XO-7 b: A Transiting Hot Jupiter with a Massive Companion on a Wide Orbit

Transiting planets orbiting bright stars are the most favorable targets for follow-up and characterization. We report the discovery of the transiting hot Jupiter XO-7 b and of a second, massive companion on a wide orbit around a circumpolar, bright, and metal rich G0 dwarf (V = 10.52, Teff = 6250±100 K, [Fe/H] = 0.432 ± 0.057 dex). We conducted photometric and radial velocity follow-up with a team of amateur and professional astronomers. XO-7 b has a period of 2.8641424±0.0000043 days, a mass of 0.709±0.034 MJ, a radius of 1.373±0.026 RJ, a density of 0.340±0.027 g cm-3 , and an equilibrium temperature of 1743 ± 23 K. Its large atmospheric scale height and the brightness of the host star make it well suited to atmospheric characterization. The wide orbit companion is detected as a linear trend in radial velocities with an amplitude of ~ 100 m s-1 over two years, yielding a minimum mass of 4 MJ; it could be a planet, a brown dwarf, or a low mass star. The hot Jupiter orbital parameters and the presence of the wide orbit companion point towards a high eccentricity migration for the hot Jupiter. Overall, this system will be valuable to understand the atmospheric properties and migration mechanisms of hot Jupiters and will help constrain the formation and evolution models of gas giant exoplanets.The XO project is supported by NASA grant NNX10AG30G. I.R., F.V. and E.H. acknowledge support by the Spanish Ministry for Science, Innovation and Universities (MCIU) and the Fondo Europeo de Desarrollo Regional (FEDER) through grant ESP2016- 80435-C2-1-R, as well as the support of the Generalitat de Catalunya/CERCA programme. The Joan Oró Telescope (TJO) of the Montsec Astronomical Observatory (OAdM) is owned by the Generalitat de Catalunya and operated by the Institute for Space Studies of Catalonia (IEEC). NCS was supported by FCT - Funda c~ao para a Ci^encia e a Tecnologia through national funds and by FEDER - Fundo Europeu de Desenvolvimento Regional through COMPETE2020 - Programa Operacional Competitividade e Internacionalizaçao by these grants: UID/FIS/04434/2019; PTDC/FISAST/ 28953/2017 & POCI-01-0145-FEDER-028953 and PTDC/FIS-AST/32113/2017 & POCI-01-0145- FEDER-032113. HPO acknowledges support from Centre National d'Etudes Spatiales (CNES) grant 131425- PLATO. This research made use of Photutils, an Astropy package for detection and photometry of astronomical sources (Bradley et al. 2019). This research has made use of the Exoplanet Orbit Database and the Exoplanet Data Explorer at exoplanets.org, the Extrasolar Planets Encyclopaedia at exoplanet.eu, and the SIMBAD and VizieR databases at simbad.ustrasbg. fr/simbad/ and http://vizier.u-strasbg.fr/vizbin/ VizieR.Peer ReviewedPostprint (author's final draft

Deuterium Toward Two Milky Way Disk Stars: Probing Extended Sight Lines with the Far Ultraviolet Spectroscopic Explorer

We have carried out an investigation of the abundance of deuterium along two extended sight lines through the interstellar medium (ISM) of the Galactic disk. The data include Far Ultraviolet Spectroscopic Explorer (FUSE) observations of HD 195965 (B1Ib) and HD 191877 (B0V), as well as Space Telescope Imaging Spectrograph (STIS) observations of HD 195965. The distances to HD 195965 and HD 191877, derived from spectroscopic parallax, are 794+/-200 pc and 2200+/-550 pc, respectively, making these the longest Galactic disk sight lines in which deuterium has been investigated with FUSE. The higher Lyman lines clearly show the presence of deuterium. We use a combination of curve of growth analyses and line profile fitting to determine the DI abundance toward each object. We also present column densities for OI and NI toward both stars, and HI measured from Ly-alpha absorption in the STIS spectrum of HD 195965. The D/H ratios along these sight lines are lower than the average value found with FUSE for the local interstellar medium (37 to 179 pc from the Sun). These observations lend support to earlier detections of variation in D/H over distances greater than a few hundred pc. The D/H and O/H values measured along these sight lines support the expectation that the ISM is not well mixed on distances of ~1000 pc.Comment: 32 pages, 18 figures. Abridged abstract. Accepted for publication in ApJ. Uses emulateapj5.st

