_version_ 1866917363472924672
author Simon, Joshua D.
Rodriguez, Joseph E.
Galarza, Jhon Yana
Latham, David W.
DiTomasso, Victoria
Collins, Karen A.
Schulte, Jack
Chiti, Anirudh
Quinn, Samuel N.
Mardini, Mohammad K.
Kanodia, Shubham
Teske, Johanna K.
Ferguson, Peter S.
Yee, Samuel W.
Tan, T. G.
Alsubai, Khalid
Barkaoui, Khalid
Benkhaldoun, Zouhair
Bernacki, Krzysztof
Bhattacharya, Jaikrit
de Leon, Jerome P.
Deveny, Sarah J.
Everett, Mark E.
Fukuda, Izuru
Fukui, Akihiko
Gillon, Michael
Gupta, Arvind F.
Howell, Steve B.
Jehin, Emmanuel
Lacedelli, Gaia
Lark, Adam
Littlefield, Colin
Murgas, Felipe
Narita, Norio
Palle, Enric
Parviainen, Hannu
Popowicz, Adam
Schwarz, Richard P.
Shporer, Avi
Soubkiou, Abderahmane
Wilkin, Francis P.
author_facet Simon, Joshua D.
Rodriguez, Joseph E.
Galarza, Jhon Yana
Latham, David W.
DiTomasso, Victoria
Collins, Karen A.
Schulte, Jack
Chiti, Anirudh
Quinn, Samuel N.
Mardini, Mohammad K.
Kanodia, Shubham
Teske, Johanna K.
Ferguson, Peter S.
Yee, Samuel W.
Tan, T. G.
Alsubai, Khalid
Barkaoui, Khalid
Benkhaldoun, Zouhair
Bernacki, Krzysztof
Bhattacharya, Jaikrit
de Leon, Jerome P.
Deveny, Sarah J.
Everett, Mark E.
Fukuda, Izuru
Fukui, Akihiko
Gillon, Michael
Gupta, Arvind F.
Howell, Steve B.
Jehin, Emmanuel
Lacedelli, Gaia
Lark, Adam
Littlefield, Colin
Murgas, Felipe
Narita, Norio
Palle, Enric
Parviainen, Hannu
Popowicz, Adam
Schwarz, Richard P.
Shporer, Avi
Soubkiou, Abderahmane
Wilkin, Francis P.
contents Most known planets are found around metal-rich host stars, which has made it difficult to determine whether a lower metallicity limit for planet formation exists and how the properties of planets born in low-metallicity environments may differ from those with metal-rich origins. We present the discovery and characterization of TOI-7169 b (TIC 372048733 b), a hot Jupiter that is orbiting a spectroscopically-confirmed metal-poor ([Fe/H] = -0.72 +/- 0.05) host star. Based on photometry from TESS and follow-up ground-based imaging, we measure an orbital period of 3.4373125 d and a planetary radius of 1.475 +/- 0.029 R_Jup. We use TRES spectroscopy to determine a mass for TOI-7169 b of 0.41 +/- 0.14 M_Jup. The planet is therefore inflated, with a low density of 0.159 +0.055/-0.054 g/cm^3. We also characterize the host star, showing that TOI-7169 is ancient (12.3 +/- 0.6 Gyr) and alpha-enhanced ([alpha/Fe] ~ 0.3), but with a Galactocentric orbit that is confined to the thin disk. TOI-7169 is perhaps the oldest and most metal-poor star currently known to host a transiting giant planet. Future transmission spectroscopy probing the atmosphere of TOI-7169 b may provide insight into the effect of metallicity on the physical properties of giant planets.
format Preprint
id arxiv_https___arxiv_org_abs_2603_25787
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle TOI-7169 b: A Hot Jupiter Transiting a Metal-Poor Star
Simon, Joshua D.
Rodriguez, Joseph E.
Galarza, Jhon Yana
Latham, David W.
DiTomasso, Victoria
Collins, Karen A.
Schulte, Jack
Chiti, Anirudh
Quinn, Samuel N.
Mardini, Mohammad K.
Kanodia, Shubham
Teske, Johanna K.
Ferguson, Peter S.
Yee, Samuel W.
Tan, T. G.
Alsubai, Khalid
Barkaoui, Khalid
Benkhaldoun, Zouhair
Bernacki, Krzysztof
Bhattacharya, Jaikrit
de Leon, Jerome P.
Deveny, Sarah J.
Everett, Mark E.
Fukuda, Izuru
Fukui, Akihiko
Gillon, Michael
Gupta, Arvind F.
Howell, Steve B.
Jehin, Emmanuel
Lacedelli, Gaia
Lark, Adam
Littlefield, Colin
Murgas, Felipe
Narita, Norio
Palle, Enric
Parviainen, Hannu
Popowicz, Adam
Schwarz, Richard P.
Shporer, Avi
Soubkiou, Abderahmane
Wilkin, Francis P.
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
Most known planets are found around metal-rich host stars, which has made it difficult to determine whether a lower metallicity limit for planet formation exists and how the properties of planets born in low-metallicity environments may differ from those with metal-rich origins. We present the discovery and characterization of TOI-7169 b (TIC 372048733 b), a hot Jupiter that is orbiting a spectroscopically-confirmed metal-poor ([Fe/H] = -0.72 +/- 0.05) host star. Based on photometry from TESS and follow-up ground-based imaging, we measure an orbital period of 3.4373125 d and a planetary radius of 1.475 +/- 0.029 R_Jup. We use TRES spectroscopy to determine a mass for TOI-7169 b of 0.41 +/- 0.14 M_Jup. The planet is therefore inflated, with a low density of 0.159 +0.055/-0.054 g/cm^3. We also characterize the host star, showing that TOI-7169 is ancient (12.3 +/- 0.6 Gyr) and alpha-enhanced ([alpha/Fe] ~ 0.3), but with a Galactocentric orbit that is confined to the thin disk. TOI-7169 is perhaps the oldest and most metal-poor star currently known to host a transiting giant planet. Future transmission spectroscopy probing the atmosphere of TOI-7169 b may provide insight into the effect of metallicity on the physical properties of giant planets.
title TOI-7169 b: A Hot Jupiter Transiting a Metal-Poor Star
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2603.25787