A second planet transiting LTT 1445A and a determination of the masses of both worlds

Jennifer G. Winters; Ryan Cloutier; Amber A. Medina; Jonathan M. Irwin; David Charbonneau; Nicola Astudillo-Defru; Xavier Bonfils; Andrew W. Howard; Howard Isaacson; Jacob L. Bean; Andreas Seifahrt; Johanna K. Teske; Jason D. Eastman; Joseph D. Twicken; Karen A. Collins; Eric L. N. Jensen; Samuel N. Quinn; Matthew J. Payne; Martti H. Kristiansen; Alton Spencer; Andrew Vanderburg; Mathias Zechmeister; Lauren M. Weiss; Sharon Xuesong Wang; Gavin Wang; Stéphane Udry; Ivan A. Terentev; Julian Stürmer; Gudmundur Stefánsson; Avi Shporer; Stephen Shectman; Ramotholo Sefako; Hans Martin Schwengeler; Richard P. Schwarz; Nicholas Scarsdale; Ryan A. Rubenzahl; Arpita Roy; Lee J. Rosenthal; Paul Robertson; Erik A. Petigura; Francesco Pepe; Mark Omohundro; Joseph M. Akana Murphy; Felipe Murgas; Teo Močnik; Benjamin T. Montet; Ronald Mennickent; Andrew W. Mayo; Bob Massey; Jack Lubin; Christophe Lovis; Pablo Lewin; David Kasper; Stephen R. Kane; Jon M. Jenkins; Daniel Huber; Keith Horne; Michelle L. Hill; Paula Gorrini; Steven Giacalone; Benjamin Fulton; Thierry Forveille; Pedro Figueira; Tara Fetherolf; Courtney Dressing; Rodrigo F. Díaz; Xavier Delfosse; Paul A. Dalba; Fei Dai; C. C. Cortés; Ian J. M. Crossfield; Jeffrey D. Crane; Dennis M. Conti; Kevin I. Collins; Ashley Chontos; R. Paul Butler; Peyton Brown; Madison Brady; Aida Behmard; Corey Beard; Natalie M. Batalha; Jose-Manuel Almenara

doi:10.3847/1538-3881/ac50a9

A second planet transiting LTT 1445A and a determination of the masses of both worlds

Jennifer G. Winters^*, Ryan Cloutier, Amber A. Medina, Jonathan M. Irwin, David Charbonneau, Nicola Astudillo-Defru, Xavier Bonfils, Andrew W. Howard, Howard Isaacson, Jacob L. Bean, Andreas Seifahrt, Johanna K. Teske, Jason D. Eastman, Joseph D. Twicken, Karen A. Collins, Eric L. N. Jensen, Samuel N. Quinn, Matthew J. Payne, Martti H. Kristiansen, Alton SpencerAndrew Vanderburg, Mathias Zechmeister, Lauren M. Weiss, Sharon Xuesong Wang, Gavin Wang, Stéphane Udry, Ivan A. Terentev, Julian Stürmer, Gudmundur Stefánsson, Avi Shporer, Stephen Shectman, Ramotholo Sefako, Hans Martin Schwengeler, Richard P. Schwarz, Nicholas Scarsdale, Ryan A. Rubenzahl, Arpita Roy, Lee J. Rosenthal, Paul Robertson, Erik A. Petigura, Francesco Pepe, Mark Omohundro, Joseph M. Akana Murphy, Felipe Murgas, Teo Močnik, Benjamin T. Montet, Ronald Mennickent, Andrew W. Mayo, Bob Massey, Jack Lubin, Christophe Lovis, Pablo Lewin, David Kasper, Stephen R. Kane, Jon M. Jenkins, Daniel Huber, Keith Horne, Michelle L. Hill, Paula Gorrini, Steven Giacalone, Benjamin Fulton, Thierry Forveille, Pedro Figueira, Tara Fetherolf, Courtney Dressing, Rodrigo F. Díaz, Xavier Delfosse, Paul A. Dalba, Fei Dai, C. C. Cortés, Ian J. M. Crossfield, Jeffrey D. Crane, Dennis M. Conti, Kevin I. Collins, Ashley Chontos, R. Paul Butler, Peyton Brown, Madison Brady, Aida Behmard, Corey Beard, Natalie M. Batalha, Jose-Manuel Almenara

