- ID:
- ivo://CDS.VizieR/J/A+A/612/A49
- Title:
- 324 CARMENES M dwarfs velocities
- Short Name:
- J/A+A/612/A49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the survey sample by publishing one CARMENES spectrum for each M dwarf. These spectra cover the wavelength range 520-1710nm at a resolution of at least R>80000, and we measure its RV, H{alpha} emission, and projected rotation velocity. We present an atlas of high-resolution M-dwarf spectra and compare the spectra to atmospheric models. To quantify the RV precision that can be achieved in low-mass stars over the CARMENES wavelength range, we analyze our empirical information on the RV precision from more than 6500 observations. We compare our high-resolution M-dwarf spectra to atmospheric models where we determine the spectroscopic RV information content, Q, and signal-to-noise ratio. We find that for all M-type dwarfs, the highest RV precision can be reached in the wavelength range 700-900nm. Observations at longer wavelengths are equally precise only at the very latest spectral types (M8 and M9). We demonstrate that in this spectroscopic range, the large amount of absorption features compensates for the intrinsic faintness of an M7 star. To reach an RV precision of 1m/s in very low mass M dwarfs at longer wavelengths likely requires the use of a 10m class telescope. For spectral types M6 and earlier, the combination of a red visual and a near-infrared spectrograph is ideal to search for low-mass planets and to distinguish between planets and stellar variability. At a 4m class telescope, an instrument like CARMENES has the potential to push the RV precision well below the typical jitter level of 3-4m/s.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/609/A117
- Title:
- CARMENES radial velocity curves of 7 M-dwarf
- Short Name:
- J/A+A/609/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The main goal of the CARMENES survey is to find Earth-mass planets around nearby M-dwarf stars. Seven M-dwarfs included in the CARMENES sample had been observed before with HIRES and HARPS and either were reported to have one short period planetary companion (GJ 15 A, GJ 176, GJ 436, GJ 536 and GJ 1148) or are multiple planetary systems (GJ 581 and GJ 876). Aims. We aim to report new precise optical radial velocity measurements for these planet hosts and test the overall capabilities of CARMENES. We combined our CARMENES precise Doppler measurements with those available from HIRES and HARPS and derived new orbital parameters for the systems. Bona-fide single planet systems are fitted with a Keplerian model. The multiple planet systems were analyzed using a self-consistent dynamical model and their best fit orbits were tested for long-term stability. Results. We confirm or provide supportive arguments for planets around all the investigated stars except for GJ 15 A, for which we find that the post-discovery HIRES data and our CARMENES data do not show a signal at 11.4days. Although we cannot confirm the super-Earth planet GJ 15 Ab, we show evidence for a possible long-period (Pc=7025^+972^_-629_days) Saturn-mass (m_c_sini=51.8^+5.5^_-5.8_M_{Earth}_) planet around GJ 15 A. In addition, based on our CARMENES and HIRES data we discover a second planet around GJ 1148, for which we estimate a period Pc=532.6^+4.2^_-2.5_days, eccentricity e_c_=0.342^+0.050^_-0.062_ and minimum mass m_c_sini=68.1^+4.9^_-2.2_M_{Earth}_. The CARMENES optical radial velocities have similar precision and overall scatter when compared to the Doppler measurements conducted with HARPS and HIRES. We conclude that CARMENES is an instrument that is up to the challenge of discovering rocky planets around low-mass stars.