Kepler-413b: a slightly misaligned, Neptune-size transiting circumbinary planet

We report the discovery of a transiting, Rp = 4.347+/-0.099REarth, circumbinary planet (CBP) orbiting the Kepler K+M Eclipsing Binary (EB) system KIC 12351927 (Kepler-413) every ~66 days on an eccentric orbit with ap = 0.355+/-0.002AU, ep = 0.118+/-0.002. The two stars, with MA = 0.820+/-0.015MSun, RA = 0.776+/-0.009RSun and MB = 0.542+/-0.008MSun, RB = 0.484+/-0.024RSun respectively revolve around each other every 10.11615+/-0.00001 days on a nearly circular (eEB = 0.037+/-0.002) orbit. The orbital plane of the EB is slightly inclined to the line of sight (iEB = 87.33+/-0.06 degrees) while that of the planet is inclined by ~2.5 degrees to the binary plane at the reference epoch. Orbital precession with a period of ~11 years causes the inclination of the latter to the sky plane to continuously change. As a result, the planet often fails to transit the primary star at inferior conjunction, causing stretches of hundreds of days with no transits (corresponding to multiple planetary orbital periods). We predict that the next transit will not occur until 2020. The orbital configuration of the system places the planet slightly closer to its host stars than the inner edge of the extended habitable zone. Additionally, the orbital configuration of the system is such that the CBP may experience Cassini-States dynamics under the influence of the EB, in which the planet's obliquity precesses with a rate comparable to its orbital precession. Depending on the angular precession frequency of the CBP, it could potentially undergo obliquity fluctuations of dozens of degrees (and complex seasonal cycles) on precession timescales.Comment: 48 pages, 13 figure

Variations in the D/H ratio of extended sightlines from FUSE observations

We use new FUSE data to determine the column densities of interstellar DI, NI, OI, FeII, and H2 along the HD41161 and HD53975 sightlines. Together with N(HI) from the literature (derived from Copernicus and IUE data) we derive D/H, N/H, and O/H ratios. These high column density sightlines have both log H(HI)>21.00 and allow us to probe gas up to 1300 pc. In particular these sightlines allow us to determine the gas phase D/H ratio in a hydrogen column density range, log N(H)>20.70, where the only five measurements available in the literature yield a weighted average of D/H = (0.86 +/- 0.08)E-5. We find D/H=(2.14+ 0.51 - 0.43)E-5 along the HD41161 sightline. This ratio is 3sigma higher than the weighted mean D/H ratio quoted above, for sightlines with log N(H)>20.70, while the D/H ratio for the HD53975 line of sight, D/H = (1.02 +0.23 -0.20)E-5, agrees within the 1sigma uncertainties. Our D/H measurement along the HD 41161 sightline presents the first evidence of variations of D/H at high N(H). Our result seems to indicate that either the long sightlines that according to the deuterium depletion model are dominated by cold undisturbed gas where deuterium would be depleted onto carbonaceous grains occur at higher N(H) than previously thought or that the clumping of low D/H values in the literature for the long sightlines has another explanation. In addition, the relatively high signal-to-noise ratio of the HD41161 data allows us to place constraints on the f-values of some neutral chlorine transitions, present in the FUSE bandpass, for which only theoretical values are available.Comment: Accepted for publication on the Dec 10 2006 issue of the Ap

TOI-1452 b: SPIRou and TESS Reveal a Super-Earth in a Temperate Orbit Transiting an M4 Dwarf

Exploring the properties of exoplanets near or inside the radius valley provides insight on the transition from the rocky super-Earths to the larger, hydrogen-rich atmosphere mini-Neptunes. Here, we report the discovery of TOI-1452b, a transiting super-Earth (R-p = 1.67 +/- 0.07 R-circle times) in an 11.1 day temperate orbit (T-eq = 326 +/- 7 K) around the primary member (H = 10.0, T-eff = 3185 +/- 50 K) of a nearby visual-binary M dwarf. The transits were first detected by the Transiting Exoplanet Survey Satellite, then successfully isolated between the two 3.'' 2 companions with ground-based photometry from the Observatoire du Mont-Megantic and MuSCAT3. The planetary nature of TOI-1452b was established through high-precision velocimetry with the near-infrared SPTRou spectropolarimeter as part of the ongoing SPIRou Legacy Survey. The measured planetary mass (4.8 +/- 1.3 M-circle times) and inferred bulk density (5.6(-)(1.)(6)(+1.8) g cm(-3)) is suggestive of a rocky core surrounded by a volatile-rich envelope. More quantitatively, the mass and radius of TOI-1452b, combined with the stellar abundance of refractory elements (Fe, Mg, and Si) measured by SPTRou, is consistent with a core-mass fraction of 18% +/- 6% and a water-mass fraction of 22(-13)(+21)%. The water world candidate TOI-14521) is a prime target for future atmospheric characterization with JWST, featuring a transmission spectroscopy metric similar to other well-known temperate small planets such as LHS 1140b and K2-18 b. The system is located near Webb's northern continuous viewing zone, implying that is can be followed at almost any moment of the year

