ/779/188
- Title:
- Spectra of nearby late K and M Kepler stars
- Short Name:
- J/ApJ/779/188
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use moderate-resolution spectra of nearby late K and M dwarf stars with parallaxes and interferometrically determined radii to refine their effective temperatures, luminosities, and metallicities. We use these revised values to calibrate spectroscopic techniques to infer the fundamental parameters of more distant late-type dwarf stars. We demonstrate that, after masking out poorly modeled regions, the newest version of the PHOENIX atmosphere models accurately reproduce temperatures derived bolometrically. We apply methods to late-type hosts of transiting planet candidates in the Kepler field, and calculate effective temperature, radius, mass, and luminosity with typical errors of 57K, 7%, 11%, and 13%, respectively. We find systematic offsets between our values and those from previous analyses of the same stars, which we attribute to differences in atmospheric models utilized for each study. We investigate which of the planets in this sample are likely to orbit in the circumstellar habitable zone. We determine that four candidate planets (KOI 854.01, 1298.02, 1686.01, and 2992.01) are inside of or within 1{sigma} of a conservative definition of the habitable zone, but that several planets identified by previous analyses are not (e.g., KOI 1422.02 and KOI 2626.01). Only one of the four habitable-zone planets is Earth sized, suggesting a downward revision in the occurrence of such planets around M dwarfs. These findings highlight the importance of measuring accurate stellar parameters when deriving parameters of their orbiting planets.
- ID:
- ivo://CDS.VizieR/J/A+A/414/699
- Title:
- Spectra of southern late-type dwarfs
- Short Name:
- J/A+A/414/699
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Echelle spectra of 91 late-type dwarfs, of spectral types from F to M and of different levels of chromospheric activity, obtained with the 2.15-m telescope of the CASLEO Observatory located in the Argentinean Andes. Our observations range from 3890 to 6690{AA}, at a spectral resolution from 0.141 to 0.249{AA} per pixel (R={lambda}/{delta}{lambda}~26400). The observations were flux calibrated with the aid of long slit spectra (R~1050-2070), also available.
