Hunting for the brethren of the Sun - and their exoplanets
Go look for these sunlike stars that you can see yourself without telescopes.
![[Translate to English:] Himmelkortet viser fordelingen af stjernerne i TESS Luminaries Sample. Størrelsen af pletterne svarer til stjernens lysstyrke. Stjerner med et kryds er flerdobbelte, og farverne svarer til overlap med den kommende satellitmission PLATO. De lilla områder er dem, hvor PLATO observerer over særligt lang tid. Stjerner over og til højre for den røde kurve befinder sig på den nordlige himmelhalvkugle, så de vil i årets løb være synlige fra Danmark. Grafik: Artiklens forfattere.](/fileadmin/_processed_/e/b/csm_TLS_all_sky_1d1a1c1237.png "This all-sky map shows the distribution of stars in the TESS Luminaries Sample. The size of the dots represent the brightness of each star. Crossed over stars are binaries, and the colours represent overlaps with those to be observed with the future PLATO")
![[Translate to English:]](/fileadmin/_processed_/7/f/csm_Draco_2_90dee29e2c.png "Area around the constellation Draco and the Pole Star. Several of the stars in the TSL-list are situated close to the North Star making them visible from Denmark all year around. On this sky map they are marked with a circle. Graphics: OJK and the program")
In an international collaboration a group of Aarhus University based astronomers have identified a list of bright stars with Sunlike oscillations. Some even have exoplanets orbiting them. All of the stars on the list can be seen with a bit of practice and with the naked eye under a dark night sky. The paper, published recently in Astronomy & Astrophysics, is titeled: 'Luminaries in the Sky: The TESS Legacy Sample of Bright Stars'.
Stellar oscillations or asteroseismology reveals a lot to us concerning the nature and origin of the stars, and the same data used in asteroseismology are also used in the hunt for exoplanets orbiting the same stars. These oscillations are measurable both with Earthbased and spacebased telescopes, like e.g. the NASA space telescope TESS, launched in 2018 with the task of supplying observations of the brightest stars all over the sky. The group of researcers have mainly used measurements from TESS to characterize a long list of stars, and out of this list 196 stars show stellar oscillations similar to what we see for the Sun. For 128 of these stars this is entirely new knowledge.
Main author of the paper, post doc Mikkel N. Lund of the Department of Physics and Astronomy, Aarhus University explains: "We did not do this survey especially to look for the brethren of our Sun, that is stars formed at the same time as the Sun in the same stellar cluster, but we are certain that astronomers will concentrate their search for our lost celestial family in our new list, named the 'TESS Luminaries Sample'. The listed stars will also with great certainty be used in the search for near earthlike exoplanets orbiting stars like our own. For the time being two new international space telescopes are being planned for this purpose: PLATO (PLAnetary Transits and Oscillations of stars) and the Habitable Worlds Observatory (HWO). On top of that we are very far off with the coming Danish satellite telescope STEP, also built for that purpose. We expect STEP to be launched into space in 2026."
The researchers continue working with observations of the stars on the TLS list to obtain a more detailed characteristic of them and their orbiting exoplanets or binary stellar companions. The stars in the list are all of a stellar magnitude less than 6, meaning that they are observable with the naked eye and with very many smaller telescopes, as they are used by thousands of active amateur astronomers. On top of this, the stars on the list are spread all over the sky enabling observatories both in space and everywhere on the surface of the Earth to observe at least some of them.
The paper is available here.