Evidence of Truly Young High-α Dwarf Stars
The existence of high- α stars with inferred ages <6 Gyr has been confirmed recently with large spectroscopic and photometric surveys. However, stellar mergers or binary interactions can induce properties associated with young ages, such as high mass, rapid rotation, or high activity, even in old...
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IOP Publishing
2025-01-01
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| Series: | The Astronomical Journal |
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| Online Access: | https://doi.org/10.3847/1538-3881/ada9e0 |
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| author | Yuxi(Lucy) Lu Isabel L. Colman Maryum Sayeed Louis Amard Sven Buder Catherine Manea Soichiro Hattori Marc H. Pinsonneault Adrian M. Price-Whelan Megan Bedell David Nidever Jennifer A. Johnson Melissa Ness Ruth Angus Zachary R. Claytor Danny Horta Aida Behmard |
| author_facet | Yuxi(Lucy) Lu Isabel L. Colman Maryum Sayeed Louis Amard Sven Buder Catherine Manea Soichiro Hattori Marc H. Pinsonneault Adrian M. Price-Whelan Megan Bedell David Nidever Jennifer A. Johnson Melissa Ness Ruth Angus Zachary R. Claytor Danny Horta Aida Behmard |
| author_sort | Yuxi(Lucy) Lu |
| collection | DOAJ |
| description | The existence of high- α stars with inferred ages <6 Gyr has been confirmed recently with large spectroscopic and photometric surveys. However, stellar mergers or binary interactions can induce properties associated with young ages, such as high mass, rapid rotation, or high activity, even in old populations. Literature studies have confirmed that at least some of these apparently young stars are old merger products. However, none have ruled out the possibility of genuinely young high- α stars. Because cool GKM dwarfs spin down, rapid rotation can be used to indicate youth. In this paper, we provide strong evidence that truly young high- α stars exist by studying high- α rotators in the Kepler and K2 field with abundance measurements from GALAH and APOGEE. After excluding close binaries using radial velocity (RV) measurements from Gaia DR3 and multiepoch RVs from APOGEE, we find a total of 32 high- α rapid rotators with periods ∼10–30 days, 14 of which have lithium measurements from GALAH, indicating that they have not gone through past mass transfer or stellar merger events. We identify 10 young high- α candidates with no signs of merger-induced mixing or close companions. One clear example is a G dwarf with a measurable rotation and an age of < 5 Gyr that is likely a single star with multiple RV measurements from APOGEE, has significant lithium detection from GALAH ( A (Li) = 1.79), and has no signs of planet engulfment. |
| format | Article |
| id | doaj-art-b08642ed1b224fd7a7ae622fc0ba20ec |
| institution | DOAJ |
| issn | 1538-3881 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astronomical Journal |
| spelling | doaj-art-b08642ed1b224fd7a7ae622fc0ba20ec2025-08-20T02:44:47ZengIOP PublishingThe Astronomical Journal1538-38812025-01-01169316810.3847/1538-3881/ada9e0Evidence of Truly Young High-α Dwarf StarsYuxi(Lucy) Lu0https://orcid.org/0000-0003-4769-3273Isabel L. Colman1https://orcid.org/0000-0001-8196-516XMaryum Sayeed2https://orcid.org/0000-0001-6180-8482Louis Amard3https://orcid.org/0000-0003-2508-6093Sven Buder4https://orcid.org/0000-0002-4031-8553Catherine Manea5https://orcid.org/0000-0002-0900-6076Soichiro Hattori6https://orcid.org/0000-0002-0842-863XMarc H. Pinsonneault7https://orcid.org/0000-0002-7549-7766Adrian M. Price-Whelan8https://orcid.org/0000-0003-0872-7098Megan Bedell9https://orcid.org/0000-0001-9907-7742David Nidever10https://orcid.org/0000-0002-1793-3689Jennifer A. Johnson11Melissa Ness12https://orcid.org/0000-0001-5082-6693Ruth Angus13https://orcid.org/0000-0003-4540-5661Zachary R. Claytor14https://orcid.org/0000-0002-9879-3904Danny Horta15https://orcid.org/0000-0003-1856-2151Aida Behmard16https://orcid.org/0000-0003-0012-9093Department of Astronomy, The Ohio State University , Columbus, 140 W. 18th Avenue, OH 43210, USA ; lucylulu12311@gmail.com; Center for Cosmology and Astroparticle Physics (CCAPP), The Ohio State University , 191 W. Woodruff Avenue, Columbus, OH 43210, USA; American Museum of Natural History , Central Park West, New York, NY 10024, USAAmerican Museum of Natural History , Central Park West, New York, NY 10024, USA; Liberal Studies, New York University , 726 Broadway, New York, NY 10003, USADepartment of Astronomy, Columbia University , 550 West 120th Street, New York, NY 10027, USAAIM, CEA, CNRS, Université Paris-Saclay, Université de Paris , Sorbonne Paris Cité, Sorbonne