A red dwarf swallows a brown dwarf: the ZTF J0440+2325 system
I read a piece of news that really caught my attention: astronomers have seen, for the first time, a red dwarf absorbing an object orbiting around it. The system is ZTF J0440+2325, where a brown dwarf orbits a red dwarf. The work was published in Nature Astronomy.
The numbers are impressive. The brown dwarf completes one orbit in 86.65 minutes. For comparison, Mercury, the planet closest to the Sun, takes 88 days for one orbit. Observations in five wavelength ranges revealed a bright, hot spot on the red dwarf with a temperature between five and nine thousand degrees.
The distance to the system is estimated at 326 light-years, with 489 given as an upper limit. This affects the size of the spot: about 6,700 kilometres in the first case and around 10,000 in the second. The only explanation the researchers found that agrees with the observations is matter falling from the brown dwarf onto the red dwarf.
The authors believe this is the first observed case of such a transfer of material. I especially liked the idea that the process could go on for billions of years, like a slow "external digestion" rather than a dramatic explosion. The cosmos is not always spectacular; sometimes it is simply very patient.
On the same day, another paper appeared in the same journal, about the white dwarf HS 0209+0832, near which lies a giant planet formed from the debris of earlier planets. I will definitely come back to that story separately.
Source: Naked Science
The numbers are impressive. The brown dwarf completes one orbit in 86.65 minutes. For comparison, Mercury, the planet closest to the Sun, takes 88 days for one orbit. Observations in five wavelength ranges revealed a bright, hot spot on the red dwarf with a temperature between five and nine thousand degrees.
The distance to the system is estimated at 326 light-years, with 489 given as an upper limit. This affects the size of the spot: about 6,700 kilometres in the first case and around 10,000 in the second. The only explanation the researchers found that agrees with the observations is matter falling from the brown dwarf onto the red dwarf.
The authors believe this is the first observed case of such a transfer of material. I especially liked the idea that the process could go on for billions of years, like a slow "external digestion" rather than a dramatic explosion. The cosmos is not always spectacular; sometimes it is simply very patient.
On the same day, another paper appeared in the same journal, about the white dwarf HS 0209+0832, near which lies a giant planet formed from the debris of earlier planets. I will definitely come back to that story separately.
Source: Naked Science
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