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- ID:
- ivo://CDS.VizieR/J/A+A/392/215
- Title:
- The CORALIE survey for extrasolar planets. IX.
- Short Name:
- J/A+A/392/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Table 1 contains the CORALIE radial-velocity measurements for the stellar system HD41004. CORALIE is a fiber-fed echelle spectrograph designed for high-precision radial-velocity measurements. It is mounted on the 1.2-m "Leonard Euler" Swiss Telescope at ESO-La Silla Observatory (Chile).
- ID:
- ivo://CDS.VizieR/J/A+A/390/267
- Title:
- The CORALIE survey for extrasolar planets VIII
- Short Name:
- J/A+A/390/267
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Doppler CORALIE measurements of the solar-type stars HD 141937, HD 162020, HD 168443 and HD 202206 show Keplerian radial-velocity variations revealing the presence of 4 new companions with minimum masses close to the planet/brown-dwarf transition, namely with m_2_sini=9.7, 14.4, 16.9, and 17.5M_Jup_, respectively. The orbits present fairly large eccentricities (0.22<=e<=0.43). Except for HD 162020 , the parent stars are metal rich compared to the Sun, as are most of the detected extra-solar planet hosts. Considerations of tidal dissipation in the short-period HD 162020 system points towards a brown-dwarf nature for the low-mass companion. HD 168443 is a multiple system with two low-mass companions being either brown dwarfs or formed simultaneously in the protoplanetary disks as superplanets. For HD 202206, the radial velocities show an additional drift revealing a further outer companion, the nature of which is still unknown. Finally, the stellar-host and orbital properties of massive planets are examined in comparison to lighter exoplanets. Observed trends include the need of metal-rich stars to form massive exoplanets and the lack of short periods for massive planets. If confirmed with improved statistics, these features may provide constraints for the migration scenario.
- ID:
- ivo://CDS.VizieR/J/ApJ/723/1072
- Title:
- The ELM survey. I. Low-mass white dwarfs
- Short Name:
- J/ApJ/723/1072
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze radial velocity observations of the 12 extremely low-mass (ELM), with <=0.25M_{sun}_, white dwarfs (WDs) in the MMT Hypervelocity Star Survey. Eleven of the twelve WDs are binaries with orbital periods shorter than 14hr; the one non-variable WD is possibly a pole-on system among our non-kinematically selected targets. Our sample is unique: it is complete in a well-defined range of apparent magnitude and color. The orbital mass functions imply that the unseen companions are most likely other WDs, although neutron star companions cannot be excluded. Six of the eleven systems with orbital solutions will merge within a Hubble time due to the loss of angular momentum through gravitational wave radiation. The quickest merger is J0923+3028, a g=15.7 ELM WD binary with a 1.08hr orbital period and a <=130Myr merger time. The chance of a supernova Ia event among our ELM WDs is only 1%-7%, however. Three binary systems (J0755+4906, J1233+1602, and J2119-0018) have extreme mass ratios and will most likely form stable mass-transfer AM CVn systems. Two of these objects, SDSS J1233+1602 and J2119-0018, are the lowest surface gravity WDs ever found; both show CaII absorption likely from accretion of circumbinary material. We predict that at least one of our WDs is an eclipsing detached double WD system, important for constraining helium core WD models.
- ID:
- ivo://CDS.VizieR/J/ApJ/818/155
- Title:
- The ELM survey. VII. 15 new ELM white dwarf cand.
- Short Name:
- J/ApJ/818/155
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery of 15 extremely low-mass (5<logg<7) white dwarf (WD) candidates, 9 of which are in ultra-compact double-degenerate binaries. Our targeted extremely low-mass Survey sample now includes 76 binaries. The sample has a lognormal distribution of orbital periods with a median period of 5.4hr. The velocity amplitudes imply that the binary companions have a normal distribution of mass with 0.76 M_{sun}_ mean and 0.25M_{sun}_ dispersion. Thus extremely low-mass WDs are found in binaries with a typical mass ratio of 1:4. Statistically speaking, 95% of the WD binaries have a total mass below the Chandrasekhar mass, and thus are not type Ia supernova progenitors. Yet half of the observed binaries will merge in less than 6Gyr due to gravitational wave radiation; probable outcomes include single massive WDs and stable mass transfer AM CVn binaries.