Paris Cité, Gif-sur-Yvette, 91191, FranceResearch School of Astronomy & Astrophysics, Australian National University , Canberra ACT 2611, Australia; Center of Excellence for Astrophysics in Three Dimensions (ASTRO-3D) , AustraliaDepartment of Astronomy, The University of Texas at Austin , 2515 Speedway, Austin, TX 78712, USAAmerican Museum of Natural History , Central Park West, New York, NY 10024, USA; Department of Astronomy, Columbia University , 550 West 120th Street, New York, NY 10027, USADepartment of Astronomy, The Ohio State University , Columbus, 140 W. 18th Avenue, OH 43210, USA ; lucylulu12311@gmail.com; Center for Cosmology and Astroparticle Physics (CCAPP), The Ohio State University , 191 W. Woodruff Avenue, Columbus, OH 43210, USACenter for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USACenter for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USAMontana State University , P.O. Box 173840, Bozeman, MT 59717, USADepartment of Astronomy, The Ohio State University , Columbus, 140 W. 18th Avenue, OH 43210, USA ; lucylulu12311@gmail.com; Center for Cosmology and Astroparticle Physics (CCAPP), The Ohio State University , 191 W. Woodruff Avenue, Columbus, OH 43210, USADepartment of Astronomy, Columbia University , 550 West 120th Street, New York, NY 10027, USA; Research School of Astronomy & Astrophysics, Australian National University , Canberra ACT 2611, Australia; Center of Excellence for Astrophysics in Three Dimensions (ASTRO-3D) , AustraliaAmerican Museum of Natural History , Central Park West, New York, NY 10024, USA; Center for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USASpace Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Astronomy, University of Florida , 211 Bryant Space Science Center, Gainesville, FL 32611, USACenter for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USAAmerican Museum of Natural History , Central Park West, New York, NY 10024, USA; Center for Computational Astrophysics, Flatiron Institute , 162 5th Avenue, New York, NY 10010, USAThe existence of high- α stars with inferred ages <6 Gyr has been confirmed recently with large spectroscopic and photometric surveys. However, stellar mergers or binary interactions can induce properties associated with young ages, such as high mass, rapid rotation, or high activity, even in old populations. Literature studies have confirmed that at least some of these apparently young stars are old merger products. However, none have ruled out the possibility of genuinely young high- α stars. Because cool GKM dwarfs spin down, rapid rotation can be used to indicate youth. In this paper, we provide strong evidence that truly young high- α stars exist by studying high- α rotators in the Kepler and K2 field with abundance measurements from GALAH and APOGEE. After excluding close binaries using radial velocity (RV) measurements from Gaia DR3 and multiepoch RVs from APOGEE, we find a total of 32 high- α rapid rotators with periods ∼10–30 days, 14 of which have lithium measurements from GALAH, indicating that they have not gone through past mass transfer or stellar merger events. We identify 10 young high- α candidates with no signs of merger-induced mixing or close companions. One clear example is a G dwarf with a measurable rotation and an age of < 5 Gyr that is likely a single star with multiple RV measurements from APOGEE, has significant lithium detection from GALAH ( A (Li) = 1.79), and has no signs of planet engulfment.https://doi.org/10.3847/1538-3881/ada9e0Stellar agesStellar rotationGalaxy abundancesGalaxy formationGalaxy dynamicsGalaxy chemical evolution |
| spellingShingle | Yuxi(Lucy) Lu Isabel L. Colman Maryum Sayeed Louis Amard Sven Buder Catherine Manea Soichiro Hattori Marc H. Pinsonneault Adrian M. Price-Whelan Megan Bedell David Nidever Jennifer A. Johnson Melissa Ness Ruth Angus Zachary R. Claytor Danny Horta Aida Behmard Evidence of Truly Young High-α Dwarf Stars The Astronomical Journal Stellar ages Stellar rotation Galaxy abundances Galaxy formation Galaxy dynamics Galaxy chemical evolution |
| title | Evidence of Truly Young High-α Dwarf Stars |
| title_full | Evidence of Truly Young High-α Dwarf Stars |
| title_fullStr | Evidence of Truly Young High-α Dwarf Stars |
| title_full_unstemmed | Evidence of Truly Young High-α Dwarf Stars |
| title_short | Evidence of Truly Young High-α Dwarf Stars |
| title_sort | evidence of truly young high α dwarf stars |
| topic | Stellar ages Stellar rotation Galaxy abundances Galaxy formation Galaxy dynamics Galaxy chemical evolution |
| url | https://doi.org/10.3847/1538-3881/ada9e0 |
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