- ID:
- ivo://CDS.VizieR/J/A+A/652/A116
- Title:
- CARMENES time-resolved CaII H&K catalog
- Short Name:
- J/A+A/652/A116
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Radial-velocity (RV) jitter caused by stellar magnetic activity is an important factor in state-of-the-art exoplanet discovery surveys such as CARMENES. Stellar rotation, along with heterogeneities in the photosphere and chromosphere caused by activity, can result in false-positive planet detections. Hence, it is necessary to determine the stellar rotation period and compare it to any putative planetary RV signature. Long-term measurements of activity indicators such as the chromospheric emission in the CaII H&K lines enable the identification of magnetic activity cycles. In order to determine stellar rotation periods and study the long-term behavior of magnetic activity of the CARMENES guaranteed time observations (GTO) sample, it is advantageous to extract R'HK time series from archival data, since the CARMENES spectrograph does not cover the blue range of the stellar spectrum containing the Ca II H&K lines. We have assembled a catalog of 11634 archival spectra of 186 M dwarfs acquired by seven different instruments covering the CaII H&K regime: ESPADONS, FEROS, HARPS, HIRES, NARVAL, TIGRE, and UVES. The relative chromospheric flux in these lines, R'HK, was directly extracted from the spectra by rectification with PHOENIX synthetic spectra via narrow passbands around the Ca II H&K line cores. The combination of archival spectra from various instruments results in time series for 186 stars from the CARMENES GTO sample. As an example of the use of the catalog, we report the tentative discovery of three previously unknown activity cycles of M dwarfs. We conclude that the method of extracting R'HK with the use of model spectra yields consistent results for different instruments and that the compilation of this catalog will enable the analysis of long-term activity time series for a large number of M dwarfs.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A112
- Title:
- CARMENES VIS RVs of 3 M dwarfs
- Short Name:
- J/A+A/643/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We announce the discovery of two planets orbiting the M dwarfs GJ 251 (0.360+/-0.015M_{sun}_) and HD 238090 (0.578+/-0.021M_{sun}_) based on CARMENES radial velocity (RV) data. In addition, we independently confirm with CARMENES data the existence of Lalande 21185 b, a planet that has recently been discovered with the SOPHIE spectrograph. All three planets belong to the class of warm or temperate super-Earths and share similar properties. The orbital periods are 14.24d, 13.67d, and 12.95d and the minimum masses are 4.0+/-0.4M_{sun}_, 6.9+/-0.9M_{sun}_, and 2.7+/-0.3M_{sun}_ for GJ 251 b, HD 238090 b, and Lalande 21185 b, respectively. Based on the orbital and stellar properties, we estimate equilibrium temperatures of 351.0+/-1.4K for GJ 251 b, 469.6+/-2.6K for HD 238090 b, and 370.1+/-6.8K for Lalande 21185 b. For the latter we resolve the daily aliases that were present in the SOPHIE data and that hindered an unambiguous determination of the orbital period. We find no significant signals in any of our spectral activity indicators at the planetary periods. The RV observations were accompanied by contemporaneous photometric observations. We derive stellar rotation periods of 122.1+/-2.2d and 96.7+/-3.7d for GJ 251 and HD 238090, respectively. The RV data of all three stars exhibit significant signals at the rotational period or its first harmonic. For GJ 251 and Lalande 21185, we also find long-period signals around 600d, and 2900d, respectively, which we tentatively attribute to long-term magnetic cycles. We apply a Bayesian approach to carefully model the Keplerian signals simultaneously with the stellar activity using Gaussian process regression models and extensively search for additional significant planetary signals hidden behind the stellar activity. Current planet formation theories suggest that the three systems represent a common architecture, consistent with formation following the core accretion paradigm.
- ID:
- ivo://CDS.VizieR/J/AJ/109/2376
- Title:
- Case blue/emission-line galaxies
- Short Name:
- J/AJ/109/2376
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present CCD imaging and spectroscopic data for 176 blue and/or emission-line galaxies from Lists I and II of the Case Northern Sky Survey. Our sample consists of all Case galaxies which lie in the region which overlaps the original Slice of the Universe survey. We use the observational data to investigate the physical properties of the galaxies selected by the surveys to compare with various parameters published in the survey lists, and to investigate the selection characteristics and completeness limit of the survey. The majority of the Case galaxies are energized by regions of active star formation; only 5% of the sample are Seyfert galaxies. The dual selection techniques used (both UV-excess and emission lines) allow the survey to detect star-forming galaxies with a wide range of properties and evolutionary states. In particular, the Case survey selects galaxies with lower levels of activity than most previous surveys. The survey also includes a larger fraction of intermediate and low-luminosity galaxies than would be present in a purely magnitude-limited sample. Although galaxies as faint as m_B_=19 are present in the sample, the completeness limit of the UV-excess selected portion of the survey is closer to m_B_=16. The luminosity function of the Case galaxies is derived and compared with that of the "normal" field galaxies in the same volume of space. The shape of the Case luminosity function is similar to that for the field sample. A surprising result is that 31% of the field galaxy population can be accounted for by galaxies of the type selected in the Case survey.
