All Outputs (173)

GJ 3090 b: one of the most favourable mini-Neptune for atmospheric characterisation (2022)
Journal Article
Hellier. (2022). GJ 3090 b: one of the most favourable mini-Neptune for atmospheric characterisation. Astronomy & Astrophysics, https://doi.org/10.1051/0004-6361/202243975

We report the detection of GJ 3090 b (TOI-177.01), a mini-Neptune on a 2.9-day orbit transiting a bright (K = 7.3 mag) M2 dwarf located at 22 pc. The planet was identified by the Transiting Exoplanet Survey Satellite and was confirmed with the High A... Read More about GJ 3090 b: one of the most favourable mini-Neptune for atmospheric characterisation.

The HD 260655 system: Two rocky worlds transiting a bright M dwarf at 10 pc (2022)
Journal Article
Hellier. (2022). The HD 260655 system: Two rocky worlds transiting a bright M dwarf at 10 pc. Astronomy & Astrophysics, 1 - 23. https://doi.org/10.1051/0004-6361/202243834

We report the discovery of a multiplanetary system transiting the M0 V dwarf HD 260655 (GJ 239, TOI-4599). The system consists of at least two transiting planets, namely HD 260655 b, with a period of 2.77 d, a radius of Rb = 1.240 ± 0.023 R?, a mass... Read More about The HD 260655 system: Two rocky worlds transiting a bright M dwarf at 10 pc.

TOI-712: A System of Adolescent Mini-Neptunes Extending to the Habitable Zone (2022)
Journal Article
Hellier. (2022). TOI-712: A System of Adolescent Mini-Neptunes Extending to the Habitable Zone. Astronomical Journal, https://doi.org/10.3847/1538-3881/ac7954

As an all-sky survey, NASA's Transiting Exoplanet Survey Satellite (TESS) mission is able to detect the brightest and rarest types of transiting planetary systems, including young planets that enable study of the evolutionary processes that occur wit... Read More about TOI-712: A System of Adolescent Mini-Neptunes Extending to the Habitable Zone.

A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system (2022)
Journal Article
Hellier. (2022). A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system. Nature Astronomy, https://doi.org/10.1038/s41550-022-01641-y

It is commonly accepted that exoplanets with orbital periods shorter than one day, also known as ultra-short-period (USP) planets, formed further out within their natal protoplanetary disks before migrating to their current-day orbits via dynamical i... Read More about A low-eccentricity migration pathway for a 13-h-period Earth analogue in a four-planet system.

The young HD 73583 (TOI-560) planetary system: two 10-M-circle plus mini-Neptunes transiting a 500-Myr-old, bright, and active K dwarf (2022)
Journal Article
Hellier. (2022). The young HD 73583 (TOI-560) planetary system: two 10-M-circle plus mini-Neptunes transiting a 500-Myr-old, bright, and active K dwarf. Monthly Notices of the Royal Astronomical Society, 1606 - 1627. https://doi.org/10.1093/mnras/stac638

We present the discovery and characterization of two transiting planets observed by TESS in the light curves of the young and bright (V = 9.67) star HD73583 (TOI-560). We perform an intensive spectroscopic and photometric space- and ground-based foll... Read More about The young HD 73583 (TOI-560) planetary system: two 10-M-circle plus mini-Neptunes transiting a 500-Myr-old, bright, and active K dwarf.

BEBOP II: sensitivity to sub-Saturn circumbinary planets using radial-velocities (2022)
Journal Article
Maxted, & Hellier. (2022). BEBOP II: sensitivity to sub-Saturn circumbinary planets using radial-velocities. Monthly Notices of the Royal Astronomical Society, 3571 - 3583. https://doi.org/10.1093/mnras/stac113

BEBOP is a radial-velocity survey that monitors a sample of single-lined eclipsing binaries, in search of circumbinary planets by using high-resolution spectrographs. Here, we describe and test the methods we use to identify planetary signals within... Read More about BEBOP II: sensitivity to sub-Saturn circumbinary planets using radial-velocities.

TOI-1201 b: A mini-Neptune transiting a bright and moderately young M dwarf (2021)
Journal Article
Hellier. (2021). TOI-1201 b: A mini-Neptune transiting a bright and moderately young M dwarf. Astronomy & Astrophysics, https://doi.org/10.1051/0004-6361/202141587

We present the discovery of a transiting mini-Neptune around TOI-1201, a relatively bright and moderately young early M dwarf (J ˜ 9.5 mag, ~600–800 Myr) in an equal-mass ~8 arcsecond-wide binary system, using data from the Transiting Exoplanet Surve... Read More about TOI-1201 b: A mini-Neptune transiting a bright and moderately young M dwarf.