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

Abstract

LTT 1445 is a hierarchical triple M-dwarf star system located at a distance of 6.86 pc. The primary star LTT 1445A (0.257 M⊙) is known to host the transiting planet LTT 1445Ab with an orbital period of 5.36 days, making it the second-closest known transiting exoplanet system, and the closest one for which the host is an M dwarf. Using Transiting Exoplanet Survey Satellite data, we present the discovery of a second planet in the LTT 1445 system, with an orbital period of 3.12 days. We combine radial-velocity measurements obtained from the five spectrographs, Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations, High Accuracy Radial Velocity Planet Searcher, High-Resolution Echelle Spectrometer, MAROON-X, and Planet Finder Spectrograph to establish that the new world also orbits LTT 1445A. We determine the mass and radius of LTT 1445Ab to be 2.87 ± 0.25 M⊕ and 1.304-_0.060^+0.067 R⊕, consistent with an Earth-like composition. For the newly discovered LTT 1445Ac, we measure a mass of 1.54_-0.19^+0.20 M⊕ and a minimum radius of 1.15 R⊕, but we cannot determine the radius directly as the signal-to-noise ratio of our light curve permits both grazing and nongrazing configurations. Using MEarth photometry and ground-based spectroscopy, we establish that star C (0.161 M⊙) is likely the source of the 1.4 day rotation period, and star B (0.215 M⊙) has a likely rotation period of 6.7 days. We estimate a probable rotation period of 85 days for LTT 1445A. Thus, this triple M-dwarf system appears to be in a special evolutionary stage where the most massive M dwarf has spun down, the intermediate mass M dwarf is in the process of spinning down, while the least massive stellar component has not yet begun to spin down.

Original language	English
Article number	168
Number of pages	18
Journal	Astronomical Journal
Volume	163
Issue number	4
Early online date	14 Mar 2022
DOIs	https://doi.org/10.3847/1538-3881/ac50a9
Publication status	Published - 1 Apr 2022

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Astronomy at St Andrews 2018-2021: Astronomy at St Andrews 2018-2021
Jardine, M. M. (PI), Bonnell, I. A. (CoI), Cameron, A. C. (CoI), Cyganowski, C. J. (CoI), Dominik, M. (CoI), Helling, C. (CoI), Horne, K. D. (CoI), Scholz, A. (CoI), Tojeiro, R. (CoI), Weijmans, A.-M. (CoI), Wild, V. (CoI), Woitke, P. (CoI), Wood, K. (CoI) & Zhao, H. (CoI)
1/04/18 → 31/03/22
Project: Standard

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Winters, J. G., Cloutier, R., Medina, A. A., Irwin, J. M., Charbonneau, D., Astudillo-Defru, N., Bonfils, X., Howard, A. W., Isaacson, H., Bean, J. L., Seifahrt, A., Teske, J. K., Eastman, J. D., Twicken, J. D., Collins, K. A., Jensen, E. L. N., Quinn, S. N., Payne, M. J., Kristiansen, M. H., ... Almenara, J.-M. (2022). A second planet transiting LTT 1445A and a determination of the masses of both worlds. Astronomical Journal, 163(4), Article 168. https://doi.org/10.3847/1538-3881/ac50a9

@article{9eaf213b980748e3893391d9fa9ebda9,

title = "A second planet transiting LTT 1445A and a determination of the masses of both worlds",