- ID:
- ivo://CDS.VizieR/J/AJ/145/43
- Title:
- CASE. V. Three eclipsing binaries in M4
- Short Name:
- J/AJ/145/43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use photometric and spectroscopic observations of the eclipsing binaries V65, V66, and V69 in the field of the globular cluster M4 to derive masses, radii, and luminosities of their components. The orbital periods of these systems are 2.29, 8.11, and 48.19days, respectively. The measured masses of the primary and secondary components (M_p_ and M_s_) are 0.8035+/-0.0086 and 0.6050+/-0.0044M_{sun}_ for V65, 0.7842+/-0.0045 and 0.7443+/-0.0042M_{sun}_ for V66, and 0.7665+/-0.0053 and 0.7278+/-0/0048M_{sun}_ for V69. The measured radii (R_p_ and R_s_) are 1.147+/-0.010 and 0.6110 +/- 0.0092R_{sun}_ for V66, 0.9347+/-0.0048 and 0.8298+/-0.0053R_{sun}_ for V66, and 0.8655+/-0.0097 and 0.8074+/-0.0080R_{sun}_ for V69. The orbits of V65 and V66 are circular, whereas that of V69 has an eccentricity of 0.38. Based on systemic velocities and relative proper motions, we show that all three systems are members of the cluster. We find that the distance to M4 is 1.82+/-0.04kpc-in good agreement with recent estimates based on entirely different methods. We compare the absolute parameters of V66 and V69 with two sets of theoretical isochrones in mass-radius and mass-luminosity diagrams, and for assumed [Fe/H]=-1.20, [{alpha}/Fe]=0.4, and Y=0.25 we find the most probable age of M4 to be between 11.2 and 11.3Gyr. Color-magnitude diagram (CMD) fitting with the same parameters yields an age close to, or slightly in excess of, 12Gyr. However, considering the sources of uncertainty involved in CMD fitting, these two methods of age determination are not discrepant. Age and distance determinations can be further improved when infrared eclipse photometry is obtained.
- ID:
- ivo://CDS.VizieR/J/A+A/312/93
- Title:
- Cataclysmic variables systemic-velocity
- Short Name:
- J/A+A/312/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have collected {gamma} velocities of cataclysmic variables from a survey of published orbital radial-velocity studies. We argue that for the non-magnetic cataclysmic variables the {gamma} distribution gives a fair description of the systemic radial velocities; for magnetic cataclysmic variables the effect of motions within the system appears to be substantial. Assuming that the distribution of the spatial velocities of cataclysmic variables in the solar neighbourhood follows the velocity ellipsoid, with dispersions as given by Wielen (1977), we estimate that the dispersion of z-velocities of CVs is in the range 16 to 21km/s. With the galactic potential of Kuijken and Gilmore (1989) we then derive the distribution of distances, z, above the galactic plane. This distribution has an exponential scale height in the range 160-230pc, which is nearly a factor of two larger than that obtained for the z distribution of systems with known distances. This probably reflects the incompleteness of the census of cataclysmic variables at distances even as small as ~100pc. The velocity distribution of cataclysmic variables indicates that they are an old disk population, with a mix of ages up to 10Gyr.
- ID:
- ivo://CDS.VizieR/J/other/Ap/41.1
- Title:
- Catalog of barred galaxies
- Short Name:
- J/other/Ap/41.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of barred spiral galaxies of types SB and SAB with B_T_=<13.5 and DE>-10{deg} has been compiled. Some parameters of these galaxies are given.
- ID:
- ivo://CDS.VizieR/J/AZh/84/579
- Title:
- Catalog of Class I methanol masers
- Short Name:
- J/AZh/84/579
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of class I methanol masers discovered so far in the Southern and Northern hemispheres is presented. The catalog contains 160 sources. A statistical analysis shows that, within 2' of the telescope pointing (which corresponds approximately to the field of view of single antennas used in search surveys), 50% of class I methanol masers are associated with objects characteristic of active starforming regions: IRAS sources, ultracompact HII regions, and dense gas dust clouds, as well as OH and H2O interstellar masers. At the same time, bipolar out flows (which could play an active part in pumping the methanol masers) are associated with fewer than 25% of class I methanol masers. In 72% of cases, class I methanol masers are associated with class II methanol maser sources. These results suggest that methanol maser condensations are more appropriately classified by the transition type (that is, the pumping mechanism) than their association with other astronomical objects.
- ID:
- ivo://CDS.VizieR/J/ApJS/158/193
- Title:
- Catalog of Galactic {beta} Cephei stars
- Short Name:
- J/ApJS/158/193
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an extensive and up-to-date catalog of Galactic {beta} Cephei stars. This catalog is intended to give a comprehensive overview of observational characteristics of all known {beta} Cephei stars, covering information until 2004 June. Ninety-three stars could be confirmed to be {beta} Cephei stars. We use data from more than 250 papers published over the last nearly 100 years, and we provide over 45 notes on individual stars. For some stars we reanalyzed published data or conducted our own analyses. Sixty-one stars were rejected from the final {beta} Cephei list, and 77 stars are suspected to be {beta} Cephei stars. A list of critically selected pulsation frequencies for confirmed {beta} Cephei stars is also presented.