GJ 367b: A dense, ultrashort-period sub-Earth planet transiting a nearby red dwarf star. (2021)
Journal Article
Hellier. (2021). GJ 367b: A dense, ultrashort-period sub-Earth planet transiting a nearby red dwarf star. Science, 1271 - 1275. https://doi.org/10.1126/science.aay3253

Ultrashort-period (USP) exoplanets have orbital periods shorter than 1 day. Precise masses and radii of USP exoplanets could provide constraints on their unknown formation and evolution processes. We report the detection and characterization of the U... Read More about GJ 367b: A dense, ultrashort-period sub-Earth planet transiting a nearby red dwarf star..

TIC 172900988: A Transiting Circumbinary Planet Detected in One Sector of TESS Data (2021)
Journal Article
Hellier, & Maxted. (2021). TIC 172900988: A Transiting Circumbinary Planet Detected in One Sector of TESS Data. Astronomical Journal, https://doi.org/10.3847/1538-3881/ac223a

We report the first discovery of a transiting circumbinary planet detected from a single sector of Transiting Exoplanet Survey Satellite (TESS) data. During Sector 21, the planet TIC 172900988b transited the primary star and then five days later it t... Read More about TIC 172900988: A Transiting Circumbinary Planet Detected in One Sector of TESS Data.

HD 183579b: a warm sub-Neptune transiting a solar twin detected by TESS (2021)
Journal Article
Hellier. (2021). HD 183579b: a warm sub-Neptune transiting a solar twin detected by TESS. Monthly Notices of the Royal Astronomical Society, 2220 - 2240. https://doi.org/10.1093/mnras/stab2224

We report the discovery and characterization of a transiting warm sub-Neptune planet around the nearby bright (V = 8.75 mag, K = 7.15 mag) solar twin HD 183579, delivered by the Transiting Exoplanet Survey Satellite (TESS). The host star is located 5... Read More about HD 183579b: a warm sub-Neptune transiting a solar twin detected by TESS.

The EBLM project - VIII. First results for M-dwarf mass, radius, and effective temperature measurements using CHEOPS light curves (2021)
Journal Article
Hellier, & Maxted. (2021). The EBLM project - VIII. First results for M-dwarf mass, radius, and effective temperature measurements using CHEOPS light curves. Monthly Notices of the Royal Astronomical Society, 306 - 322. https://doi.org/10.1093/mnras/stab1687

The accuracy of theoretical mass, radius, and effective temperature values for M-dwarf stars is an active topic of debate. Differences between observed and theoretical values have raised the possibility that current theoretical stellar structure and... Read More about The EBLM project - VIII. First results for M-dwarf mass, radius, and effective temperature measurements using CHEOPS light curves.

TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet (2021)
Journal Article
Osborn, A., Armstrong, D. J., Cale, B., Brahm, R., Wittenmyer, R. A., Dai, F., Crossfield, I. J. M., Bryant, E. M., Adibekyan, V., Cloutier, R., Collins, K. A., Mena, E. D., Fridlund, M., Hellier, C., Howell, S. B., King, G. W., Lillo-Box, J., Otegi, J., Sousa, S., Stassun, K. G., …Zohrabi, F. (2021). TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet. Monthly Notices of the Royal Astronomical Society, 507(2), 2782 - 2803. https://doi.org/10.1093/mnras/stab2313

We present the bright (Vmag = 9.12), multiplanet system TOI-431, characterized with photometry and radial velocities (RVs). We estimate the stellar rotation period to be 30.5 ± 0.7 d using archival photometry and RVs. Transiting Exoplanet Survey Sate... Read More about TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet.

TIC 454140642: A Compact, Coplanar, Quadruple-lined Quadruple Star System Consisting of Two Eclipsing Binaries (2021)
Journal Article
Hellier. (2021). TIC 454140642: A Compact, Coplanar, Quadruple-lined Quadruple Star System Consisting of Two Eclipsing Binaries. Astrophysical Journal, 93 - 93. https://doi.org/10.3847/1538-4357/ac04ad

We report the discovery of a compact, coplanar, quadruple-lined, eclipsing quadruple star system from Transiting Exoplanet Survey Satellite data, TIC 454140642, also known as TYC 0074-01254-1. The target was first detected in Sector 5 with a 30-minut... Read More about TIC 454140642: A Compact, Coplanar, Quadruple-lined Quadruple Star System Consisting of Two Eclipsing Binaries.