abstract = "LTT 1445 is a hierarchical triple M-dwarf star system located at a distance of 6.86 pc. The primary star LTT 1445A (0.257 M⊙) is known to host the transiting planet LTT 1445Ab with an orbital period of 5.36 days, making it the second-closest known transiting exoplanet system, and the closest one for which the host is an M dwarf. Using Transiting Exoplanet Survey Satellite data, we present the discovery of a second planet in the LTT 1445 system, with an orbital period of 3.12 days. We combine radial-velocity measurements obtained from the five spectrographs, Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations, High Accuracy Radial Velocity Planet Searcher, High-Resolution Echelle Spectrometer, MAROON-X, and Planet Finder Spectrograph to establish that the new world also orbits LTT 1445A. We determine the mass and radius of LTT 1445Ab to be 2.87 ± 0.25 M⊕ and 1.304-0.060+0.067 R⊕, consistent with an Earth-like composition. For the newly discovered LTT 1445Ac, we measure a mass of 1.54-0.19+0.20 M⊕ and a minimum radius of 1.15 R⊕, but we cannot determine the radius directly as the signal-to-noise ratio of our light curve permits both grazing and nongrazing configurations. Using MEarth photometry and ground-based spectroscopy, we establish that star C (0.161 M⊙) is likely the source of the 1.4 day rotation period, and star B (0.215 M⊙) has a likely rotation period of 6.7 days. We estimate a probable rotation period of 85 days for LTT 1445A. Thus, this triple M-dwarf system appears to be in a special evolutionary stage where the most massive M dwarf has spun down, the intermediate mass M dwarf is in the process of spinning down, while the least massive stellar component has not yet begun to spin down.",

author = "Winters, {Jennifer G.} and Ryan Cloutier and Medina, {Amber A.} and Irwin, {Jonathan M.} and David Charbonneau and Nicola Astudillo-Defru and Xavier Bonfils and Howard, {Andrew W.} and Howard Isaacson and Bean, {Jacob L.} and Andreas Seifahrt and Teske, {Johanna K.} and Eastman, {Jason D.} and Twicken, {Joseph D.} and Collins, {Karen A.} and Jensen, {Eric L. N.} and Quinn, {Samuel N.} and Payne, {Matthew J.} and Kristiansen, {Martti H.} and Alton Spencer and Andrew Vanderburg and Mathias Zechmeister and Weiss, {Lauren M.} and Wang, {Sharon Xuesong} and Gavin Wang and St{\'e}phane Udry and Terentev, {Ivan A.} and Julian St{\"u}rmer and Gudmundur Stef{\'a}nsson and Avi Shporer and Stephen Shectman and Ramotholo Sefako and Schwengeler, {Hans Martin} and Schwarz, {Richard P.} and Nicholas Scarsdale and Rubenzahl, {Ryan A.} and Arpita Roy and Rosenthal, {Lee J.} and Paul Robertson and Petigura, {Erik A.} and Francesco Pepe and Mark Omohundro and Murphy, {Joseph M. Akana} and Felipe Murgas and Teo Mo{\v c}nik and Montet, {Benjamin T.} and Ronald Mennickent and Mayo, {Andrew W.} and Bob Massey and Jack Lubin and Christophe Lovis and Pablo Lewin and David Kasper and Kane, {Stephen R.} and Jenkins, {Jon M.} and Daniel Huber and Keith Horne and Hill, {Michelle L.} and Paula Gorrini and Steven Giacalone and Benjamin Fulton and Thierry Forveille and Pedro Figueira and Tara Fetherolf and Courtney Dressing and D{\'i}az, {Rodrigo F.} and Xavier Delfosse and Dalba, {Paul A.} and Fei Dai and Cort{\'e}s, {C. C.} and Crossfield, {Ian J. M.} and Crane, {Jeffrey D.} and Conti, {Dennis M.} and Collins, {Kevin I.} and Ashley Chontos and Butler, {R. Paul} and Peyton Brown and Madison Brady and Aida Behmard and Corey Beard and Batalha, {Natalie M.} and Jose-Manuel Almenara",

note = "K.H. acknowledges support from STFC grant ST/R000824/1.",

year = "2022",

month = apr,

day = "1",

doi = "10.3847/1538-3881/ac50a9",

language = "English",

volume = "163",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "American Astronomical Society",

