Astronomy:K2-25

From HandWiki

K2-25 is a young red dwarf star located in the Hyades cluster. There is a single known Neptune-sized planet in a 3.5 day orbit.

Hyades cluster

Using proper motion measurements in a search for low-luminosity members of the Hyades cluster, William van Altena first identified the star vA 50 (later known as K2-25) as a probable cluster member.[1] Membership in the Hyades cluster was later confirmed.[2][3][4]

Properties

K2-25 is the star at the center of this image.

K2-25 is a red dwarf that is only 26% the mass of the Sun and less than 1% of the luminosity.[5] As a member of the Hyades cluster, it is only 650 million years old as compared to the Sun's 4.5 billion.[6]

There is clear evidence for starspot activity in both the Kepler data and radial velocities as well as the associated activity indicators.[7]

Planetary system

The star has one known planet, K2-25b, with searches of the Kepler space telescope data for transits of additional planets being negative.[4] Analysis of transit-timing variations from the Spitzer Space Telescope as well as the MEarth Project also found no evidence of additional planets.[8]

Discovery

Brightness measurements of K2-25 taken by the Kepler space telescope during its extended K2 mission led to the discovery of the transiting planet K2-25b.[4][9]

Characteristics

K2-25b is a Hot Neptune type planet in an eccentric 3.48 day orbit.[7]

Due to its proximity and the activity levels of its host star, K2-25b should be losing some of its atmosphere to space; however, observations of two transits by the Hubble Space Telescope to search for escaping neutral hydrogen were negative.[10]

The K2-25 planetary system[7]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
K2-25b 24.5+5.7
−5.2 M⊕ 		0.0287(12) 3.48456408+0.0000006
−0.0000005 		0.428+0.050
−0.049 		88.16+0.18
−0.21° 		3.44(12) R⊕

References

  1. ↑ van Altena, W. F. (1966). "Low-luminosity members of the Hyades cluster.". The Astronomical Journal 71: 482–512. doi:10.1086/109952. Bibcode: 1966AJ.....71..482V. 
  2. ↑ Röser, S. et al. (2011). "A deep all-sky census of the Hyades". Astronomy & Astrophysics 531: A92. doi:10.1051/0004-6361/201116948. Bibcode: 2011A&A...531A..92R.  Vizier catalog entry
  3. ↑ Douglas, S. T. et al. (2014). "The Factory and the Beehive. II. Activity and Rotation in Praesepe and the Hyades". The Astrophysical Journal 795 (2). doi:10.1088/0004-637X/795/2/161. Bibcode: 2014ApJ...795..161D. 
  4. ↑ 4.0 4.1 4.2 Mann, Andrew W. et al. (2016). "Zodiacal Exoplanets in Time (ZEIT). I. A Neptune-sized Planet Orbiting an M4.5 Dwarf in the Hyades Star Cluster". The Astrophysical Journal 818 (1). doi:10.3847/0004-637X/818/1/46. Bibcode: 2016ApJ...818...46M. 
  5. ↑ Thao, Pa Chia et al. (2020). "Zodiacal Exoplanets in Time (ZEIT). IX. A Flat Transmission Spectrum and a Highly Eccentric Orbit for the Young Neptune K2-25b as Revealed by Spitzer". The Astronomical Journal 159 (1). doi:10.3847/1538-3881/ab579b. Bibcode: 2020AJ....159...32T. 
  6. ↑ Gaidos, E. et al. (2020). "Zodiacal Exoplanets in Time. XI. The Orbit and Radiation Environment of the Young M Dwarf-Hosted Planet K2-25b". Monthly Notices of the Royal Astronomical Society: Letters 498 (1). doi:10.1093/mnrasl/slaa136. Bibcode: 2020MNRAS.498L.119G. 
  7. ↑ 7.0 7.1 7.2 Stefansson, Gudmundur et al. (2020-09-30). "The Habitable Zone Planet Finder Reveals a High Mass and Low Obliquity for the Young Neptune K2-25b". The Astronomical Journal 160 (4). doi:10.3847/1538-3881/abb13a. Bibcode: 2020AJ....160..192S. 
  8. ↑ Kain, Isabel J. et al. (2020-03-01). "The Young Planetary System K2-25: Constraints on Companions and Starspots". The Astronomical Journal 159 (3). doi:10.3847/1538-3881/ab655b. Bibcode: 2020AJ....159...83K. 
  9. ↑ David, Trevor J. et al. (2016). "New Pleiades Eclipsing Binaries and a Hyades Transiting System Identified by K2". The Astronomical Journal 151 (5). doi:10.3847/0004-6256/151/5/112. Bibcode: 2016AJ....151..112D. 
  10. ↑ Rockcliffe, Keighley E. et al. (2021-09-01). "A Lyα Transit Left Undetected: the Environment and Atmospheric Behavior of K2-25b". The Astronomical Journal 162 (3). doi:10.3847/1538-3881/ac126f. Bibcode: 2021AJ....162..116R. 

Cite error: <ref> tag with name "APASS DR9" defined in <references> is not used in prior text.
Cite error: <ref> tag with name "Gaia DR3" defined in <references> is not used in prior text.
Cite error: <ref> tag with name "Martín2018" defined in <references> is not used in prior text.
Cite error: <ref> tag with name "Mori2024" defined in <references> is not used in prior text.
Cite error: <ref> tag with name "Roman1987" defined in <references> is not used in prior text.
Cite error: <ref> tag with name "Simbad" defined in <references> is not used in prior text.

Cite error: <ref> tag with name "Skrutskie2006" defined in <references> is not used in prior text.



Retrieved from "https://handwiki.org/wiki/index.php?title=Astronomy:K2-25&oldid=3947660"