Warm Jupiters in TESS Full-frame Images: A Catalog and Observed Eccentricity Distribution for Year 1 (2021)
Journal Article
Hellier. (2021). Warm Jupiters in TESS Full-frame Images: A Catalog and Observed Eccentricity Distribution for Year 1. Astrophysical Journal, https://doi.org/10.3847/1538-4365/abf73c

Warm Jupiters—defined here as planets larger than 6 Earth radii with orbital periods of 8–200 days—are a key missing piece in our understanding of how planetary systems form and evolve. It is currently debated whether Warm Jupiters form in situ, unde... Read More about Warm Jupiters in TESS Full-frame Images: A Catalog and Observed Eccentricity Distribution for Year 1.

TOI-269 b: an eccentric sub-Neptune transiting a M2 dwarf revisited with ExTrA (2021)
Journal Article
Cointepas, M., Almenara, J. M., Bonfils, X., Bouchy, F., Astudillo-Defru, N., Murgas, F., Otegi, J. F., Wyttenbach, A., Anderson, D. R., Artigau, E., Martins, B. L. C., Charbonneau, D., Collins, K. A., Collins, K., Correia, J.-J., Curaba, S., Delboulbe, A., Delfosse, X., Diaz, R. F., Dorn, C., …Jenkins, J. M. (2021). TOI-269 b: an eccentric sub-Neptune transiting a M2 dwarf revisited with ExTrA. Astronomy & Astrophysics, 650, Article ARTN A145. https://doi.org/10.1051/0004-6361/202140328

We present the confirmation of a new sub-Neptune close to the transition between super-Earths and sub-Neptunes transiting the M2 dwarf TOI-269 (TIC 220 479 565, V = 14.4 mag, J = 10.9 mag, R⋆ = 0.40 R⊙, M⋆ = 0.39 M⊙, d = 57 pc). The exoplanet candida... Read More about TOI-269 b: an eccentric sub-Neptune transiting a M2 dwarf revisited with ExTrA.

A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113 (2021)
Journal Article
Hellier. (2021). A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113. Monthly Notices of the Royal Astronomical Society, 4842 - 4857. https://doi.org/10.1093/mnras/stab182

We report the discovery of HD?110113?b (TESS object of interest-755.01), a transiting mini-Neptune exoplanet on a 2.5-d orbit around the solar-analogue HD?110113 (Teff = 5730 K). Using TESS photometry and High Accuracy Radial velocity Planet Searcher... Read More about A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113.

TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images (2021)
Journal Article
Hellier. (2021). TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images. Astronomical Journal, https://doi.org/10.3847/1538-3881/abe38a

We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960)—based on... Read More about TESS Delivers Five New Hot Giant Planets Orbiting Bright Stars from the Full-frame Images.

TIC 168789840: A Sextuply Eclipsing Sextuple Star System (2021)
Journal Article
Hellier. (2021). TIC 168789840: A Sextuply Eclipsing Sextuple Star System. Astronomical Journal, 162 - 162. https://doi.org/10.3847/1538-3881/abddb5

We report the discovery of a sextuply eclipsing sextuple star system from TESS data, TIC 168789840, also known as TYC 7037-89-1, the first known sextuple system consisting of three eclipsing binaries. The target was observed in Sectors 4 and 5 during... Read More about TIC 168789840: A Sextuply Eclipsing Sextuple Star System.

A nearby transiting rocky exoplanet that is suitable for atmospheric investigation. (2021)
Journal Article
Hellier. (2021). A nearby transiting rocky exoplanet that is suitable for atmospheric investigation. Science, 1038 - 1041. https://doi.org/10.1126/science.abd7645

Spectroscopy of transiting exoplanets can be used to investigate their atmospheric properties and habitability. Combining radial velocity (RV) and transit data provides additional information on exoplanet physical properties. We detect a transiting r... Read More about A nearby transiting rocky exoplanet that is suitable for atmospheric investigation..

TESS Discovery of a Super-Earth and Three Sub-Neptunes Hosted by the Bright, Sun-like Star HD 108236 (2021)
Journal Article
Hellier. (2021). TESS Discovery of a Super-Earth and Three Sub-Neptunes Hosted by the Bright, Sun-like Star HD 108236. Astronomical Journal, https://doi.org/10.3847/1538-3881/abd73e

We report the discovery and validation of four extrasolar planets hosted by the nearby, bright, Sun-like (G3V) star HD 108236 using data from the Transiting Exoplanet Survey Satellite (TESS). We present transit photometry, reconnaissance, and precise... Read More about TESS Discovery of a Super-Earth and Three Sub-Neptunes Hosted by the Bright, Sun-like Star HD 108236.