number = "4",

}

Winters, JG, Cloutier, R, Medina, AA, Irwin, JM, Charbonneau, D, Astudillo-Defru, N, Bonfils, X, Howard, AW, Isaacson, H, Bean, JL, Seifahrt, A, Teske, JK, Eastman, JD, Twicken, JD, Collins, KA, Jensen, ELN, Quinn, SN, Payne, MJ, Kristiansen, MH, Spencer, A, Vanderburg, A, Zechmeister, M, Weiss, LM, Wang, SX, Wang, G, Udry, S, Terentev, IA, Stürmer, J, Stefánsson, G, Shporer, A, Shectman, S, Sefako, R, Schwengeler, HM, Schwarz, RP, Scarsdale, N, Rubenzahl, RA, Roy, A, Rosenthal, LJ, Robertson, P, Petigura, EA, Pepe, F, Omohundro, M, Murphy, JMA, Murgas, F, Močnik, T, Montet, BT, Mennickent, R, Mayo, AW, Massey, B, Lubin, J, Lovis, C, Lewin, P, Kasper, D, Kane, SR, Jenkins, JM, Huber, D, Horne, K, Hill, ML, Gorrini, P, Giacalone, S, Fulton, B, Forveille, T, Figueira, P, Fetherolf, T, Dressing, C, Díaz, RF, Delfosse, X, Dalba, PA, Dai, F, Cortés, CC, Crossfield, IJM, Crane, JD, Conti, DM, Collins, KI, Chontos, A, Butler, RP, Brown, P, Brady, M, Behmard, A, Beard, C, Batalha, NM & Almenara, J-M 2022, 'A second planet transiting LTT 1445A and a determination of the masses of both worlds', Astronomical Journal, vol. 163, no. 4, 168. https://doi.org/10.3847/1538-3881/ac50a9

TY - JOUR

T1 - A second planet transiting LTT 1445A and a determination of the masses of both worlds

AU - Winters, Jennifer G.

AU - Cloutier, Ryan

AU - Medina, Amber A.

AU - Irwin, Jonathan M.

AU - Charbonneau, David

AU - Astudillo-Defru, Nicola

AU - Bonfils, Xavier

AU - Howard, Andrew W.

AU - Isaacson, Howard

AU - Bean, Jacob L.

AU - Seifahrt, Andreas

AU - Teske, Johanna K.

AU - Eastman, Jason D.

AU - Twicken, Joseph D.

AU - Collins, Karen A.

AU - Jensen, Eric L. N.

AU - Quinn, Samuel N.

AU - Payne, Matthew J.

AU - Kristiansen, Martti H.

AU - Spencer, Alton

AU - Vanderburg, Andrew

AU - Zechmeister, Mathias

AU - Weiss, Lauren M.

AU - Wang, Sharon Xuesong

AU - Wang, Gavin

AU - Udry, Stéphane

AU - Terentev, Ivan A.

AU - Stürmer, Julian

AU - Stefánsson, Gudmundur

AU - Shporer, Avi

AU - Shectman, Stephen

AU - Sefako, Ramotholo

AU - Schwengeler, Hans Martin

AU - Schwarz, Richard P.

AU - Scarsdale, Nicholas

AU - Rubenzahl, Ryan A.

AU - Roy, Arpita

AU - Rosenthal, Lee J.

AU - Robertson, Paul

AU - Petigura, Erik A.

AU - Pepe, Francesco

AU - Omohundro, Mark

AU - Murphy, Joseph M. Akana

AU - Murgas, Felipe

AU - Močnik, Teo

AU - Montet, Benjamin T.

AU - Mennickent, Ronald

AU - Mayo, Andrew W.

AU - Massey, Bob

AU - Lubin, Jack

AU - Lovis, Christophe

AU - Lewin, Pablo

AU - Kasper, David

AU - Kane, Stephen R.

AU - Jenkins, Jon M.

AU - Huber, Daniel

AU - Horne, Keith

AU - Hill, Michelle L.

AU - Gorrini, Paula

AU - Giacalone, Steven

AU - Fulton, Benjamin

AU - Forveille, Thierry

AU - Figueira, Pedro

AU - Fetherolf, Tara

AU - Dressing, Courtney

AU - Díaz, Rodrigo F.

AU - Delfosse, Xavier

AU - Dalba, Paul A.

AU - Dai, Fei

AU - Cortés, C. C.

AU - Crossfield, Ian J. M.

AU - Crane, Jeffrey D.

AU - Conti, Dennis M.

