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Theories of planet formation predict that low-mass stars should rarely host exoplanets with masses exceeding that of Neptune. We used radial velocity observations to detect a Neptune-mass exoplanet orbiting LHS 3154, a star that is nine times less massive than the Sun. The exoplanet’s orbital period is 3.7 days, and its minimum mass is 13.2 Earth masses. We used simulations to show that the high planet-to-star mass ratio (>3.5 × 10⁻⁴) is not an expected outcome of either the core accretion or gravitational instability theories of planet formation. In the core-accretion simulations, we show that close-in Neptune-mass planets are only formed if the dust mass of the protoplanetary disk is an order of magnitude greater than typically observed around very low-mass stars.

 

We demonstrate a 10 GHz octave-spanning frequency comb from a 1550 nm resonant waveguide-type electro-optic comb generator. The impact of cavity filtering on the amplified spontaneous emission and shot noise is studied experimentally and theoretically. 

Abstract TOI-1899 b is a rare exoplanet, a temperate warm Jupiter orbiting an M dwarf, first discovered by Cañas et al. (2020) from a TESS single-transit event. Using new radial velocities (RVs) from the precision RV spectrographs HPF and NEID, along with additional TESS photometry and ground-based transit follow-up, we are able to derive a much more precise orbital period of P = 29.090312 − 0.000035 + 0.000036 days, along with a radius of R p = 0.99 ± 0.03 R J . We have also improved the constraints on planet mass, M p = 0.67 ± 0.04 M J , and eccentricity, which is consistent with a circular orbit at 2 σ ( e = 0.044 − 0.027 + 0.029 ). TOI-1899 b occupies a unique region of parameter space as the coolest known ( T eq ≈ 380 K) Jovian-sized transiting planet around an M dwarf; we show that it has great potential to provide clues regarding the formation and migration mechanisms of these rare gas giants through transmission spectroscopy with JWST, as well as studies of tidal evolution. 

Abstract We confirm the planetary nature of two gas giants discovered by TESS to transit M dwarfs with stellar companions at wide separations. TOI-3984 A ( J = 11.93) is an M4 dwarf hosting a short-period (4.353326 ± 0.000005 days) gas giant ( M p = 0.14 ± 0.03 M J and R p = 0.71 ± 0.02 R J ) with a wide-separation white dwarf companion. TOI-5293 A ( J = 12.47) is an M3 dwarf hosting a short-period (2.930289 ± 0.000004 days) gas giant ( M p = 0.54 ± 0.07 M J and R p = 1.06 ± 0.04 R J ) with a wide-separation M dwarf companion. We characterize both systems using a combination of ground- and space-based photometry, speckle imaging, and high-precision radial velocities from the Habitable-zone Planet Finder and NEID spectrographs. TOI-3984 A b ( T eq = 563 ± 15 K and TSM = 138 − 27 + 29 ) and TOI-5293 A b ( T eq = 675 − 30 + 42 K and TSM = 92 ± 14) are two of the coolest gas giants among the population of hot Jupiter–sized gas planets orbiting M dwarfs and are favorable targets for atmospheric characterization of temperate gas giants and 3D obliquity measurements to probe system architecture and migration scenarios. 

Precision laser spectroscopy is key to many developments in atomic and molecular physics and the advancement of related technologies such as atomic clocks and sensors. However, in important spectroscopic scenarios, such as astronomy and remote sensing, the light is of thermal origin, and interferometric or diffractive spectrometers typically replace laser spectroscopy. In this work, we employ laser-based heterodyne radiometry to measure incoherent light sources in the near-infrared and introduce techniques for absolute frequency calibration with a laser frequency comb. Measuring the solar continuum, we obtain a signal-to-noise ratio that matches the fundamental quantum-limited prediction given by the thermal photon distribution and our system’s efficiency, bandwidth, and averaging time. With resolving power$R\sim <\#comment/>{10}^6$, we determine the center frequency of an iron line in the solar spectrum to sub-MHz absolute frequency uncertainty in under 10 min, a fractional precision 1/4000 the linewidth. Additionally, we propose concepts that take advantage of refractive beam shaping to decrease the effects of pointing instabilities by$100\times <\#comment/>$, and of frequency comb multiplexing to increase data acquisition rates and spectral bandwidths by comparable factors. Taken together, our work brings the power of telecommunications photonics and the precision of frequency comb metrology to laser heterodyne radiometry, with implications for solar and astronomical spectroscopy, remote sensing, and precise Doppler velocimetry.

 

We demonstrate thin-film lithium niobate waveguides with chirped poling periods for efficient supercontinuum viaχ⁽²⁾andχ⁽³⁾nonlinearities. With picojoule energies, we generate gap free frequency combs spanning 330 to 2400 nm. 

We employ an efficient 1550 nm resonant waveguide-type electro-optic comb generator with PM nonlinear fiber optics to generate 50 fs pulses and 500 nm broad super- continuum at 20 GHz. 

Abstract We report the discovery of an M = 67 ± 2 M J brown dwarf transiting the early M dwarf TOI-2119 on an eccentric orbit ( e = 0.3362 ± 0.0005) at an orbital period of 7.200861 ± 0.000005 days. We confirm the brown dwarf nature of the transiting companion using a combination of ground-based and space-based photometry and high-precision velocimetry from the Habitable-zone Planet Finder. Detection of the secondary eclipse with TESS photometry enables a precise determination of the eccentricity and reveals the brown dwarf has a brightness temperature of 2100 ± 80 K, a value which is consistent with an early L dwarf. TOI-2119 is one of the most eccentric known brown dwarfs with P < 10 days, possibly due to the long circularization timescales for an object orbiting an M dwarf. We assess the prospects for determining the obliquity of the host star to probe formation scenarios and the possibility of additional companions in the system using Gaia EDR3 and our radial velocities. 

Abstract We present the discovery of a new Jovian-sized planet, TOI-3757 b, the lowest-density transiting planet known to orbit an M dwarf (M0V). This planet was discovered around a solar-metallicity M dwarf, using Transiting Exoplanet Survey Satellite photometry and confirmed with precise radial velocities from the Habitable-zone Planet Finder (HPF) and NEID. With a planetary radius of 12.0 − 0.5 + 0.4 R ⊕ and mass of 85.3 − 8.7 + 8.8 M ⊕ , not only does this object add to the small sample of gas giants (∼10) around M dwarfs, but also its low density ( ρ = 0.27 − 0.04 + 0.05 g cm −3 ) provides an opportunity to test theories of planet formation. We present two hypotheses to explain its low density; first, we posit that the low metallicity of its stellar host (∼0.3 dex lower than the median metallicity of M dwarfs hosting gas giants) could have played a role in the delayed formation of a solid core massive enough to initiate runaway accretion. Second, using the eccentricity estimate of 0.14 ± 0.06, we determine it is also plausible for tidal heating to at least partially be responsible for inflating the radius of TOI-3757b b. The low density and large scale height of TOI-3757 b makes it an excellent target for transmission spectroscopy studies of atmospheric escape and composition (transmission spectroscopy measurement of ∼ 190). We use HPF to perform transmission spectroscopy of TOI-3757 b using the helium 10830 Å line. Doing this, we place an upper limit of 6.9% (with 90% confidence) on the maximum depth of the absorption from the metastable transition of He at ∼10830 Å, which can help constraint the atmospheric mass-loss rate in this energy-limited regime.