- ID:
- ivo://CDS.VizieR/J/AJ/157/177
- Title:
- The evolutionary status of GK subgiants
- Short Name:
- J/AJ/157/177
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Snowden & Young (2005ApJS..157..126S) suggested that the reason why there are GK subgiants is because they are members of binaries, which would bring them above the main sequence in an Hertzsprung-Russell (HR) diagram. They studied a sample of 30 G0-K1 IV stars and were disappointed to find only two to be spectroscopic binaries. With more accurate radial velocities I found seven binaries in their samples of subgiants and control stars; orbital elements are given for those seven. Using Hipparcos parallaxes and SIMBAD data, I found that nearly all of the G0-K1 IV stars fall on the evolutionary tracks by Girardi et al. (2000, J/A+AS/141/371) for Population I stars with masses of 0.9-1.9 M_{sun}_ and ages of up to 10^10^ yr, which are normal parameters for nearby field stars. Therefore there is no problem regarding the existence of GK subgiants.
- ID:
- ivo://CDS.VizieR/J/ApJ/724/835
- Title:
- The Spitzer c2d survey of WTTSs. III.
- Short Name:
- J/ApJ/724/835
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 3.6 to 70um Spitzer photometry of 154 weak-line T Tauri stars (WTTSs) in the Chamaeleon, Lupus, Ophiuchus, and Taurus star formation regions, all of which are within 200pc of the Sun. For a comparative study, we also include 33 classical T Tauri stars which are located in the same star-forming regions. Spitzer sensitivities allow us to robustly detect the photosphere in the IRAC bands (3.6 to 8um) and the 24um MIPS band. In the 70um MIPS band, we are able to detect dust emission brighter than roughly 40 times the photosphere. These observations represent the most sensitive WTTSs survey in the mid- to far-infrared to date and reveal the frequency of outer disks (r=3-50AU) around WTTSs. The 70um photometry for half the c2d WTTSs sample (the on-cloud objects), which were not included in the earlier papers in this series, those of Padgett et al. (2006ApJ...645.1283P) and Cieza et al. (2007, Cat. J/ApJ/667/308) are presented here for the first time.
- ID:
- ivo://CDS.VizieR/J/AN/341/989
- Title:
- theta Cep radial velocity curve
- Short Name:
- J/AN/341/989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In 2015 a radial velocity monitoring campaign was started in order to redetermine and/or constrain the orbital solutions of spectroscopic binary systems. The observations were carried out at the University Observatory Jena with the echelle spectrograph FLECHAS. The results from the main part of our target sample are already published. For the final target of this campaign, theta Cep, we can now present an orbital solution based on a homogeneously covered radial velocity curve. The period of this single-lined spectroscopic binary turns out to be significantly larger and the orbit is much more eccentric compared to the given values in the 9th Catalogue of Spectroscopic Binary Orbits (Pourbaix et al., Cat. B/sb9).
- ID:
- ivo://CDS.VizieR/J/A+A/343/806
- Title:
- The trapezium system BD+00 1617
- Short Name:
- J/A+A/343/806
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Internal kinematics, spectroscopic binaries and galactic motion are investigated for the trapezium system BD+00 1617 (which lies at the heart of the young open cluster Bochum 2) by means on 73 high resolution Echelle+CCD spectra secured over the period 1994-98. Two of the three O-type member stars are found to be binaries on close and highly eccentric orbits of 6.8 and 11.0 day period. Tables 2 and 3, that are available only in electronic form, give the journal of the observations and the individual radial velocities.
- ID:
- ivo://CDS.VizieR/J/PAZh/24/868
- Title:
- The triple system ADS 9167
- Short Name:
- J/PAZh/24/868
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It is found from the observations with the correlation radial velocity meter that the primary component of the visual double star ADS 9167 is a single-lined spectroscopic binary with 2.87- yr period and 0.75 eccentricity. Using the 26-year-long series of Pulkovo photographic relative-positions observations, a new visual orbit of AB is calculated with a period of about 1000 years.