AU - Collins, Kevin I.

AU - Chontos, Ashley

AU - Butler, R. Paul

AU - Brown, Peyton

AU - Brady, Madison

AU - Behmard, Aida

AU - Beard, Corey

AU - Batalha, Natalie M.

AU - Almenara, Jose-Manuel

N1 - K.H. acknowledges support from STFC grant ST/R000824/1.

PY - 2022/4/1

Y1 - 2022/4/1

N2 - LTT 1445 is a hierarchical triple M-dwarf star system located at a distance of 6.86 pc. The primary star LTT 1445A (0.257 M⊙) is known to host the transiting planet LTT 1445Ab with an orbital period of 5.36 days, making it the second-closest known transiting exoplanet system, and the closest one for which the host is an M dwarf. Using Transiting Exoplanet Survey Satellite data, we present the discovery of a second planet in the LTT 1445 system, with an orbital period of 3.12 days. We combine radial-velocity measurements obtained from the five spectrographs, Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations, High Accuracy Radial Velocity Planet Searcher, High-Resolution Echelle Spectrometer, MAROON-X, and Planet Finder Spectrograph to establish that the new world also orbits LTT 1445A. We determine the mass and radius of LTT 1445Ab to be 2.87 ± 0.25 M⊕ and 1.304-0.060+0.067 R⊕, consistent with an Earth-like composition. For the newly discovered LTT 1445Ac, we measure a mass of 1.54-0.19+0.20 M⊕ and a minimum radius of 1.15 R⊕, but we cannot determine the radius directly as the signal-to-noise ratio of our light curve permits both grazing and nongrazing configurations. Using MEarth photometry and ground-based spectroscopy, we establish that star C (0.161 M⊙) is likely the source of the 1.4 day rotation period, and star B (0.215 M⊙) has a likely rotation period of 6.7 days. We estimate a probable rotation period of 85 days for LTT 1445A. Thus, this triple M-dwarf system appears to be in a special evolutionary stage where the most massive M dwarf has spun down, the intermediate mass M dwarf is in the process of spinning down, while the least massive stellar component has not yet begun to spin down.

AB - LTT 1445 is a hierarchical triple M-dwarf star system located at a distance of 6.86 pc. The primary star LTT 1445A (0.257 M⊙) is known to host the transiting planet LTT 1445Ab with an orbital period of 5.36 days, making it the second-closest known transiting exoplanet system, and the closest one for which the host is an M dwarf. Using Transiting Exoplanet Survey Satellite data, we present the discovery of a second planet in the LTT 1445 system, with an orbital period of 3.12 days. We combine radial-velocity measurements obtained from the five spectrographs, Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations, High Accuracy Radial Velocity Planet Searcher, High-Resolution Echelle Spectrometer, MAROON-X, and Planet Finder Spectrograph to establish that the new world also orbits LTT 1445A. We determine the mass and radius of LTT 1445Ab to be 2.87 ± 0.25 M⊕ and 1.304-0.060+0.067 R⊕, consistent with an Earth-like composition. For the newly discovered LTT 1445Ac, we measure a mass of 1.54-0.19+0.20 M⊕ and a minimum radius of 1.15 R⊕, but we cannot determine the radius directly as the signal-to-noise ratio of our light curve permits both grazing and nongrazing configurations. Using MEarth photometry and ground-based spectroscopy, we establish that star C (0.161 M⊙) is likely the source of the 1.4 day rotation period, and star B (0.215 M⊙) has a likely rotation period of 6.7 days. We estimate a probable rotation period of 85 days for LTT 1445A. Thus, this triple M-dwarf system appears to be in a special evolutionary stage where the most massive M dwarf has spun down, the intermediate mass M dwarf is in the process of spinning down, while the least massive stellar component has not yet begun to spin down.

U2 - 10.3847/1538-3881/ac50a9

DO - 10.3847/1538-3881/ac50a9

M3 - Article

SN - 0004-6256

VL - 163

JO - Astronomical Journal

JF - Astronomical Journal

IS - 4

M1 - 168

ER -

A second planet transiting LTT 1445A and a determination of the masses of both worlds

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