The D/H Ratio in the Interstellar Medium toward the White Dwarf PG0038+199

We determine the D/H ratio in the interstellar medium toward the DO white dwarf PG0038+199 using spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE), with ground-based support from Keck HIRES. We employ curve of growth, apparent optical depth and profile fitting techniques to measure column densities and limits of many other species (H2, NaI, CI, CII, CIII, NI, NII, OI, SiII, PII, SIII, ArI and FeII) which allow us to determine related ratios such as D/O, D/N and the H2 fraction. Our efforts are concentrated on measuring gas-phase D/H, which is key to understanding Galactic chemical evolution and comparing it to predictions from Big Bang nucleosynthesis. We find column densities log N(HI) = 20.41+-0.08, log N(DI)=15.75+-0.08 and log N(H2) = 19.33+-0.04, yielding a molecular hydrogen fraction of 0.14+-0.02 (2 sigma errors), with an excitation temperature of 143+-5K. The high HI column density implies that PG0038+199 lies outside of the Local Bubble; we estimate its distance to be 297 (+164,-104)pc (1 sigma). D/[HI+2H2] toward PG0038+199 is 1.91(+0.52,-0.42) e-5 (2 sigma). There is no evidence of component structure on the scale of Delta v > 8 km/s based on NaI, but there is marginal evidence for structure on smaller scales. The D/H value is high compared to the majority of recent D/H measurements, but consistent with the values for two other measurements at similar distances. D/O is in agreement with other distant measurements. The scatter in D/H values beyond ~100pc remains a challenge for Galactic chemical evolution.Comment: 59 pages, 7 tables, 18 figures (1 standalone), accepted by ApJ v2 minor typos correcte

The deuterium-to-oxygen ratio in the interstellar medium

Because the ionization balances for HI, OI, and DI are locked together by charge exchange, D/O is an important tracer for the value of the D/H ratio and for potential spatial variations in the ratio. As the DI and OI column densities are of similar orders of magnitude for a given sight line, comparisons of the two values will generally be less subject to systematic errors than comparisons of DI and HI, which differ by about five orders of magnitude. Moreover, D/O is additionally sensitive to astration, because as stars destroy deuterium, they should produce oxygen. We report here the results of a survey of D/O in the interstellar medium performed with FUSE. We also compare these results with those for D/N. Together with a few results from previous missions, the sample totals 24 lines of sight. The distances range from a few pc to ~2000 pc and log N(DI) from ~13 to ~16 (cm-2). The D/O ratio is constant in the local interstellar medium out to distances of ~150 pc and N(DI) ~ 1x10^15 cm-2, i.e. within the Local Bubble. In this region of the interstellar space, we find D/O = (3.84+/-0.16)x10^-2 (1 sigma in the mean). The homogeneity of the local D/O measurements shows that the spatial variations in the local D/H and O/H must be extremely small, if any. A comparison of the Local Bubble mean value with the few D/O measurements available for low metallicity quasar sight lines shows that the D/O ratio decreases with cosmic evolution, as expected. Beyond the Local Bubble we detected significant spatial variations in the value of D/O. This likely implies a variation in D/H, as O/H is known to not vary significantly over the distances covered in this study. Our dataset suggests a present-epoch deuterium abundance below 1x10^-5, i.e. lower than the value usually assumed, around 1.5x10^-5.Comment: 17 pages, 9 figures, 4 tables, accepted for publication in the Astrophysical Journa

Interstellar Deuterium, Nitrogen, and Oxygen Abundances Toward GD 246, WD 2331−-475, HZ 21, and Lan 23: Results from the FUSE Mission

The interstellar abundances of D I, N I, and O I in the local ISM are studied us ing high-resolution spectra of four hot white dwarfs. The spectra of GD 246, WD 2331$-$475, HZ 21, and Lan 23 were obtained with the {\it Far Ultraviolet Spectroscopic Explorer} FUSE in the wavelength range 905-1187 A. The line of sight to GD 246 probes the Local Interstellar Cloud and at least one other H I cloud inside the Local Bubble, which contains most of the gas seen al ong this line of sight. The column densities of H I, C II*, S II, and Si II are measured using archival STIS echelle-mode observations. The H I column density is determined by fitting the strong damping wings of inte rstellar Lyman alpha using a model atmosphere to account for the stellar continuum. We combine the different abundance ratios computed here with previous published values to produce revised FUSE abundance ratios for DI/HI, OI/HI, NI/HI, DI/NI, DI/OI, and OI/NI.Comment: 12 figures, 48 page

FUSE Observation of the Ultramassive White Dwarf PG1658+441

We present an analysis of the Far Ultraviolet Spectroscopic Explorer (FUSE) spectrum of the ultramassive (M = 1.31 solar mass), magnetic (B_s = 2.3 MG) white dwarf PG 1658+441. The far ultraviolet (FUV) spectrum exhibits very broad Lyman lines and quasi-molecular Lyman beta satellites, but weak Lyman gamma satellites may also be present. PG 1658+441 is the hottest white dwarf known to show these satellite features. We fit the Lyman lines with stellar models and obtain atmospheric parameters consistent with a published analysis of the Balmer lines. By averaging results obtained for the different FUSE segments, we determine Teff = 29,620 +/- 500K and log g = 9.31 +/- 0.07. The models match the data over large portions of the spectrum but discrepancies remain near the satellite features. Finally, no trace elements have been identified in the FUV spectrum, and we provide abundance upper limits for C, N, Si, and P.Comment: 17 pages, 4 figure